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Anesthesia awareness with recall: an integrative review and best practice recommendations
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Anesthesia awareness with recall: an integrative review and best practice recommendations
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ANESTHESIA AWARENESS WITH RECALL
ANESTHESIA AWARENESS WITH RECALL:
AN INTEGRATIVE REVIEW AND BEST PRACTICE RECOMMENDATIONS
by
Keaton Lantrip
A Doctoral Capstone Presented to the
FACULTY OF THE USC KECK SCHOOL OF MEDICINE
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the Requirements for the Degree
DOCTOR OF NURSE ANESTHESIA PRACTICE
May 2024
ANESTHESIA AWARENESS WITH RECALL
ii
The following manuscript was contributed to in equal parts by Keaton Lantrip, Jewell Morris &
Linet Ondari.
ANESTHESIA AWARENESS WITH RECALL
iii
Dedication
Keaton Lantrip dedicates this project to his late grandmother Blondell Powers, late aunt
Terrie Starling Powers, and the grandson/son/cousin they continue to protect, Landon Starling.
Jewell Morris dedicates this project to her loving mother Thelma Morris and her
supportive, esteemed colleagues: Linet Ondari, Amanda Farris, Keaton Lantrip, Kali Wachter,
Alex Gueli, and Utha Lumbantobing.
Linet Ondari dedicates this project to Megan, Whitney, Brendan, and Vane Ondari for
continual support through this program and to Monica Ondari for always watching from above.
ANESTHESIA AWARENESS WITH RECALL
iv
Acknowledgements
The authors wish to thank the following individuals for their assistance with this project:
Charles Griffis, PhD, CRNA; Elizabeth Bamgbose, PhD, CRNA; Jeffrey Darna, PhD, DNP,
CRNA, ACNP-BC
ANESTHESIA AWARENESS WITH RECALL
v
Table of Contents
List of Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii
Abstract. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .viii
Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Research Question and Specific Aims. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Background and Significance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Early Reported Incidences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Goals of Anesthesia Care. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Consciousness and Anesthesia Awareness with Recall . . . . . . . . . . . . . . . . . . . . . 5
Deleterious Effects of Anesthesia Awareness with Recall. . . . . . . . . . . . . . . . . . . 6
Chapter 2: Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Chapter 3: Literature Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Seminal References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Non-Modifiable Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Age. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Gender. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Prior Episode of Anesthesia Awareness with Recall. . . . . . . . . . . . . . . . . . . . . . .21
Modifiable Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Obesity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Difficult Airway. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Provider Error. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Pharmacologic Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Benzodiazepines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Neuromuscular Blockade. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Phases of Anesthesia Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Induction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Emergence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Surgery Type Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Obstetrics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Cardiothoracic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Monitoring Devices and Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Isolated Forearm Technique. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
Minimum Alveolar Concentration and Bispectral Index. . . . . . . . . . . . . .37
Postoperative Recognition and Treatment of AAWR. . . . . . . . . . . . . . . . . . . . . . . . . . . .39
Questionnaire Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Documentation and Referral. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Chapter 4: Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
ANESTHESIA AWARENESS WITH RECALL
vi
Chapter 5: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Appendix A: PRISMA Flow Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Appendix B: The NAP 5 Anesthesia Awareness Support Pack. . . . . . . . . . . . . . . . . . . . . . . . . . .82
ANESTHESIA AWARENESS WITH RECALL
vii
List of Tables
Table 1: Operational Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Table 2: The NAP5 Awareness Support Pathway for AAWR. . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Table 3: Brice-style Questionnaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
Table 4: Michigan Awareness Classification Instrument (MiAC). . . . . . . . . . . . . . . . . . . . . . . . 77
Table 5: Modified NPSA Classification of Patient Harm after AAWR. . . . . . . . . . . . . . . . . . . . 78
Table 6: The NAP 5 Classification of AAWR Reports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Table 7: The NAP 5 Strength of AAWR Reports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
ANESTHESIA AWARENESS WITH RECALL
viii
Abstract
Nearly 75% of surgical patients fear facing incidental awareness intraoperatively (Ruhaiyen et
al., 2016). A reported 0.1-0.2% of the population undergoing general anesthesia experience
various degrees of awareness with recall (Ghoneim et al., 2007). When awareness occurs, the
patient may suffer severe psychological consequences (Bruchas, 2011), often requiring treatment
by a mental health professional (Bischoff, 2011). Despite a low incidence of intraoperative
awareness, anesthesia providers must remain vigilant; this starts with stratifying the risks
involved and identifying integral practice adaptations to minimize the occurrence. Anesthesia
awareness with recall has notably been deemed preventable in as many as 75-90% of reported
cases (Pandit et al., 2014a). For this reason, an extensive literature review was conducted to
identify modifiable and non-modifiable considerations (Table 1) for avoiding AAWR. Research
revealed several important perioperative techniques which have been organized into practice
recommendations.
ANESTHESIA AWARENESS WITH RECALL
1
Chapter 1
Introduction
The Anesthesia Awareness with Recall (AAWR) (Table 1) phenomenon represents a
complication of general anesthesia (GA) (Table 1) consisting of a recollection of intraoperative
events reported by the patient after surgical or procedural intervention (Cascella et al., 2020).
AAWR is associated with patients who undergo surgery and receive GA where the goals include
unconsciousness, amnesia, and immobility. When AAWR occurs, it may cause detrimental
psychological consequences (Pandit et al., 2014a). In the most recent descriptive study
examining the incidence of AAWR, data were collected from 329 hospitals in the United
Kingdom. There were 471 reports of AAWR between June 2012 to May 2013. After analyzing
and categorizing all reports, 141 confirmed cases of AAWR were identified; this translates to a 1
in 20,000 chance of experiencing AAWR. Of the 141 cases, 41% of subjects reported moderate
to severe long-term psychological sequelae. More importantly, the study determined that 75-90%
of the reported cases of AAWR were directly caused by factors that could be prevented. In 78%
of the cases, anesthesia providers failed to meet an acceptable standard of care; ten percent of
those cases led to patient complaints, while 5% resulted in litigation. Thus, AAWR was deemed
to be a primarily preventable, distressing event that has an impact on the provider and the
patient.
According to a cross-sectional study performed by Ruhaiyen et al. (2016), 73.7% of
patients have a fear of AAWR, despite the actual low incidence of AAWR. For example, a
prospective, nonrandomized descriptive study conducted by Sebel et al. (2004) in the United
States evaluated 19,575 patients and identified a 0.13% incidence rate of AAWR, occurring at a
rate of 1-2 per 1,000 patients. In another study published by Ghoneim et al. (2007), in the general
ANESTHESIA AWARENESS WITH RECALL
2
population with no predisposing risk factors, there is a 0.1-0.2% incidence of AAWR. For
patients at high risk, Avidan et al. (2008) stated that AAWR affects up to 1% of this population.
In subsequent years, the heavily cited BIS or Anesthetic Gas to Reduce Explicit Recall (BAG-
RECALL) trial conducted a prospective, randomized evaluator-blinded trial on 6,041 patients at
three medical centers and reported an incidence of 0.16% (Avidan et al., 2011).
It is important for the anesthesia provider to recognize risk factors for AAWR,
experiences the patient may encounter during an episode (auditory perceptions, the inability to
move or control breathing, feeling the sensation of surgery), and the psychological sequelae that
follow. AAWR may lead to psychological consequences that negatively impact the following:
emotional effects (i.e., fear and anxiety), thought processes (i.e., suicidal ideation), and
behavioral responses (i.e., post-traumatic stress disorder [PTSD] (Bruchas, 2011). It is essential
for anesthesia providers who identify AAWR in a patient to consult a licensed professional
trained in psychology or psychiatry to manage the patient's treatment (Bischoff, 2011).
In this extensive literature review, the research team analyzed the phenomenon of
AAWR, identified contributing factors, discussed the sequelae, and proposed treatment options.
Additionally, best practice recommendations are provided based on these findings. For the
purposes of this project, the term anesthesia awareness with recall (AAWR) (Table 1) will be
used, although it has been used interchangeably with other terms (Sullivan, 2016).
ANESTHESIA AWARENESS WITH RECALL
3
Research Question and Specific Aims
The research question guiding this integrative review is: What are the current evidence-based
recommendations for the following, in regard to AAWR: minimizing the risk, identifying the
occurrence, and providing treatment?
Specific Aims
The specific aims guiding this investigation include:
1. Describe the phenomenon of anesthesia awareness with recall.
2. Perform an integrative review of the current literature regarding non-modifiable
considerations, modifiable considerations, and postoperative recognition and treatment of
anesthesia awareness with recall.
3. Synthesize evidence-based recommendations for modifying anesthesia practices aimed at
preventing anesthesia awareness with recall.
4. Synthesize evidence-based recommendations for postoperative recognition and treatment
of anesthesia awareness with recall.
ANESTHESIA AWARENESS WITH RECALL
4
Background and Significance
Early Reported Incidences
In 1846, an American dental surgeon, William Morton, first demonstrated the use of
inhaled ether to relieve pain during a dental extraction in his office. He placed an ether-soaked
cloth over a patient’s nose and mouth to induce an anesthetized state; following the successful
tooth extraction Morton poured water over the patient’s face to promote arousal. Soon after this
event, Morton used ether in a public demonstration on a patient undergoing tumor resection of
the neck on October 16
th
, 1846. The patient, Gilbert Abbott, underwent the procedure with no
complications (LeVasseur et al., 2012). Morton’s demonstration appeared successful in blunting
surgical pain, however, the patient later reported awareness of the sensation of surgery, but
without pain (Collins, 1846).
Curare – a plant originally used as arrow poison – was introduced into anesthesia and
surgical practice in 1942 as a means to blunt voluntary and involuntary muscle responses and
induce motor paralysis to aid in surgical manipulation and repair (Griffith et al., 1942). Blunting
muscle responses, such as coughing was beneficial to surgical intervention and eased ventilator
tolerance for the patient. Muscle relaxation blunts spontaneous respirations and an increase in
respiratory rate can help alert the provider of “light anesthesia” – an insufficient level of
anesthesia to block the pain of surgical intervention. The growing use of curare in anesthesia
practice, and the lack of understanding of the syndrome of AAWR, likely contributed to the
growing reports of AAWR. The British Medical Journal published the first report regarding
awareness during GA in 1950 (Bruchas et al., 2011). A patient of E. H. Winterbottom reported
auditory recollections along with the explicit recall of pain and paralysis during an intended
general anesthetic.
ANESTHESIA AWARENESS WITH RECALL
5
Goals of Anesthesia Care
The goals of safe anesthesia care include protecting patients from noxious stimuli while
maintaining physiologic stability (Mashour & Avidan, 2011). Anesthesia professionals may
accomplish these goals by administering pharmacologic agents that alter the level of
consciousness (Table 1) to a variable degree, prevent memory formation, inhibit mobility, and
provide pain relief. Depending on the patient’s history, physical examination, and the needs of
the procedure there will be alterations to the anesthetic technique (Robin et al., 2011). If the
planned technique is Monitored Anesthesia Care (MACr) (Table 1), the intended level of
consciousness may not be deepened to the level that eliminates conscious awareness, and the
patient should be informed of this prior to initiation of the procedure. Transparent
communication will help establish goals of care, manage expectations, and decrease AAWR
reports endorsed by patients who did not receive GA. If the planned anesthetic technique is GA,
then the intended level of consciousness includes the depression of cortical function sufficient to
completely prevent the perception and memory of perioperative events (Sanders et al., 2012).
Consciousness and Anesthesia Awareness with Recall
The connection between GA and unresponsiveness is more elaborate than the simple
absence of consciousness (Bonhmome et al., 2019). Anesthesia alters consciousness with drug
administration that produces a hypnotic state, making tolerance of surgical or procedural
intervention possible. General anesthesia is not intended to cease the operation of the brain. With
the deliberate selection of pharmacologic treatment, a spectrum of consciousness can be
achieved while maintaining cerebral function.
The discussion of the alteration of central nervous system (CNS) function has been
enriched with the concepts of connected and disconnected consciousness (Table 1) (Radek et al.,
ANESTHESIA AWARENESS WITH RECALL
6
2018). Connected consciousness is the ability to take in information from the outside
environment; disconnected consciousness comes from experiences generated internally and is
similar to dreaming. These terms merge with the principles of implicit and explicit memory
(Table 1) although the two concepts are often found separately in the literature. Explicit memory
is the ability to consciously recall an event. Implicit memory is the inability of an individual to
consciously discern a specific experience (Linassi et al., 2021). These experiences, although not
explicitly recalled, have ties to disconnected consciousness and can alter an individual’s behavior
and psyche.
Implicit and explicit memory formation have differing impacts on the patient undergoing
GA (Linassi et al., 2021). The intention of GA is to prevent the formation of explicit and implicit
memory connected to noxious or painful events during the procedure. Intraoperative awareness
with explicit memory formation assumes connected consciousness and can occur in a
behaviorally unresponsive patient (Table 1). Some research teams have hypothesized that
unresponsiveness does not equal unconsciousness, an important precept for anesthesia providers
to note when taking measures to avoid AAWR (Sanders et al., 2012). Implicit memory can be
difficult to pinpoint but has been identified through psychological tests (Linassi et al., 2021) and
studied using measured biomarkers including cortisol and prolactin (Aceto et al., 2013).
Deleterious Effects of AAWR
Bruchas et al. conducted a review of the impact of AAWR; the authors uncovered a range
of psychological effects linked to explicit memory formation ranging from anxiety-induced
flashbacks to life-halting PTSD (2011). Patients often reported feeling helplessness, anxiety, and
panic. The rationale for varying degrees of psychological effect is difficult to identify, but the
researchers noticed an association between PTSD and experiences of pain and immobility. Some
ANESTHESIA AWARENESS WITH RECALL
7
researchers opined that awareness during anesthesia “simulates death”, which influences its
widespread expression and sequelae (Macleod & Maycock, 1992, p. 381).
Additional factors potentially related to the degree of psychological sequelae include the
degree to which the patient feels they are in danger during the AAWR event (Bruchas et al.,
2011). This speaks to the importance of building rapport with the patient pre-procedure and
validating the patient the moment AAWR is suspected by the provider to ameliorate feelings of
danger or threat. Although this is only one component of management, reassurance from the
anesthesia professional matters (Macleod & Maycock, 1992). Further reports indicate patients
reexperience the event through dreams or intrusive thoughts. Other patients report seeking an
awake state by avoiding sleep or anything that mimics an anesthetized state.
ANESTHESIA AWARENESS WITH RECALL
8
Chapter 2
Methods
An extensive review of the literature was conducted utilizing the PubMed and CINAHL
databases. In both searches, the terms “general anesthesia”, “awareness”, and “recall” were used.
Exclusion criteria consisted of research from developing nations, pediatric-only studies, all-age
studies in which adult data (age ≥ 18) could not be distinguished, animal studies, and studies
greater than 10 years old, with the exception of seminal references that helped provide historical
background and information considered useful to contemporary practice. Inclusion criteria were
met if the participants were under GA during their procedure and if the data provided prevention-
related techniques for reducing AAWR.
Using the snowballing technique, additional studies were identified by examining
primary research sources in the previously reviewed papers. Among them were three additional
prospective, randomized trials dating as far as 2004. These high-profile studies have not been
replicated to date. Due to their magnitude, strength, and relevance in anesthesia practice, they
were included in the final analysis.
A total of 67 articles resulted in the PubMed and CINAHL databases; after inclusion and
exclusion review and snowballing technique, 27 articles were included for critical analysis in the
literature review. A Preferred Reporting Items for Systematic Reviews and Meta-Analyses
(PRISMA) flowchart documenting the search process for article selection is shown in Appendix
A. All articles were evaluated for strength and reliability. Information presented will be
synthesized into practice recommendations for preventing and managing the phenomenon of
AAWR.
ANESTHESIA AWARENESS WITH RECALL
9
Chapter 3
Literature Review
Seminal References
In this critical literature review, we will be discussing the phenomenon of AAWR.
Numerous articles are referred to, with a few of them being identified as landmark studies in the
history of AAWR.
Pandit et al. (2014a) is the largest descriptive report to date regarding AAWR. The title of
the 5
th
National Audit Project will be abbreviated to The NAP 5 Report. This study consisted of a
massive review and practice recommendations, and was conducted outside of the United States
where anesthetic practices may differ but are still applicable.
The NAP 5 Report will be cited as Pandit et al. (2014, a, b, and/or c) according to which
section of the report is under discussion. Pandit et al. (2014a) is The NAP 5 Report in its entirety.
Pandit et al. (2014b) is the Protocol, Methods, and Analysis of Data portion of the report and
Pandit et al. (2014c) is the Summary of Main Findings and Risk Factors. The NAP 5 Report
collected original data, but no descriptive statistics were calculated. To provide reasoning for
their original findings, they referred to primary sources that will be described in detail as they
appear.
