SPECIAL ARTICLE
Using Computer-Controlled Interactive Manikins in Medical Education -
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STEPHEN ABRAHAMSON and PEGGY MALLACE Stephen A brahamson, PH.D, is Director, Division of Research in Medical Education, and Peggy Wallace, PH.D, & Instructional Media Specialist, Sim Two Project, Department of Medical Education, University of Southern Calqornia School of Medicine, Los Angeles, Calgornia, USA. I n the July/August issue of Medical Teacher, Jack Marshall provided a n overview of various methods that have been developed to help students learn procedural skills. Here, Stephen Abrahamson and Peggy Wallace describe i n detail and offer practical advice on the use of one of these techniques, computer-controlled interactive manikins-simulators which respond to what students are doing to them. T h e use of static simulators and simulated patients will be the subject of future articles in Medical Teacher. Computer-controlled manikins are quite new and quite rare in education. The earliest form in medical education, ‘Sim One’, was introduced in 1967 (Demon and Abrahamson, 1969). Indeed, there are still only three simulators - ‘Sim One’, ‘Harvey’and ‘Hers'-which make use of a manikin and which can properly be classified as computer-controlled and interactive. In a comprehensive review of ‘simulation technology’in medical education, Maatsch listed six different types of simulation, of which one is manikins and simulators (Maatsch et al. 1976). We further limited this definition by dividing the classification into static and interactive simulators because some of the plastic-skinned patient simulators can interact in some way with students while others merely permit examination and/or manipulation without responding to what students are doing to them (Abrahamson et al. 1979). This article includes reference to the three existing interactive models, discusses in some detail the way in which Sim One has been used, and then describes the projected future of this form of simulation by reference to plans for Sim Two. Interactive Manikins There are three major applications of this form of simulation technology in use in medical education. All
Medical Teacher V o l 2 No 1 1980
three include plastic-skinned manikins, authentic simulation of human function and response, and some degree of interaction between the simulator and the person using it .
Harvey Back in 1974 Michael S. Gordon of the University of Miami School of Medicine reported the development of “an animated manikin simulating 50 cardiovascular disease states” (Gordon 1974). Today Harvey (Figure 1) presents 20 disease states and includes a plastic representation of the human torso, neck and head and such diagnostic features as “synchronized bilateral arterial (carotid, brachial, radial and femoral) and jugular venous pulsations, precordial movements, respiration, blood pressure and auscultation in the four classic acoustic areas. . .” (Gordon and Patterson 1977). While Harvey is limited in its interaction capabilities, it is a superbly authentic simulator of the physiological events it presents. Extensive developmental work is taking place.
Hera This simulator is a life-size manikin with “a pelvis, vaginal canal, uterus, placenta, umbilical cord, and a fetus with heart sounds (Figure 2). A programmable electropneumatic system controls the uterine contractions, position of the uterus, rupture of the membranes, expulsion of the fetus, and fetal heart rate during labor and delivery sequence”. (Knapp 1972). The simulation is so authentic that “during a simulated exercise . . . the student may palpate the abdomen and assess the frequency, duration, and intensity of contractions to determine the progress of labor; make digid examination of changes in the cervix; take fetal heart tones in order to evaluate the status of the fetus“. [ b p ~ 1972). 25
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Figure 1: ‘Hawey’, the Cardiology Patient Simulator. Reproduced by courtesy of Dr Michael S . Gordon, University of Miami School of Medicine.
Figure 2: The ‘Hera’childbirth simulator. Reproduced by courtesy of Professor G . F. Knapp, Wenner-Gren Research Laboratoy, University of Kentucky. As with Harvey, this simulator has limited interactive capabilities. The very fact of its existence and continuous functioning through at least 71 ‘deliveries’is important testimony to the potential of this form of simulation in medical education. However, with regard to the present (or future), the words of the inventors are somewhat ominous. Reporting on the use of the simulator “through 71 simulated labor and delivery sequences” they indicated generally “encouraging” capability of the device to endure but added that the “vaginal lining, which must stand shear stress of delivery, was worn to the degree that it interfered with the delivery of the baby on the 72nd cycle”. (Lane and Knapp 1972). We understand that Hera is not operational at present; with its reported capabilities it is hoped that Hera’s absence is temporary and that a new -improved -model will soon be in use. Sim One This interactive manikin was the earliest reported in medical education and still represents the most advanced model to be tested to date. Created by investigators at the University of Southern California, Aerojet General 26
Figure 3: Sirn One zyth r n : e ~ : mJ . S. Denson and Stephen A brahamson.
