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Cognitive task analysis for instruction in single-injection ultrasound-guided regional anesthesia
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Cognitive task analysis for instruction in single-injection ultrasound-guided regional anesthesia
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Content
COGNITIVE TASK ANALYSIS FOR INSTRUCTION IN SINGLE-INJECTION
ULTRASOUND GUIDED-REGIONAL ANESTHESIA
by
Gligor V. Gucev
_______________________________________________________________________
A Dissertation Presented to the
FACULTY OF THE USC ROSSIER SCHOOL OF EDUCATION
UNIVIERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF EDUCATION
May 2012
Copyright 2012 Gligor V. Gucev
ii
DEDICATION
I would like to dedicate this work to the loved ones who were with me every step
of this journey. Above all, I would like to dedicate it to my children, Vasil and Tijana,
with the hope that that they will realize that “where there’s a will, there’s a way” sooner
rather than later.
iii
ACKNOWLEDGEMENTS
There is one person without whom this dissertation would never have happened.
For that I would like to thank Dr. Kenneth Yates for his inspiring dedication to this
project. His mentorship and guidance changed forever the way I mentor and guide my
students.
Also, I would like to thank Dr. Kimberly Hirabayashi and Dr. Maura Sullivan for
their time and valuable advice.
Thanks are in order for Karen Embrey CRNA, Ed.D. candidate for beating the last
windward leg with me. To Dr. Dimitri Arnaudov, Dr. Andrew Fond, Dr. Rana Movahedi
and Dr. Chuck Ngyen for their help in conducting the study. To Dr. Shankar Hariharan,
Dr. Peter Marhofer, and Dr. Gundamraj Narasimha, for sharing their specialty knowledge
of ultrasound guided regional anesthesia in the cognitive task analysis. To Dr. Robert
Keim, for the consult on the statistical analysis. To Dr. Annalisa Zox-Weaver for editing
the manuscript. Finally, to my colleagues at the Department of Anesthesiology of the
Keck School of Medicine for their motivating support.
iv
TABLE OF CONTENTS
Dedication ii
Acknowledgements iii
Abstract vii
Chapter One: Introduction 1
Statement of the Problem 1
!
Chapter Two: Review of the Literature 4
The UGRA Procedure 4
Current Methods of Training in UGRA 4
Apprenticeship Model 6
Structured Curriculum 7
Learner-Centered Curriculum and Simulation 8
Limitations to Current Training Methods 11
Expertise 12
Experts and Instruction 13
Limitations of Expertise for Surgical Training 14
Types of Knowledge 15
Declarative Knowledge 15
Procedural Knowledge 16
Conditional Knowledge 17
CTA 19
History and Background 19
Concepts, Processes, and Principles (CPP)
Framework 20
Evidence of Effectiveness of CTA Outside of
Medicine 21
Evidence of Effectiveness of CTA in Surgery 22
Summary 25
Chapter Three: Method
27
Pre-Experimental Curricular Development 27
Phase 1: Collecting Preliminary Knowledge 28
Phase 2: Identifying Knowledge Representations 28
Phase 3: Application of Knowledge Elicitation Methods 28
Phase 4: Data Analysis and Verification – CTA Coding 29
Inter-Rater Reliability 30
Development of the CTA Protocol and Data Analysis 30
Phase 5: Formatting the Results 30
Experimental Design 31
v
Figure 1: Study Design 31
UGRA Task 34
Participants 34
Students 34
Instructors 35
Materials 35
Equipment 35
High-Fidelity UGRA Simulator 35
Study Protocol 36
Data Collection and Analysis 37
Chapter Four: Results 39
Pre-Instruction Tests 39
Demographic Analysis 39
Table 1: Demographic Analysis
Declarative Knowledge Pre-test
40
40
Post-Instruction Tests 41
Declarative Knowledge Post-test 41
Procedural Knowledge Test 41
Time for Task Performance 42
Summary 42
Chapter Five: Discussion 43
Demographics 43
Declarative Knowledge 44
Procedural Knowledge 44
Time for Task Performance 45
Limitations 46
Future Studies 47
Implications 47
Conclusion 48
References 50
Appendices
Appendix A: Skill Sets Associated with UGRA Proficiency
56
Appendix B: Cognitive Task Analysis Gold Standard for Single-
Injection Ultrasound Guided Regional Anesthesia 57
Appendix C: Instructor Lesson Script 63
Appendix D: Informed Consent 72
Appendix E: Participant Demographic Data Survey 75
Appendix F: Declarative Knowledge Test 1 76
Appendix G: Declarative Knowledge Test 2 78
Appendix H: UGRA Skills Procedural Checklist 80
vi
Appendix I: Statistical Analysis of Declarative Knowledge Pre-test 82
Appendix J: Statistical Analysis of Declarative Knowledge Post-test 83
Appendix K: Statistical Analysis of Procedural Knowledge Test 84
Appendix L: Statistical Analysis of Time for Task Performance 85
vii
ABSTRACT
Cognitive task analysis (CTA) is methodology for eliciting knowledge from
subject matter experts. CTA has been used to capture the cognitive processes, decision-
making, and judgments that underlie expert behaviors. A review of the literature
revealed that CTA has not yet been used to capture the knowledge required to perform
ultrasound guided regional anesthesia (UGRA). The purpose of this study was to utilize
CTA to extract knowledge from UGRA experts and to determine whether instruction
based on CTA of UGRA will produce results superior to the results of traditional
training. This study adds to the knowledge base of CTA in being the first one to
effectively capture the expert knowledge of UGRA. The derived protocol was used in a
randomized, double blinded experiment involving UGRA instruction to 39 novice
learners. The results of this study strongly support the hypothesis that CTA-based
instruction in UGRA is more effective than conventional clinical instruction, as measured
by conceptual pre- and post-tests, performance of a simulated UGRA procedure, and time
necessary for the task performance. This study adds to the number of studies that have
proven the superiority of CTA-informed instruction. Finally, it produced several
validated instruments that can be used in instructing and evaluating UGRA.
1
CHAPTER ONE
INTRODUCTION
Statement of the Problem
A variety of peripheral nerve block techniques can be used to provide excellent
surgical anesthesia and postoperative analgesia. Peripheral nerve block is a regional
anesthesia technique that relies on the injection of local anesthetic in the vicinity of a
nerve to render a part of the body insensitive to surgical stimuli. A growing body of
evidence has suggested that peripheral nerve blocks allow early mobilization, improve
physical therapy, decrease length of hospital stay, reduce overall health care costs, and
ultimately improve the quality of patient care (Marhofer & Chan, 2007). As such,
regional anesthesia is one of the fastest growing anesthesia subspecialties. The
introduction of ultrasound guided regional anesthesia (UGRA) over the past decade is
probably the most significant change in the field. The real-time guidance has notably
altered the approach to many of the traditional blocks (Marhofer, Greher, & Kapral,
2005). The introduction of this novel method requires the development of an appropriate
curriculum; however, there is little information on the learning process and the set of
skills required to conduct safe and effective ultrasound guided regional anesthesia.
Sites et al. (2007) studied the behavior of novices, who had no prior exposure to
the procedure, learning ultrasound guided peripheral regional anesthesia. This research
pointed to several errors typical of inexperienced practitioners. Notably, 70.6% of errors
were reported on misalignment of the needle and the ultrasound plane. A joint
2
commission of opinion leaders and experts of ASRA and ESRA offered guidelines on
core competencies and skill sets associated with proficiency in UGRA (Sites et al., 2009).
One of the four major categories of skills is visualization of the needle insertion.
Although it has been recognized that needle visualization is important—and is the error
that novices make the most—there has been no evidence-based instruction solution to the
problem (Sites et al., 2007). As such, educational centers often resort to the “see one, do
one, teach one” Halstedian approach (Smith, Kopp, Jacob, Torsher, & Hebl, 2009). The
application of this approach to training is challenging because it relies on an expert’s
ability to communicate knowledge to learners. It has been well documented that experts,
especially in the psychomotor domain, achieve high levels of skill automatization
(Ericsson & Charness, 1994). As a result, the knowledge and skills of these experts are,
for the most part, unconscious and therefore difficult or impossible to communicate
accurately and completely. Medical education and especially surgical fields rely heavily
on instruction from expert practitioners. In a study that looked into vascular surgeries,
Clark, Pugh, Yates, Early, and Sullivan (2008) found that experts omitted up to 70% of
critical steps when describing a surgical procedure. Similar results were found for open
cricothyrotomy (Crispen, 2010; Tirapelle, 2010) and central line placement (Canillas,
2010; Kim, 2010).
Cognitive task analysis (CTA) is a methodology that has been used to capture the
cognitive processes, decision making, and judgments that underlie expert behaviors
(Cooke, 1999; Schraagen, Chipman, & Shalin, 2000; Yates, 2007). It is particularly
useful for analysis of complex tasks. The results of CTA have been successfully applied
3
to instruction in several fields and have shown superior results in industry, military, and
medicine (Clark & Estes, 1996). In the field of medicine, CTA-based training has been
shown to be superior to existing clinical teaching. Sullivan et al. (2007) found CTA
effective in improving cognitive processes and technical skills in surgical residents
performing percutaneous tracheotomy. Luker, Sullivan, Peyre, Sherman, and Grunwald
(2008) found that surgical residents who received CTA-based training in flexor tendon
repair achieved better problem-solving skills and demonstrated superior decision making.
Velmahos et al. (2004) demonstrated that CTA-based training improved the knowledge
and technical skills of surgery residents in central venous catheterization.
A review of the literature reveals that CTA has not yet been used to capture the
knowledge required to perform ultrasound guided regional anesthesia. The purpose of
this study is to determine whether instruction based on CTA will produce results superior
to the results of traditional training.
Thus, the research question for this study is:
1. Is CTA-based instruction in UGRA more effective than conventional clinical
instruction as measured by conceptual and procedural pre and post-tests and time
required for performance of a UGRA procedure?
4
CHAPTER TWO
REVIEW OF THE LITERATURE
This review will explore the current approaches on instruction in UGRA. It will
also emphasize the frameworks explaining the different types of knowledge and cognitive
processing. Special attention will be given to development of expert knowledge and its
character. A separate section will provide an overview of expert-based instruction.
Finally, CTA will be reviewed in detail with implications for instruction design and
training effectiveness.
The UGRA Procedure
Regional anesthesia is a method that uses the injection of local anesthetic in the
proximity of peripheral nerves to block neural transmission, rendering parts of the body
insensitive to surgical stimulus or pain. The application of ultrasound guidance
revolutionized the field of regional anesthesia (Marhofer et al., 2005). Before ultrasound,
injections were done blindly, using superficial or deep landmarks. Ultrasound offers
direct visualization of the nerves and the surrounding anatomy. It also enables the
anesthesiologist to visualize the needle on the ultrasound image and to follow its
trajectory from skin to nerve. Finally, the injection of local anesthetic and its spread
around the nerve can be visualized as final proof that procedure has been done correctly.
Current Methods of Training in UGRA
Since the first article on UGRA was published (Kapral et al., 1994), there has
been tremendous interest in the technique. Over this period, an increasing body of
5
evidence has been accumulated on the advantages of UGRA. Kapral et al. (2008) studied
160 patients receiving an interscalene block for upper extremity surgery. Patients were
randomly assigned to have the block performed with ultrasound guidance or without.
Results of the study demonstrated that ultrasound guidance of the needle and monitoring
of the local anesthetic spread improved the success rate of the interscalene blocks.
Patients in UGRA group achieved surgical grade block more often, and it lasted longer
than the block in the control group. Chan at al. (2007) studied 188 patients undergoing
elective hand surgery in regional anesthesia to determine whether ultrasound guidance
would increase the success rate. The authors found a significantly higher success rate of
the axillary block with use of ultrasound. Marhofer et al. (1997) studied the impact of
ultrasound guidance on the three-in-one block onset. The authors found significantly
faster block onset time in the UGRA group, suggesting better placement of the injection
of local anesthetic. Using ultrasound, Willschake et al. (2006) and Casati et al. (2007)
demonstrated that lower volumes of local anesthetic were necessary to achieve surgical
grade block for ilioinguinal-iliohypogastric and femoral block, respectively.
Ivani and Ferrante (2009), in their editorial on the recommendations for education
and training in ultrasound guided regional anesthesia, pointed to growth in the UGRA
field through a number of published studies. From 2004 to 2009, 1,220 articles were
published in the academic journals recognized by ASRA and ESRA. Over the last 20
years, instruction in UGRA has rapidly evolved from a point where few enthusiasts
demonstrated the technique to other enthusiasts at academic meetings and conferences to
6
becoming a mainstream in regional anesthesia and a part of mandatory anesthesiology
residency curriculum (Smith et al., 2009).