The NAP 5 Report collected primary source data between 2012-2013 in the United
Kingdom and Ireland. Patients were able to self-report, or someone could report on their behalf.
All reports of AAWR were made official if the event occurred during 2012-2013 and the patient
received a form of anesthesia from a public hospital. Data were collected and reviewed monthly
and further reviewed by a secondary panel. Reports were categorized into Class A
(certain/probable AAWR), Class B (possible AAWR), Class C (sedation), Class D (intensive
ANESTHESIA AWARENESS WITH RECALL
10
care unit), Class E (Un-assessable), Class F (Unlikely), Class G (swaps/drug error), and the last
category titled “Statement Only” (unverifiable). For the duration of this literature review, when
Pandit et al. (2014) is mentioned, the specific class of AAWR is identified, which is typically
Class A or Class B.
Class A is a report of AAWR in a surgical setting where the patient’s stated experience of
AAWR is consistent with previously described definitions of AAWR (Table 1) and could be
independently verified by hospital documentation. Class B reports also occurred in a surgical
setting and met the AAWR criteria, but there was no hospital documentation to verify. Class C
includes cases where the intended level of consciousness was sedation, not GA. Class D is a case
of AAWR that occurred in the intensive care unit (ICU) and GA was intended. Class E describes
a report that did not have enough overall detail. Class F are reports that are deemed unlikely.
Class G refers to drug errors specifically referring to instances where the patient suffered awake
paralysis as a direct result of a medication error or an accidental syringe swap. For example, in
one report of AAWR, the anesthesia provider accidentally injected normal saline instead of fully
completing the reconstitution process of the anesthetic agent. Finally, SO (Statement Only) is
when the patient makes a historical statement that has no evidence/documentation to verify the
event happened.
The NAP 5 report had 300 reports that could be classified as follows: Class A (110),
Class B (31), Class C (32), Class D (6), Class E (19), Class F (12), Class G (20), and Statement
Only (20). The primary focus includes Classes A and B case analysis (Pandit et al., 2014a). The
incidence of certain/probable (Class A) cases of AAWR (“accidental awareness with general
anesthesia” abbreviated as AAGA in this report) was estimated at 1 in every 20,000 anesthetics.
The incidence was further subdivided into 1 in every 8,000 with the use of neuromuscular
ANESTHESIA AWARENESS WITH RECALL
11
blockade (Table 1), 1 in 8,600 in cardiothoracic anesthesia, and 1 in every 670 in cesarean
sections. Almost 2/3 of certain/probable (Class A) cases of AAWR occurred during induction
(Table 1) and emergence. Twenty-eight out of 141 cases of AAWR occurred with the use of total
intravenous anesthesia (TIVA) (Table 1), with more than 75% of those being deemed
preventable. In 97% of the reports of AAWR, those patients had received neuromuscular
blockade (Table 1). Thiopental was only used in 3% of inductions but was implicated in 23% of
cases of AAWR.
Another impactful study is the B-Aware trial based in Australia (Myles et al., 2004). This
was a prospective, multicenter, double-blind, randomized, controlled trial that examined the
efficacy of bispectral index (BIS) monitoring in decreasing the incidence of awareness during
GA. BIS monitoring uses an electroencephalogram to monitor brain waves and correlate
hypnotic state and anesthetic dose. This correlational relationship is determined by the BIS
machine and displays a number between 0 and 100 informing the provider of the depth of
sedation or anesthesia (absence of brain activity to a fully conscious state, respectively). The
study included 2,463 surgical patients undergoing GA. The patients were 18 years of age and
older and at high risk for awareness. Patients had one of the following patient and/or procedural
risk factors that the authors identified as associated with an increased incidence of AAWR:
cesarean section; high-risk cardiac surgery; severe aortic stenosis; pulmonary hypertension; acute
trauma with hypovolemia; end-stage lung disease; past history of awareness; heavy
alcohol/opioid/benzodiazepine use and others. Some patients received regional anesthesia along
with GA, but all patients studied received GA with neuromuscular blockade. Patients were
randomized to receive BIS monitoring intraoperatively (n = 1225) or routine care without BIS
monitoring (n = 1238). Routine care refers to the use of clinical indicators such as hemodynamic
ANESTHESIA AWARENESS WITH RECALL
12
values, ventilatory changes, patient movement, and other monitoring techniques. Patients and
interviewers were blinded to the assigned groups and the anesthesia provider was randomly
assigned to a group. The BIS-guided patients were maintained at a BIS reading between 40 and
60 – values considered consistent with a total lack of awareness. The routine care group solely
utilized the clinical indicators mentioned above.
The study findings showed two reports of AAWR from the BIS group (0.17%) and 11
reports of AAWR from the routine care group (0.91%) (p = 0.022). The number needed to treat
statistic was calculated to be 138 (95% CI, 77-641). Of the two awareness events in the BIS
group, one occurred during laryngoscopy; the recorded BIS reading at that time was 79-82. The
second occurred at the beginning of a coronary artery surgery; the recorded BIS reading at that
time was 55-59. Due to these events, the authors recommended maintaining a BIS range with an
upper limit of 55 to ensure AAWR would be avoided in most cases.
The B-Unaware Trial assessed whether BIS monitoring decreased the incidence of
awareness more effectively than measuring end-tidal anesthetic gas (ETAG) (Table 1) (Avidan et
al., 2008). This study was a prospective, single-center, randomized, controlled trial that
examined a population of 2,000 patients undergoing routine surgery under GA. Participants were
considered as high risk for awareness if they met one of the following criteria: long-term use of
anticonvulsants, opioids, or benzodiazepines, daily alcohol consumption; cardiac ejection
fraction < 40%; history of AAWR; history of difficult intubation; American Society of
Anesthesiology (ASA) Physical Status Classification 4 or 5 (Table 1); aortic stenosis; end-stage
lung disease; marginal exercise tolerance not resulting from musculoskeletal dysfunction;
pulmonary hypertension; open heart surgery; and daily alcohol consumption. Participants were
18 years or older and were randomly divided into a BIS group and an ETAG group. In the BIS-
ANESTHESIA AWARENESS WITH RECALL
13
guided group, providers administered anesthesia to maintain a BIS level between 40 and 60
while the ETAG group maintained ETAG concentrations between 0.7 – 1.3 minimum alveolar
concentration (MAC). The minimum end-tidal anesthetic agent concentration preventing 50% of
subjects from responding to verbal commands is 0.33 MAC; doubling this or maintaining an age-
adjusted MAC of 0.7 should decrease the likelihood of awareness in most patients (Avidan et al.,
2011). Providers in both groups were able to view ETAG concentrations, however, only the BIS
group providers could view the BIS monitor display. The BIS group was not instructed to keep
ETAG at any specific range. Three interviews were conducted postoperatively with expert
interviewers using the Brice Questionnaire (Table 3). The first interview was conducted within
24 hours, the second between 24 and 72 hours, and the last was within 30 days post-operation.
A total of 1,941 patients completed the study with 1,754 patients completing all three
interviews, 133 patients completing two interviews, and 18 patients completing one interview.
Three blinded reviewers independently categorized patients into three groups: definite
awareness, possible awareness, or no awareness. The final determination was made when at least
two reviewers agreed; if needed, a fourth reviewer was involved.
The study findings demonstrated two cases of definite AAWR in each group. The overall
incidence of definite AAWR was 0.21% (95% CI, 0.08 to 0.53). An additional five participants
were found to have possible awareness–four cases from the BIS group and one case from the
ETAG group. The overall incidence of definite and possible anesthesia awareness was 0.46%
(95% CI, 0.24 to 0.87). One of the four cases of definite awareness occurred when the BIS
reading was greater than 60 and three of the total cases of definite awareness occurred with
ETAG concentrations below 0.7 MAC. These results differed from previous reports which found
that AAWR occurred even when BIS values were within predetermined ranges. The authors
ANESTHESIA AWARENESS WITH RECALL
14
concluded that the BIS protocol did not surpass the ETAG protocol in preventing AAWR in
high-risk patients and could not be suggested as a standard monitor in practice.
The BIS or Anesthetic Gas to Reduce Explicit Recall (BAG-RECALL) trial was a
follow-up to Avidan’s 2008 trial, and it further examined whether the BIS monitor was superior
to the end-tidal anesthetic-agent concentration (ETAC) (Table 1) regarding the prevention of
AAWR (Avidan et al., 2011). This study was a prospective, randomized, controlled trial held at
three medical centers evaluating a population of 6,041 patients at high risk for awareness
because of one or more of the following factors: planned open-heart surgery, aortic stenosis,
pulmonary hypertension, daily alcohol use, ASA Classification 4 or 5 (Table 1), end-stage lung
disease, history of intraoperative awareness, history of or anticipated difficult airway intubation,
cardiac ejection fraction <40%, marginal exercise tolerance, or use of opiates, benzodiazepines,
or anticonvulsants. Patients were 18 years of age or older and undergoing elective surgery under
GA. Participants were randomly divided into a BIS group (n = 2861) where monitors were
maintained between 40 and 60 with no recommendation on the management of ETAC, and an
ETAC group (n = 2852) where the ETAC concentration was kept between 0.7 and 1.3 MAC.
Patients in both groups received GA, with combinations of TIVA along with regional anesthesia.
Practitioners in the ETAC group were not able to view the BIS reading while practitioners in the
BIS group were able to view both the BIS reading and the ETAC reading. Readings outside of
the designated ranges were accompanied by an alarm to alert practitioners, and BIS and ETAC
values were electronically recorded in one-minute intervals with software that uploaded
information onto an excel spreadsheet. Out of the 6,041 patients enrolled, 5,809 patients were
included in the trial, and 5,713 patients completed at least one postoperative interview.
Postoperative interviews were conducted with assigned experts at 72 hours and 30 days post-
ANESTHESIA AWARENESS WITH RECALL
15
procedure using the Brice Questionnaire (Table 3), and every patient that reported an
intraoperative memory was referred to a psychologist.
The study findings showed a total of nine patients with definite awareness concluding an
incidence rate of 0.16% (95% CI: 0.08 to 0.30). Seven patients with confirmed awareness were
from the BIS group and two cases of confirmed awareness were from the ETAC group. In
addition, twelve patients from the BIS group and six patients from the ETAC group were found
to have possible awareness bringing the incidence rate of definite or possible awareness to 0.47%
(95% CI: 0.32 to 0.68). These investigators also found that some patients experienced awareness
despite remaining within specified BIS and ETAC ranges. Five out of the 9 patients with definite
awareness and 6 out of the 18 patients with possible awareness did not exceed a BIS reading
above 60 or an ETAC reading below 0.7 age-adjusted MAC. The researchers were unable to find
an advantage in using the BIS monitor over monitoring ETAC. The researchers supported
implementing ETAC protocols for patients at high risk for AAWR undergoing GA with inhaled
anesthetics to assist with prevention.
Mashour et al. (2012) conducted one of the largest prospective, randomized, controlled
trials of various procedures, the Michigan Awareness Control Study (MACS); the primary
outcome was the incidence of definite AAWR. Eligible subjects were those aged 18 and older,
receiving GA, and expected to be available for follow-up interviews. Intracranial procedures or
those involving the forehead were excluded, and other exclusion criteria included those with
adhesive allergy, psychosis, or a history of traumatic brain injury. Patients were randomized into
one of two groups for assessing depth of anesthesia: BIS-monitored or MAC-monitored
(previously referred to as ETAG or ETAC). A total of 18,836 (87% of those recruited) were
assessed by postoperative interview and included in the final analyses – 9,460 from the BIS
ANESTHESIA AWARENESS WITH RECALL
16
group and 9,376 from the MAC group. No BIS data were recorded for 3,384 (36%) subjects
from the BIS group due to technical issues, therefore, this group was used as a post-hoc control
group because they received neither intervention.
Patients and interviewers were blinded to the assigned groups. Anesthesia providers were
not blinded to their respective monitoring group since they received alerts for BIS or MAC
values, however, they were unaware of the randomization methods used throughout the study,
such as how patients or operating rooms were allocated for selection. Anesthesia providers for
the BIS-monitored or MAC-monitored groups were alerted if BIS values reached higher than 60
or if the median age-adjusted MAC reached less than 0.5, respectively.
Patients were screened for AAWR events on postoperative day 28-30 by trained
interviewers utilizing a modified Brice interview (Table 3). For those reporting AAWR events,
three separate interviews were conducted to determine the occurrence of AAWR–categorized as
definite, possible, or no awareness. Any uncertainty or disagreement among interviewers
prompted a fourth interview.
The researchers utilized the Michigan Awareness Classification (MiAC) method, an
instrument developed and validated by Mashour et al. (2010) as a means to objectively
categorize a patient’s experience of AAWR as Class 0 (no accidental awareness during GA),
Class 1 (isolated auditory perceptions), Class 2 (tactile perceptions, with or without auditory),
Class 3 (pain, with or without tactile or auditory), Class 4 (paralysis, with or without tactile or
auditory), or Class 5 (paralysis and pain, with or without tactile or auditory); in addition, the
letter “D” indicates feelings of distress related to fear, anxiety, suffocation, sense of doom, sense
of impending death, and others not specified (Table 4).
ANESTHESIA AWARENESS WITH RECALL
17
The researchers identified 15 studies involving 151 cases of anesthesia awareness that
could be analyzed. The date ranges of studies were from 1961 to 2010. Twenty-five individuals
(attending anesthesiologists, anesthesiology residents, nurse anesthetists, medical students, and
ancillary staff) across multiple medical centers separately evaluated the cases of awareness and
classified them as Class 1-5 and with or without a “D” designation. Each analyzer’s observation
was compared to others for strength utilizing a statistical value, referred to as “kappa”, which
quantifies the degree of agreement between multiple observers, theoretically ranging from 0.0-
1.0. For example, a kappa value closer to 1.0 indicates a stronger agreement that did not happen
by chance alone.
Incidence rates of AAWR were 19 of 18,836 (0.1%). The superiority of BIS versus MAC
monitoring was indeterminate, however, post-hoc secondary analysis revealed statistically
significant findings. Considering the combination of “definite” and “possible” AAWR cases,
there was a 0.08% incidence in the BIS-monitored group, 0.20% in the MAC group, and 0.38%
in the control group who received no intervention (p = 0.006). This revealed an incidence rate
4.7 times higher in the no-intervention group versus the BIS group (p = 0.001; 95% CI: 1.7-
13.1). The study indicates the superiority of BIS monitoring over clinical signs alone, in the
absence of MAC monitoring. A major limitation of the study was the insufficient number of
participants to determine whether a true difference exists between BIS and MAC monitoring for
reducing AAWR; post-hoc analysis determined a need for over 100,000 subjects in each group to
make this determination.
ANESTHESIA AWARENESS WITH RECALL
18
Non-Modifiable Considerations
Age
Pandit et al. (2014a) found that the following incidence of certain/probable (Class A)
cases of AAWR by age group: 23.9% between the ages of 26-35, 17.4% between the ages of 36-
45, and 18.2% between the ages of 46-55. After the age of 55, the risk of AAWR decreases
progressively with increasing age, culminating with subjects over the age of 86 with the lowest
incidence of AAWR of 0.9%. The risk of AAWR was higher among the 26-35 age group than
any other age group (no inferential statistics provided).
Ghoneim et al. (2009) is referenced by Pandit et al. (2014a) as one of the most recent
studies conducted on AAWR that examined if there was a correlation between age and AAWR.
In this study, an extensive literature search was conducted between 1950-2005 looking for the
keywords “Anesthesia” and “Awareness.” They collected 271 cases of AAWR from the
electronic literature review. Then, the authors explored separate databases for two control groups
to compare to the third group of patients who had AAWR. The first group consisted of 19,504
patients who did not experience awareness (Sebel et al., 2004). The second group consisted of a
combination of the following two data sets: age and gender from patients who underwent GA
(data derived from the 1996 data from the National Survey of Ambulatory Surgery) and weight
and BMI (data derived from the 1988-1994 National Health and Nutrition Examination Survey
of the United States household population). The two groups were compared for patient’s age,
gender, ASA Classification, premedication, drugs used for induction and maintenance of
anesthesia, intraoperative hypertension and/or tachycardia, type of surgery, and postoperative
sequelae. After comparison, those who experienced AAWR were more likely to be younger
(p<0.01). The mean age of patients with AAWR was 46 (+/- SD 15 years) and in patients
ANESTHESIA AWARENESS WITH RECALL
19
without AAWR was 49 +/- 15 years (Sebel et al., 2004) and 46 years old from the National
Survey of Ambulatory Surgery (Centers for Disease Control and Prevention [CDC], 2015). In
conclusion, when the strength of evidence from all studies under consideration was examined,
the Ghoneim et al. (2009) study did not include age as a clear risk factor for AAWR. Instead, the
researcher concluded AAWR was most likely attributed to overly light anesthesia. To date, there
is not a consistent recommendation as to the correlation between the age of patients and AAWR,
which warrants further investigation.