Corporation and the Sierra Engineering Company, Sirn One (Figure 3) was originally developed to test the feasibility of simulating selected human characteristics physically and functionally for teaching-learning pur poses, and to test its effectiveness as a teaching-learning device. Sirn One, housed at the Medical School of the University of Southern California, is described by one of its inventors as “life-like in appearance, having a plastic skin that resembles its human counterpart in color and texture. The configuration is that of a patient lying on an operating table with his left arm extended, ready for intravenous injection. The right arm is fitted with a blood pressure cuff, and to the chest wall a stethoscope is taped in place over the approximate location of the heart. Sim One breathes, has a heart beat with temporal and carotid pulses and a measurable blood pressure. It opens and closes its mouth, blinks its eyes and ‘responds’ to four intravenously administered drugs and two gases (oxygen and nitrous oxide) administered through mask or tube. The analagous physiological responses to the agents and methods of treatment occur in real time, detected, controlled and enacted under the control of the computer program” (Abrahamson 1974). Since then Sirn One has been modified and now, in addition to permitting the simulation of the original anaesthetic procedure of endotracheal intubation and induction of anaesthesia, allows training of a broader group of health professionals in a wider variety of tasks. In simple terms, Sirn One ‘behaves’ as a real patient would be expected to and so can be treated like a human being. Sirn One was designed to provide learning experiences for anesthesiology residents (anaesthetic registrars) in the complex health-care task of endotracheal intubation and induction of anaesthesia, After its introduction in 1967, Sirn One was tested for educational effectiveness. Anesthesiology residents trained on Sim One attained predetermined levels of competence in half the time and with half the number of operating-room mistakes compared to a control group of anesthesiology residents trained in the conventional manner (Denson and Abrahamson 1969). In addition to the continuous training of Medical Teacher Vol2 No 1 1980
can be started on a simple, non-complicated procedure; when he completes that one satisfactorily, the next ones can be more and more complex, including the real-life distraction of multiple and extraneous stimuli -but only as the student demonstrates competence and confidence in his skills. 4. Sim One provides real time as a factor, requiring the students to perform with real urgency-a condition not available with static simulation devices and available otherwise only in real patients. 5. Sirn One permits introduction of emergencies at the push of a button, allowing the student to be prepared systematically to deal with conditions that otherwise cannot be predictably produced for students’ learning. 6 . Training in the management of chronic conditions can be provided through computer -controlled com pression of real time for the student. For example, one of the plans for Harvey, the cardiac disease simulator, is to be able to present initially a particular chronic disease state to the student, after which the simulator would be made to age a given number of years-the hair would gray, the face would wrinkle and the cardiac condition would progress-so that the student can learn what the future outcome of each disease state might be. 7. While the simulation can be started in a standard format, the computer permits variation in the manikin’s response so that the student does not become conditioned to a one-response format or pattern. Sirn Two (described later) will have a random-access capability which will provide responses slightly different from each other but all within real-life limits. 8. The use of this form of simulation can save faculty time and/or student time necessary for the teaching and/or learning of the tasks involved.