Apprenticeship model. The apprenticeship model has been the one most often
used in UGRA instruction (Smith et al., 2009). For over a century, this model has been
used in surgery and other medical fields that depend on technical skills (Grantcharov &
Reznick, 2008; Halsted, 1904). It has produced what has been perceived as solid results,
but has also had significant difficulties. Grantcharov and Reznick (2008) classified the
difficulties as ones associated with the system, the learner, and the trainer. The authors
suggested that the system limits educational opportunities in the apprenticeship model by
demanding speed and maximum efficiency. The clinical time and exposure to technical
procedures is limited and uneven, and often based on available opportunities, which can
prolong the time before competency with a procedure is achieved. Difficulties associated
with the learner, for Grantcharov and Reznick (2008), were based on the fact that trainees
acquire skills at different rates. Different learners need different time and effort to
acquire certain skills. A preclinical training program would ensure that all the learners
have acquired basic skills and knowledge. The learners would then have better utilization
of the valuable clinical time. Finally, this kind of a program would address the concerns
of faculty uncomfortable about teaching advanced procedures to junior doctors.
Procedures that are delicate—and sometimes may be life-threatening or organ-
threatening—are always a challenge for educators because of the patient safety issues and
the liability of the teacher. Each of the difficulties has the ability to offset the learning
process and alter the outcome.
7
Structured curriculum. In order to balance the variability, and answer concerns
for patient safety and medical education of higher quality, the Accreditation Council of
Graduate Medical Education ACGME introduced a set of requirements for medical
training. A set of competencies and skills was defined that residents must achieve by
graduation from the residency program. This structured curriculum has been
implemented in an effort to standardize medical education. The standardized goals and
objectives were designed to insure that each and every graduating resident has achieved
proficiency in the competencies defined by the content experts to be essential for the safe
practice of medicine. The standardized goals and objectives also offered myriad
opportunities for the development of nationwide curricula, for better teaching and
evaluation of competencies, and—finally—for introducing more accountability into
academic medicine.
Following the introduction of the standardized curriculum by ACGME, and in an
effort to unify the education in UGRA, the American Society of Regional Anesthesia
(ASRA) and the European Society of Regional Anesthesia (ESRA) published guidelines
for training in UGRA (Sites et al. 2009). The guidelines explain in detail what skills
constitute proficiency in UGRA (Appendix A). These skills can be divided into four
major categories: (a) understanding device operations, (b) image optimization, (c) image
interpretation, and (d) visualization of needle insertion and injection of the local
anesthetic solution. For each one of these categories, the Joint Committee of ASRA and
ESRA on training in UGRA recognized a defined skill set. In order to demonstrate
proficiency in understanding the device operation, learners should be able to explain the
8
basic technical principals of image generation and gain function; select the appropriate
transducer, depth, and focal setting; use color Doppler; and archive images. For image
optimization, learners are expected to appreciate the importance of pressure, alignment,
rotation, and the tilt of the transducer. For image interpretation, learners are expected to
identify nerves, muscles, blood vessels, bone, pleura, lung, and acoustic artifacts, and to
project the needle trajectory. Finally, proficiency in visualization of needle insertion and
injection of the local anesthetic solution is achieved when learners are able to
demonstrate in-plane and out-of-plane technique with maximized needle visualization,
recognize the correct and incorrect spread of the local anesthetic, conduct proper
ergonomics, and minimize unintentional transducer movement.
Learner-centered curriculum and simulation. Although the guidelines define
the core competencies and the skill set required for achieving proficiency in UGRA, no
recommendations exist on how the skills should be taught. Information on the learning
process and skill development to conduct safe and effective UGRA is scarce (Sites et al.,
2007), and definitive evidence on the effectiveness of commonly used UGRA training
tools is lacking (Ramlogan et al., 2010). Recently, Ramlogan et al. (2010) surveyed the
members of ASRA on the challenges of performing UGRA, the types and efficacy of
training tools used, the frequency with which different blocks are performed, the number
of supervised blocks required before independent practice, and the level of difficulty of
different nerve blocks. The survey pointed to eleven training tools used by the ASRA
members to acquire UGRA skills and knowledge. Practicing anesthesiologists rated
didactic lectures, scanning workshops, scanning cadavers, scanning animals, phantom
9
practice, perceptorship, online learning, textbooks, electronic media, self-teaching, and
learning from colleagues for effectiveness of the tool and the teaching time using it.
More than 90% of respondents indicated that the following training tools were the most
effective: scanning on human volunteers (workshops), learning from colleagues, and real-
time observation (perceptorship). The greatest amount of teaching time (20 hrs) was
allocated to self-taught training (34% of respondents), learning from colleagues (17%),
and attending didactic lectures (16%). Most respondents had no experience with training
on cadavers (80% of respondents) or animal models (86%). The participants in the survey
perceived that the median number of supervised blocks recommended before independent
practice should be six to ten regardless of the type of block. The fact that more than one
third of the practicing anesthesiologists in this survey were self-taught in UGRA suggests
a big gap between educational curricula available and the need of the anesthesiologists
society.
Simulator practice or use of artificial media has been a widely adopted UGRA
teaching method (Cheung et al., 2011; Chin, Perlas, Chang, & Brull, 2008; Hocking
Hebard, & Mitchell, 2011; Pollard, 2008; Sites, Gallagher, Cravero, Lundberg, & Blike,
2007). Studying the learning curve of inexperienced anesthesia residents in performing a
simulated ultrasound-guided interventional procedure, Sites et al. (2007) found that
anesthesiology residents with little or no ultrasound experience can rapidly learn and
improve their speed and accuracy in performing a simulated interventional ultrasound
procedure. After a brief introduction to the ultrasound system, the subjects were asked to
perform six sequential trials of a simulated breast cyst aspiration. The authors found that
10
the mean time to perform the task was reduced by 38% and 48%, respectively, for the
second and third trials. Also, for the same trials, a composite score of accuracy showed
an improvement of 36% and 59%, respectively. The steep learning curve suggests that
artificial medium practice results in rapidly achieved proficiency in ultrasound beam-
needle alignment. Although it is intuitive to assume that proficiency in ultrasound beam-
needle alignment ultimately benefits UGRA skills, there is neither systematic study nor
evidence of the impact of this kind of simulation on UGRA skills. Recent study of
Cheung et al. (2011) looked at the use of a high-fidelity simulator for teaching
undergraduate novice students UGRA techniques. The authors found that despite some
improvement in the second simulator trial, the ability to maintain visualization of the
needle, align the needle with the probe, angle the needle approach, and reduce the needle
passes did not improve significantly. Cheung et al. (2011) found that students had
difficulty learning skills that required more coordination and fine motor control.
Smith et al. (2009) presented the design and implementation of a comprehensive
learner-centered regional anesthesia curriculum. In an effort to overcome the
shortcomings of the apprenticeship model, the authors followed the recommendations of
ASRA/ESRA (Sites et al., 2009) to create: “educational tasks that require self-directed
knowledge and skill development shifting the focus from faculty to resident and from
what is being taught to what is being learned.” The UGRA curriculum was integral to this
effort. It was organized as a series of interactive sessions that facilitate proficiency,
integration, and understanding of the three primary components of UGRA: (1) ultrasound
physics and equipment, (2) scanning techniques and sonoanatomy, and (3) sonographic
11
needle guidance. In a fourth session, each resident went through a standardized technical
skills assessment during an UGRA simulation session using phantom gel models.
Residents were assessed with a standardized UGRA proficiency checklist that is used to
assess the integration and application of the educational content taught within the
ultrasound curriculum. Smith et al. (2009) managed to implement the current guidelines
into a clinical and particularly preclinical curriculum that will need objective validation.
What is not apparent in the curriculum is how the actual knowledge and skills are
transmitted from expert to novice learner during the interactive sessions.
Limitations to current training methods. Limitations of the apprenticeship
model were analyzed in detail by Grantcharov and Reznick (2008) and discussed in the
previous section. As they pointed out, today the apprenticeship model may be inadequate
for clinical medicine education. The structured curriculum model was introduced to
ameliorate this problem, but the credentialing bodies only defined the competencies that
need to be achieved. Education programs are expected to find their way and help learners
achieve expertise. Regardless of what methods are used for instruction, the critical point
in all of them is the actual transmission of knowledge from expert to novice. A major
problem with instruction by experts is that experts may unintentionally omit up to 70% of
critical information when teaching what novices must master to perform a procedure
adequately (Canillas, 2010; Chao & Salvendy, 1994; Clark, Pugh, Yates, Early, &
Sullivan, 2008; Hoffman, Crandall, & Shadbolt, 1998). In this kind of setting, the
methodology capable of capturing expert knowledge is essential to meaningful
instruction. CTA has already been proven able to elicit expert knowledge and to provide
12
superior results when applied to instruction. A CTA-based curriculum in UGRA could
fill the gap and provide appropriate education for residents and practicing
anesthesiologists. The following section will review the current understanding of
expertise. It will also examine the interaction of expertise and instruction and dedicate
particular attention to experts’ tendency to leave out critically important information
during the instruction process.
Expertise
Throughout a long period in history, expertise was considered innate and only
those with the divine gift could reach a level of outstanding achievement (Ericsson &
Charness, 1994). The first general theory of expertise was based on the work of Newell
(1973) on information processing and was presented by Simon and Chase (1973). The
authors proposed that experts have the same capacity of working memory as anyone. The
difference is that, with experience, experts store an increasing number of complex
patterns in their long-term memory that are available for retrieval in similar situations.
Being based on simple pattern recognition, the theory was criticized for oversimplifying
expertise. Summarizing the early research on expertise, Glaser and Chi (1988) proposed
seven general statements. Experts (a) excel primarily within their own domains, (b)
perceive meaningful, interconnected patterns in their domain, (c) are faster and more
accurate than novices when performing the skills of their domain, (d) have better short-
and long-term memory than novices, (e) perceive problems in their domain at a deeper
(more principled) level than novices, (f) spend a larger proportion of time qualitatively
analyzing problems, and (g) self-monitor effectively during problem solving. Experts in
13
various domains exhibit these characteristics; however, research has not identified the
extent to which these skills might be necessary or sufficient elements of a specific
expert’s performance.
In order to adequately study the factors mediating expert performance, Ericsson
and Smith (1991) suggested the importance of identifying tasks that define expertise for
certain domains. They defined experts as individuals who can consistently demonstrate
superior performance on tasks designed to capture essential aspects of a skill in the
domain under investigation. Ericsson, Krampe, and Tesh-Romer (1993) found deliberate
practice to be essential for acquisition of expertise and continuous performance
improvement. They insisted that expert performance reflects extended periods of intense
training and preparation and, in most domains, at least 10 years are required to reach
expert levels of performance. During the extended periods of training, performance and
knowledge became automatic and therefore unconscious (Anderson, 1996; Clark & Estes,
1996).
Experts and instruction. It is a rule prevalent in all academic and professional
fields that most accomplished experts are recruited to teach their domain of expertise. As
mentioned above, with increased expertise, knowledge becomes automated. The process
of automatization, as desirable as it is for developing expertise, degrades experts’ ability
to purposefully and consciously access their knowledge during performance or
instruction (Ericsson, 2004). Sullivan et al. (2008) found that experts are often unaware
of how much they omit when simply relying on recall. In a study examining if a
cognitive task analysis (CTA) could capture steps and decision points that were not
14
articulated during the traditional teaching of a colonoscopy, Sullivan et al. (2008)
demonstrated that a maximum of 50% of “how-to” steps and 43% of decision points were
presented to the learners. Omissions in expert instruction are ubiquitous to all fields.
Feldon (2004) studied the instruction of research design in psychology. He found that
automaticity and the accuracy of self-reporting were negatively correlated, as up to 70%
of experts were unaware of the strategies they were using. Chao and Salvendy (1994)
studied the errors made by a number of top programming experts. They found that the
experts were unaware of around 70% of the steps they used to debug computer programs.
Limitations of expertise for surgical training. A number of studies have
examined the accuracy of an expert’s ability to explain the procedural skills by
comparing the self-reported surgical protocols, procedural algorithms, and problem
solving processes to what is considered the gold standard. As mentioned earlier, Clark et
al. (2007) examined vascular surgeons performing after action review for placement of a
femoral shunt for vascular trauma. Authors found that experts omitted up to 70% of
critical steps when describing surgical procedure. They also found that unaided, self-
reported surgical protocol information varied within different segments of the surgical
protocol. Sullivan et al. (2008) examined surgeon recall of how-to steps and decision
steps in their instruction of colonoscopy. The surgeons were able to describe 25%–50%
of the required steps in both categories. Similar results were found for open
cricothyrotomy. Crispen (2010) studied surgeons explaining open cricothyrotomy
procedure, and found that, on average, each surgical subject matter expert who
participated in this study omitted 44% of the total steps, 34% of the action steps, and 72%
15
of the decision-making steps compared to the gold standard. Kim (2010) observed
omissions in instruction of decision making in central venous catheter placement. The
author found omission rates from 34%–72% at different conditional steps.