Gender
Pandit et al. (2014a) discovered that of the certain/probable (Class A) cases of AAWR
(110), 63.6% of them were female (no inferential statistics cited). Buchanan et al. (2006) was
cited as Pandit’s NAP5’s primary source that concludes that women appear to recover more
quickly from GA. Buchanan et al. (2006) sought to discover if women recover faster than men
under GA by analyzing secondary data extracted from the B-Aware trial previously reviewed
(Myles et al., 2004). The investigators examined 584 men and 495 women and found that female
patients had a higher BIS value than male patients despite similar amounts of anesthetic drug
administration (time-averaged mean BIS value [sd]; male 44.6 [7.1] versus female 46.4 [6.6]; p =
0.005). The amount of time it took for the patient to open their eyes after anesthesia (which was
considered as one of the discharge criteria) in males versus females was 13.9 [13.2] minutes
versus 10.6 [11.6] minutes; (p<0.001) and time to discharge in the post-anesthesia care unit was
male 133 [209] minutes versus female 78 [106] minutes; (p<0.001). These differences persisted
after multivariate adjustment (both p ≤ 0.001). This study demonstrated potential gender-based
differences in sensitivity to anesthetic agent depression of consciousness. While this study did
not directly claim that gender plays a role in an increased risk for AAWR, they claim that
ANESTHESIA AWARENESS WITH RECALL
20
women’s ability to recover faster from anesthesia could potentially be correlated with an
increased risk of AAWR.
Buchanan et al. (2006) briefly cite additional sources within the article for potential
reasons why women may be at an increased risk for AAWR. A few of the potential reasons cited
include the fact that women have a larger proportion of body fat and smaller water content than
men. For lipid-soluble drugs, the volume of distribution is generally larger in women (leading to
a longer duration of action). In addition, female sex hormones modulate the activity of this
system and may increase drug clearance (i.e., alfentanil was 70% more rapid in women younger
than 50 years compared to older women). A larger volume of distribution and a more rapid rate
of metabolism would facilitate a faster cessation of drug action and enhance the speed of
emergence.
Buchanan et al. (2006) cited additional studies that found women are more resistant to
propofol. At similar blood concentrations of propofol comparable to men, women consistently
record higher BIS values. The same finding has also been reported with the use of remifentanil
when used in conjunction with nitrous oxide. In addition, another study found that women
required higher desflurane concentrations than men.
In summary, the Pandit et al. (2014a) descriptive report found that more women
experienced AAWR. Buchanan et al. (2006) found that women have faster anesthesia recovery
times, indicating that women may be less sensitive to the hypnotic effect of anesthetic drugs.
While they did not directly study the rates of AAWR, they opined that women’s faster recovery
times from anesthesia could be implicated in cases of AAWR. More studies are recommended to
elucidate whether gender definitively plays a role in AAWR.
ANESTHESIA AWARENESS WITH RECALL
21
Prior Episode of Anesthesia Awareness with Recall
Aranake et al. (2013) performed a secondary analysis of the data provided by three
randomized, controlled trials previously reviewed above: B-Unaware Trial, Michigan Awareness
Control Study (MACS), and BAG-RECALL. The primary aim of this study was to assess the
risk of AAWR in patients who have already experienced AAWR. Each trial either included the
use of a BIS monitor or ETAC as a means to monitor if the patient was at a level consistent with
GA. Anesthetic management of the three trials was compared using Hotelling's T
2
statistic. The
incidence of AWR was 1.7% (4 of 241) in patients with a history of AAWR and 0.3% (4 of
1,205) in control patients (relative risk = 5.0; 95% CI, 1.3–19.9). In addition, anesthetic
management did not differ between cohorts. It was concluded that patients with a history of
AAWR are five times more likely to experience AAWR than those who do not.
However, Pandit et al. (2014a) reported 6 out of the 141 (4.2%) cases of certain/probable
(Class A) and possible (Class B) cases of AAWR had a history of awareness with recall. Due to
the nature of this descriptive study, no inferential statistics were calculated. The research team
was unable to collect the history of AAWR in a separate 19 subjects who experienced AAWR,
thus potentially underestimating the real incidence. Based on the data provided, 135 subjects out
of 141 (95.7%) who experienced AAWR did not have a history of awareness with recall, which
differs from the findings by Aranake et al. (2013). Further research using inferential statistics
may help clarify the influence, if any, of this factor.
ANESTHESIA AWARENESS WITH RECALL
22
Modifiable Considerations
Obesity
The Pandit et al. (2014a) NAP 5 Report categorized patients as underweight, normal,
overweight, obese, and morbidly obese (weight or BMI ranges not provided). Of the AAWR
cases that were considered certain/probable (Class A), 4% were underweight, 36.4% of the
patients were of normal weight, 27% were overweight and 32.3% of patients were
obese/morbidly obese. For the Activity Survey, the researchers reported that 18.7% of patients
were obese/morbidly obese. Due to the large, increased difference between the Activity Survey
(18.7%) and The NAP 5 Report Class a AAWR cases (32.3%), the researchers concluded that
there was a disproportionately high number of obese/morbidly obese patients who filed a Class A
report of AAWR (p = 0.01). Of note, 37% of the obese/morbidly obese patients who experienced
AAWR had difficult airways (difficult intubation, difficult mask ventilation, difficult insertion of
a supraglottic airway device, and bronchospasm).
Difficult Airway
Pandit et al. (2014a) found that 26.5% of certain/probable cases of AAWR were defined
in the context of The NAP 5 Report as having difficult airways. In 23 of the AAWR reports, the
patients were classified as difficult to intubate (requiring 3 or more intubation attempts); 1-5% of
the patients were difficult to mask ventilate; 1-2% of the cases the provider had difficulty or
failed to place the supraglottic airway device; up to 6% of patients were reported as having a
Cormack-Lehane grade three view (epiglottis visualized only) at laryngoscopy and there was one
report of bronchospasm (UpToDate, 2022). Another cited reason why a difficult airway was
indicated as a risk factor for AAWR was that the anesthesia provider did not perform a pre-
anesthetic assessment which would have revealed a potentially difficult airway risk. If the
ANESTHESIA AWARENESS WITH RECALL
23
anesthesia provider had performed the anesthetic assessment, they would have been able to
mitigate the situation and reduce the patient’s risk for AAWR.
When reviewing the cases of AAWR among those with difficult airways, the NAP 5
report researchers stated that it was difficult to determine if the anesthetic team intended to
persist with attempts at intubation or awaken the patient. In some of the cases, during difficult
airway situations, the anesthesia provider relied on volatile anesthetics; they did not administer
additional intravenous anesthetic agents because they were preoccupied with trying to secure the
airway. In addition, in some of the cases, the patients were not given an adequate amount of
neuromuscular blockade. Since the patient was not adequately paralyzed, airway instrumentation
was more difficult, which subsequently led to prolonged intubation and may have contributed to
AAWR (Pandit et al., 2014a).
In contrast, The NAP 5 Report cited Ghoneim et al. (2009), a study that was previously
detailed in this literature review, which also looked at the different factors that contribute to the
risk of AAWR. In all the patients who suffered AAWR, 4.5% of the cases were attributed to
difficult and/or prolonged laryngoscopy/intubation (though no inferential statistics were
calculated, the implication was that this was a low percentage of patients with AAWR) (Pandit et
al., 2014a).
Also, as noted, in the context of the current investigation, AAWR considerations would
not apply to the situation of an airway emergency in any patient where the intention is to
discontinue anesthesia administration and awaken the patient to preserve respiratory function. In
this situation, the intended level of consciousness is safely awakening the patient to full
awareness.
ANESTHESIA AWARENESS WITH RECALL
24
Provider Error
A 7-year multisource, retrospective analysis was conducted to study the prevalence of
AAWR among adult cancer patients undergoing GA (Cascella et al., 2016). A total of 21,099
patient cases were analyzed for patient perceptions. The researchers utilized the MiAC method,
previously described, for reporting perceptions experienced by patients. Two patients
experienced AAWR and reported the following perceptions: one MiAC Class 1, and one MiAC
Class 5D. In the case of the patient reporting MiAC Class 5D perceptions, the anesthesia
provider admittingly reported the incorrect administration of the volatile anesthetic. The 25-year-
old White female patient experienced a sense of suffocation and paralysis (consistent with a
MiAC Class 5D experience). The procedure, a total thyroidectomy, was her first surgery and she
had no risk factors for postoperative complications. She received premedication with midazolam
1.5mg and fentanyl 100mcg and maintenance of GA with sevoflurane 2.5% and fentanyl
200mcg. The anesthesia provider recognized continuous tachycardia and lacrimation
intraoperatively and responded by deepening the anesthesia with propofol. It was later confirmed
that the vaporizer was not correctly attached, and depth of inhaled anesthetic monitoring was not
utilized, resulting in a potentially avoidable episode of AAWR. The patient’s distress was treated
with minimal psychological intervention by a professional and was considered resolved without
any ongoing complications. Limitations to the study revolved around the use of retrospective
analysis methods, which rely on patients voluntarily and accurately reporting an awareness event
and the availability of a reporting system once the patient has been discharged.
Pandit et al. (2014a) in The NAP 5 Report utilized the National Patient Safety Agency
(NPSA) as a classification tool that would assist in delineating contributory anesthesia provider
error that may have led to the patient’s experience of AAWR (Table 5). The NPSA tool consists
ANESTHESIA AWARENESS WITH RECALL
25
of behavioral categories for the classification of human factors impacting safety. Each category
is defined as follows: Communication (verbal or non-verbal, written, and occurring between
individuals, teams, and/or organizations), Education and Training (i.e., availability of training),
Equipment/resource factors (i.e., clear machine displays, poor working order, size, placement,
ease of use), Medication (where one or more drugs directly contributed to the incident),
Organization and Strategic (i.e., organizational structure, contractor/agency use, culture), Patient
(i.e., clinical condition, social/physical/psychological factors, relationships), Task (includes work
guidelines/procedures/policies, availability of decision-making aids), Team and Social (i.e., role
definitions, leadership, support, and cultural factors), Work and Environment (i.e., poor/excess
administration, physical environment, workload and hours of work, time pressures), and Other.
After analyzing the data, with no inferential statistics provided, it was determined that the
NPSA classifications directly related to anesthesia provider error resulted in the highest
percentages of certain/probable (Class A) cases of AAWR reported as follows: Medication
(78.2%), Education and Training (58.2%), Equipment/resource factors (33.6%) and Task
(33.6%) (Pandit et al., 2014a). After reviewing the cases individually, the research team found
that 81% of the certain/probable (Class A) cases of AAWR could have been prevented.
The NAP 5 investigators additionally took a secondary approach to evaluate the
anesthesia provider error (Pandit et al., 2014a). The NAP 5 Panel utilized three processes to
extrapolate key provider-related human factors: The Human Factors Investigational Tool (HFIT)
(Gordon, et al., 2005), the Simplified Human Factors Investigation Tool categories for coding
anaesthetic events as applied to the investigation of cases reported in the 4th National Audit
Project (The NAP 4 Report) (Flin et al., 2013), and The Yorkshire Contributory Factors
Framework (Lawton et al., 2012).
ANESTHESIA AWARENESS WITH RECALL
26
The HFIT instrument used in The NAP 5 Report focuses on four main elements: threats,
situations, awareness, action errors, and error recovery mechanisms. The Simplified Human
Factors Investigation Tool used in the NAP 4 Report focuses on bridging the aspect of anesthetic
management and action errors, situation awareness, and potential threats. Lastly, The Yorkshire
Contributory Factors Framework focuses on numerous categories including, but not limited to
the following: active failures, individual factors, physical environment, staff workload, training
and education, etc. None of these tools had scoring systems, but The NAP 5 Report seemed to
develop an amalgamation of the three guidelines to create an abbreviated version of the three.
The integrated human factors table was diluted into ten categories: judgment, communication,
education, tiredness, distraction, theatre design, organization, decision-making, other, and none.
Of the class A certain/probable (Class A) class of AAWR (no inferential statistics calculated),
the following four were the most common human factors that increased the risk for AAWR:
judgment (26.7%), communication (16.2%), education (8.6%), and being tired (6.7%) (Pandit et
al., 2014a).
Lastly, a special consideration worth mentioning in the NAP 5 Report was some of the
preventable provider errors that occurred in the obstetric population (Pandit et al., 2014a). Four
of the cases of AAWR in the obstetric population were deemed preventable by the NAP panel
for the following reasons: in two instances the anesthesia provider forgot to turn on the volatile
anesthesia following induction and the other two cases involved syringe mix-ups (antibiotics
were confused with anesthetic agents.
Paech et al. (2008) conducted a prospective observational study in New Zealand between
2005-2006 that included 1,095 parturients undergoing cesarean section and determined that
0.26% (CI 0.03-0.9%) experienced AAWR. While this study only focused on parturients, their
ANESTHESIA AWARENESS WITH RECALL
27
findings were not exclusive to the obstetric population; instead, they were more related to
anesthesia provider error, which enabled the researchers to extrapolate the findings to the general
population.
In one instance of AAWR, an emergency cesarean section was performed by an
“anesthetic trainee” working alone after hours. Anesthesia was provided without the use of depth
of anesthesia monitoring and the provider intended to administer thiopental (which is a
barbiturate that requires sterile water reconstitution) but failed to reconstitute the vial and
administered sterile water only. This medication error could have been prevented if the provider
had ensured that the patient was unresponsive to verbal communication by assessing the eyelash
response before the administration of the neuromuscular blockade agent (NMB),
suxamethonium.
In another instance of AAWR, the provider did not administer an adequate amount of
anesthesia (3.3 mg/kg of thiopental for induction, compared to the recommended mean dose for
induction of 4.9 mg/kg that was given to the rest of the study population who did not experience
awareness). Not only did the patient receive an inadequate dose, but the anesthesia provider
made two attempts to intubate the patient, which prolongs intubation time and puts the patient at
increased risk for AAWR due to delays in the administration of additional anesthetic.
Pharmacologic Management
Benzodiazepines
Errando et al. (2008) conducted a prospective, observational study of 4,001 surgical
patients to evaluate awareness with recall (AWR), described in this literature review as AAWR.
In the study, prior to the induction phase, premedication with benzodiazepines was given to
2,222 subjects (54.5%) and premedication with opioids was given to 3,448 (86.2%) subjects.
ANESTHESIA AWARENESS WITH RECALL
28
Blinded interviews were conducted followed by retrieval of patient characteristics, surgery
information, and medication usage. Subjects were interviewed at three postoperative periods:
immediately after surgery and on postoperative day 7 and day 30. The phenomenon of awareness
with recall was described categorically as follows: not awake during surgery, AWR, AWR-
possible, AWR-not evaluable. The study found a statistically significantly lower incidence of
anesthesia awareness in subjects who received premedication with benzodiazepines (p = 0.001).
Neuromuscular Blockade
The NAP 5 Report, previously reviewed, also revealed an important connection between
the use of neuromuscular blockade (Table 1) and the incidence of AAWR (Pandit et al., 2014c).
In the report, various studies involving 329 hospitals throughout the United Kingdom and 46
public hospitals in Ireland reported data on intraoperative awareness during a one-year reporting
period. Within the same year, an activity survey was conducted to collect information on current,
common anesthesia practices and provide comparison data for interpretation of The NAP 5
results (Sury et al., 2014). The purpose of the activity survey was to collect a variety of baseline
data including, but not limited to the following: distribution of caseload by specialty, age groups,
admission type, the urgency of anesthesia care, ASA Classification, pregnancy status, location of
the procedure, number of cases of each type of anesthesia care, and types of medications given.
Local coordinators among all hospitals, trusts, and boards in the United Kingdom (UK)
conducted surveys of their respective hospitals on every patient under the care of an anesthesia
provider. All patients receiving general, local, neuraxial, and epidural anesthesia, as well as
monitored anesthesia care, were included. This was completed over a two-day period for each
local coordinator within a specified week in September 2013. The survey indicated 2.8 million
ANESTHESIA AWARENESS WITH RECALL
29
GA cases were performed (Sury et al., 2014), and during the NAP 5 study, 300 reports of
intraoperative awareness were made (Pandit et al., 2014c).