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anesthesiology residents, Sirn One has been used, with similar results, to teach third- and fourth-year medical students in the anesthesiology clerkship. Indeed, Sim One is an integral part of the curriculum. Later studies of the use of Sirn One by other personnel in performing such tasks as intramuscular injection, intravenous puncture and drawing of blood showed that here, too, the manikin had significant teaching-learning advantages (Abrahamson and Hoffman 1974). The effectiveness of the use of Sim One compared with conventional teaching methods in promoting learning was clearly demonstrated in fifteen out of eighteen experiments involving residents, medical students, inhalation therapists, nurses and ward attendants conducted over a three-year period (Table 1) (Hoffman and Abrahamson 1975). All of these studies involved formal testing and/or certification of skills. Discussion of this form of simulation
Advantages 1. There is a significant reduction in potential discomfort or harm to patients posed by students in the early stages of learning skills. Obviously there is no risk to a real patient during the time that the student is learning on the simulator. And, by the time the student is ready for experience with the real patient, his skills should be significantly improved. 2. Learning with Sim One (or a similar interactive manikin) permits students to learn from mistakes far more readily. If Sim One ‘dies’, a push of a button on the control panel can ‘bring him back to life’ and start the problem over again for the student. 3. Sirn One permits the planned and gradual increase in difficulty of situations faced by the learner. The student
Table 1. Variety of tasks performed by different groups of health professionals using Sirn One. Licensed Interns
Medical students
Nurses
Respirator application
X
X
X
Endotracheal intubation
X
X
Learners
Residents
Nursing students
voca t iona 1
nurses
I n ha la t ion therapists
Paramedical personnel
Tasks
X X
Intramuscular injection
X
Recovery room care
X X
Pulse and respiration measurement Induction of anaesthesia
Medical Teacher V o l 2 No 1 1980
X
27
9. Complex tasks can be standardized for effective, objective assessment of student skill level.
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Disadvantages 1. The initial cost of an interactive simulator is usually high. In addition, there are the costs of operation, maintenance, and service. They should not be ignoredthey are a disadvantage; these costs, however, should be amortized over time. While the quoted cost of Sim One was $100,000 in 1974, the present cost is not available because Sim One is not in current manufacture. 2. Teachers tend to have a ‘natural’ reluctance to learn how to use newer educational technology. Teachers must be (a) motivated, (b) orientated, and (c) guided to use such a simulator properly. 3. Introducing this form of technology is like other innovations in that its introduction into and integration with the existing educalional programme(s) of the institution poses a problem. The use of a sophisticated simulation system may require the systematic review of the entire existing curriculum so that implementation and integration can truly capitalize on the advantages available. 4. If the simulation is faulty-or becomes less authentic -it poses the threat of teaching the student to perform the tasks incorrectly. 5 . If the simulation becomes unreliable, both teacher and student will react by losing enthusiasm for this form of teaching and learning.
Comments 1. This form of simulation is best used (i.e., provides biggest benefit) in teaching the use of a combination of already learned individual skills. That is, Sirn One showed greater cost-benefit in the learning of the complex set of skills of intubation and induction than in the simple tasks of intubation or intravenous puncture or intramuscular injection. 2. This form of simulation works best as a training tool because complexity can be gradually programmed into the learning experience, and as an evaluation tool because complex procedures can be standardized for testing purposes. 3. It is best used with individual students or very small groups. 4. It can be used by students alone to practise skills already demonstrated by the teacher and attempted by the student with the teacher present.
Practical Guide for Use of Sirn One Sirn One was used more or less continuously between 1972, when the cost-effectivenessstudies were completed, and 1978. Last year, the steady increase in the number of age-induced problems caused a corresponding increase in those times when the simulator system was unavailable for use because of maintenance problems. We have used 28
Sirn One with a variety of healh-care personnel (e.g., anesthesiology residents (anaesrhetic registrars) interns, (senior house officers), medical students, nursing students, nurses, inhalation rherapisrs. ward attendants) in a number of health-care task (e.g., intubation, induction of anesthesia, intramuscular injection, intravenous puncture and drawing of blood, use of the Bird respirator, checking blood prermre, pulse and respiration), and this has enabled us to draw up a logical sequence of necessary events for the user to derive the maximum benefit. Some of these steps are philosophical, others are quite mechanical. All are clearly indicated. 1. At the outset, there is a familiar first question: what do we want the student to learn? Despite the frequency with which asking this question has been recommended, and the many words that have been written about the need for ‘objectives’,there is still an outrageous tendency for educators to ‘forget’the need to speclfy exactly what it is that students are expected to learn. In the case of simulation exercises, this specification is essential. With so sophisticated a simulator as Sim One, the absence of this statement (of objectives) may lead the student to perform tasks which are not part of the desired learning outcomes. 2. Having stated quite specifically what we want the students to learn, a second question must be asked and answered: what ‘entry behaviour’ is required of students? That is, it is important to specify what knowledge and skills the students must possess in order to be able to master the tasks about to be taught on the simulator. Obviously, there may be a range of prerequisite knowledge and/or skills, but there is probably a minimum level as well -and that must be stated.