Studies of omissions in expert instruction unequivocally point to serious errors
that originate in the very essence of the expertise, and the theoretical frameworks of
cognitive processing have a solid explanation for this phenomenon. Therefore, as Feldon
(2006) has suggested, an expert’s role as the direct source of knowledge has to be
critically reexamined. The following section will examine the types of knowledge and
the mechanisms involved in the development of expertise.
Types of Knowledge
Learning UGRA as suggested by the joint commission involves mastering
knowledge and a set of skills that define proficiency in the subject. The knowledge
representing this set of skills can be classified as declarative, procedural, and conditional.
The following section will take a closer look at the different types of knowledge and their
importance in knowledge compilation.
Declarative knowledge. Declarative knowledge refers to all of the information
and all the facts a person knows (Anderson, 1982). According to Anderson’s ACT-R
(Adaptive Control of Thought, -Rational theory), knowledge starts out as declarative
information. It is stored in the long-term memory in chunks. A basic characteristic of the
declarative system is that it does not require one to know how the knowledge will be used
in order to store it. Converting it into behavior or proceduralizing it may take
considerable effort. Procedural knowledge is acquired through inferences from already-
16
existing declarative knowledge. Clark and Estes (1996) referred to declarative
knowledge as concepts, processes, and principles of which a person is consciously aware
and able to describe. Merrill (2002) has described declarative knowledge as facts
concepts, processes, and principles.
A declarative knowledge system has the capacity to store our experiences in any
domain, including instruction (if it is available), models of correct behavior, and the
successes and failures of our attempts (Anderson, 1987). This knowledge is stored in
relatively unanalyzed form. From this position, besides the basic facts of ultrasound
image generation, interpretation, and the principles of operation, some decision-making
points and responses to frequently encountered problems in UGRA could also be
classified as declarative knowledge. There are observations that in specific fields,
declarative knowledge is emphasized more than procedural knowledge during training
(Clark & Elen, 2006; Yates, 2007). And, indeed, most training programs focus on
various forms of didactic presentations of the domain content, culminating with the
specialty licensing board exam, which only evaluates the candidate’s declarative
knowledge.
Procedural knowledge. The ACT-R Theory postulates a distinction between
declarative and procedural knowledge. Whereas declarative knowledge deals with
facts—what things are and how they work—procedural knowledge stores information on
how to do things. Procedural knowledge is stored in long-term memory as productions.
Anderson (1987) summarized that cognitive skills are encoded by a set of productions,
which are organized according to a hierarchical goal structure. As mentioned above, and
17
explained with ACT-R, problems are solved in new domains by applying weak problem-
solving procedures to declarative knowledge that already exists on a particular domain.
Anderson (1987) explained how production rules are compiled from initial problem
solutions specific to a domain and particular use of the knowledge. In the same article,
he described the two mechanisms that define knowledge compilation: composition and
proceduralization. Composition combines consecutive productions into single
production, and therefore enhances performance. The working memory is a limiting
factor for composition because the conditions specified in a production must be
represented in working memory. Through proceduralization, declarative knowledge is
turned directly into productions, thereby eliminating the need to represent declarative
information in working memory. An example of proceduralization is a telephone number
that we can dial, but we are not able to retrieve. Generalization, discrimination, and
strengthening are the three learning mechanisms responsible for proceduralization. Each
time a production is successfully applied, its strength is augmented. This process
provides natural selection for production rules that repeatedly prove useful. The longer
the production is applied, the less conscientious effort it requires and the more automated
it becomes. Experts have procedural knowledge that is automated to the point where they
cannot explain it conscientiously, and thus methods like CTA are necessary to
deconstruct it to the original steps (Clark & Estes, 1996).
Conditional knowledge. Conditional knowledge answers the “when” question.
It is important when a decision has to be made whether to perform a task. It is a form of
procedural knowledge that solves the if/then dilemma or establishes the indications and
18
contraindications for performance of a task. Although some theorists consider it a
separate category (Paris, Lipson, & Wixson, 1983), the majority agrees that it is a part of
procedural knowledge. Anderson (1987), in ACT-R theory, explained procedural
knowledge cognitive processing as creation of productions: “Productions are condition-
action pairs that specify that if a certain state occurs in working memory, and then
particular mental (and possibly physical) actions should take place” (p. 193). Utilizing
the if-then algorithm as a condition-action pair in Anderson’s function results in the
conditional knowledge-processing model, suggesting the close reaction of the two types
of knowledge.
The application of conditional knowledge in medicine is considered one of the
most important skills. Performance of any surgical or UGRA procedure is based on a
sequence of action steps that lead to the desired outcome. The following sequence of
steps illustrates one part of the performance of brachial plexus block in UGRA. Do not
insert needle if you haven’t given some local anesthetic in the skin. If you inserted the
needle, then you must see it on the ultrasound image. Do not advance the needle if you
don’t see it. Carefully advance the needle to a position close to the brachial plexus. If
you see the needle and the brachial plexus in acceptable proximity, then inject the local
anesthetic. Each one of the steps in the process is based on subsets of productions that
are conditioned by the actual situation. Performance for a novice means that each step
needs evaluation and processing. For the expert, it is translation from the language of
problems to the language of solutions—in one step.
19
CTA
Cognitive task analysis (CTA) is a methodology that has been used to capture the
cognitive processes, decision making, and judgments that underlie the expert behaviors
(Cooke, 1999; Schraagen et al., 2000; Yates, 2007). Eliciting expert knowledge,
analyzing the data, and implementing the results in instructional programs are the most
important goals of CTA. Clark, Feldon, van Merriënboer, Yates, and Early (2008) have
suggested that CTA captures a description of the knowledge that experts use to perform
complex tasks by using a variety of interview and observation strategies. Outcomes of
CTA are most frequently descriptions of performance objectives, equipment, conceptual
knowledge, and procedural knowledge and performance standards used by experts as
they perform the task. According to Crandall, Klein, and Hoffman (2006), the purpose of
CTA is to examine how the human mind works. They proposed that the cognition of what
people are thinking when performing a task, information and strategies used to make
decisions and applied toward solving problems are outcomes of CTA. The authors found
three primary components to CTA: knowledge elicitation, data analysis, and knowledge
representation. Yates (2007) described CTA as a family of knowledge elicitation
techniques that have been shown to effectively capture the unobservable cognitive
processes, decisions, and judgments involved in expert performance.
History and background. Clark and Estes (1996) suggested that origins of task
analysis go back to the late 19
th
century and the industrial revolution. It was developed to
answer the need for a greater number of better-trained workers in an increasingly
demanding environment. As new tasks facing the workers became more complex, simple
20
behavioral analysis that focused primarily on observations was insufficient. Observation
of an experienced practitioner performing the task is not enough because it does not
provide insight into the cognitive processes underlying the performance (Clark, & Estes,
1996). Behavioral analysis cannot capture the advanced problem-solving or decision-
making points so critical for performance of complex tasks. Complex tasks require
integrated use of both declarative and procedural knowledge, as defined by Van
Merrienboër, Clark and de Crook (2002). Following developments in cognitive science,
methodologies focused on the analysis of a cognitive task offered insight to better
understand complex tasks.
Having performance improvement as the ultimate goal, CTA techniques were
developed, in part, to capture expert knowledge. Cooke (1994) identified more than 100
different methodologies. Several classification systems were designed and have been
used with variable success in an effort to provide practitioners with guidelines on the
appropriate selection of CTA method based on desired outcomes. Regardless of the
abundance of different methods, most of them have five analogous steps at the core of the
process (Chipman, Schraagen, & Shalin, 2000; Clark, & Estes, 1996; Coffey & Hoffman,
2003; Cooke, 1994; Jonassen, Tessmer & Hannum, 1999). Clark et al. (2008) formulated
these steps in the following sequence: (1) Collect preliminary knowledge, (2) Identify
knowledge representations, (3) Apply focused knowledge elicitation methods, (4)
Analyze and verify data acquired, (5) Format results for the intended application.
Concepts, processes, and principles (CPP) framework. One example of CTA
is the CPP model (Clark et al., 2008), which employs a series of semistructured
21
interviews with multiple subject matter experts (SMEs) to capture the relevant knowledge
for accurate task performance. The interviews are intended to describe all concepts,
processes, and principles of the task and subtasks and to identify the sequence for task
engagement and subtask hierarchies, as well as to identify the cues, necessary equipment,
materials, and sensory experiences preceding and occurring throughout subtask and task
execution. During the interviews, SMEs are asked to define possible, or likely,
complications or problems. Subsequently, the captured data, including automated and
implicit knowledge, is revisited via repeated SME self and peer review analyses aimed at
authenticating and aggregating the elicited findings (Clark et al., 2008). Following CPP,
a comprehensive task outline or template for appropriate task execution is generated from
the combined and validated interview findings, which will then serve as a summary gold
standard. The gold standard is then employed to underpin instructional design (ID) or
generate job aids, task performance, or task evaluation criteria.
Evidence of effectiveness of CTA outside of medicine. CTA has been
successfully applied to instruction in several fields and has shown superior results in
industry, military, psychology, and computer sciences (Clark & Estes, 1996). Schaafstal,
Schraagen, and Van Berlo (2000) compared the effectiveness of a pre-existing course and
CTA-based course in radar system troubleshooting. The authors found that although the
results of the written test were similar between the groups, the CTA group solved twice
as many radar malfunctions in shorter time than the control group.
Merrill (2002) studied the effectiveness of CTA-based instruction in a spreadsheet
computer software application, comparing it to guided internet-based and discovery
22
methods. The results of this study suggested the superiority of the CTA-based instruction
to guided and discovery learning with the average scores on exit test of 89%, 68%, and
34%, respectively. Faster completion of the tasks was also observed in the CTA-based
group.
Meta-analysis performed by Tofel-Grehl (2011) examined the potential impacts
of cognitive task analysis on training efficiency and effectiveness. The author searched
PsycINFO, ERIC, Education Research Complete, ProQuest Dissertations and Theses,
Medline, PubMed, and ISI Web of Science databases for “cognitive task analysis” or
“knowledge elicitation” and training or instruction. From 467 studies that were initially
recovered, only 18 were included in the meta-analysis after rigorous exclusions. The
author found that CTA-based instruction was more effective than conventional
instruction (effect size g = 0.88). The CTA method with the highest impact on learning
was PARI (g = 1.6), Other/undisclosed (g = .75), and CDM (g = .3). Most of the cases
were done in the medical field (25), followed by the military (14), academic (7), industry
(6), and government (4). Stratified by the type of knowledge, studies looking into
procedural knowledge had effect size (g) of .85, declarative knowledge g = .93. The
meta-analysis also found significant effect of CTA based instruction on self-efficacy with
effect size of g=.88.
Evidence of effectiveness of CTA in surgery. In the field of medicine, CTA-
based training has been shown to be superior to existing clinical teaching. Sullivan et al.
(2007) found that CTA was effective in improving cognitive decision processes and
technical skills in surgical residents performing percutaneous tracheotomy. The authors
23
studied 20 postgraduate surgical residents randomly assigned into two groups. The
experimental CTA group was instructed with curriculum based on CTA of three expert
surgeons and video material on a percutaneous tracheotomy. The control group received
a lecture covering the topic and watched the same video. Sullivan et al. (2007) found that
the residents in the CTA group not only demonstrated better technical competence at one
month (CTA: 43.5+3.7, control: 35.2 + 3.9, P >.05) and six months (CTA: 39.4 + 4.2,
control: 31.8 + 5.8, P >.05), but that they also exhibited better cognitive processes during
the procedure that lasted up to six months postinstruction.
Tirapelle (2010) studied the impact of CTA on instruction in an open
cricothyrotomy (OC). She enrolled 33 medical students and residents that were stratified
and randomly assigned in two groups. CTA was conducted in five steps as outlined by
Clark (2004). After initial research, knowledge types necessary for the performance of
OC were defined. The knowledge of six expert trauma surgeons was elicited through
semistructured interviews in order to establish a gold standard for the performance of OC.
Analysis of the results revealed that CTA-based instruction has a significant positive
effect on procedural knowledge and performance as compared to traditional surgical
education. Although participants in the CTA-based instruction group did not demonstrate
greater declarative knowledge of the procedure on a postinstruction measure than the
control (p = .59), they did demonstrate significantly more procedural action step
knowledge and applied more decision step knowledge than the control group (p = .05).