A review process was conducted to address potential biases in categorizing types of
awareness, and therefore a standardized category system was implemented by the researchers
(Table 6). Of the total 300 reports of awareness, the number of certain/probable and possible
awareness cases was determined to be 141 (47%) with an incidence reported at around 1:19,600
(95% CI 1:16,700–23,450).
The frequency of awareness involving neuromuscular blockade was about 1:8,200 (95%
CI 1:7,030-9,700) and without neuromuscular blockade was around 1:135,900 (95% CI
1:78,600-299,000). It is important to note that there was a remarkably high representation of
neuromuscular blockade usage among cases of AAWR in this study (93%) (Pandit et al., 2014c)
when compared to the activity study (46%) (Sury et al., 2014). Nerve stimulators and
neuromuscular blockade antagonist agents were used proportionately less among cases of
AAWR (Pandit et al., 2014c). The authors discuss that distress may occur when a patient
becomes aware but is unable to resume motor control over respiration and movement. These
findings may demonstrate an association between AAWR and both inadequate antagonization of
neuromuscular blockade drugs and omission of nerve stimulator monitoring.
In The NAP 5 Report, to differentiate between adult data–the primary focus of this
review–it should be considered that children (defined as less than 16 years of age in this study)
made up only 24 of the reported cases of intraoperative awareness and only nine of the cases
deemed certain/probable or possible (Pandit et al., 2014a).
ANESTHESIA AWARENESS WITH RECALL
30
Phases of Anesthesia Considerations
Induction
A novel finding of The NAP 5 Report was that 72 out of 141 cases of certain/probable
and possible cases of AAWR occurred during the induction phase (Pandit et al., 2014a). Fifty-
eight of these cases occurred during the moment of induction and 12 of them occurred upon
transfer to the operating room (Pandit et al., 2014a). In the United Kingdom, it is common for
there to be a dedicated anesthesia room where the anesthesia provider induces their patient and
subsequently transfers them to the operating room. This practice is thought to provide privacy in
performing procedures (i.e., induction, epidurals, etc.), teaching, and no interruptions during the
induction phase. Additional contributing factors to the increased risk of AAWR during the
induction phase include the fact that in 32% of AAWR cases during induction, an inadequate
dose of the induction agent was used. Thirty-six percent of AAWR cases occurred during rapid
sequence intubation (RSI), where 39% of patients did not receive opioid administration upon
induction. Ninety-two percent of cases of AAWR during RSI involved the administration of
Thiopental. Thirty percent occurred during difficult airway management (no additional
intravenous anesthetic agent was administered despite additional attempts at instrumenting the
airway). Eight percent failed to turn on the vaporizer after induction or on arrival into the
operating room. Seven percent of AAWR occurred when the intravenous induction agent
infiltrated the site or went backward in the tubing.
Pandit et al. (2014a) also noted additional findings, although not as frequent as the
aforementioned, that contributed to AAWR: the volatile agent used was too low, the vaporizer
was faulty, fresh gas flows were too low, administration of a low dose of neuromuscular
blockade which led to insufficient muscle relaxation and therefore contributed to a difficult
ANESTHESIA AWARENESS WITH RECALL
31
airway, distractions, fatigue, the provider feeling forced to rush due to last minute changes in
case scheduling, a desire to finish the case faster, and/or administration of the neuromuscular
blockade drug prior to the onset of unconsciousness.
The NAP 5 Report’s primary findings also elucidate that 51% of the cases of AAWR on
induction were considered urgent or emergent (Pandit et al., 2014a). While some of the
following may also be categorized as pharmacologic considerations, the NAP 5 Report identified
these as contributory to the incidence of AAWR during urgent/emergent situations surrounding
the induction phase. In the AAWR cases who underwent rapid sequence intubation (RSI), only
one-third of them received opioids. Including those who did not undergo RSI, 39% of cases,
opioids were not used. In addition, in 92% of the cases of AAWR that underwent RSI the
provider used thiopental. Based on the researchers’ findings, there is a clear association during
the induction phase when using RSI and thiopental and increased incidence of AAWR. The
overall goal of an RSI is to achieve prompt unconsciousness and neuromuscular blockade by
rapid administration of an induction agent and neuromuscular blocking drug to a pre-oxygenated
patient. The NAP 5 Report clearly indicates that the speed of induction (lack of time between
administration of the anesthetic agent and subsequent neuromuscular blocker intervention) and
the lack of opioid during RSI greatly contributes to the increased risk of AAWR. In addition, this
brings into question the United Kingdom’s current widespread use of thiopental as an induction
agent. This drug is commonly used during RSI and is noted to have a short duration of action due
to its rapid redistributive nature, which may result in a shorter time frame of unconsciousness
than necessary for airway interventions and subsequent volatile anesthetic administration, thus
predisposing the patient to AAWR.
ANESTHESIA AWARENESS WITH RECALL
32
Another contributing factor to an increased risk for AAWR during the induction phase is
obesity. Out of the 72 out of 141 cases of certain/probable and possible cases of AAWR that
occurred during the induction phase, weight was documented for 62 of the patients. Twenty-five
patients (35%) were categorized as overweight, obese, or morbidly obese. Ingrande & Lemmens
(2010) was cited by Pandit et al. (2014a) as an investigation providing potential data explaining
why patients who were obese/morbidly obese may be at an increased risk for AAWR during the
induction phase (no inferential statistics calculated). In this literature review, the findings of
other studies regarding the pharmacodynamics and pharmacokinetics of common anesthetic
agents and the obese patient population were summarized as follows: as BMI increases, total
body weight and fat body weight increase. However, lean body weight tapers off and plateaus at
a much lower level than the aforementioned. Dosing recommendations are typically based on
total body weight in normal-weight patients and since the total body weight increases, the obese
patients should receive a higher dose. Thus, basing induction doses on an obese patient’s ideal
body weight can lead to under-dosing, which theoretically could be related to AAWR.
In addition, Ingrande & Lemmens (2010) stated obese patients have an increased amount
of adipose tissue and lean body weight compared to those of similar height, weight, and gender,
but not obese. The increase in lean body weight leads to a 20-40% increase in total body weight,
drastically affecting the volume of distribution.
In order to explain the relationship between the volume of distribution of drugs and how
that can be affected by weight, Pandit et al (2014a) used data from a study that examined how
certain physiological values (degrees of cardiac output, degrees of obesity, gender, and age)
could affect the pharmacokinetics of sodium thiopental and concluded that the larger adiposity
increased the volume of distribution, with the implication that obese patients may need larger
ANESTHESIA AWARENESS WITH RECALL
33
anesthetic drug dosages to achieve plasma levels associated with the desired pharmacodynamic
effect (Wada et al., 1997).
Maintenance
The NAP 5 Report found that only 51 cases (36%) of certain/probable (Class A) and
possible (Class B) AAWR cases occurred during the maintenance phase (Pandit et al., 2014a).
Thirty-seven patients (74%) received inadequate care, which was described as stopping the
administration of anesthetic agents too early (8%), failing to turn on or refill the vaporizer (26%),
and intentionally delivering low doses of anesthesia in inappropriate situations (34%). In 13
cases (26%) of AAWR, there was no identifiable cause of AAWR in the maintenance phase.
Emergence
Lastly, 18% of 141 certain/probable (Class A) and possible (Class B) reports of AAWR
reports occurred during the emergence phase (Pandit et al., 2014a). This was attributed to failing
to use a nerve stimulator to monitor neuromuscular blockade and the failure to reverse the NMB
agent. In 42% of AAWR cases, it was found that a nerve stimulator was not used. In 23% of the
AAWR cases, the neuromuscular blocking agent was either given too close to the end of the
procedure, administered at an excessively high dose, or was not indicated for the surgery’s
duration. In addition, 30% of the causes of AAWR were attributed to poor communication
between medical providers relevant to the phase of the procedure (i.e., surgeon to anesthesia
provider) for reasons such as the surgeon stating that they are finished, when in fact they needed
more time (no inferential statistics calculated).
ANESTHESIA AWARENESS WITH RECALL
34
Surgery Type Considerations
Obstetrics
A randomized control trial out of Poland by Czarko et al. (2013) examined the
phenomenon of AAWR in 337 women undergoing GA for cesarian sections and gynecological
procedures. ASA Classification 1 and 2 women were divided into groups A-D: A-C received
elective gynecological surgery and Group D was cesarean section patients. Group A received
TIVA with target-controlled infusion (TCI); group B received thiopentone (another name for
sodium thiopental), fentanyl, cisatracurium, and sevoflurane; group C received propofol,
fentanyl, sevoflurane; and group D received thiopentone, suxamethonium, fentanyl, and
cisatracurium. The depth of anesthesia was monitored using an arterial line that measures
auditory evoked potentials (AEP). Electrodes are placed on the head to evaluate basic vital
functions and sleep depth following a transient acoustic stimulus. The arterial line AEP monitor
aimed for a range between 15-25.
Czarko et al. (2013) surveyed patients to assess the occurrence of AAWR. There were
three cases of awareness, two of them belonging to group D (cesarean sections). While 66% of
the cases of AAWR occurred among women having cesarean sections, the incidence of AAWR
may be overestimated because group D had 175 patients, while Group A, B, and C only had 51,
95, and 16, respectively. The researchers concluded that the incidence of awareness among
cesarean patients is due to the practice of limiting the amount of anesthesia the mother receives
to limit neonatal exposure, thus avoiding the risk of sedated newborns.
The NAP 5 Report collected primary data regarding the likelihood of pregnant women to
experience AAWR (Pandit et al., 2014a). Overall, they concluded that the increased risk for
AAWR in the obstetric population was due to thiopental, RSI, difficult airway, and emergent
ANESTHESIA AWARENESS WITH RECALL
35
procedures occurring after hours. During the study, the women were divided into four cesarean
section categories: categories 1-3 (in increasing degree of urgency) and category 4 (elective).
With no inferential statistics calculated, the obstetric cases represent 10% (14/141) of the total
certain/probable (Class A) and possible AAWR. In seven of the cases of AAWR, it was
speculated that an insufficient dose of thiopental was utilized for induction, thus increasing the
chance of AAWR. The authors note that this is especially the case for category 1 (emergency)
cesarean section, which requires rapid sequence intubation for induction of GA. The hastened
speed required during emergency cesarean sections leads to a concept that the NAP 5 team coins
as “mind the gap,” referring to the brief period between induction of anesthesia and the start of
surgery during an RSI. Although short, this period is enough to allow for redistribution of the
intravenous induction agent, while the volatile anesthetic is still building in the patient’s system
to equilibrate in the brain – its effect site – resulting in levels of the agent being too low to
produce the desired GA.
In addition, five of the obstetric patients diagnosed with AAWR were classified as having
difficult airways (i.e., failed/difficulty intubating and/or bronchospasm) and four of them were
obese (BMI greater than 30 kg/m
2
) cases (Pandit et al., 2014a). Authors opined that the incidence
of obesity in the obstetric population is increasing and may be an independent risk factor for
AAWR, due to the association with difficult airway management.
The NAP 5 Report found that nine of the 14 cases of AAWR associated with obstetrical
care occurred during the out-of-hours operating time (0100 to 0800) while under the supervision
of trainees. These were cesarean section cases classified as category 1 or 2 (emergent and highly
urgent, respectively). Trainees performed approximately 50% of category 1-2 cesarean sections.
ANESTHESIA AWARENESS WITH RECALL
36
In comparison, experienced consultants performed approximately 25% of category 1-2 cesarean
sections. The remaining 25% was performed by ‘other career grade doctor.’
Cardiothoracic
There is a lack of recent studies that specifically study the incidence of AAWR in the
cardiothoracic surgical population. The most recent descriptive study was The NAP 5 Report,
which found eight cases of certain/probable (Class A) and possible (Class B) cases of AAWR
(1:8,600; 0.1%) in the cardiothoracic population (Pandit et al., 2014a). All eight cases were
thought to be mainly due to intentional delivery of “light anesthesia” due to labile hemodynamic
status and malfunctioning intravenous access when administered the induction agents (Pandit et
al., 2014a). Light anesthesia – defined as the administration of sedative-hypnotic drugs in an
insufficient dose to produce an unconscious state (Table 1) – is the most common reason for
AAWR in this patient population according to the findings of the NAP 5 report.
Monitoring Devices and Detection
Isolated Forearm Technique
Sanders et al. (2017) conducted a cohort study to evaluate the isolated forearm technique
(IFT–described below) and connected consciousness (Table 1) after intubation. This
international multicenter study involved 260 patients, ages 18 years and older, undergoing GA
with endotracheal intubation. All surgery types were eligible for inclusion in the study. The
researchers evaluated IFT responsiveness and the incidence of postoperative explicit recall
(Table 1). Drug selection and dosage were left to the discretion of the anesthetist; 31 participants
were given TIVA and 229 participants received an inhaled anesthetic.
In this study, IFT was conducted by placing a blood pressure cuff on the patient’s
forearm. The blood pressure cuff was inflated 50 mmHg above the systolic blood pressure during
ANESTHESIA AWARENESS WITH RECALL
37
the injection of induction agents but before the administration of neuromuscular blockers. The
cuff remained inflated as the patient was asked to follow verbal commands for a duration of
fewer than 5 minutes. Verbal commands included two questions: [NAME], squeeze my hand,
and [NAME], squeeze my hand if you have pain. A positive IFT was indicated by the patient
moving their forearm or hand in response to the command; this event was recorded by an
observer that was not the anesthetist.
In response to IFT, 12 patients followed verbal commands after induction, and 241
patients did not. This demonstrated a 4.6% incidence of positive IFT response. Of the 12 patients
that responded to the IFT, one was excluded due to not meeting the criteria; 5 of the remaining
11 participants received volatile anesthetics (p = 0.08), and the other 6 participants received
either midazolam (p = 0.38) or ketamine (p = 0.13) in combination with propofol and fentanyl.
None of the patients positive for IFT experienced explicit recall. The researchers established that
IFT responsiveness was not associated with explicit recall postoperatively and speculated that
connected consciousness (Table 1) could occur in the unresponsive patient leaving no trace of
explicit memory (Table 1). Of significance, researchers concluded that the rate of connected
consciousness is 25 times higher than the rate of explicit recall of the events in patients in the
conditions of this study (no inferential statistics noted).
Minimum Alveolar Concentration (MAC) and Bispectral Index (BIS)
As previously described, the B-Unaware Trial, BAG-RECALL study, and B-Aware trial
are important to this discussion for many reasons (Avidan et al., 2008; Avidan et al., 2011;
Myles et al., 2004). The B-Unaware Trial sought to examine the more effective method of
minimizing AAWR: BIS monitoring or ETAG concentration. The results of the study showed
four participants with definite awareness, two participants from each group. Furthermore, three
ANESTHESIA AWARENESS WITH RECALL
38
of the four participants with definite awareness had MAC concentrations falling below 0.7
during surgery, and four of the five participants with possible awareness had ETAG
concentrations that fell below 0.7 MAC. During the maintenance phase of anesthesia, the
average ETAG concentration was 0.81 MAC, with a standard deviation of 0.25 in the BIS group
and 0.82 MAC with a standard deviation of 0.23. Researchers noted periods of sustained BIS
values above 60 or ETAG below 0.7; the low ETAG values showed more correlation with
AAWR. Three of the four patients with definite awareness had periods of ETAG levels less than
0.7 MAC, whereas one out of the four patients with definite awareness had BIS values above 60.
The BAG-RECALL study, previously mentioned, evaluated the superiority between BIS
monitoring and ETAC concentrations in preventing AAWR (Avidan et al., 2011). Explicit
awareness was noted in two patients in the ETAC group and seven patients in the BIS group. The
difference between the two groups was not statistically significant (p = 0.98). The same outcome
was found when looking at confirmed cases combined with probable cases of awareness. Neither
group showed superiority, however, it is noted that the overall incidence of AAWR in the study
was less than predicted based on previously reported rates of AAWR; this may indicate an
equivalent benefit by both forms of anesthesia depth monitoring.
As previously elucidated, the B-Aware trial aimed at evaluating the efficacy of BIS
monitoring in decreasing the incidence of AAWR (Myles et al., 2004). The study protocol
included an attempt at keeping BIS readings between 40-60 intraoperatively in the experimental
group. There were 13 cases of awareness with recall: two reports in the BIS group and 11 in the
standard care group (p = 0.022). The outcome was an 82% (95% CI: 17-98%) reduction in
intraoperative awareness in the BIS monitoring group as compared to usual care (utilizing
ANESTHESIA AWARENESS WITH RECALL
39
clinical signs such as heart rate and blood pressure). The two subjects with awareness and BIS
monitoring were associated with readings of 79-82 and 55-59.