3. Not only must requirements be stated, however, but an assessment must be made to ensure that students possess the necessary traits. Thus, assessment methods must be developed and applied -perhaps involving the use of the simulator itself, perhaps demanding the use of another teaching aid. For instance, before our students began to practise induction of anaesthesia on Sirn One, we had them ‘checked out’ on their skills in intubation, using the Laerdal Company’s static, plastic-skinned manikin consisting of a head and neck accompanied by realistic oral and tracheal anatomy. Moreover, students had to learn about drugs that are used in the induction procedure: what each drugs does, its reaction time, and its proper place in the order in which the agents are used. Students also had to learn how to operate the anaesthesia machine, what gases were available, and how those gases interacted with the drugs given. Finally, the students had to be familiar with taking the blood pressure, listening to heart sounds, and the like. In other words, the simulator’s place in the learning sequence was quite well defined, and a student was not introduced to learning exercises on Sirn One until he was deemed ready for the learning. 4. In addition to ascertaining that students possess the necessary prerequisite skills and knowledge, it is necessary to train them in a protocol for performance of the tasks about to be learned. In the case of induction, we had Medical Teacher V o l 2 No 1 1980
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students learn the procedure step-by-step. That is, they learned what to do first, what to look for in the ‘patient’s’ response, what to do next (depending on the ‘patient’s’ reaction), what the next appropriate step was, and so on. 5 . Once the protocol is understood (and again assessment is needed) the teacher should demonstrate the procedure to be learned. In the case of induction, our teacher would perform a simple, straightforward intubation and induction procedure (Figure 4). Both during and after the demonstration, students should be encouraged to ask questions of the teacher. This question-and-answer period should, of course, be conducted with a small group of students-six or eight at most. 6. Following the teacher’s demonstration, all of the students in the small group should participate in performing the same procedure, each student being responsible for a different task in the overall procedure. For example, in the intubation and induction procedure, we had one student take blood pressure, another check the heart rate, another administer the drugs, while one more maintained the operating-room anaesthesia record, and yet another managed the anaesthesia machine and intubated the patient. In this way, each student is actively involved in some significant phase of the total process. The process can be repeated often enough for each student to perform all of the significant tasks. 7. After each of these joint efforts, students’ performances should be assessed and reviewed with the
Figure 4 : Instructor completing demonstration of simple intubation and induction of anaesthesia.
students. This process can be achieved by the teacher’s observation and comments (Figure 5 ) . In the case of a sophisticated simulation system like Sim One, however, the system itself provides accurate and objective feedback in two forms: an analog recorder’s graphic readout of significant physiological parameters (e.g., respiratory spiral, C 0 2 , anaesthesia level, heart rate, blood pressure) (Figure 6), and a teletype printout of all of the significant events which took place, the order in which they occurred, and the time that elapsed from the beginning of the learning exercise until each of the events took place (Figure 7). 8. It is only at this point that each student should have a n opportunity to perform the entire procedure on his own. For a first individual trial, a teacher and only one or two other students should be present (Figure 8). One student can observe another’s performance and comment and/or make suggestions, after which they change roles. As students and teacher become comfortable with the system, a technician can be used in the role of teacher (thus effecting a saving in valuable teacher time) and the technician can gradually introduce increasingly serious complications for students to confront as the practice sessions continue. In the case of Sim One, we introduced such conditions as cardiac arrhythmias, cardiac arrest, elevated blood pressure, depressed respiration, bucking (an attempt to cough out the tube when the patient becomes too light on the anaesthesia), and the like. 9. At this point, a student may make an appointment to practise on his own according to his needs and so continue until he feels confident in his ability to anaesthetize a patient. 10. The student’s declaration that he is ready to treat a patient should be reviewed by the teacher through the teacher’s observation and/or review records. It is the teacher who should make the final judgement concerning readiness to practise skills involving real patients. Obviously, the student’s skills should be far better developed through practice with the simulator than they would have been with conventional teaching approaches.