Luker et al. (2008) studied instruction in plastic and reconstructive surgery. They
found that surgical residents who received CTA-based training in flexor tendon repair
24
achieved better problem-solving skills and demonstrated superior decision making for the
task. Utilizing 10 postgraduate surgical residents as their own control group, the authors
demonstrated that the group that received cognitive task analysis–based multimedia
surgical curriculum instruction achieved greater command of problem solving and was
better equipped to make correct decisions in flexor tendon repair (p<.01).
Velmahos et al. (2004) demonstrated that CTA-based training improved the
knowledge and technical skills of surgery interns in central venous catheterization
(CVC). Analysis was performed on 26 postgraduate surgical interns without previous
experience with CVC, randomly assigned to two groups. Two subject matter experts
were interviewed using CTA methodology. The results of the analysis were then
formatted into instructional course and evaluation checklist. The CTA-based instruction
group received three hours of lecture, demonstration, and practice. The control group
received the traditional lecture and practice course. Velmahos et al. (2004) found no
differences between the two groups in the background characteristics of the interns or the
patients having CVC. The scores at the initial multiple-choice test were similar. The
course interns however, scored significantly higher in the repeat test compared with the
traditional interns (p = .03). Also, the course interns achieved a higher score on the 14-
item checklist, suggesting superior performance (p<.003). They had to make
significantly fewer attempts to find the vein (p = .046) and demonstrated a trend toward
less time to complete the catheterization.
Summary
25
The in-depth review of the educational research literature provided in this study
explored the current approaches on instruction in UGRA. The apprenticeship model was
found to be marginally adequate and the alternatives were explored in detail. The review
found that all of the instruction methods currently used in UGRA depend on experts
conveying knowledge to novice learners. The review of expertise and expert instruction
pointed to deficiencies in using experts in instruction due to the fact that their knowledge
is automated and unconscious. The omission studies elucidating this phenomenon were
found to be of particular importance. A possible solution was recommended in the use of
CTA to elicit the expert knowledge encrypted by the processes of automatization. By
sampling both the explicit and implicit cognitive functions associated with the
performance of UGRA, CTA may reveal vital elements connected to the conditions,
decisions, and actions that experts employ while practicing. A large and accumulating
body of evidence suggests that the use of CTA-based instruction significantly improves
educational outcomes. The application of CTA techniques has proven successful in
improving instruction in different areas of medicine, industry, military training, and
government (Tofel-Grehl, 2011). Therefore, proposing CTA supported instruction in
UGRA is a logical extension of prior research.
The review of the literature revealed that CTA has not yet been used to capture
the knowledge required to perform UGRA. The purpose of this study was to examine
whether instruction based on CTA will produce results superior to traditional instruction.
This randomized, single-blinded experiment will add to the body of existing evidence
regarding the effectiveness of using CTA to capture medical expertise, particularly
26
expertise in regional anesthesia and ultrasound-guided procedures. Also, this work may
add to evidence comparing the effectiveness of CTA-based instructional methods to
current standard methods of instruction in medicine.
27
CHAPTER THREE
METHOD
The following chapter will review the research methodology used in this study.
The study employed CTA-guided interviews for knowledge elicitation from three UGRA
experts in order to generate a gold standard for instructing UGRA to novice learners.
Instruction with the newly developed CTA-guided technique was compared to standard
methods of teaching UGRA. Details on the study design, participants, UGRA task, CTA,
as well as the instruments used for instruction and evaluation, the study protocol, and the
statistical methods are presented in the following section.
Pre-Experimental Curricular Development
Because the purpose of this study was to compare CTA-informed UGRA
instruction curriculum to traditional UGRA curriculum, the pre-experimental phase of the
study was focused on developing the CTA-based UGRA gold standard. The CTA
procedure followed the five steps suggested by Clark et al. (2008) for knowledge
elicitation, which included (a) collecting preliminary domain-specific knowledge, (b)
identifying the types of knowledge associated with the task, (c) applying the knowledge
elicitation technique in a semistructured interview, subsequently (d) verifying and
analyzing the results from the interviews, and ultimately (e) applying the findings to
curriculum design. Because the author of this study has attained a high level of expertise
in UGRA, a senior knowledge analyst who has no familiarity with the procedure
conducted the initial CTA interviews to avoid inserting bias during the interview process.
28
Phase 1: Collecting preliminary knowledge. The senior researcher reviewed
relevant literature from peer reviewed journals and anesthesiology textbooks on UGRA.
The senior researcher also observed the actual performance of UGRA in a clinical setting.
This “bootstrapping” was undertaken to familiarize the senior researcher with the
language of anesthesia practice and to facilitate gaining domain-specific knowledge on
UGRA. In order to limit confirmation bias by the author, as a junior researcher, who is
an anesthesiology practitioner and expert in UGRA, a senior researcher, who is not an
anesthesiology practitioner, conducted the first CTA interview alone. The author, with
oversight and guidance from the senior researcher, conducted two additional SME
interviews.
Phase 2: Identifying knowledge representations. All concepts, processes,
principles as well as motor skills associated with performance of UGRA were identified.
The identified knowledge types were further analyzed and the necessary action and
decision steps of the task were established.
Phase 3: Application of knowledge elicitation methods. The elicitation of
knowledge from the subject matter experts (SME) was achieved via semistructured
interviews based on the CTA method proposed by Clark et al. (2008). Three subject
matter experts (SMEs) were interviewed during the curriculum design phase of the study.
The SMEs were regional anesthesiologists with extensive experience in the performance
of ultrasound-guided procedures. In the interview, all of the SMEs declared that they
performed thousands of UGRA procedures. One of the SMEs is an internationally
renowned expert and editor of the regional anesthesia section of the British Journal of
29
Anaesthesiology. The other two SMEs are also nationally and internationally renowned
experts. All of them have published and lectured on UGRA. The inquiries were aimed at
capturing the concepts, processes and principles, as well as the action steps and decision
steps, required to perform UGRA. The SMEs were referred to as anesthesiology
practitioners A, B, and C. The interviews were digitally recorded for verbatim
transcription and included information on the intended use of the data collected. Verbal
consent was obtained from the SMEs prior to the knowledge-elicitation phase of
discussion and was acknowledged in the interview. The CTA interviews incorporated the
following steps, adapted from the Clark et al. (2008) method: (a) The decisions and order
of decisions necessary for task and subtask execution during UGRA, (b) The concepts,
prior knowledge necessary for the process of the task, and the principles and alternatives
that inform the decisions of the task, (c) The events or conditions that precede the task
and cue the appropriate responses in task actions and decisions, (d) The necessary
equipment, monitoring devices, and materials needed for appropriate task execution, (e)
Any additional sensory information relevant to the task execution, such as smells, sounds,
or tactile input that surround or cue the task or subtasks, (f) Indicators of appropriate task
execution, such as those revealing accuracy, speed, time, or quality of task performance.
Phase 4: Data analysis and verification - CTA coding. The transcribed SME
interviews were coded to reveal elicited conditional knowledge, specifically indications
(I) and contraindications (CI) to actions during the task execution. Coding also reflected
equipment and materials (EM) needed in task execution and sensory cues surrounding the
task and subtasks, such as hearing (SH), seeing (SS), and touching (ST). The primary
30
focus of coding was to identify the action steps (AS) and decision steps (DS). AS and DS,
indicated the “IF” points. Each “IF” point presented decision step alternatives (DSA),
which elucidated the “THEN” points during task execution. A complete description of
codes is available in the Abbreviation section at the beginning of this dissertation.
Inter-rater reliability. The author and another trained coder coded the transcribed
CTA interviews and data were collected on agreements and disagreements in coding to
establish the rigor of inter-rater reliability. The percent of consensus for each of the coded
items was generated from the tallies of agreements and disagreements between the
coders. Any disagreements in coding not resolved by discussion were reviewed by a
third coder for consensus.
Development of the CTA protocol and data analysis. The information gathered
during the semistructured CTA interviews from the anesthesia practice SMEs was
employed to generate a draft protocol for performing UGRA. The draft protocol was
reviewed by each of the SMEs individually for completeness and accuracy before the
final draft was compiled from changes suggested by the SMEs. This process of
additions, changes, and verification of data was accomplished through a word processing
in-line document review format. Conflicting situations were resolved with consensus.
Phase 5: Formatting the results. The final protocols generated from the SMEs
interviews were aggregated into a single summary “gold standard” (GS) for the UGRA
task (Appendix B). This GS was then used to develop a training outline, which was
utilized by the instructor of the experimental group during instruction on UGRA
(Appendix C) and for the design of a procedural checklist (Appendix H). The questions
31
of the pretest and post-test were also based on the GS and are presented in Appendixes F
and G.
Experimental Design
This prospective randomized double-blinded study compared the outcomes of
instruction in UGRA based on CTA with traditional UGRA instruction. Type of
instruction was considered an independent variable. The performance of UGRA on a
high-fidelity simulator was considered the first dependent variable. Performance on the
postinstruction knowledge test was the second dependent variable. The graphic
description of the study design is presented as Figure 1, below.
Figure 1: Study Design
32
Schematic presentation of the proposed study design is:
RT
1
X
1
T
2
T
3
RT
1
X
2
T
2
T
3
(R - randomization, T
1
- declarative knowledge pretest, T
2
- declarative knowledge
posttest, T
3
- procedural knowledge skill test, X
1
– instruction for control group, X
2
–
CTA-based instruction for experimental group).
Following approval by the Institutional Review Board, thirty-nine medical
students were randomly divided in two groups. After randomization, both groups were
tested for baseline knowledge of UGRA. The purpose of testing was to determine if the
groups were comparable on this variable. Two 11-question tests were developed for this
purpose, based on the UGRA gold standard (Appendixes F and G). The tests had similar
structure and difficulty. At randomization, each student had received an envelope with
both tests. One test was immediately available and was administered before the
instruction as a pretest. The other test was placed in a smaller, sealed envelope to be
open after the instruction. The tests were randomly split to pretest or post-test in order to
control for sensitization bias of the pretest.
Both groups had instruction curriculum with identical elements and duration,
except for the content of the lecture. The control group had curriculum that is
traditionally given to junior anesthesia residents. It was based on the presenting faculty
knowledge and expertise and covered all of the objectives and goals, as defined by the
ASRA-ESRA guidelines (Sites et al., 2007). A 45-minute lecture addressed topics from
ultrasound physics, scanning techniques, and ultrasound anatomy to needle manipulation.
33
After the lecture, the instructor demonstrated scanning on a simulator, followed by needle
advancement to target structure. The control group lecture was followed by practice on a
high-fidelity UGRA simulator.
The CTA-based curriculum also had a 45-minute lecture, followed by guided
practice on a high-fidelity UGRA simulator. Both elements of the curriculum were based
on the results of the CTA gold standard. In order to avoid biased evaluation of subjects
and to maintain the anonymity of the groups in which the subjects received instruction,
both instructing faculty were dismissed after the instruction. Faculty blinded to the
source of instruction performed the evaluation of attained knowledge and skills.
The first outcome of the study was performance of the simulated UGRA
procedure. Each of the participants—regardless of the instruction group—was evaluated
on performance of UGRA on a high-fidelity UGRA simulator. The performance was
measured with a UGRA skills rating scale. The instrument was based on the CTA gold
standard and developed to capture generic UGRA technical skills and task-specific
UGRA skills. The instrument is included in Appendix H. Students were asked to think
aloud during the performance in order for the evaluator to follow their decision making as
they progressed through the task. After his or her skills were evaluated, each student
answered the second declarative knowledge test (post-test). This test was the alternative
one to the pretest and was the one placed in a sealed envelope at randomization (See
Appendixes F and G).
34
UGRA Task
The UGRA task that students were asked to demonstrate mimicked the
performance of ultrasound guided popliteal block. Students were expected to prepare the
ultrasound machine, select the appropriate transducer, prepare the simulator, and scan and
demonstrate an image of acceptable quality. After the image was obtained, students were
expected to place the needle into the plane of the ultrasound beam and advance it toward
the simulated nerve. Once they reach the proximity of the simulated nerve, they would
inject water and accept or reject the spread of the liquid around the simulated nerve as
adequate.
Participants
Students. Following University IRB approval, 39 medical students were recruited
for the study. Students were attending their first and second year of medical school at
Keck School of Medicine, University of Southern California. Sampling from the first
and second year provided access to novice learners because UGRA is not part of medical
school curriculum. The only requirement, and that was the only inclusion criteria, was
that subjects had to have completed an anatomy course.
In order to ensure homogeneity of the sample with respect to prior knowledge,
subjects who had previous experience with ultrasound-guided procedures were excluded
from the study. Subjects who voluntarily withdrew from the study at any point would
have been excluded as well.
In order to comply with the double-blind design of the study, students were not
aware of the type of instruction they were receiving. At introduction of the study and
35
randomization they were told that there would be two groups that would receive different
instruction, but it was never disclosed to the students, which group received CTA based
instruction.