Postoperative Recognition and Treatment of AAWR
Questionnaire Instruments
Brice et al. (1970) conducted a study to explore awareness events in subjects at greatest
risk for the event. In this study, the term “awareness” is used in place of AAWR, while holding
the same meaning. The experimental risk situation was created by anesthetizing subjects with
nitrous oxide in oxygen and providing muscle relaxation with tubocurarine. The short-acting
general anesthetic thiopental was used for induction. Within 1-3 minutes after adequate muscle
relaxation, intubation was performed with a cuffed, oral endotracheal tube. A consistent
concentration of nitrous oxide was used to maintain anesthesia for each patient intraoperatively.
No intraoperative opioid or volatile anesthetic was administered. For 38 subjects, choir music or
piano music was played throughout the case. For the remaining 19 subjects acting as the control
group, no music was played. Subjects were allocated at random to each group and were adult age
(20-77 years) individuals undergoing non-obstetric procedures. The anesthetized period lasted
40-230 minutes with an average operation time of 57 minutes. The anesthesia provider recorded
the patient’s vital signs and degree of movement intraoperatively, as well as the activity
occurring within the operating room. The patient's movement was graded from 0 (little or no
movement) to 3 (movement during most of the anesthesia period). At the end of the procedure,
neuromuscular blockade was antagonized with neostigmine 1-2 minutes after administering
atropine. Upon return of spontaneous ventilation, nitrous oxide was discontinued, and oxygen
alone was administered for at least one minute before removal of the endotracheal tube. A few
ANESTHESIA AWARENESS WITH RECALL
40
minutes into the postoperative period, patients were asked if they had dreamed during the
procedure, and to describe the dream.
Focused interviews were later conducted by a psychologist or one of two anesthetists at
24-48 hours postoperative and then 7-8 days postoperative using a series of 5 questions: 1. What
was the last thing you remembered happening before you went to sleep? 2. What is the first thing
you remember happening on waking? 3. Did you dream or have any other experiences whilst you
were asleep? 4. What was the worst thing about your operation? 5. What was the next worst?
There were no findings of awareness during the procedures. However, dreams occurred
in 44% of patients, about two-thirds of whom were able to recall details of the dreams. Subjects
who exhibited more profound movement (scores of 2-3) during the procedure correlated with
higher incidences of dreaming intraoperatively, compared to those who exhibited little
movement (scores of 0-1) (p<0.01). Among the control group, who did not receive recorded
music, there was a high incidence of dreams that involved conversations. It is unknown whether
these conversations were exclusively part of a dream, or whether chatter within the operating
room was perceived by the patient as part of a dream. Nevertheless, the incidence of dreams
involving conversations was statistically significantly higher in the group of subjects who did not
receive recorded music (p<0.05). Most of the other dreams reported in the study involved
situations and events in which the subject perceived themselves as being a part of the situation.
There was little correlation between subjects reporting dreaming immediately following the
procedure and subjects reporting dreaming during the focused interviews 24 hours and beyond;
moreover, some patients who denied dreaming immediately after surgery later recalled dreams
during the interviews. There was no significant correlation between the length of the operation
and reports of dreaming. The most unpleasant experience of the perioperative period was
ANESTHESIA AWARENESS WITH RECALL
41
reported to be waiting for the procedure (nearly 50% of subjects) or postoperative pain (20% of
subjects). The next most common complaints were subjects being asked to do something they
were unable to do postoperatively, such as lift their head, and unpleasant dreams were the fourth
most common complaint.
Brice et al. (1970) noted the study does not guarantee that subjects did not experience
awareness due to the possibility that some awareness may have occurred and evaded memory. It
is unknown whether alternative choices of music, sounds, or even conversations may have
produced the same results among the subjects. Also, limited information was obtained regarding
the subjects’ usage of alcohol or drugs that affect the central nervous system. Therefore,
researchers could not extract information on whether drug or alcohol use impacted the incidence
of dreaming.
In the Michigan Awareness Control Study (MACS) – discussed previously – a pre-
determined secondary outcome was the comparison of techniques for detecting AAWR
(Mashour et al., 2013). Variability in recently reported incidence rates of AAWR at the time of
the study prompted the subsequent analysis, which aimed to determine the superiority of the
modified Brice interview (Table 3) over quality assurance techniques (described below) for
detecting AAWR. At the time, other than the MACS, there were no direct comparison studies of
the two methods of AAWR detection within the same cohort of subjects. The modified Brice
interview, previously described in a review of the classic study (Brice et al., 1970) on
postoperative day 28-30, involved a set of direct questions to assess whether patients experienced
any recall of events or memories surrounding anesthesia administration: 1. What was the last
thing you remember before anesthesia? 2. What is the first thing you remember after waking
up? 3. Do you remember anything between going under anesthesia and waking up? 4. Did you
ANESTHESIA AWARENESS WITH RECALL
42
dream during your procedure? 5. What was the worst thing about your operation? Quality
assurance techniques consisted of routine open-ended interview questions on day-one
postoperative such as, “Did you have any problems with the anesthesia for your surgery?” These
routine interviews were conducted by clinicians who were uninvolved in the current study, the
parent study, or any other interview that took place of the subjects; nor, were they involved with
the final decision of what distinguished an AAWR event. The researchers examined how many
of the detected cases of awareness by the modified Brice interview were also detected
beforehand by routine quality assurance interviews. The incidence of AAWR as determined by
the modified Brice interview was 19 per 18,847 (0.1%), and the incidence determined by the
quality assurance method was 0.02% (p<0.0001).
It should be noted that a possible limitation of the MACS is the timeframe of interviews.
The initial interviews occurred on postoperative day one (utilizing the quality assurance method),
while the higher incidence rates were detected nearly one month after anesthesia (utilizing the
modified Brice interview) (Table 3). The researchers compared these results to previous reports
of interview timeframes and found it unlikely that the timeframe interfered with the results.
There is not an established standard for identifying AAWR, however, this analysis provides
strong support for the use of a modified Brice interview for future studies and in clinical practice.
As previously discussed, during the BAG-RECALL study, 5,413 participants were
successfully screened for AAWR at two time periods: within 72 hours of surgery and at 30 days
postoperative (Avidan et al., 2011). Definite or possible awareness was detected in 27
participants. In congruence with the MACS, the modified Brice Questionnaire (Table 3) and
MiAC method were both utilized for the BAG-RECALL trial.
ANESTHESIA AWARENESS WITH RECALL
43
Similarly, the B-Unaware Trial implemented the Brice Questionnaire (Table 3) and
subjects were interviewed at three postoperative time points: within 24 hours, between 24-72
hours, and at 30 days (Avidan et al., 2008). There were four cases of definite AAWR with an
incidence rate of 0.21% (95% CI: 0.08 to 0.53). Only two of these patients reported memories of
recall at all three interview time points. One patient recalled events at only the second and third
interview, and one patient reported recall at only the 30-day interview. The multi-interview
approach has consistently shown success at capturing additional instances of AAWR.
Additionally, in the B-Aware trial by Myles et al. (2004), subjects were interviewed at
three postoperative time points: 2-6 hours, 24-36 hours, and 30 days after surgery. A total of 13
patients were determined to have experienced definite or possible AAWR. Two of these subjects
reported no AAWR until the 30-day interview.
Documentation and Referral
Pandit et al. emphasized that while the primary goal of anesthesia is to prevent AAWR, if
an AAWR event is suspected, it is crucial to prevent or mitigate the psychological sequelae that
may follow, such as post-traumatic stress disorder (PTSD) (2014a). Therefore, Pandit et al.
(2014a) developed the NAP 5 Anesthesia Awareness Support Pack which includes the NAP 5
Awareness Support Pathway and the NAP 5 AAWR Support Pack Output (Appendix B; Cook et
al., 2014). This tool can be used by anesthesia providers to accurately document and treat
AAWR.
The first step in Stage 1 is known as the “initial meeting” (Pandit et al., 2014a).
According to the authors, the anesthesia provider should meet in person with the patient after
surgery when the patient is physically and mentally ready to communicate. If the provider is a
junior provider, senior anesthesia personnel should also be present. It is important to listen to the
ANESTHESIA AWARENESS WITH RECALL
44
patient and concurrently utilize the Michigan Awareness Classification Instrument developed by
Mashour et al. (2010) to objectively categorize the patient’s experience of AAWR This tool can
be used by anesthesia providers to accurately document and treat AAWR (Table 4). The provider
should also use the Modified NPSA Classification of patient harm after AAWR (Table 5) (Cook
et al., 2014). This was based on the original NPSA guidelines published in 2004 by the National
Health Service (NHS) of the UK, which provides the following classifications of harm: 0 (no
harm occurred); 1 (low level: likely to resolve with no or little professional intervention); 2
(moderate: moderate anxiety about future anesthesia events, symptoms may impact daily living,
the individual would likely benefit from professional intervention); 3 (severe: patient at risk to
suffer long term psychological consequences and would greatly benefit from professional
intervention; there is severe anxiety regarding future surgeries and it impacts everyday living); 4
(death related to the AAWR experience).
Next, the provider should listen to the patient’s experience with an open mind and respect
their views, as this will help build trust and facilitate communication. The provider should
express their regret that the patient experienced AAWR. Expressing regret is not an admission of
culpability and should not result in medicolegal consequences. Upon conclusion of the meeting,
an order should be placed for a licensed, clinical psychologist to assess the patient for
psychological consequences.
Stage 2 of the support pathway is entitled "analysis" and utilizes The NAP 5
Classification of AAWR Reports (Table 6). Reports of AAWR are classified as one of the
following: Class A (certain/probable AAWR), Class B (possible AAWR), Class C (sedation; a
report of AAWR when the patient was under sedation, where there is an expected level of
awareness), Class D (ICU; a patient who reports AAWR in the ICU during a procedure where
ANESTHESIA AWARENESS WITH RECALL
45
GA was intended), Class E (unassessable), Class F (unlikely), Class G (drug error), and SO
(statement only: a patient makes a single statement of AAWR with no further verbal claims or
documentation to verify). In Class A reports of AAWR, the provider should categorize the
strength of available evidence by using The NAP 5 Strength of AAWR Reports. The strength of
the evidence is as follows: high quality (the report can easily be confirmed with evidence),
circumstantial (the report can only be confirmed by clinical suspicion or circumstance), plausible
(additional evidence is available, but it does not contribute to confirming AAWR), unconfirmed
(no evidence is available to confirm the patient's report of AAWR), or implausible (no evidence
is available to confirm the patient's report of AAWR, and the reported event is deemed
implausible) (Table 7) (Cook et al., 2014). Providers may also consult professionals uninvolved
in the direct care of the patient to obtain an unbiased opinion.
Stage 3 is known as the “support” stage. It is important to follow up with the patient
within 24 hours to assess whether they can provide any additional details via telephone. If these
additional details are concerning, a psychologist consult should be made as necessary. This
process should be repeated at two-weeks postoperative; if the patient is still experiencing
psychological distress, they are to be evaluated for PTSD.
The second part of the NAP 5 support pack is the NAP 5 AAWR Support Pack Output
(Cook et al. 2014). The form is mostly blank to provide space for documenting the detailed
report of AAWR throughout each interaction: meeting, analysis, and support.
ANESTHESIA AWARENESS WITH RECALL
46
Chapter 4
Results
Specific Aim #1: Describe the phenomenon of anesthesia awareness with recall.
Specific aim number one was met by identifying the desired state of unconsciousness
during GA and the undesired consciousness that occurs with AAWR. The phenomenon of
AAWR is always an unintended complication of GA for a surgery or procedure (Avidan et al.,
2011; Sanders et al., 2012). The desired state of unconsciousness during GA includes the
absence of connected consciousness to intraoperative events and the absence of implicit or
explicit memory formation (Cascella et al., 2020; Linassi et al., 2021; Sanders et al., 2012).
Indeed, patients experiencing AAWR may have auditory inputs or experience noxious and/or
painful events that occurred during intraoperative care. These recalled events may trigger a
constellation of psychological symptoms from anxiety to post-traumatic stress disorder (PTSD)
(Bruchas et al., 2011; Macleod & Maycock, 1992; Pandit et al., 2014c). Psychological
consequences include the development of anxiety disorders, insomnia, and hyperarousal from
nightmares associated with the event causing patients to avoid sleep. Patients may report feeling
helpless or have moments of unexplained panic, and extreme reports of psychological harm
including residual effects that impact the patient’s job performance and cause patients to avoid
medical care altogether. The researchers suggest that implicit and explicit memory (Table 1) at
the time of AAWR is what leads to the subsequent development of PTSD (Pandit et al., 2014a).
ANESTHESIA AWARENESS WITH RECALL
47
Specific Aim #2: Perform an integrative review of the current literature regarding non-modifiable
considerations, modifiable considerations, and postoperative recognition and treatment of
anesthesia awareness with recall.
Multiple major themes appeared within the contents of the review. AAWR is a rare
complication of anesthesia care but can be associated with non-modifiable and modifiable
considerations (Table 1) that pose an increased risk of experiencing the phenomenon. (Cascella
et al., 2020; Pandit et al., 2014c).
Of the non-modifiable considerations, individuals between the ages of 26 and 35 have a
23.9 % chance of experiencing AAWR when compared to all other age groups. This makes this
age group the highest-risk age group for experiencing AAWR (no inferential statistics provided).
Differences in gender found that women have higher BIS readings than men when
comparable doses of anesthetic were given (Buchanan et al., 2006). Other factors such as volume
of distribution and rate of drug metabolism were evaluated indicating a potential for accelerated
emergence, but no direct claim could be made toward one gender having an increased risk of
AAWR (Buchanan et al., 2006).
Lastly, there has been conflicting evidence surrounding the increased risk for AAWR in
patients who have a prior episode of AAWR. Aranake et al. (2013) performed a secondary
analysis of the data provided by three randomized, controlled trials: B-Unaware Trial, Michigan
Awareness Control Study (MACS), and BAG-RECALL. The incidence of AAWR was 1.7% (4
of 241) in patients with a history of AAWR and 0.3% (4 of 1,205) in control patients (relative
risk = 5.0; 95% CI, 1.3–19.9). The primary finding of this study was that patients with a history
of AAWR are five times more likely to experience AAWR than those who do not. A descriptive
report by Pandit et al. (2014a) reported that 6 out of the 141 (4.2%) cases of certain/probable
ANESTHESIA AWARENESS WITH RECALL
48
(Class A) and possible (Class B) cases of AAWR had a history of awareness with recall. The
latter did not calculate any inferential statistics, so the rate of risk of AAWR between those who
had a prior episode of AAWR compared to those without is lacking.
When evaluating modifiable considerations, obesity is associated with a potentially
difficult airway which can lead to an increased risk of AAWR during induction (Cascella et al.,
2020). Pandit et al. (2014a) also found that 26.5% of certain/probable cases of AAWR had
difficult airways. This leads to prolonged attempts to instrument the airway, wherein the provider
may inadvertently cause the patient to regain consciousness.
Provider-related errors contributing to AAWR stem from a lack of equipment testing,
inadequate utilization of methods to monitor anesthetic depth, and underdosing of anesthesia
(Aranake et al., 2013a; Cascella et al., 2020; Pandit et al., 2014c). Cascella et al. (2016)
identified a potentially avoidable episode of AAWR related to the following: a lack of properly
functioning equipment and the absence of monitoring for anesthesia depth. However, the
provider did recognize physiologic changes indicating awareness such as tachycardia and
lacrimation during the procedure. In this scenario, routine monitoring of hemodynamic values
and physiologic changes were crucial for alerting the provider of awareness, although it may
have been avoided with vigilant equipment testing. Utilizing depth of anesthesia monitoring
(ETAC or BIS) would have been a fail-safe method for the detection of AAWR in the event of
equipment malfunction.
Regarding pharmacologic management, Errando et al. (2008) found a statistically
significant lower incidence of AAWR in subjects who received premedication with
benzodiazepines (p = 0.001). Pandit et al. (2014c) and Sury et al. (2014) linked the use of NMB
antagonization and nerve stimulator monitoring, showing that improper use of both may amplify
ANESTHESIA AWARENESS WITH RECALL
49
the distress of AAWR by causing a patient to not only be aware but also immobile. The use of
NMB may also mask physiologic signs of AAWR.
When analyzing phases of anesthesia, 72 out of 141 cases of certain/probable and
possible cases of AAWR occurred during the induction phase (51% considered emergent or
urgent; 32% due to inadequate induction dose; 36% due to RSI).
The surgical-related factors include patients requiring cesarean section and cardiac
surgery (Avidan et al., 2011; Cascella et al., 2020; Sebel et al., 2004). In obstetrics, the increased
risk of AAWR is due to the limitation of anesthetic agents to limit exposure to the fetus (Czarko
et al., 2013). Obstetric cases represent 10% (14/141) of the total certain/probable (Class A) and
possible (class B) AAWR, mainly due to an insufficient dose of induction agent during
emergency cesarean sections, obesity, difficulty airway, and/or emergent cesarean sections being
performed by junior trainees during out of hours operating times (Pandit et al., 2014a).