A Look to the Future
Medical Teacher V o l 2 No 1 1980
For the past decade or more, medical educators concerned with improvement of teaching practices have been consistent in their prediction that simulation is the teaching method of the future. The wide variety of forms of simulation has distracted us from realizing that this variety of teaching-learning is truly growing and being integrated into the mainstream of medical education. In the United States, one cannot find a specialty certification examination that does not make use of the ‘patient-management problem’- a pencil-and-paper form of simulation of a clinical problem to be solved. Many medical schools make extensive use of plastic models and/or manikins; some use non-patients (sometimes actors or actresses) to simulate real patients in interaction with health-care students. Now, interactive manikins are on the verge of making a significant, worldwide entrance into medical education. 29
1. Cardiac arrest and r a t life-threatening arrhythmias. 2. Hypovolemic, cardiac. and sepdc shock. 3. Respiratory distress syndrome. 4. Acute overdose of barbiturate or narcotics. Essentially, the simulation will p-nt the student with the problem of an unconscious went.The student will have to ascertain which of the Me-threatening (if any) conditions the simulated patient is manifesting, stabilize the ‘patient’, and then proceed w i t h resuscitation. The mangement will be considered complete when the ‘patient’ has been returned to consciousness, has been weaned from assisted ventilation. and shows normal vital signs. Figure 5: Assessment of student 2 performance. Med Teach Downloaded from informahealthcare.com by University of Otago on 01/05/15 For personal use only.
Simulation in General Sim Two Plans are underway to develop a new simulation system which will incorporate all of the present capabilities of Sim One and extend them into new areas. Sim Two will be basically an emergency care simulation system potentially of use to a wide variety of health-care personnel. It will be available for use in both training and evaluation of personnel in skills dealing with lifethreatening situations. Initially, Sim Two will include simulation of four life-threatening conditions:
One need only read medical education papers produced during the last few years to see the promise and contribution of simulation of all types. From the simplest form of pencil-and-paper clinical problem-solving exercise to the most complex form of computercontrolled interactive manikin, simulation is assuming an increasingly important role in medical education. The advantages so far outweigh the disadvantages that the case almost need no longer be made in defence of innovative instructional activities of this kind. Moreover, the steady erosion of availability of indigent
Figure 6: Typical graphic readout f r o m an analog recorder
30
Medical Teacher V o l 2 No 1 1980
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Figure 8: First individual trial. A teacher and only one or two other students should be present.
expectation that continuous updating of software must accompany each system. Although Sirn Two is still in developmental stages, Applied Biomedical Sciences* of Los Angela is presently engaged in producing, promoting, and marketing the simulation system. According to Michael Chaffee, President of ABS, Sim Two will be functioning in four different settings by the end of 1980, with every indication that this is only the beginning. Those of us who have been working with this form of simulation rejoice that our brainchild seems finally to have come of age. References Abrahamson, S . , Human Simulation of Training in Anesthesiology, in Medical Engineering, Year Book Medical Publishers, Chicago, 1974. Abrahamson, S. and Hoffman, K., Sirn One: a computer-controlled patient simulator, Lf’kartidningen, 1974, 71, 4756.4758. Abrahamson, S., Wallace, P. and Hansen, S., Simulation in medical education: static and interactive manikins, Journal of the Assocation for Programmed Leaning and Educational Technology (VK), 1979, in press. Demon, J. S. and Abrahamson S., A computer-controlled patient simulator, Journal of the American Medical Axsociation, 1969, 208, 504-508.
Figure 7: Typical teletype readout of szgnqicant events in the procedure. (‘Bucking’= attempt t o ‘cough’ out the endotracheal airway).
patients for teaching purposes simply underlines the need for alternative forms of clinical education. What better approach than augmentation of direct clinical experience by simulated encounters -particularly in the early stages of learning clinical skills? The state of the art, furthermore, in the use of plastics, in computer technology, and in electromechanics, is particularly conducive to significant progress. Sim Two is being planned as a ‘system’and not as a ‘simulator’ because of the certainty of continued progress and, therefore, because of the Medical Teacher V o l 2 No 1 1980
Gordon, M. S.. Cardiology patient simulator, T h e AmericanJournal of Cardiology, 1974,34,350-355. Gordon, M. S. and Patterson, D. G . , ‘Haruey’-Cardiology Patient Simuhtor, Progress report from Section of Cardiology, University of Miami, 1977. Hoffman, K. I. and Abrahamson. S., The ‘cost-effectiveness’ of Sim One, Journal of Medical Education, 1975, 50, 1127-1128. (See also Further Study of Computerized Patient Simulator in Medical Education, Educational Resources Information Centre, EDRS, National Cash Register Company, 4936 Fairmount Avenue, Bethesda, Maryland. Contract no. OE-6-10-135.) Knapp, C. F.. A childbirth simulator for training students in maternity patient care, Proceedings of San Diego Biomedical Symposium, 1972, 11, 121-124.