Instructors. Four anesthesiologists, faculty of the USC Department of
Anesthesiology participated in the study. All of them were members of the regional
anesthesia group and were therefore experts in UGRA with significant clinical
experience. All of the instructors declared that they performed over one thousand UGRA
procedures. Also, all four have been actively involved in teaching anesthesiology
residents and had lectured on UGRA statewide and nationwide. Three were male and one
was female. Two were involved in the instruction and two conducted the final evaluation.
All faculty were familiar with the task that students were expected to perform. The
experimental group instructor was given the CTA-based curriculum and was asked to
adhere strictly to the content. Before the study, both evaluators performed evaluations on
simulated performance to establish inter-rater reliability. The inter-rater reliability was
100%. Evaluators were blinded to the source of the student instruction.
Materials
Equipment. A Sonosite Ultarsound Imaging System, SonoSite Inc., Bothell, WA,
with 6-13 MHz linear transducer was used for scanning. Spinal needles, Beckton
Dickinson, Inc., Franklin Lakes, NJ, of 21-gauge size were used for the needling tasks.
High-fidelity UGRA simulator. The high-fidelity simulator used in this study
was modified from the porcine model developed by the University of Toronto group (Xu,
Abas, & Chan, 2005). The modification was using a bovine hamstring tendon embedded
36
in pork loin. The bovine hamstring tendon splits in two and closely resembles the split of
the sciatic nerve into tibial and common peronial in human anatomy. With this simulator,
one can distinguish between the ultrasonographic appearance of muscles and nerve. The
embedded tendon appears predominantly hyperechoic, round to oval in short axis, and
tubular in long axis. The “fibrillar pattern” seen on ultrasound resembles nerve fascicles.
The simulator has been validated for analysis of novice performance by Cheung et al.
(2011). The simulator was constructed following the steps suggested by Xu et al. (2005).
Two simulators were used in the instruction phase of the study and two for the evaluation
phase. A new set of simulators for the evaluation was provided in order to eliminate or
minimize the interference from artifacts caused by damage to the simulator during
practice.
Study Protocol
Registered and confirmed subjects were randomly assigned to the control or
experimental group on site upon arrival. At randomization, students were given the study
code—a number used to identify the written test and performance checklist. All students
were also given an envelope containing the written consent, demographic survey, pretest,
and sealed envelope with the post-test. After a brief introduction to the study, students
who wanted to participate were asked to sign the consent (Appendix C). Participating
students filled the demographic survey (Appendix E) and the pretest. After the pretest,
each group was taken to separate classroom for instruction.
The control group received 45-minutes lecture on UGRA. The lecture was one
traditionally given to junior anesthesia residents and covered all of the objectives and
37
goals, as defined by the ASRA-ESRA guidelines. Following the lecture, all subjects
from this group engaged in simulator practice. The control group instructor demonstrated
all steps in performance of UGRA, after which every student performed the procedure
under supervision of the same expert. After the course was done, the instructor was
dismissed from further participation in the study.
The experimental group also had a 45-minutes lecture on UGRA. This lecture
was informed by the gold standard generated from results of the CTA interviews. It also
covered all of the objectives and goals, as defined by the ASRA-ESRA guidelines.
Following the lecture, all subjects from this group engaged in simulator practice. The
experimental group instructor demonstrated all steps in performance of UGRA, after
which every student performed the procedure under supervision by the same expert. This
instructor was also dismissed from further proceedings.
After the instruction cycle was over, all equipment was pooled in one classroom
and all students were evaluated on performance of UGRA. Experts evaluating the final
performance were blinded to the initial group assignment. Subjects who completed the
final performance evaluation were dismissed after answering the declarative knowledge
post-test.
Data Collection and Analysis
All data sheets were coded in order to protect confidentiality. Each subject was
assigned a number at random, and all scores were recorded under this number. The
pretest, post-test, and performance skill checklist were graded by two raters, who reached
consensus on every item for 100% inter-rater reliability. The raw data was entered in an
38
Excel spreadsheet and then used for statistical analysis. SPSS Statistics Version 16.0,
SPSS, Inc., Chicago, IL software was used for statistical analysis. The effect sizes for the
main outcomes were calculated as suggested by Cohen, (1988).
A two-tailed independent sample t-test was used to determine if there was a
difference in the pretest knowledge of the subjects, with ! = 0.5 and a significance
interval of 95%. A one-tailed independent sample t-test was used to determine if the final
scores on the declarative knowledge test of the experimental group were significantly
better that the final scores of the control group, with ! = 0.5 and a significance interval of
95% (p<.05). To determine the effect size, Cohen’s d value was calculated for this
outcome.
A one-tailed independent sample t-test was used to determine if there was
significant difference in the postinstruction procedural knowledge of the subjects from
the control and the experimental group, with ! = 0.5 and a significance interval of 95%
(p<.05). The effect size was calculated by determining the Cohen’s d value.
A one-tailed independent sample t-test was used to determine if the time for UGRA task
performance in the experimental group was significantly shorter that the time for task
performance in the control group, with ! = 0.5 and a significance interval of 95%
(p<.05). The effect size was calculated by determining the Cohen’s d value.
39
CHAPTER FOUR
RESULTS
This study compared two UGRA instructional models. The traditional
instruction, based on expert knowledge, was compared to a CTA-informed model. The
research question—Is CTA-based instruction in UGRA more effective than conventional
clinical instruction as measured by conceptual pre- and post-tests and the performance of
simulated UGRA procedure? —was analyzed through students’ performance on
declarative knowledge tests and performance on a simulated UGRA task. The simulation
mimicked a performance of popliteal nerve block on a high-fidelity UGRA simulator.
The hypothesis was that the experimental group receiving CTA-informed instruction
would perform better, demonstrate greater declarative and procedural knowledge and
produce fewer procedural mistakes than the control group receiving traditional instruction
on UGRA, at a 95% confidence level with p < 0.05.
Pre-instruction tests
Before instruction, the students completed a demographic survey and pretest. The
purpose was to establish that groups are equivalent and comparable.
Demographic analysis. Thirty-nine medical students registered for the study. All
of them satisfied the inclusion criteria and successfully completed the assignments and
were included in the study. After the researcher obtained written informed consent, the
students were randomly assigned to two groups. The experimental group had 19
participants: 13 male and 6 female. The control group had 20 participants: 11 male and 9
40
female. For each group, the breakdown of the participants based upon years of training
in medical school and gender is presented in Table 1, below.
Table 1: Demographic Analysis
Experimental Group
(n = 19)
Control Group
(n = 20)
Males
(n=13)
Females
(n=6)
Males
(n=11)
Females
(n=9)
First Year
Medical Students
5 1 5 5
Second Year
Medical Students
7 5 6 4
Third Year
Medical Students
1 0 0 0
All participants had passed an anatomy course. One participant in the
experimental group and one participant in the control group disclosed prior experience
with UGRA; both of them had only observed UGRA procedure.
Declarative knowledge pre-test. On the 11-question pretest (maximum of 22
points), the experimental group achieved mean score of 4.45 points (SD = 3.35). The
control group scored a 5.2 point mean, with SD = 3.2. A two-tailed independent sample
t-test was used to determine if there is a significant difference between the mean scores of
the two groups. Levine’s test for analysis of variance pointed to equal variances (F =
.034 and p = .85). The t-test did not reveal a significant difference between the scores of
the pretest (t = -.69 and p = .495), therefore validating the hypothesis that the participants
from the experimental and control groups had similar preexisting knowledge of UGRA.
Details of the pretest statistical analysis are presented in Appendix I.
41
Postinstruction tests
Declarative knowledge post-test. A declarative knowledge post-test was
administered immediately after the instruction was completed. The hypothesis was that
the experimental group would perform better than the control group. The post-test had
11 questions (maximum of 22 points) equivalent to the pretest. The mean score of the
experimental group was 17.53 (SD = 2.8). The mean score of the control group was 13.9
(SD = 2.4). A one-tailed independent sample t-test was used to determine if there is a
significant difference between the mean scores of the two groups. The t-test results were
t = 4.33 with p<.05, suggesting significantly better scores in the experimental group.
Details of the post-test statistical analysis are presented in Appendix J. The calculated
effect size was d=1.43
Procedural knowledge test. The procedural knowledge of UGRA was evaluated
with a procedural skills checklist. Before the study, the evaluators graded three simulated
procedures using the study instrument. The inter-rater reliability was 100%. For the
study, the evaluators graded the performance with “not done,” “done incorrectly,” and
“done correctly,” assigning 0, 1, and 2 points, respectively. The highest possible score of
50 points was given for a flawless performance. The hypothesis was that the
experimental group would perform better than the control group. The experimental
group achieved a mean score of 40.1 (SD = 5.92). The control group scored a mean of
32.0 with SD = 3.95. A one-tailed independent sample t-test was used to determine if
there is a significant difference between the mean scores of the two groups. The
experimental group performed significantly better than the control, with t = 5.2 and
42
p<.05. Details of the procedural knowledge statistical analysis are presented in Appendix
K. The effect size was calculated to be d=1.65
Time for task performance. The time necessary for performance of UGRA task
was also recorded. The average time for performance of an UGRA task for the
experimental group was 6’23” (SD = 1.02). The average time for the control group was
7’37” (SD = 1.05). A one-tailed independent sample t-test demonstrated significantly
shorter performance time for the experimental group (p<.05). Details of the statistical
analysis of the time necessary for the performance of UGRA are presented in Appendix
L. Effect size for the time for task performance was d=-1.12
Summary
The statistical analysis of the results of this study suggest that CTA-based
instruction has significantly improved the acquisition of declarative and procedural
knowledge by novice learners. The results of this study strongly support the hypothesis
that CTA-based instruction in UGRA is more effective than conventional clinical
instruction, as measured by conceptual pre- and post-tests, performance of simulated
UGRA procedure, and time necessary for the task performance.
43
CHAPTER FIVE
DISCUSSION
The purpose of this study was to examine whether instruction based on CTA
would produce results superior to traditional instruction in UGRA because a review of
the literature revealed that CTA has not yet been used to capture the expertise in regional
anesthesia and ultrasound-guided procedures. To test the formal hypothesis that CTA-
informed instruction would be superior to the traditional instruction in UGRA, a
randomized, single-blinded experiment was organized with 39 novice learners.
Performance of UGRA is a complex task that requires both declarative and procedural
knowledge; therefore, performance on the declarative knowledge test, simulated UGRA
procedure, and time for the procedure performance were considered outcomes that would
provide complete analysis of the task. The following section will discuss the different
outcomes used to confirm the hypothesis, review the study limitations, and offer
suggestions for future research.
Demographics
The results of the demographic analysis were anticipated. Because medical
students do not have an anesthesia course, their exposure to UGRA was accidental. Only
two of the participants had seen UGRA before the study—one in the experimental and
one in the control group. Their exposure was observational only and did not involve
performing any of the tasks. Therefore, these participants were not excluded from the
study and were considered what they truly were—novices. This assumption was
44
confirmed with the results of the pretest. Both groups scored poorly, with mean scores of
4.45 and 5.2 out of a possible 22. The statistical analysis could not distinguish the mean
scores at a confidence interval of 95%. Both descriptive and inferential methods used in
the analysis suggested homogenous group of participants with very limited knowledge of
UGRA, allowing further evaluation.
Declarative Knowledge
A knowledge test equivalent to the pretest was administered after the instruction.
Results demonstrated that CTA-informed instruction had significant positive effect on the
participants’ performance on the test. The effect size calculated was exceedingly large.
With d=1.43 the result suggest that the mean test scores of the experimental group were
at 92
nd
percentile of the control group. These results are consistent with the hypothesis
and with the previous research. An increasing body of evidence suggests that CTA-based
instruction in medicine and in other fields offers advantages to traditional instruction in
the acquisition of declarative knowledge. Velmahos et al. (2004), in a study with a
similar design, found that the results of the declarative knowledge post-test were
significantly higher in the experimental group. The meta-analysis of Tofel-Grehl (2011)
found CTA to be more effective for developing training for declarative knowledge.
Mean Hedge’s effect size scores established for declarative knowledge demonstrated an
effect size of g = .93.
Procedural Knowledge
Procedural knowledge was tested with the performance of a simulated UGRA
task. The high-fidelity simulator provides an environment that is almost identical to the
45
real patient experience (Xu et al., 2005) and has been used before to study novice
behavior in research conducted by Cheung et al. (2011) and Sites et al. (2007). The
performance was evaluated with a checklist based on the CTA “gold standard.” The
results of this study demonstrated significantly better performance on the part of the
experimental group. The effect size for this outcome was the largest in the study. The
mean test scores of the experimental group were at 95
th
percentile of the mean of the
control group. Findings were consistent with the results of similar studies. Sullivan et al.