Regarding cardiothoracic surgeries, The NAP 5 Report found eight cases of certain/probable
(Class A) and possible (Class B) cases of AAWR (1:8,600; 0.1%) (Pandit et al., 2014a). All eight
cases were thought to be primarily due to the intentional delivery of “light anesthesia” due to
labile hemodynamic status.
The use of devices for monitoring anesthetic depth is another modifiable consideration in
AAWR prevention. The study by Sanders et al. (2017) revealed that none of the patients positive
for IFT experienced explicit recall and there was no association found between the IFT and
AAWR. Therefore, its use is not recommended but it should be noted that connected
consciousness may occur even without subsequent explicit recall. Several major studies
produced significant findings related to the use of depth of anesthesia monitoring devices such as
BIS and ETAC (Avidan et al., 2008; Avidan et al., 2011; Myles et al., 2004). Avidan et al.
ANESTHESIA AWARENESS WITH RECALL
50
(2008) revealed a significant correlation between AAWR and low ETAC values (below 0.7) and
a less drastic correlation between AAWR and high BIS values (above 60). Avidan et al. (2011)
found no superiority in utilizing BIS or ETAC values for preventing AAWR (p = 0.98).
However, the overall incidence of AAWR was less than predicted based on previous reports of
AAWR. The outcome shown by Myles et al. (2004) was an 82% (95% CI: 17-98%) reduction in
intraoperative awareness in the BIS monitoring group compared to routine monitoring of clinical
signs such as heart rate and blood pressure (p = 0.022). The two BIS-monitored subjects who
experienced AAWR had BIS readings of 79-82 and 55-59, respectively.
Specific Aim #3: Synthesize evidence-based recommendations for modifying anesthesia practices
aimed at preventing anesthesia awareness with recall.
Preoperative
1. Complete a preoperative assessment evaluating the patient’s BMI. Obese patients are at
an increased risk for AAWR, partly due to their difficult airway status (Cascella et al.,
2020; Ingrande & Lemmens, 2010; Pandit et al., 2014a; Wada et al., 1997).
2. Complete an airway assessment to identify a difficult airway. A patient with a difficult
airway is at a higher risk of AAWR at the time of induction (Ghoneim et al. 2009; Pandit
et al. 2014a).
3. Minimize the risk of drug error by avoiding distractions, clearly labeling syringes, and/or
physically separating syringes. Meticulous care should be taken when
preparing/administering high-risk drugs such as NMB agents (Aranake et al., 2013a;
Cascella et al., 2016; Cascella et al., 2020; Flin et al., 2013; Lawton et al., 2012; Pandit et
al. 2014a; Pandit et al., 2014c).
ANESTHESIA AWARENESS WITH RECALL
51
4. Consider the administration of preoperative benzodiazepines when clinically appropriate
(Errando et al., 2008).
Induction
5. When airway management difficulties become prolonged, the anesthesia provider should
decide whether to awaken the patient or continue attempting to secure the airway while
maintaining adequate anesthetic depth. Additional doses of induction agents should be
readily available for patients with anticipated difficult airway management (e.g.,
obstetric and obese patients) (Paech et al., 2008; Pandit et al., 2014a).
6. Confirm loss of consciousness prior to NMB administration by methods which may
include assessing response to verbal command and simple airway manipulation (e.g.,
jaw thrust) (Paech et al., 2008; Pandit et al., 2014a).
7. Ensure adequate dosing when inducing obese patients, who are at higher risk for
AAWR, especially if RSI is planned (Cascella et al., 2020; Ingrande & Lemmens, 2010;
Pandit et al., 2014a; Wada et al., 1997).
8. When anesthetizing the parturient, be cautious of the potential association with the
following: obesity, difficult airway, RSI, and urgency of surgery (Czarko et al., 2013).
Intraoperative
9. Employ multiple means of detecting and preventing AAWR, rather than relying on a
single method. Examples include, but are not limited to, testing equipment functionality
prior to all procedures, depth of anesthesia monitoring, vigilant attention to physiologic
changes, and audible alarms (Cascella et al., 2016; Avidan et al., 2008; Avidan et al.,
2011; Myles et al., 2004).
ANESTHESIA AWARENESS WITH RECALL
52
10. If AAWR is suspected, provide verbal reassurance to the patient while deepening the
anesthetic and providing analgesia. Consider antagonizing the paralytic if appropriate
(Bruchas et al., 2011; Cook et al, 2014; Macleod & Maycock, 1992; Pandit et al., 2014a).
11. When anesthetizing the cardiothoracic surgery patient or parturient, consider preserving
mobility (avoid neuromuscular blocking agents) if not contraindicated by surgical and
safety needs (Mashour & Avidan, 2011; Pandit et al., 2014a).
12. Employ audible alerts for ETAC below 0.7 when using solely inhaled anesthetic gases,
and audible alerts for BIS values greater than 60 when administering TIVA. Use
physiological factors as an adjunct to guide anesthetic depth, but not as a sole indicator
(Cascella et al., 2016; Avidan et al., 2008; Avidan et al., 2011; Myles et al., 2004).
Emergence
13. Antagonize neuromuscular blockade with nerve stimulator guidance for all patients
receiving NMB (Pandit et al., 2014c).
14. Maintain communication with the surgeon regarding the completion of the case so that the
depth of GA and NMB may be maintained or weaned appropriately (Pandit et al., 2014a).
15. If an awake extubation is planned, verbally reassure the patient through the extubation
process (Bruchas et al., 2011; Cook et al, 2014; Macleod & Maycock, 1992; Pandit et
al., 2014a).
Postoperative
16. Conduct a debrief of AAWR events to prevent the same error from reoccurring
(Appendix B) (Aranake et al., 2013a; Cascella et al., 2016; Cascella et al., 2020; Cook et
al. 2014; Flin et al., 2013; Lawton et al., 2012; Pandit et al., 2014a; Pandit et al., 2014c).
ANESTHESIA AWARENESS WITH RECALL
53
Specific Aim #4: Synthesize evidence-based recommendations for postoperative recognition and
treatment of anesthesia awareness with recall.
1. Conduct the Brice-style interview (Table 3) at several intervals including the days
immediately following surgery and up to 30 days following the anesthetic (Brice et al.,
1970; Avidan et al., 2008; Avidan et al., 2012; Mashour et al., 2012; Myles et al., 2004).
2. Utilize the NAP 5 Awareness Support Pack for interviewing the patient who has
reported AAWR, documenting their experience, and making appropriate psychiatric
referrals. (Appendix B; Cook et al., 2014).
ANESTHESIA AWARENESS WITH RECALL
54
Chapter 5
Discussion
The integrative review process yielded several important themes about the syndrome of
AAWR. The results of meeting each specific aim in this investigation will be discussed in order
below.
Specific Aims:
1. Describe the phenomenon of anesthesia awareness with recall.
First, though rare, AAWR is very real and can exert devastating effects on patients. Its
limited prevalence should not minimize its discussion. The occurrence of AAWR has life-
altering psychological associations ranging from anxiety to post-traumatic stress disorder. The
effects can disrupt many aspects of one’s life – impacting relationships and how one enjoys
everyday life. The acute recollection of a traumatic event can cause one to avoid situations that
remind them of the event. The undue stress from flashbacks and hyperarousal further emphasizes
the importance of identifying patients at risk and maintaining vigilance during anesthetic
administration.
What struck this research team as valuable is the importance of setting expectations and
remaining transparent with patients. Establishing a realistic course of action in advance can
mitigate both the damaging sequela of AAWR along with false accounts of AAWR. This is of
chief importance when caring for patients receiving MACr (Table 1) where a dreamlike state
with auditory recollection may occur due to the variable states of sedation.
ANESTHESIA AWARENESS WITH RECALL
55
2. Perform an integrative review of the current literature regarding non-modifiable
considerations, modifiable considerations, and postoperative recognition and treatment of
anesthesia awareness with recall.
The strengths of our findings stem from the use of prospective, randomized, double-blind
trials with large sample sizes. Prospective cohort studies were incorporated as they provide the
highest-level evidence of the most current literature, and nationwide data collection reports were
used due to the expansive primary data collected from reported cases. This research team’s
results differ from that of The NAP5 Report due to the incorporation of additional higher-level
evidence literature to form modern, multifaceted recommendations. The integration of
descriptive and causal studies helped form recommendations for the continuum of perioperative
care.
Acknowledging limitations of the research includes recognizing potential discrepancies
in anesthesia practice between various countries. Many of the studies used were conducted in
places outside of the United States and may alter the generalizability of results. Additionally,
several seminal studies evaluated only those patients considered to be at high risk for AAWR;
these same studies were also the most dated ones. These factors may alter the observed
prevalence of the phenomenon or fail to capture recent adaptations of practice.
The major thrust of this integrative review was establishing modifiable and non-
modifiable considerations for AAWR. These classifications were selected based on the ability to
enact change with perioperative management. Bringing awareness to these factors is intended to
enhance the anesthesia provider’s decision-making and their judgment to make patient-specific
modifications.
ANESTHESIA AWARENESS WITH RECALL
56
Modifiable considerations identify patients with risk factors for AAWR and incorporate
strategies for anesthesia management focused on its prevention. Improved communication,
identification of high-risk patients, and double-checking medication doses can reduce provider-
related modifiable factors that contribute to AAWR. Likewise, modifications made to decrease
obesity can decrease the chance of a patient having a suspected difficult airway and decrease the
possibility of underdosing a patient when deciding between using lean body weight or total body
weight on induction. Additionally, the usefulness of monitoring devices was evaluated in several
seminal references. What resonated with this research team is that BIS monitors did not show as
much utility as ETAG monitoring for patients receiving inhaled anesthetics (Avidan et al., 2011).
BIS monitors are beneficial when a total intravenous administration of GA is provided.
Non-modifiable considerations identify patients at risk for AAWR with factors such as
age and gender that cannot be amended prior to surgical intervention. While these factors cannot
be modified, knowledge of these factors is the most valuable aspect. For instance, knowing that
younger patients have an accelerated metabolism of drugs, and knowing that female patients
have elevated BIS values intraoperatively and open their eyes faster on emergence provides the
knowledge necessary to make alterations to dose administration and provides the basis for use of
appropriate monitoring tools. Simply put, the prevention of AAWR requires patient
identification along with a dynamic combination of these elements tied to appropriate anesthesia
management strategies.
Of note, this research team finds it prudent to identify the small population of patients in
which AAWR cannot be prevented. These situations may include traumas and emergencies that
prioritize adequate perfusion and tissue oxygenation over adequate depth of anesthesia. These
patients should be informed of their elevated AAWR risk to maintain transparency and minimize
ANESTHESIA AWARENESS WITH RECALL
57
the psychological impact of AAWR (Cascella et al., 2020). Such patients should be assessed
postoperatively for signs of AAWR, and prompt treatment initiated if the syndrome has
occurred.
3. Synthesize evidence-based recommendations for modifying anesthesia practices aimed at
preventing anesthesia awareness with recall.
While formulating methods to avoid AAWR, the research team became acutely aware of
the pivotal role the anesthesia provider plays in patient advocacy and adherence to basic
standards of practice.
Preoperative recommendations indicate it is the responsibility of the anesthesia provider
to adhere to the basic standards of care. These include but are not limited to assessing for the risk
of a difficult airway (especially in obese patients) and being meticulous when preparing and
administering anesthetic medications (particularly induction agents such as sedatives and/or
NMB agents). These recommendations are foundational to providing quality anesthetic care
despite high-stress environments and production pressure.
Recommendations for induction emphasize the importance of checking for the level of
responsiveness after inducing the patient with propofol and before NMB administration. This can
be done with a verbal command and jaw thrust as recommended by The NAP 5 Panel, or by
assessing for eyelash reflex. As for difficult airway considerations during induction, additional
sedative administration will be needed for repeated attempts to instrument the airway. In clinical
practice, ensuring adequate oxygenation, ventilation, and hemodynamic stability takes
precedence over administering additional sedatives. If possible, the anesthesia provider can
ideally administer a higher induction agent if the patient is a known difficult airway, or consider
a faster technique for intubation (i.e., glidescope and CMAC).
ANESTHESIA AWARENESS WITH RECALL
58
Intraoperative recommendations suggest the anesthesia provider rely on more than one
method for measuring the level of sedation. While it is common in clinical practice to focus on
physiologic signs of a patient becoming ‘light,’ the anesthesia provider should also utilize
objective measures of anesthetic depth such as maintaining ETAC above 0.7 (during the use of
inhaled anesthetic gases) and audible alerts for BIS values greater than 60 (during use of TIVA).
While the objective measures are easy enough to employ, BIS monitors may not be available at
all institutions, and BIS monitors may not be feasible for surgeries such as craniotomies, where
access to the forehead is limited.
Postoperative recommendations suggest a debriefing after an AAWR occurrence, but this
would be difficult to incorporate into clinical practice. Taking additional time out of one’s
schedule to perform a debriefing while under the constraints of production pressure can be
challenging. While it may be time-consuming, debriefing can be viewed as a learning
opportunity for the primary provider and colleagues and can be beneficial for the patient.
Allowing a patient to feel heard and valued during this time can lessen the psychological effects
of AAWR.
Overall, the researchers are advocates for the sequential thought process offered by
Mashour & Avidan (2011) for the avoiding AAWR: ensuring unconsciousness is the primary
aim, followed by amnesia, then analgesia; when each of these is not feasible, the provider is to
maintain mobility by avoiding neuromuscular relaxation. These steps can guide anesthetic
techniques for an individualized plan of care.
ANESTHESIA AWARENESS WITH RECALL
59
4. Synthesize evidence-based recommendations for postoperative recognition and treatment
of anesthesia awareness with recall.
AAWR is a syndrome of symptoms and responses to the unique situation in anesthesia
care where-in a patient is aware of noxious stimuli and events which the general anesthetic
process is intended to prevent. Reliance on spontaneous reporting of AAWR events may not be
effective in capturing all occurrences (Mashour et al., 2013). It is imperative that AAWR is
recognized as early as possible and treated subsequently thereafter. The Brice-style interview
(Table 3) is a quick, systematic technique to assess the occurrence of AAWR when suspected.
However, it may be difficult to incorporate this into clinical practice because many anesthesia
providers believe that asking about AAWR encourages the patient to report something, so the
tendency is to avoid that topic. In addition, the likelihood is so low, the tendency is to not
acknowledge this as part of their assessment. However, the Brice tool is a very quick and
effective tool that should be utilized as necessary.
Currently, in clinical practice in the United States, it is very uncommon to have
guidelines and/or policies to address how to treat patients who have experienced AAWR. The
NAP 5 Anesthesia Awareness Support Pack which includes The NAP 5 Awareness Support
Pathway and The NAP 5 AAWR Support Pack Output (Appendix B; Cook et al., 2014) is a
useful tool. We strongly recommend the use of The NAP 5 Anesthesia Awareness Support Pack
because it is a systematic, stepwise approach to addressing AAWR. However, one potential
limitation is that this process can be time-consuming. Anesthesia providers are part of the
perioperative process, however, treating a true occurrence of AAWR would require the
anesthesia provider to be involved in the patient’s care for several weeks after the
surgery/procedure. While this may seem like a long time, one must remember that the incidence
ANESTHESIA AWARENESS WITH RECALL
60
of AAWR is low and that once The NAP 5 AAWR Support Pack Output is initially completed,
there is only minimal documentation required to complete thereafter (24 hours, 1 week, and 2-
week intervals to contact the patient to assess for the presence of flashbacks nightmare, new
anxiety states, and/or symptoms of depression that would indicate the need for a
psychology/psychiatrist consult, if not already in place).
A uniquely optimistic view of AAWR is that it is distinctly contrary to the anticipated
outcome of GA. Therefore, avoiding explicit memory formation may become a concise area of
focus for future research. Facility-specific protocols may also be examined to determine those
that help avoid AAWR in a specific setting.
Conclusion
This investigation has examined the phenomenon of AAWR. This rare complication
carries with it the possibility of severe psychological sequelae, including post-traumatic stress
disorder. It is imperative that providers learn about the causative factors associated with AAWR
to prevent it. Should patients appear to have AAWR, providers must be able to swiftly diagnose
the syndrome and provide support.
Several components of AAWR were multi-faceted. Common themes were improper
adherence to standards of care such as utilizing appropriate monitoring, adequate antagonization
of NMB, and ensuring functional equipment. These themes point to what may be an optimistic
conclusion, which is that we know the practices that can avoid this phenomenon, but strict
adherence to those protocols should be heavily focused upon.