Lane, V. and Knapp, C. F . , The Use and Evaluation of a Dynamic Childbirth Simuhtor, Paper from College of Nursing and College of Engineering, University of Kentucky, circa 1972, 15pp. Maatsch J. L., Hoban, J. D . , Sprafka, S. A., Hendershot, N. A. and Messick, J. R., A Study of Simulation Technology in Medical Education, Office of Medical Education Research and Development, Michigan State University, 1976.
*1885 Kinneloa Canyon Road, Pasadena, California 91 107. 31
Using Computer-Controlled Interactive Manikins in Medical Education -
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STEPHEN ABRAHAMSON and PEGGY MALLACE Stephen A brahamson, PH.D, is Director, Division of Research in Medical Education, and Peggy Wallace, PH.D, & Instructional Media Specialist, Sim Two Project, Department of Medical Education, University of Southern Calqornia School of Medicine, Los Angeles, Calgornia, USA. I n the July/August issue of Medical Teacher, Jack Marshall provided a n overview of various methods that have been developed to help students learn procedural skills. Here, Stephen Abrahamson and Peggy Wallace describe i n detail and offer practical advice on the use of one of these techniques, computer-controlled interactive manikins-simulators which respond to what students are doing to them. T h e use of static simulators and simulated patients will be the subject of future articles in Medical Teacher. Computer-controlled manikins are quite new and quite rare in education. The earliest form in medical education, ‘Sim One’, was introduced in 1967 (Demon and Abrahamson, 1969). Indeed, there are still only three simulators - ‘Sim One’, ‘Harvey’and ‘Hers'-which make use of a manikin and which can properly be classified as computer-controlled and interactive. In a comprehensive review of ‘simulation technology’in medical education, Maatsch listed six different types of simulation, of which one is manikins and simulators (Maatsch et al. 1976). We further limited this definition by dividing the classification into static and interactive simulators because some of the plastic-skinned patient simulators can interact in some way with students while others merely permit examination and/or manipulation without responding to what students are doing to them (Abrahamson et al. 1979). This article includes reference to the three existing interactive models, discusses in some detail the way in which Sim One has been used, and then describes the projected future of this form of simulation by reference to plans for Sim Two. Interactive Manikins There are three major applications of this form of simulation technology in use in medical education. All
Medical Teacher V o l 2 No 1 1980
three include plastic-skinned manikins, authentic simulation of human function and response, and some degree of interaction between the simulator and the person using it .
Harvey Back in 1974 Michael S. Gordon of the University of Miami School of Medicine reported the development of “an animated manikin simulating 50 cardiovascular disease states” (Gordon 1974). Today Harvey (Figure 1) presents 20 disease states and includes a plastic representation of the human torso, neck and head and such diagnostic features as “synchronized bilateral arterial (carotid, brachial, radial and femoral) and jugular venous pulsations, precordial movements, respiration, blood pressure and auscultation in the four classic acoustic areas. . .” (Gordon and Patterson 1977). While Harvey is limited in its interaction capabilities, it is a superbly authentic simulator of the physiological events it presents. Extensive developmental work is taking place.
Hera This simulator is a life-size manikin with “a pelvis, vaginal canal, uterus, placenta, umbilical cord, and a fetus with heart sounds (Figure 2). A programmable electropneumatic system controls the uterine contractions, position of the uterus, rupture of the membranes, expulsion of the fetus, and fetal heart rate during labor and delivery sequence”. (Knapp 1972). The simulation is so authentic that “during a simulated exercise . . . the student may palpate the abdomen and assess the frequency, duration, and intensity of contractions to determine the progress of labor; make digid examination of changes in the cervix; take fetal heart tones in order to evaluate the status of the fetus“. [ b p ~ 1972). 25
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Figure 1: ‘Hawey’, the Cardiology Patient Simulator. Reproduced by courtesy of Dr Michael S . Gordon, University of Miami School of Medicine.