(2007) found significantly higher performance scores of the CTA group, as did Tirapelle
(2010), Campbell (2010) and Velmahos et al. (2004). The meta-analysis of Tofel-Grehl,
(2011) found CTA more effective for procedural knowledge instruction. Mean Hedge’s
effect size scores established for procedural knowledge demonstrated an effect size of g =
.87.
Time for Task Performance
In the study of expertise, time for task performance is one of the classic attributes
that define an expert (Glaser & Chi, 1988). Although a 45-minute CTA-informed course
would not create an expert in regional anesthesia, it is interesting to note that the
experimental group completed the simulated UGRA task in significantly shorter time
than the control group did. The effect size of d=-1.12, suggested mean time for
performance of the task of the experimental group at 14
th
percentile of the mean time for
performance of the task in the control group.
46
Limitations
Though building on studies already published, this study made a significant effort
to overcome the problems encountered in previous work. Controlling the independent
variable—the type of instruction—presented Campbell (2010) and Tirapelle (2010) with
challenges originating from both instructors having added their own content to the
presentation. In order to prevent this problem, the script for the experimental group was
available to the experimental instructor one week before the study. The instructor was
trained to present only content from the script. Whereas the experimental group was
carefully controlled, the instructor for the control group was asked to conduct the training
as he normally does. The implications are two-fold. On one side, it is possible that the
control group instructor would deliver instruction very close to the one for the
experimental group. This scenario would produce a Type-1 error and confound the
results. The results of this study provide strong argument against such possibility. On the
other side, substandard, confusing instruction would produce a Type-2 error. To prevent
this kind of problem, the instructor of the control group was asked to provide the standard
course being taught to our residents, which covers the standard UGRA topics. Because
the content of the control group instruction is impossible to control—and from the
omission studies it is well known that experts omit a significant amount of critically
important content—it may be beneficial for future studies to monitor the control group
instruction with a checklist that would indicate how many of the necessary elements were
present.
47
Future Studies
In this study the effect of the instruction was measured immediately after the
instruction was completed. It would be interesting to follow up with another evaluation
for the retention of the content. A longitudinal experiment may follow the retention of the
UGRA skills acquired with or without CTA based instruction. Utilizing the same
population from tis study, repeated evaluation after 3,6 and 12 months, could examine if
there is advantage of CTA based training on the retention of the knowledge and skill.
The results of this study for the performance of the UGRA task presented with
wide standard deviation of the mean score. This phenomenon occurred in carefully
randomized population controlled for all theoretical design considerations. Further
studies may provide finer grain image of the variables that govern this processes. UGRA
is highly dependent on visual spatial skills. Controlling for the visual spatial skills with
an adequate test may offer another dimension to the results. Finally, a multicenter study
involving several programs and instructors may provide better understanding of the role
of the instructors.
Implications
This study has strongly supported the superiority of CTA-based UGRA
instruction. It confirmed the results of several previous studies suggesting the advantages
of CTA based instruction. Future instruction based on the educational material produced
by this study should yield better educational outcomes. Development of UGRA courses
for anesthesiology residents, as well as practicing anesthesiologist would be the next
logical step. Wider application of CTA based curriculum may offer further opportunities
48
for refinement and evaluation of the methodology. Analysis of performance of expert
practitioners would validate the evaluation instruments. Fully validated instruments could
have wider application in formative and summative evaluation of UGRA training and
performance.
A more comprehensive understanding of the UGRA skills acquisition would have
implications on the clinical practice of UGRA. While this study advocates the utilization
of CTA based instruction and evaluation, a longitudinal study, mentioned in the previous
section, that examines the patterns of skill retention, would have application in
credentialing and re-credentialing.
Conclusion
This study adds to the knowledge base of CTA as first one to effectively capture
expert knowledge of UGRA. The purpose of this study was to examine weather
instruction based on CTA would produce results superior to traditional instruction. The
results obtained with randomized, double blinded experiment demonstrated significant
positive effect of CTA informed instruction on acquisition of declarative and procedural
knowledge as well as time necessary for performance of the task, therefore adding to the
number of studies that have proven the superiority of CTA informed instruction. Also,
based on the CTA analysis this study produced several instruments that can be used in
instruction and evaluation of UGRA. Evidence from this experiment suggests validity of
the instruments however, further studies are necessary to establish validity and determine
the test parameters.
49
Application of cognitive science and educational psychology to instruction in
UGRA is another contribution of this study. Demonstrating superior effectiveness and
efficiency of CTA based instructional methods to current, standard methods of instruction
in UGRA, complements the body of evidence-based instruction in medicine. Instruction
that delivers improved training in medical fields with increased accountability to patients,
learners and instructors will be the focus of the medical education of the future.
50
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56
APPENDIX A
SKILL SETS ASSOCIATED WITH UGRA PROFICIENCY
Skill Sets Associated With Proficiency (Sites et al. 2009)
Understanding Ultrasound
Image Generation and
Device Operations
Image Optimization Image Interpretation
Needle Insertion and
Injection
Understanding basic technical
principles of image generation
Learn the importance of
transducer pressure
Identify nerves
Learn the in-plane technique,
maximizing needle
visualization
Selection of the appropriate
transducer
Learn the importance of
transducer alignment
Identify muscles and
fascia
Learn the out-of-plane
technique
Selection of the appropriate
depth and focus settings
Learn the importance of
transducer rotation
Identify blood vessels,
distinguish artery from
vein
Learn the benefits and
limitations of both techniques
Understanding and appropriate
use of both time gain
compensation and overall gain
Learn the importance of
transducer tilting
Identify bone and
pleura
Learn to recognize
intramuscular needle location
Understanding and application
of color Doppler
Identify common
acoustic artifacts
Learn to recognize correct and
incorrect local anesthetic
spread
Archiving images Identify common
anatomic artifacts
(pitfall errors)
Conduct proper ergonomics
Follow ASRA-ESRA
standardization for screen
orientation to the patient
Identify vascularity
associated with needle
trajectory
Minimize unintentional
transducer movement
Identify intraneuronal needle
location
57
APPENDIX B
COGNITIVE TASK ANALYSIS GOLD STANDARD FOR
SINGLE-INJECTION ULTRASOUND GUIDED REGIONAL ANESTHESIA
Version 5
Last Updated: Monday, December 31, 2011
Gligor Gucev
Procedure Title: Ultrasound Guided Regional Anesthesia
1. Objective:
1.1. Deposit local anesthetic around nerve structures (A 55, B 61).
2. Reasons:
2.1. Perform surgical procedure (A 67).
2.2. Provide management of pain (A67, BF, C 14-18).
3. Conditions:
3.1. Indications:
3.1.1. Patient needs anesthesia for surgery.
3.1.2. Patient requires pain relief.
3.2. Contraindications
3.2.1. Patient refusal (B 79, C 106).
4. Standards:
4.1 Time
Approximately 5-10 minutes for the procedure itself. Additional 10-15 min for
consent and patient questions (C 89).
4.2 Accuracy
Greater then 95%.
5. Equipment:
5.1 Mandatory equipment:
Resuscitation set
Ultrasound machine
Sterile cover for the ultrasound probe
Sterile ultrasound jell
Sterile drape
Antiseptic solution
Local Anesthetic
58
Block needle
Syringe
Sterile gloves
Sterile gauze
Band-Aid
Standard ASA monitoring (blood pressure, pulse oxymetry, EKG)
IV access
5.2 Optional equipment:
Printer
Networked storage for video clips
Pressure controlled injection line
Needle guides for the ultrasound probe
Needle enhancing software for the ultrasound machine
6. Task List:
6.1. Consent patient (A 239).
6.2. Position the patient (A 242).
6.3. Equipment and patient preparation (A 246).
6.4. Perform the ultrasound exam (A 247).
6.5. Insert the needle in proximity to the nerve (A 251).
6.6. Inject the anesthetic/medication (A 252).
7. Procedure steps:
7.1. Consent the patient (A 239).
7.1.1. Explain the procedure to the patient (A 257).
7.1.1.1. Explain the technique (CF)
7.1.1.2. Explain the benefits of the block (CF)
7.1.1.3. Explain the benefits of the pain control during and after the surgery
(CF)
7.1.1.4. Explain the risks and the low incidence of complications (CF)
7.1.2. Explain alternative anesthetic techniques (general anesthesia and local
anesthesia). (A 259).
7.1.3. Answer all patient questions (B, C).
7.1.4. Obtain written informed consent (B, C).
7.2. Positioning (A 242).
7.2.1. Select the most ergonomic position that will align the anesthesiologist, the
block site and the ultrasound machine (A 334). Based on the block being
performed, select position most confortable for the patient and provider and
align the ultrasound machine in fashion where provider will have direct
vision of the patient and ultrasound machine.
7.2.2. IF unable to perform step 7.2.1, THEN select position most confortable for
patient and position provider and the ultrasound machine in fashion where
provider will have direct vision of the patient and ultrasound machine.
59
7.2.3. Sit on the block side of the patient (A 288, A 299), if possible, and
position the patient facing the provider (A 271).
7.2.3.1. IF the patient is receiving a block of the anterior side of the body
THAN place the patient in supine position.
7.2.3.2. IF the patient is receiving a block of the posterior side of the body
THEN place the patient in prone or sitting position.
7.3. Equipment and patient preparation (A 246).
7.3.1. Plug the ultrasound machine to power source. Check if the network
connections to printer or server are available and operational.
7.3.2. Select appropriate probe for the block (A612).
7.3.2.1. IF the block is superficial THEN use linear probe (A 618).
7.3.2.2. IF the block is deep THEN use sector probe (A 618).
7.3.3. Approximate the expected depth where the nerve structure will be based
on patient size and normal anatomy. Adjust the appropriate depth of the
ultrasound beam using the corresponding button on the ultrasound machine.
7.3.4. Disinfect the skin (A244). Use standard surgical sterile technique (A 356).
Apply 4% Chlorhexidine three times starting from the center of the field in
concentric circles towards the periphery.
7.3.5. Put on sterile gloves (A 407).
7.3.6. Cover the area with sterile drape.
7.3.7. Apply ultrasound gel to the probe (A 428). Cover the ultrasound probe (A
245) by grabbing it with the sterile cover so that outside remains sterile (A
424). Make sure there are no air bubbles between the probe and the sterile
cover (A 343)
7.3.8. Determine whether you need long- acting or short acting local anesthetic.
Consider the anesthetic length and match it with the length of surgery. If
using short-acting local anesthetic, make sure that it will last long enough to
cover the surgery time. If using long-acting local anesthetic explain the
patient that there will be residual nerve block after the surgery is done. (A
466).
7.3.9. Prepare the syringe by drawing the local anesthetic in a sterile fashion. (A
444). Connect the syringe with the needle (A 448). Fill the needle with local
anesthetic (A 491).
7.4. Perform the ultrasound exam (A 247).
7.4.1. Position the probe in plane appropriate for the block being performed so
that the nerve structures are visualized in cross section (A 524).
7.4.2. Verify the orientation of the probe by placing your finger on the probe.
Pressure from the finger will create distraction of the image on the
corresponding side. Align the probe in a way that what is left on the screen
corresponds to the left side of the work field (A 746).
7.4.3. Optimize the image (A 563).
7.4.3.1. IF nerve structures are not positioned in the center THEN adjust
the depth of the ultrasound beam by turning the corresponding button
of the ultrasound machine (A 635).
60
7.4.3.2. IF nerve structures are not seen in cross-section THEN rotate the
long axis of the ultrasound probe (B, C).
7.4.3.3. IF nerve structures are not easily recognizable THEN tilt the probe
to adjust the angle of the ultrasound beam for optimal reflection (B, C).
7.4.3.4. IF image is too dark or too bright THEN adjust the gain by turning
the gain button on the ultrasound machine (A672).
7.4.3.5. Check if the ultrasound machine has automatic or adjustable
focusing. IF adjustable, position the focus of the ultrasound machine at
the depth of the nerve structures (A 567).
7.4.4. Analyze the initial ultrasound scan (A 496). The image on the screen
should correspond with the normal anatomical section of that particular area.
Nerve should be visible in the center of the image. All structures present on
the image need to be identified and explained. IF there are anatomical
variations (blood vessels, vital structures) that will compromise the safe
performance of the block, THEN approach the nerve at different level that
will avoid the obstacle (A 390).
7.5. Insert the needle in proximity to the nerve (A 251).
7.5.1. IF using sharp, single-shot needle, insert the needle.
7.5.2. IF using blunt, large bore needle for catheter placement, THEN inject
local anesthetic to anesthetize the skin prior to introduction of the needle (A
709).
7.5.3. Advance the needle to optimal position to the nerve (A 902).
7.5.3.1. IF using in-plane technique, THEN longitudinal section of the
entire needle must be visible at all times (A 825).