ANESTHESIA AWARENESS WITH RECALL
61
References
Aceto, P., Lai, C., Perilli, V., Dello Russo, C., Federico, B., Navarra, P., Proietti, R., Sollazzi, L.
(2013). Stress-related biomarkers of dream recall and implicit memory under anaesthesia.
Anaesthesia, 68(11), 1141-1147. http://doi.org/doi:10.1111/anae.12386
American Society of Anesthesiologists (2020). ASA Physical Status Classification System.
https://www.asahq.org/standards-and-guidelines/asa-physical-status-classification-system
American Society of Anesthesiologists Task Force on Intraoperative Awareness (2006). Practice
advisory for intraoperative awareness and brain function monitoring. Anesthesiology.
104(4), 847–864. https://doi.org/10.1097/00000542-200604000-00031
Aranake, A., Gradwohl, S., Ben-Abdallah, A., Lin, N., Shanks, A., Helsten, D.L., Glick, D.B.,
Jacobsohn, E., Villafranca, A.J., Evers, A.S., Avidan, M.S., & Mashour, G.A. (2013,
December). Increased risk of intraoperative awareness in patients with a history of
awareness. Anesthesiology. 119(6), 1275-1283.
https://doi.org/10.1097/ALN.0000000000000023
Aranake, A., Mashour, G. A., Avidan, M., S. (2013). Minimum alveolar concentration: Ongoing
relevance and clinical utility. Anesthesia, 68(5), 512-522.
https://doi.org/10.1111/anae.12168
Avidan, M.S., Jacobsohn, E., Glick, D., Burnside, B. A., Zhang, L., Villafranca, A., Karl, L.,
Kamal, S., Torres, B., O’Connor, M., Evers, A. S., Gradwohl, S., Lin, N., Ph.D.,
Palanca, B. J., Mashour, G. A. (2011). Prevention of intraoperative awareness in a high-
risk surgical population. The New England Journal of Medicine, 365(7), 591-600.
https://doi.org/DOI:10.1056/NEJMoa1100403
ANESTHESIA AWARENESS WITH RECALL
62
Avidan, M.S. & Mashour, G.A. (2013, February). Prevention of intraoperative awareness with
explicit recall: Making sense of the evidence. Anesthesiology. 118(2), 449-456.
https://doi.org/10.1097/ALN.0b013e31827ddd2c
Avidan, M.S., Zhang, L., Burnside, B.A., Finkel, K.J., Searleman, A.C., Selvidge, J.A., Saager,
L., Turner, M.S., Rao, S., Bottros, M., Hantler, C., Jacobsohn, E. & Evers A.S. (2008,
March 13). Anesthesia awareness and the bispectral index. The New England Journal of
Medicine. 358, 1097-1108. https://doi.org/10.1056/NEJMoa0707361
Bischoff, P., & Rundshagen, I. (2011). Awareness under general anesthesia. Deutsches Arzteblatt
international, 108(1-2), 1–7. https://doi.org/10.3238/arztebl.2011.0001
Brice, D. D., Hetherington, R. R., Utting, J. E. (1970). A simple study of awareness and
dreaming during anaesthesia. British Journal of Anaesthesia, 42(6), 535-542.
https://doi.org/10.1093/bja/42.6.535
Bruchas, R. R., Kent, C. D., Wilson, H. D., & Domino, K. B. (2011, April 22). Anesthesia
awareness: Narrative review of psychological sequelae, treatment, and incidence. J Clin
Psychol Med Settings. 18(3), 257-267. https://doi.org/10.1007/s10880-011-9233-8
Buchanan F. F., Myles, P. S., Leslie, K., Forbes, A., Cicuttini, F. (2006, January). Gender and
recovery after general anesthesia combined with neuromuscular blocking
drugs. Anesthesia & Analgesia. 102(1), 2910-297.
https://doi.org/10.1213/01.ANE.0000181321.55422.C6
Cascella, M., Bimonte S., Amruthraj N. J. (2020). Awareness during emergence from anesthesia:
Features and future research directions. World Journal of Clinical Cases, 8(2), 245-254.
https://doi.org/10.12998/wjcc.v8.i2.245
ANESTHESIA AWARENESS WITH RECALL
63
Cascella, M., Viscardi, D., Schiavone, V., Mehrabmi-Kermani, F., Muzio, M. R., Forte, C. A.,
De Falco, F., Barberio, D. & Cuomo (2016, February). A 7-year retrospective
multisource analysis on the incidence of anesthesia awareness with recall in cancer
patients. Medicine. 95(5), 2757.
http://dx.doi.org.libproxy2.usc.edu/10.1097/MD.0000000000002757
Centers for Disease Control and Prevention (2015). National Survey of Ambulatory Surgery.
National Center for Health Statistics.
https://www.cdc.gov/nchs/nsas/index.htm?CDC_AA_refVal=https%3A%2F%2Fwww.c
dc.gov%2Fnchs%2Fnsas.htm
Chung, H.S. (2014, May 26). Awareness and recall during general anesthesia. Korean Journal of
Anesthesiology. 66(5), 339-345. https://doi.org/10.4097/kjae.2014.66.5.339
Collins, W. J. (presumed). (ca.1846) Remarkable vascular tumor of the neck. [Unpublished
manuscript]. Gift of J. Collins Warren to the Boston Medical Library, Waltham, MA,
United States.
Cook, T., Pandit, J. Andrade, J. & Wang, M. (2014). NAP5: Anesthesia Awareness Pathway:
NAP 5 Support Pack.
https://www.nationalauditprojects.org.uk/NAP5-Anaesthetia-Awareness-Pathway#pt
Cook, T., Woodall, N. & Frerk, C. (2011). Major complications of airway management in the
United Kingdom. 4
th
National Audit Project of The Royal College of Anaesthetists &
The Difficult Airway Society. Retrieved from
https://www.nationalauditprojects.org.uk/NAP4-Report
ANESTHESIA AWARENESS WITH RECALL
64
Czarko, K. Kwiatosz-Muc, M., Fijalkowska, A., Kowalczyk, M. & Rutyna, R. (2013).
Intraoperative awareness — comparison of its incidence in women undergoing general
anaesthesia for caesarean section and for gynaecological procedures. Anaesthesiology
Intensive Therapy. 45(4), 200-204. https://doi.org/10.5603/AIT.2013.0039
Errando, C.L., Sigl, J. C., Robles, M., Calabuig, E., Garcia, J., Arocas, F., Higueras, R., del
Rosario, E., Lopez, D., Peiro, C. M., Soriano, J. L., Chaves, S., Gil, F., & Garcia-
Aguado, R. (2008, May 30). Awareness with recall during general anaesthesia: a
prospective observational evaluation of 4001 patients. British Journal of Anaesthesia.
101(2), 178-185. https://doi.org/10.1093/bja/aen144
Flin, R., Fioratou, E., Frerk, C., Trotter C & Cook TM (2013). Human factors in the development
of complications of airway management: preliminary evaluation of an interview tool.
Anaesthesia,68, 817–25. https://doi.org/10.1111/anae.12253
Frugoni, B., Mizuguchi, A. K. (2019) General, Regional, or Monitored Anesthesia Care for the
Cardiac Patient Undergoing Noncardiac Surgery. In B. Cronin, J. A. Kaplan, T. M. Maus,
Kaplan's essentials of cardiac anesthesia for noncardiac surgery (289-312) Elsevier.
https://doi.org/10.1016/B978-0-323-56716-9.00012-6
Ghoneim, M. M. (2007, September). Incidence of and risk factors for awareness during
anaesthesia. Elsevier. 21(3), 327-343. https://doi.org/10.1016/j.bpa.2007.05.002
Ghoneim, M. M., Block, R. I., Haffarnan, M., & Mathews, M. J. (2009). Awareness during
anesthesia: Risk factors, causes and sequelae: A review of reported cases in the
literature. Anesthesia & Analgesia, 108(2), 527-535.
DOI: 10.1213/ane.0b013e318193c634
ANESTHESIA AWARENESS WITH RECALL
65
Griffith, H. R., Johnson, E. G., (1942). The use of curare in general anesthesia. Anesthesiology,
3, 418-420. https://doi.org/10.1097/00000542-194207000-00006
Gordon, R., Flin, R., & Mearns, K., (2005). Designing and evaluating a human factors
investigation tool (HFIT) for accident analysis. Safety Science,43(3), 147-71.
https://doi.org/10.1016/j.ssci.2005.02.002
Harris, M. & Chung, F. (2013, August 1). Complications of general anesthesia. Elsevier. 40(4),
503-513. https://doi.org/10.1016/j.cps.2013.07.001
Ingrande, J. & Lemmens, H. J. M. (2010, December). Dose adjustment of anaesthetics in the
morbidly obese. British Journal of Anaesthesia. 105(1), 116-123.
https://doi.org/10.1093/bja/aeq312
Lawton, R., McEachan, R.R., Giles, S.J., Sirriyeh, R. Watt, I.S. & Wright, J., (2012).
Development of an evidence-based framework of factors contributing to patient safety
incidents in hospital settings: A systematic review. British Medical Journal Quality &
Safety, 21, 369–80. https://dx.doi.org/10.1136/bmjqs-2011-000443
LeVasseur, R., Desai, S. P. (2012). Ebenezer hopkins frost (1824–1866): William T.G. Morton's
first identified patient and why he was invited to the ether demonstration of October 16,
1846. Anesthesiology, 117(2) 238-242. https://doi.org/10.1097/ALN.0b013e31825f01b7
Linassi, F., Obert, D. P., Maran, E., Tellaroli, P., Kreuzer, M., Sanders, R. D., Carron, M.
(2021). Implicit memory and anesthesia: A systematic review and meta-analysis. Life,
11(8). https://doi.org/10.3390/life11080850
ANESTHESIA AWARENESS WITH RECALL
66
Linassi, F., Zanatta, P., Tellaroli, P., Ori, C., Carron, M. (2018). Isolated forearm technique: A
meta-analysis of connected consciousness during different general anaesthesia regimens.
British Journal of Anaesthesia, 121(1), 198-209. https://doi.org/10.1016/j.bja.2018.02.019
Macleod A. D., Maycock, E. (1992). Awareness during anaesthesia and post traumatic stress
disorder. Anaesthesia and Intensive Care, 20(3), 378-382.
https://journals.sagepub.com/doi/pdf/10.1177/0310057X9202000323
Mashour, A. M., Shanks, A., Tremper, K. K., Kheterpal, S., Turner, C. R., Ramachandran, S. K.,
Picton, P., Schueller, C., Morris, M., Vandervest, J. C., Lin, N., Avidan, M. S. (2012).
Prevention of intraoperative awareness with explicit recall in an unselected surgical
population: A randomized comparative effectiveness trial. Anesthesiology. 117(4), 717-
725. https://doi.org/10.1097/ALN.0b013e31826904a6
Mashour, G. A., Avidan, M. S. (2011). Pharmacologic approaches to the prevention of
intraoperative awareness. Expert Review of Neurotherapeutics, 11(5), 611-613.
https://doi.org/10.1586/ern.11.46
Mashour, G. A., Esaki, R. K., Tremper, K. K., Glick, D. B., O’Connor, M. & Avidan M. S.
(2010). A novel classification instrument for intraoperative awareness events.
Anesthesia & Analgesia, 110(3), 813-815. https://10.1213/ANE.0b013e3181b6267d
Mashour, G. A., Kent, C., Picton, P., Ramachandran, S. K., Tremper, K. K., Turner, C. R.,
Shanks, A., Avidan, M. S. (2013). Assessment of intraoperative awareness with explicit
recall: A comparison of 2 methods. Anesthesia & Analgesia, 116(4), 889-891.
https://doi.org/10.1213/ANE.0b013e318281e9ad
ANESTHESIA AWARENESS WITH RECALL
67
Myles, P. S., Leslie, K., McNeil, J., Forbes, A., Chan, M. T. V. (2004). Bispectral index
monitoring to prevent awareness during anaesthesia: the B-Aware randomized
controlled trial. Lancet, 363(9423), 1757-63. https://10.1016/S0140-6736(04)16300-9
National Audit Projects (2014). NAP5: Anesthesia Awareness Pathway: NAP 5 Support Pack.
https://www.nationalauditprojects.org.uk/NAP5-Anaesthetia-Awareness-Pathway#pt
National Health Service (2004). Seven steps to patient safety: the full reference guide.
https://www.publichealth.hscni.net/sites/default/files/directorates/files/Seven%20steps%
20to%20safety.pdf
Paech, M. J., Scott, K. L., Clavisi, O., Chua, S., McDonnell, N. (2008, July 10). A prospective
study of awareness and recall associated with general anaesthesia for caesarean section.
International Journal of Obstetric Anesthesia. 17(4), 298-303.
https://doi.org/10.1016/j.ijoa.2008.01.016
Pandit, J. J., Andrade, J., Bogod, D. G., Hitchman, J. M., Jonker, W. R., Lucas, N., Mackay, J.
H., Nimmo, A. F., O’Connor, K., O’Sullivan, E. P., Paul, R. G., MacG-Palmer, J. H.,
Plaat, F., Radcliffe, J. J., Sury, M. R. J., Torevell, H. E., Wang, M., Cook, T. M. & The
Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain
and Ireland (2014a, October). 5th National Audit Project (NAP5) on accidental
awareness during general anaesthesia: Protocol, methods, and analysis of data. British
Journal of Anaesthesia. 113(4), 540-548. https://doi.org/10.1093/bja/aeu312
ANESTHESIA AWARENESS WITH RECALL
68
Pandit, J. J., Andrade, J., Bogod, D. G., Hitchman, J. M., Jonker, W. R., Lucas, N., Mackay, J.
H., Nimmo, A. F., O’Connor, K., O’Sullivan, E. P., Paul, R. G., MacG-Palmer, J. H.,
Plaat, F., Radcliffe, J. J., Sury, M. R. J., Torevell, H. E., Wang, M., Hainsworth, J. &
Cook, T. M. (2014b, October). The 5th National Audit Project (NAP5) on accidental
awareness during general anaesthesia: Summary of main findings and risk factors.
Association of Anaesthetists. 69(10), 1089-1101. https://doi.org/10.1111/anae.12826
Pandit, J. J., Cook, T. M. & NAP 5 Steering Panel (2014c, September). Accidental awareness
during general anaesthesia in the United Kingdom and Ireland. The Royal College of
Anaesthetists & Association of Anaesthetists of Great Britain and Ireland. Retrieved
from https://www.nationalauditprojects.org.uk/NAP5report#pt
Radek, L., Kallionpaa, R. E., Karvonen, M., Scheinin, A., Maksimow, A., Langsjo, J., Kaisti1,
K., Vahlberg, T., Revonsuo, A., Scheinin H., Valli, K. (2018). Dreaming and awareness
during dexmedetomidine- and propofol-induced unresponsiveness. British Journal of
Anaesthesia, 121(1), 260-269. http://doi.org/10.1016/j.bja.2018.03.014
Robin, R. B., Kent, C. D., Wilson, H. D., Domino K. B. (2011). Anesthesia awareness: Narrative
review of psychological sequelae, treatment, and incidence. Journal of Clinical Psychology
in Medical Settings, 18(3), 257-267. https://doi.org/10.1007/s10880-011-9233-8
Ruhaiyem, M. E., Alshehri, A. A., Saade, M., Shoabi, T. A., Zahoor, H., & Tawfeeq, N. A.
(2016). Fear of going under general anesthesia: A cross-sectional study. Saudi journal of
anaesthesia, 10(3), 317–321. https://doi.org/10.4103/1658-354X.179094
ANESTHESIA AWARENESS WITH RECALL
69
Sanders, R.D., Gaskell, A., Raz, A., Winders, J., Stevanovic, A., Rossaint, R., Boncyk, C.,
Defresne, A., Tran, G., Tasbihgou, S., Meier, S., Vlisides, P. E., Fardous, H., Hess, A.,
Bauer, R. M., Absalom, A., Mashour, G. A., Bonhomme, V., Coburn, M., Sleigh, J.
(2017). Incidence of connected consciousness after tracheal intubation. Anesthesiology,
126, 214-222. https://doi.org/10.1097/ALN.0000000000001479
Sanders, R. D., Tononi, G., Laureys, S., Sleigh, J. (2012). Unresponsiveness ≠ unconsciousness.
Anesthesiology, 116(4), 946-959 http://doi.org/doi:10.1097/ALN.0b013e318249d0a7
Sebel, P. S., Bowdle, T. A., Ghoneim, M., Rampil, I. J., Padilla, R. E., Gan, T.J., & Domino, K.