7.5.3.2. IF using out-of-plane technique, THEN the tip of the needle must
be visible at all time (A 822). Tilting the angle of the ultrasound plane
by small degrees facilitates the visualization of the needle tip. If you
think that what you see on the ultrasound screen is the needle tip, by
tilting the ultrasound plane +3 degrees the tip will disappear and then
reappear as you go back to the original position (CF).
7.5.3.3. During advancement of the needle, hydrodissection may facilitate
confirmation of the needle tip for both in-plane and out-of-plane
techniques: inject 2 milliliters of the local anesthetic. IF the spread of
the anesthetic is visible on the scan THEN the needle tip is correctly
identified (BF).
7.6. Inject the anesthetic (A 252)
7.6.1. Aspirate carefully (A 904).
7.6.2. Inject slowly (A 909). Do not inject more than 5 milliliters at time.
7.6.3. Observe the spread of local anesthetic (A 910).
7.6.3.1. IF you do not see the spread of local anesthetic, THEN stop
immediately. If the tip of the needle is not visible on the screen, then
scan again until image with the entire needle and nerve is obtained (A
959).
61
7.6.3.2. IF the nerve starts swelling THEN stop immediately, the tip of the
needle is inside the nerve (A 932). Withdraw the needle, make sure that
the needle is visible on the screen, reposition and repeat injection.
7.6.3.3. IF the local anesthetic is spreading in pattern that is not enveloping
the nerve, reposition the needle and inject again until you get
satisfactory coverage of the nerve. (A 921).
7.6.4. Withdraw the needle (A 978).
7.6.5. Clean the area (A 979).
7.6.6. Cover the puncture site with Band-Aid (A 986).
8. Conditions and Cues:
The procedure is performed in intensive patient care setting. Full-scale monitoring
and resuscitation capabilities are required. Most often patients are blocked in the pre-
operative holding area or operating room. The procedure may also be performed in
intensive care unit or post anesthetic recovery room (GG).
9. Prerequisite Skills/Knowledge:
Basic knowledge of anatomy and applied anatomy is starting point for performance of
ultrasound guided regional anesthesia. Understanding!"#$ % & !'( & ) *% & #+!,- % *& % ,+( $ !. / !
%0#1(!1(*(-#'%.* as well as basic scanning techniques are also essential.
Pharmacokinetics and pharmacodynamics of local anesthetics are important
10. Concepts
10.1. Advanced cardiac life support must be available in the area where regional
anesthesia is performed. Tracheal intubation equipment, standard and emergency
drugs, oxygen and positive pressure ventilation equipment, suction and standard
monitors are required because of the inherent risks of the procedure.
10.2. Penetration of ultrasound is higher with lower frequencies. Probe with
frequency of 4-5 MHz is necessary to image structures at depth exceeding 6 cm.
10.3. Tilting of the probe changes the angle at which the ultrasound waves
approach the target tissue. Changing the attack angle changes the refraction angle
that is different for different tissue densities, therefore changing the appearance
of the tissue in the image.
10.4. Rotation of the probe on he longitudinal axes changes the appearance of
the nerves. Since nerves are elongated tubular structures, ideal cross-section
appears circular. As the angle of the plain is rotated the circle transforms into
elliptical shape and strip when the angle of the plain becomes parallel with the
long axis of the nerve.
10.5. Applying pressure on the transducer compresses he tissue and decreases
the distance from transducer to nerve, therefore allowing for better image.
10.6. Universal safety precautions
11. Process Knowledge
11.1. How to set up ultrasound machine for procedure
11.2. How to position patient and self for the procedure
11.3. How to set the equipment and prepare the medication
11.4. How to obtain ultrasound image of a nerve in transverse section
62
11.5. How to insert the needle in plane with the ultrasound beam
11.6. How to position the needle in proximity of the nerve
11.7. How to inject the local anesthetic
12. Principles
12.1. Needle must not be advanced or repositioned if it is not visible on the
image
13. Sensory mode information
13.1. Touch
13.1.1. Advancement of the needle produces changes in the resistance as passing
through tissues with different consistency.
13.1.2. Increased pressure on injection may suggest intraneural position.
13.2. Visual
13.2.1. Tissues have different reflection of the ultrasound waves and therefore
different texture on the ultrasound image. Recognizing the textures is
important for identification of the anatomic structures.
13.2.2. Observe the axis of the needle and compare it to the plane of the
ultrasound beam.
13.2.3.
13.3. Acoustic
13.3.1. Maintain verbal communication with the patient. It is the most sensitive
way to detect complications.
13.3.2. Be vigilant of the monitor’s alarm sounds
14. Safety factors
14.1. Use universal barrier precautions
14.2. Use standard monitoring
14.3. Do not inject more than 5 ml of local anesthetic at once.
14.4. Do not advance or reposition the needle unless you see it on the ultrasound
image
15. Environmental consideration
15.1. Create quiet peaceful atmosphere where patient can relax.
15.2. Provide enough space for adequate positioning
15.3. Organize the equipment and supplies in cart that will make it easily
accessible.
16. References:
17. Problems:
17.1. Incorrect ergonomics would increase the fatigue of the anesthesiologist
and over time decrease the performance.
17.2. Intravascular injection
17.3. Intraneural injection
17.4. Failed block
63
APPENDIX C
INSTRUCTOR LESSON SCRIPT
Table C-1: Lesson Overview
Instructor Activities! Student
Activities
Estimated
Time
• Discuss goals,
objectives and
confidentiality
agreement
• Agree not to share your
knowledge of simulation
scenario with other
participants/ students
5
minutes !
• Present lecture and
demonstrate
simulated UGRA
task
• Think aloud during
actions
• Review potential
problems
• Observe & ask questions
45
minutes !
• Instruct individual
participants with
hands-on practice
• Perform the UGRA task 3
times
15
minutes !
• Evaluate trainee task
performances
• Receive evaluation while
you perform the task: think
aloud so we know what you
are doing or deciding
60 – 90
minutes !
(8 - 16
students) !
• Handout posttest !
• Receive & take posttest
20
minutes!
• Provide feedback
• Receive feedback
5
minutes !
Ultrasound guided regional anesthesia
Introduction
Instructor will share the instruction and evaluation plan with the students.
64
Course Objectives
• Introduce the Lesson Goal:
o You will learn the characteristics of ultrasound important for UGRA
performance.
o We will review the decision processes of the UGRA tasks.
o You will practice the performance of UGRA on high-fidelity simulator.
o After you have had time to ask questions your performance on the task
will be evaluated on a high fidelity simulator while you explain your
decisions and actions.
Indications for UGRA
o Patient needs anesthesia for surgery.
o Patient requires pain relief.
Contraindications to UGRA:
o Patient refusal
Necessary Equipment:
o Mandatory
o Recommended
65
Procedure Overview:
• The 6 Major Tasks for Postoperative Tracheal Extubation are:
1. Consent patient
2. Position the patient
3. Equipment and patient preparation
4. Perform the ultrasound exam
5. Insert the needle in proximity to the nerve
6. Inject the anesthetic/medication
Teaching Scenario
• Explanation: A lecture will be presented covering the main concepts of UGRA.
After the lecture, instructor describes he/she is going to perform a typical
ultrasound guided block and that she/he will review the necessary steps for the
procedure along with the students.
Scenario: Instructor explains his/her actions as he works through the simulation
scenario of ultrasound guided nerve block performance describing how the
following steps are employed:
1. Consent patient
2. Position the patient
3. Setup equipment and prepare patient
4. Perform the ultrasound exam
66
5. Insert the needle in proximity to the nerve
6. Inject the anesthetic/medication
Task 1. Consent the patient
o Explain the procedure to the patient.
o Explain the technique.
o Explain the benefits of the block.
o Explain the benefits of the pain control during and after the surgery.
o Explain the risks and the low incidence of complications.
o Explain alternative anesthetic techniques (general anesthesia and local
anesthesia).
o Answer all patient questions.
o Obtain written informed consent.
Task 2. Position the patient
o Select the most ergonomic position that will align the anesthesiologist, the block
site and the ultrasound machine. Based on the block being performed, select
position most confortable for the patient and provider and align the ultrasound
machine in fashion where provider will have direct vision of the patient and
ultrasound machine.
o IF for any reason you are unable to position the patient like described above,
THEN select position most confortable for patient and position provider and the
ultrasound machine in fashion where provider will have direct vision of the
patient and ultrasound machine.
67
o Sit on the block side of the patient, if possible, and position the patient facing the
anesthesiologist.
o IF the patient is receiving a block of the anterior side of the body THAN place the
patient in supine position.
o IF the patient is receiving a block of the posterior side of the body THEN place
the patient in prone or sitting position.
Task 3. Prepare the equipment and patient
o Plug the ultrasound machine to power source. Check if the network connections
to printer or server are available and operational.
o Select appropriate probe for the block.
o IF the block is superficial THEN use linear probe.
o IF the block is deep THEN use sector probe.
o Approximate the expected depth where the nerve structure will be based on
patient size and normal anatomy. Adjust the appropriate depth of the ultrasound
beam using the corresponding button on the ultrasound machine.
o Disinfect the skin. Use standard surgical sterile technique. Apply 4%
Chlorhexidine three times starting from the center of the field in concentric circles
towards the periphery.
o Put on sterile gloves.
o Cover the area with sterile drape.
68
o Apply ultrasound gel to the probe. Cover the ultrasound probe by grabbing it with
the sterile cover so that outside remains sterile. Make sure there are no air bubbles
between the probe and the sterile cover.
o Determine whether you need long- acting or short acting local anesthetic.
Consider the anesthetic length and match it with the length of surgery. If using
short-acting local anesthetic, ensure that it will last long enough to cover the
surgery time. If using long-acting local anesthetic explain the patient that there
will be residual nerve block after the surgery is done.
o Prepare the syringe by drawing the local anesthetic in a sterile fashion. Connect
the syringe with the needle. Fill the needle with local anesthetic.
Task 4. Perform the ultrasound exam
o Position the probe in plane appropriate for the block being performed so that the
nerve structures are visualized in cross section.
o Verify the orientation of the probe by placing your finger on the probe. Pressure
from the finger will create distraction of the image on the corresponding side.
Align the probe in a way that what is left on the screen corresponds to the left side
of the work field.
o Optimize the image.
o IF nerve structures are not positioned in the center THEN adjust the depth of the
ultrasound beam by turning the corresponding button of the ultrasound machine.
o IF nerve structures are not seen in cross-section THEN rotate the long axis of the
ultrasound probe.
69
o IF nerve structures are not easily recognizable THEN tilt the probe to adjust the
angle of the ultrasound beam for optimal reflection.
o IF image is too dark or too bright THEN adjust the gain by turning the gain button
on the ultrasound machine.
o Check if the ultrasound machine has automatic or adjustable focusing. IF
adjustable, position the focus of the ultrasound machine at the depth of the nerve
structures.
o Analyze the initial ultrasound scan. The image on the screen should correspond
with the normal anatomical section of that particular area. Nerve should be visible
in the center of the image. All structures present on the image need to be
identified and explained. IF there are anatomical variations (blood vessels, vital
structures) that will compromise the safe performance of the block, THEN
approach the nerve at different level that will avoid the obstacle (A 390).
Task 5. Insert the needle in proximity to the nerve
o IF using sharp, single-shot needle, insert the needle.
o IF using blunt, large bore needle for catheter placement, THEN inject local
anesthetic to anesthetize the skin prior to introduction of the needle.
o Advance the needle to optimal position to the nerve.
o IF using in-plane technique, THEN longitudinal section of the entire needle must
be visible at all times.
o IF using out-of-plane technique, THEN the tip of the needle must be visible at all
time. Tilting the angle of the ultrasound plane by small degrees facilitates the
70
visualization of the needle tip. If you think that what you see on the ultrasound
screen is the needle tip, by tilting the ultrasound plane +3 degrees the tip will
disappear and then reappear as you go back to the original position.
o During advancement of the needle, hydro-dissection may facilitate confirmation
of the needle tip for both in-plane and out-of-plane techniques: inject 2 milliliters
of the local anesthetic. IF the spread of the anesthetic is visible on the scan THEN
the needle tip is correctly identified.
Task 6. Inject the anesthetic
o Aspirate carefully.
o Inject slowly. Do not inject more than 5 milliliters at time.
o Observe the spread of local anesthetic.
o IF you do not see the spread of local anesthetic, THEN stop immediately. If the
tip of the needle is not visible on the screen, then scan again until image with the
entire needle and nerve is obtained.
o IF the nerve starts swelling THEN stop immediately, the tip of the needle is inside
the nerve. Withdraw the needle, make sure that the needle is visible on the screen,
reposition and repeat injection.
o IF the local anesthetic is spreading in pattern that is not enveloping the nerve,
reposition the needle and inject again until you get satisfactory coverage of the
nerve.
o Withdraw the needle.
o
71
o Clean the area.
o Cover the puncture site with Band-Aid.