B. (2004, September). The incidence of awareness during anesthesia: A multicenter
United States study. Anesthesia & Analgesia. 99(3), 833-839.
https://doi.org/10.1213/01.ANE.0000130261.90896.6C
Smith, A., (2016). Literature review: Awareness of anaesthesia. Journal of Perioperative
Practice, 27(9), 191-195. https://doi.org/10.1177/175045891702700903
Smith, G., D'Cruz, J. R., Rondeau, B. & Julie Goldman. (2021, October 21). General anesthesia
for surgeons. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK493199/
Sullivan, C. (2016). Awareness with recall: A systematic review. AANA Journal, 84(4).
https://www.aana.com/docs/default-source/aana-journal-web-documents-1/jcourse3-
0816-pp283-288.pdf?sfvrsn=f1d348b1_6
Sury, M. R., Palmer, J. H. M. G., Cook, T. M., Pandit, J. J. (2014, August 7). The state of UK
anaesthesia: A survey of national health service activity in 2013. British Journal of
Anaesthesia, 113(4), 575-584. https://doi.org/10.1093/bja/aeu292
UpToDate (2022). Cormack-Lehane grading scheme for laryngoscopy. Retrieved March 30,
2022, from https://www.uptodate.com/contents/image?imageKey=EM%2F55034
ANESTHESIA AWARENESS WITH RECALL
70
Wada, D.R., Bjorkman, S., Ebling, W.F., Harashima, H., Harapat, S.R., & Stanksi, D.R. (1997).
Computer simulation of the effects in blood flows and body composition on thiopental
pharmacokinetics in humans. Anesthesiology, 87(4), 884-899.
https://doi.org/10.1097/00000542-199710000-00024
Winterbottom, E. H. (1950). Insufficient anaesthesia. British Medical Journal, 1(4647), 247-248.
https://doi.org/10.1136/bmj.1.4647.247-c
Zand, F., Hadavi, S.M., Chohedri A., Sabetian P. (2014). Survey on the adequacy of depth of
anaesthesia with bispectral index and isolated forearm technique in elective caesarean
section under general anaesthesia with sevoflurane. British Journal of Anaesthesia,
112(5) 871-878. https://doi.org/doi:10.1093/bja/aet483
ANESTHESIA AWARENESS WITH RECALL
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Table 1
Operational Definitions
Term
Definition
American Society of
Anesthesiology (ASA)
Physical Status
Classification
According to the American Society of Anesthesiologists (ASA, 2020), the
ASA Physical Status Classification System is used by anesthesia providers
to signify a patient’s pre-anesthesia medical comorbidities. The final
assignment of ASA status is made on the day of anesthesia care by the
anesthesiologist after evaluating the patient. There are six ASA classes as
follows:
1. A normal healthy patient
2. A patient with mild systemic disease
3. A patient with severe systemic disease
4. A patient with severe systemic disease that is a constant threat to
life
5. A moribund patient who is not expected to survive without the
operation
6. A declared brain-dead patient whose organs are being removed for
donor purposes
If a patient is scheduled for emergent surgery, their ASA status would be
followed by E for emergency surgery (i.e., 4E).
Anesthesia Awareness
with Recall (AAWR)
The anesthesia awareness with recall (AAWR) phenomenon represents a
complication of general anesthesia consisting of memorization of
intraoperative events reported by the patient immediately after the end of
surgery or at variable time intervals following it (Cascella et al., 2020).
For the duration of this paper, we will use the term anesthesia awareness
with recall (AAWR). In the literature, AAWR has been interchangeably
referred to numerous terms including, but not limited to: awareness with
recall (Sullivan, 2016), accidental awareness during general anesthesia
([AAGA], Pandit et al., 2014a), or unintended intraoperative awareness
with subsequent explicit recall (Avidan & Mashour, 2013).
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Connected
consciousness
and
Disconnected
consciousness
Connected consciousness is a level of consciousness related to
unresponsiveness (Sanders et al., 2012). Connected consciousness is
associated with the ability of the patient receiving intended general
anesthesia to form explicit memory of unpleasant intra-procedural or
intraoperative events.
Disconnected consciousness is a level of consciousness related to
unresponsiveness where the individual is disconnected to the outside
environment but connected to their inner thoughts and sensations.
Disconnected consciousness is compared to dreaming and can occur in the
patient receiving general anesthesia and can impact implicit memory.
End tidal anesthetic
concentration (ETAC)
also known as:
End tidal anesthetic gas
(ETAG) concentration
A measure of the real time alveolar anesthetic agent concentration of
administered inhaled anesthetic. This measure is determined by individual
anesthetic gasses and converted to a minimum alveolar concentration value
indicating the patient’s level and depth of anesthesia. These values allow
the clinician to increase or decrease the inhaled volatile anesthetic to keep
the patient adequately anesthetized (Aranake, et al., 2013).
General Anesthesia
(GA)
General anesthesia (GA) is a drug-induced reversible state of
unconsciousness that allows patients to safely undergo surgery (Harris &
Chung, 2013) by preventing painful stimuli and controlling autonomic
reflexes (Smith et al., 2021). Complete lack of recall of intra-procedural
events is intended for patients receiving general anesthesia.
Implicit and Explicit
Memory
Implicit memory is an individual’s ability to detect a specific occurrence
without remembering specific details related to the event. Such an
experience is characterized and exhibited through behavior changes.
Explicit memory is the ability to consciously recall an event. (Linassi et al.,
2021).
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Induction
The induction phase of anesthesia involves medication administration of
selected agents per established pharmacologic and practice principles of
safe care to establish an unconscious state prior to necessary perioperative
interventions including airway management and surgical repair (Chung,
2014; Zand et al., 2014).
Level of consciousness
Neurological states that characterize the responsiveness of the cognitive
functions and perceptual awareness of the central nervous system to the
surrounding environment.
· Awake - consciousness involving connection to the outside
environment accompanied with responsiveness.
· Unresponsive - describes an individual who is unable to respond to
voice or physical stimulation from the outside environment. Memory
formation may occur in this state.
· Unconscious - a subclassification of unresponsiveness where an
individual has a varying and limited amount of connection and
disconnection to the world or the state of things. (Sanders et al., 2012). This
is the intended level of consciousness during general anesthesia.
Unconscious individuals would not be expected to have awareness of
events or memory formation.
Minimum Alveolar
Concentration (MAC)
The measured volumes percent inhaled concentration of a vaporized
anesthetic required to prevent movement in 50% of patients in response to
surgical stimulation (Aranake et al., 2012). This value is typically used as a
benchmark by providers to assure adequate drug administration sufficient to
ensure that an unconscious state has been attained in an anesthetized
patient.
Modifiable and
Non-Modifiable
Considerations
Modifiable considerations: factors and conditions that may be modified by
either the provider or the patient. These include: obesity, difficult airway,
provider error, pharmacologic management, phases of anesthesia
(induction, maintenance, emergence), and surgery type (obstetric and
cardiothoracic), and monitoring devices. Surgery type is considered a
modifiable consideration because although the surgery type itself is not
modifiable, all reports of anesthesia awareness with recall were caused by a
modifiable factor.
Non-modifiable considerations: factors that are unable to be modified by
the provider nor the patient. These include: age, gender, and prior episode
of anesthesia awareness with recall.
ANESTHESIA AWARENESS WITH RECALL
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Monitored Anesthesia
Care (MACr)
Sedation during an operation or procedure that incorporates amnesia,
analgesia or both. This technique provides a reduced state of awareness
while still allowing patients a variable ability to respond to commands
(Frugoni & Mizuguchi, 2019). Recall of intra-procedural events varies and
is not unintended during monitored anesthesia care (MACr).
Neuromuscular
Blockade
Neuromuscular blockade is skeletal muscle relaxation that produces
muscular paralysis in a sedated or anesthetized patient (Griffith et al., 1942)
and has been identified as a risk factor for awareness with recall (Smith,
2016).
Note: This table presents relevant terminology and appropriate definitions in an organized format to
facilitate understanding of technical terminology.
ANESTHESIA AWARENESS WITH RECALL
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Table 2
The NAP 5 Awareness Support Pathway for AAGA
Meeting - Face-to-face meeting with patient
- Listen carefully to patient’s story to detail and understand their experience
- Accept the patient’s story as their genuine experience
- Express regret that the event has happened (this does not constitute an admission
of liability)
- Consult with local clinical psychologist
Analysis - Seek cause of awareness using NAP 5 process
- Check details of patient’s story with monitoring details and with staff
- Seek independent opinion of analysis
Support - To detect impact early, in first 24 hours check for 4 cardinal signs of impact:
1. Flashbacks
2. Nightmares
3. New anxiety state
4. Depression
- Active follow-up at two weeks
- If impact persists, formal referral to psychiatrist/psychologist services
Note: This table provides steps for caring for a patient with AAWR based on information from the NAP 5
Awareness Support Pathway for AAGA (Pandit et al., 2014c). From “NAP5: Anesthesia Awareness
Pathway: NAP 5 Support Pack,” by National Audit Projects, 2014, p. 3
(https://www.nationalauditprojects.org.uk/NAP5-Anaesthetia-Awareness-Pathway#pt). Copyright 2014
by The Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland.
Reprinted with permission.
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Table 3
Brice-style Questionnaire
1. What is your last memory before going to sleep?
2. What is your first memory upon awakening?
3. Did you have any dreams or experiences while asleep?
4. What was the worst part of your procedure?
5. What was the next worst part of your procedure?
Note: This table presents information from Brice et al. (1970) and Mashour et al. (2013), in which the
assessment of AAWR was discussed. These questions were deemed most efficacious at identifying
patients experiencing AAWR.
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Table 4
Michigan Awareness Classification Instrument (MiAC)
Class 0 No accidental awareness during general anesthesia
Class 1 Isolated auditory perceptions
Class 2 Tactile perceptions (with or without auditory)
Class 3 Pain (with or without tactile or auditory)
Class 4 Paralysis (with or without tactile or auditory)
Class 5 Paralysis and pain (with or without tactile or auditory)
Note: This table assigns categories arranged in order of severity to patient experiences during AAWR
(Pandit et al., 2014a). From “NAP5: Anesthesia Awareness Pathway: NAP 5 Support Pack,” by National
Audit Projects, 2014, p. 4 (https://www.nationalauditprojects.org.uk/NAP5-Anaesthetia-Awareness-
Pathway#pt). Copyright 2014 by The Royal College of Anaesthetists and the Association of Anaesthetists
of Great Britain and Ireland. Reprinted with permission.
ANESTHESIA AWARENESS WITH RECALL
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Table 5
Modified NPSA Classification of Patient Harm after AAWR
Severity Revised Definitions for NAP 5
None (0) No harm occurred
Low (1) Resolved or likely to resolve with no or minimal professional intervention.
No consequences for daily living, minimal or no continuing anxiety about
future healthcare
Moderate (2) Moderate anxiety about future anesthesia or related healthcare. Symptoms
may have some impact on daily living. Patient has sought or would likely
benefit from professional intervention.
Severe (3) Striking or long-term psychological effects that have required or might
benefit from professional intervention or treatment: severe anxiety about
future healthcare and/or impact on daily living. Recurrent nightmares or
adverse thoughts or ideations about events. This may also result in formal
complaint or legal action.
Death (4) Caused death
Note: This table describes and classifies the level of harm from AAWR by severity. From “NAP5:
Anesthesia Awareness Pathway: NAP 5 Support Pack,” by National Audit Projects, 2014, p. 4
(https://www.nationalauditprojects.org.uk/NAP5-Anaesthetia-Awareness-Pathway#pt). Copyright 2014
by The Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland.
Reprinted with permission.
ANESTHESIA AWARENESS WITH RECALL
79
Table 6
The NAP 5 Classification of AAWR Reports
Severity Definitions for NAP 5
A. Certain/probable
AAWR
A report of anesthesia awareness with recall (AAWR) in a ‘surgical
setting’ in which the detail of the patient story is judged consistent with
AAWR, especially where supported by case notes or where report detail is
verified.
B. Possible AAWR A report of AAWR in a ‘surgical setting’ in which details are judged to be
consistent with AAWR or the circumstances might have reasonably led to
AAWR, but otherwise the report lacks a degree of verifiability or detail.
Where uncertain whether a report described as AAWR the case should be
classified as possible rather than excluded.
C. Sedation A report of AAWR where the intended level of consciousness was
sedation.
D. ICU A report of AAWR from a patient in, or under the care of the intensive care
unit, who underwent a specific procedure during which general anesthesia
as intended.
E. Unassessable A report, where there was simply too little detail submitted to make any
classification possible.
F. Unlikely Details of the patient story are deemed unlikely or judged to have occurred
outside of the period of anesthesia or sedation.
G. Drug Error Syringe swaps and drug errors leading to brief awake paralysis.
SO: Statement only A patient statement describing AAWR, but there were no case notes
available to verify, refute or examine that claim further.
Note: All classes are mutually exclusive: a patient report can only be classified into one group. From
“NAP5: Anesthesia Awareness Pathway: NAP 5 Support Pack,” by National Audit Projects, 2014, p. 5
(https://www.nationalauditprojects.org.uk/NAP5-Anaesthetia-Awareness-Pathway#pt). Copyright 2014
by The Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland.
Reprinted with permission.
ANESTHESIA AWARENESS WITH RECALL
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Table 7
The NAP 5 Strength of AAWR Reports
High Quality Where the report of anesthesia awareness with recall (AAWR) is, or could
easily be, confirmed by other evidence.
Circumstantial Where the report of AAWR is supported only by clinical suspicion or
circumstance.
Plausible Where other evidence was available, but this does not shed further light on
the matter.
Unconfirmed Cases where there was no evidence other than patient report.
Implausible Where there is no evidence other than the patient story and where this is
judged implausible.
Note: This table classifies AAWR patient reports according to the quality of evidence. From “NAP5:
Anesthesia Awareness Pathway: NAP 5 Support Pack,” by National Audit Projects, 2014, p. 5
(https://www.nationalauditprojects.org.uk/NAP5-Anaesthetia-Awareness-Pathway#pt). Copyright 2014
by The Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland.
Reprinted with permission.
ANESTHESIA AWARENESS WITH RECALL
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Appendix A: PRISMA Flow Diagram
Note: This figure graphically depicts the literature search process used by the research team to procure the
necessary evidence to support the research project.
ANESTHESIA AWARENESS WITH RECALL
82
Appendix B: The NAP 5 Anesthesia Awareness Support Pack
ANESTHESIA AWARENESS WITH RECALL
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Note: This figure is the physical tool to be utilized to guide the anesthesia provider in the management of
AAWR. From “NAP5: Anesthesia Awareness Pathway: NAP 5 Support Pack,” by National Audit
Projects, 2014, p. 7-11 (https://www.nationalauditprojects.org.uk/NAP5-Anaesthetia-Awareness-
Pathway#pt). Copyright 2014 by The Royal College of Anaesthetists and the Association of Anaesthetists
of Great Britain and Ireland. Reprinted with permission.
Abstract (if available)
Abstract
Nearly 75% of surgical patients fear facing incidental awareness intraoperatively (Ruhaiyen et al., 2016). A reported 0.1-0.2% of the population undergoing general anesthesia experience various degrees of awareness with recall (Ghoneim et al., 2007). When awareness occurs, the patient may suffer severe psychological consequences (Bruchas, 2011), often requiring treatment by a mental health professional (Bischoff, 2011). Despite a low incidence of intraoperative awareness, anesthesia providers must remain vigilant; this starts with stratifying the risks involved and identifying integral practice adaptations to minimize the occurrence. Anesthesia awareness with recall has notably been deemed preventable in as many as 75-90% of reported cases (Pandit et al., 2014a). For this reason, an extensive literature review was conducted to identify modifiable and non-modifiable considerations (Table 1) for avoiding AAWR. Research revealed several important perioperative techniques which have been organized into practice recommendations.
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Anesthesia awareness with recall: an integrative review and best practice recommendations
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etd-LantripKea-11899
Document Type
Capstone project
Format
theses (aat)
Rights
Lantrip, Keaton
Internet Media Type
application/pdf
Type
texts
Source
20230530-usctheses-batch-1049
(batch),
University of Southern California
(contributing entity),
University of Southern California Dissertations and Theses
(collection)
Access Conditions
The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the author, as the original true and official version of the work, but does not grant the reader permission to use the work if the desired use is covered by copyright. It is the author, as rights holder, who must provide use permission if such use is covered by copyright.
Repository Name
University of Southern California Digital Library
Repository Location
USC Digital Library, University of Southern California, University Park Campus MC 2810, 3434 South Grand Avenue, 2nd Floor, Los Angeles, California 90089-2810, USA
Repository Email
cisadmin@lib.usc.edu
Tags
aawr
anesthesia
anesthesia awareness with recall
awareness
awareness with recall
general anesthesia
incidental awareness
intraoperative awareness