Preparation for Student Evaluation
• Let the students know that following their observation they will perform the
anesthesia skill while their performance is evaluated during a “think aloud”
protocol, which allows the student to explain their decisions and actions while
they perform the task on the simulator.
Evaluation (For faculty evaluating the simulator performance)
• Closely observe the performance of the UGRA task.
• Ensure that all elements of the performance are entered in the evaluation
checklist.
• Distribute the written posttest.
Provide feedback
• After the evaluation each student will receive individual feedback. They can also
discuss their performances and the simulation experience and have their questions
answered.
72
APPENDIX D
INFORMED CONSENT
73
74
75
APPENDIX E
PARTICIPANT DEMOGRAPHIC DATA SURVEY
Student Code: _________
Student Group: A B
Cognitive Task Analysis Survey for Single-injection Ultrasound Guided Regional
Anesthesia
Current year of Medical School Training 1 2 3 4 5
Gender: Female Male
Have you passed the Human Anatomy Course? No Yes
Have you ever seen ultrasound guided regional anesthesia?
No Yes If yes how many during training? _____________
Have you ever seen any ultrasound-guided procedure?
No Yes If yes how many during training? _____________
Rate your prior experience with UGRA: (circle your answer)
" #$% ! ' %! ()*+!)'#,$-! .##/!)'#,$-!
What is your confidence level with performing this task? (circle your answer)
" #!0 #$1*/% $0 % ! 2*--3%!0#$1*/%$0% ! '%45)-!
0#$ 1* / %$ - !
6,*-%!
0#$ 1* / %$ - !
76
APPENDIX F
DECLARATIVE KNOWLEDGE TEST 1
There is a 42-year-old male scheduled for outpatient left shoulder arthroscopy and
arthroscopic rotator cuff surgery. He is 180 cm tall, weights 111 kg and has no significant
medical history. The patient has requested regional anesthesia. Surgery is scheduled for
two hours.
The blood pressure is 138/87 mmHg, there is sinus rhythm of 84/min and the saturation is
100%.
Answer the following questions to the best of your ability:
1) How would you position this patient?
2) You have decided to perform interscalene block. Based on frequency of the probe
and the depth of the brachial plexus, which ultrasound probe will you use?
3) For interscalene block, what depth of field would you select?
4) What is the standard position of the ultrasound probe for this block?
5) What are the four standard maneuvers for optimization of the ultrasound image?
77
6) With your maneuver you obtained image that has recognizable anatomy, but the
structures are elongated and distorted. Which of the maneuvers would alter the
cross section of the anatomic structure?
7) What does gain adjustment on the ultrasound machine do to the image?
8) How does hypoechoic structure appear on ultrasound image?
9) How does bone appear on ultrasound image?
10) You have successfully identified the anterior scalene muscle and the middle
scalene muscle. There are four hypo-echoic circular areas between the muscles. It
appears that the top one is changing its form at change of pressure on the
ultrasound transducer. What are the possible explanations?
11) Your needle is positioned next to the plexus. After careful aspiration, you inject 3
milliliters. You notice that one of the hypo-echoic circles is growing bigger. What
are possible explanations?
78
APPENDIX G
DECLARATIVE KNOWLEDGE TEST 2
Patient of 43 years, ASA II, 75 kg is undergoing ankle fusion after a work related
injury. He is generally in good health but smokes ! packs per day and drinks
alcohol occasionally. He refused general anesthesia, but agrees to peripheral
nerve block.
Answer the following questions to the best of your ability:
1) You have decided to perform popliteal block. Based on frequency of the probe
and the depth of the sciatic nerve, which ultrasound probe will you use?
2) How would you position this patient?
3) For popliteal block, what depth of field would you select?
4) You have obtained image with recognizable anatomy, but the nerve is difficult to
distinguish from the surrounding tissue. Which maneuver will potentiate the
difference in ultrasound reflection – resulting in better differentiation of the
tissues?
5) You have selected in-plane approach for the block. You have inserted the needle
and you advance carefully towards the sciatic nerve. Half way through the
procedure you notice that you are advancing the needle but it is not moving on the
image. How do you explain this situation?
79
6) You are performing a popliteal block on a prone positioned patient using the in-
plane approach. You follow the tip of the needle as it advances through the biceps
femoris muscle. When you exit the muscle you aspirate carefully and inject 3
milliliters. There is no change on the image. What are possible explanations?
7) What is the echogenicity of local anesthetic on ultrasound image?
8) Describe the in-plain approach in ultrasound guided regional anesthesia.
9) Patient of 450 pounds is having ACL repair. You will perform a femoral block.
What ultrasound probe will you use?
10) What is the echogenicity of nerves on ultrasound image?
11) In the femoral crease you see two circular, hypo-echoic structures. What
ultrasound characteristics would point to their identification?
80
APPENDIX H
UGRA SKILLS PROCEDURAL CHECKLIST
Student Code: _________
Student Group: A B
Task
Not
performed
Performed
incorrectly
Performed
correctly
Ensure that the ultrasound machine is operational
Select appropriate probe
Select appropriate depth of field
Apply gel on the ultrasound probe
Disinfect the skin – three times, concentric circles
Put on sterile gloves
Cover the area with sterile drape
Cover the ultrasound probe with sterile sleeve
Make sure there are no air-bubbles between the sterile
cover and the ultrasound probe
Apply sterile gel to the sterile covered ultrasound probe
Select local anesthetic
Draw the local anesthetic
Fill the needle with local anesthetic
Position the probe in plane appropriate for the block
being performed so that the nerve structures are
visualized in cross section
Align the probe in a way that what is left on the screen
corresponds to the left side of the work field
Optimize the image
Analyze the ultrasound image
Insert the needle in plane
Needle visible during advancement
Needle at appropriate position to the nerve
Aspirate
Inject slowly
Explain the spread of the local anesthetic
Accept satisfactory spread
Withdraw needle
81
Were all tasks performed in correct sequence? Yes No
If not in the correct sequence then which were performed out of order?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
Total time to complete the task:___________________
Percent accuracy of task:_________________________
82
APPENDIX I
STATISTICAL ANALYSIS OF DECLARATIVE KNOWLEDGE PRE-TEST
T-TEST GROUPS=Group(1 2)
/MISSING=ANALYSIS
/VARIABLES=pretests
/CRITERIA=CI(.9500).
T-Test
[grp]
Std. Error
Mean Std. Deviation Mean N
1
2
pretests
.72038 3.22164 5.2000 20
.76993 3.35606 4.4737 19
Grou
p
Grou
p
Group Statistics
Sig. F Sig. (2-tailed) df t
t-test for Equality of Means
Levene's Test for Equality of
Variances
Equal variances
assumed
Equal variances not
assumed
pretests
.495 36.679 -.689
.495 37 -.690 .854 .034
Independent Samples Test
Std. Error
Difference
Mean
Difference Upper Lower
95% Confidence Interval of the
Difference
t-test for Equality of Means
Equal variances
assumed
Equal variances not
assumed
pretests
1.41072 -2.86335 1.05439 -.72632
1.40779 -2.86042 1.05326 -.72632
Independent Samples Test
Page 1
83
APPENDIX J
STATISTICAL ANALYSIS OF DECLARATIVE KNOWLEDGE POST-TEST
T-TEST GROUPS=Group(1 2)
/MISSING=ANALYSIS
/VARIABLES=posttests
/CRITERIA=CI(.9500).
T-Test
[grp]
Std. Error
Mean Std. Deviation Mean N
1
2
posttests
.53754 2.40394 13.9000 20
.64149 2.79620 17.5263 19
Grou
p
Grou
p
Group Statistics
Sig. F Sig. (2-tailed) df t
t-test for Equality of Means
Levene's Test for Equality of
Variances
Equal variances
assumed
Equal variances not
assumed
posttests
.000 35.548 4.333
.000 37 4.350 .660 .197
Independent Samples Test
Std. Error
Difference
Mean
Difference Upper Lower
95% Confidence Interval of the
Difference
t-test for Equality of Means
Equal variances
assumed
Equal variances not
assumed
posttests
5.32445 1.92819 .83693 3.62632
5.31542 1.93721 .83363 3.62632
Independent Samples Test
Page 1
84
APPENDIX K
STATISTICAL ANALYSIS OF PROCEDURAL KNOWLEDGE TEST
T-TEST GROUPS=Group(1 2)
/MISSING=ANALYSIS
/VARIABLES=procedurescores
/CRITERIA=CI(.9500).
T-Test
[grp]
Std. Error
Mean Std. Deviation Mean N
1
2
procedurescores
.88258 3.94702 32.0000 20
1.35917 5.92448 40.1053 19
Grou
p
Grou
p
Group Statistics
Sig. F Sig. (2-tailed) df t
t-test for Equality of Means
Levene's Test for Equality of
Variances
Equal variances
assumed
Equal variances not
assumed
procedurescores
.000 31.136 5.001
.000 37 5.052 .199 1.709
Independent Samples Test
Std. Error
Difference
Mean
Difference Upper Lower
95% Confidence Interval of the
Difference
t-test for Equality of Means
Equal variances
assumed
Equal variances not
assumed
procedurescores
11.40988 4.80065 1.62058 8.10526
11.35572 4.85480 1.60422 8.10526
Independent Samples Test
Page 1
85
APPENDIX L
STATISTICAL ANALYSIS OF TIME FOR TASK PERFORMANCE
T-TEST GROUPS=Group(1 2)
/MISSING=ANALYSIS
/VARIABLES=time
/CRITERIA=CI(.9500).
T-Test
[grp]
Std. Error
Mean Std. Deviation Mean N
1
2
time
.23509 1.05135 7.3705 20
.23473 1.02315 6.2374 19
Grou
p
Grou
p
Group Statistics
Sig. F Sig. (2-tailed) df t
t-test for Equality of Means
Levene's Test for Equality of
Variances
Equal variances
assumed
Equal variances not
assumed
time
.002 36.976 -3.411
.002 37 -3.408 .937 .006
Independent Samples Test
Std. Error
Difference
Mean
Difference Upper Lower
95% Confidence Interval of the
Difference
t-test for Equality of Means
Equal variances
assumed
Equal variances not
assumed
time
-.46000 -1.80627 .33221 -1.13313
-.45953 -1.80674 .33245 -1.13313
Independent Samples Test
Page 1
Abstract (if available)
Abstract
Cognitive task analysis (CTA) is methodology for eliciting knowledge from subject matter experts. CTA has been used to capture the cognitive processes, decision-making, and judgments that underlie expert behaviors. A review of the literature revealed that CTA has not yet been used to capture the knowledge required to perform ultrasound guided regional anesthesia (UGRA). The purpose of this study was to utilize CTA to extract knowledge from UGRA experts and to determine whether instruction based on CTA of UGRA will produce results superior to the results of traditional training. This study adds to the knowledge base of CTA in being the first one to effectively capture the expert knowledge of UGRA. The derived protocol was used in a randomized, double blinded experiment involving UGRA instruction to 39 novice learners. The results of this study strongly support the hypothesis that CTA-based instruction in UGRA is more effective than conventional clinical instruction, as measured by conceptual pre- and post-tests, performance of a simulated UGRA procedure, and time necessary for the task performance. This study adds to the number of studies that have proven the superiority of CTA-informed instruction. Finally, it produced several validated instruments that can be used in instructing and evaluating UGRA.
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Asset Metadata
Creator
Gucev, Gligor V.
(author)
Core Title
Cognitive task analysis for instruction in single-injection ultrasound-guided regional anesthesia
School
Rossier School of Education
Degree
Doctor of Education
Degree Program
Education
Publication Date
04/13/2012
Defense Date
03/27/2012
Publisher
Los Angeles, California
(original),
University of Southern California
(original),
University of Southern California. Libraries
(digital)
Tag
cognitive task analysis,Medical education,OAI-PMH Harvest,UGRA,ultrasound guided regional anesthesia
Language
English
Contributor
Electronically uploaded by the author
(provenance)
Advisor
Yates, Kenneth A. (
committee chair
), Hirabayashi, Kimberly (
committee member
), Sullivan, Maura (
committee member
)
Creator Email
ggucev@yahoo.com,gucev@usc.edu
Permanent Link (DOI)
https://doi.org/10.25549/usctheses-c3-5934
Unique identifier
UC1111687
Identifier
usctheses-c3-5934 (legacy record id)
Legacy Identifier
etd-GucevGligo-604.pdf
Dmrecord
5934
Document Type
Dissertation
Rights
Gucev, Gligor V.
Type
texts
Source
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 a...
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
Tags
cognitive task analysis
UGRA
ultrasound guided regional anesthesia