Figure 2: The ‘Hera’childbirth simulator. Reproduced by courtesy of Professor G . F. Knapp, Wenner-Gren Research Laboratoy, University of Kentucky. As with Harvey, this simulator has limited interactive capabilities. The very fact of its existence and continuous functioning through at least 71 ‘deliveries’is important testimony to the potential of this form of simulation in medical education. However, with regard to the present (or future), the words of the inventors are somewhat ominous. Reporting on the use of the simulator “through 71 simulated labor and delivery sequences” they indicated generally “encouraging” capability of the device to endure but added that the “vaginal lining, which must stand shear stress of delivery, was worn to the degree that it interfered with the delivery of the baby on the 72nd cycle”. (Lane and Knapp 1972). We understand that Hera is not operational at present; with its reported capabilities it is hoped that Hera’s absence is temporary and that a new -improved -model will soon be in use. Sim One This interactive manikin was the earliest reported in medical education and still represents the most advanced model to be tested to date. Created by investigators at the University of Southern California, Aerojet General 26
Figure 3: Sirn One zyth r n : e ~ : mJ . S. Denson and Stephen A brahamson.
Corporation and the Sierra Engineering Company, Sirn One (Figure 3) was originally developed to test the feasibility of simulating selected human characteristics physically and functionally for teaching-learning pur poses, and to test its effectiveness as a teaching-learning device. Sirn One, housed at the Medical School of the University of Southern California, is described by one of its inventors as “life-like in appearance, having a plastic skin that resembles its human counterpart in color and texture. The configuration is that of a patient lying on an operating table with his left arm extended, ready for intravenous injection. The right arm is fitted with a blood pressure cuff, and to the chest wall a stethoscope is taped in place over the approximate location of the heart. Sim One breathes, has a heart beat with temporal and carotid pulses and a measurable blood pressure. It opens and closes its mouth, blinks its eyes and ‘responds’ to four intravenously administered drugs and two gases (oxygen and nitrous oxide) administered through mask or tube. The analagous physiological responses to the agents and methods of treatment occur in real time, detected, controlled and enacted under the control of the computer program” (Abrahamson 1974). Since then Sirn One has been modified and now, in addition to permitting the simulation of the original anaesthetic procedure of endotracheal intubation and induction of anaesthesia, allows training of a broader group of health professionals in a wider variety of tasks. In simple terms, Sirn One ‘behaves’ as a real patient would be expected to and so can be treated like a human being. Sirn One was designed to provide learning experiences for anesthesiology residents (anaesthetic registrars) in the complex health-care task of endotracheal intubation and induction of anaesthesia, After its introduction in 1967, Sirn One was tested for educational effectiveness. Anesthesiology residents trained on Sim One attained predetermined levels of competence in half the time and with half the number of operating-room mistakes compared to a control group of anesthesiology residents trained in the conventional manner (Denson and Abrahamson 1969). In addition to the continuous training of Medical Teacher Vol2 No 1 1980
can be started on a simple, non-complicated procedure; when he completes that one satisfactorily, the next ones can be more and more complex, including the real-life distraction of multiple and extraneous stimuli -but only as the student demonstrates competence and confidence in his skills. 4. Sim One provides real time as a factor, requiring the students to perform with real urgency-a condition not available with static simulation devices and available otherwise only in real patients. 5. Sirn One permits introduction of emergencies at the push of a button, allowing the student to be prepared systematically to deal with conditions that otherwise cannot be predictably produced for students’ learning. 6 . Training in the management of chronic conditions can be provided through computer -controlled com pression of real time for the student. For example, one of the plans for Harvey, the cardiac disease simulator, is to be able to present initially a particular chronic disease state to the student, after which the simulator would be made to age a given number of years-the hair would gray, the face would wrinkle and the cardiac condition would progress-so that the student can learn what the future outcome of each disease state might be. 7. While the simulation can be started in a standard format, the computer permits variation in the manikin’s response so that the student does not become conditioned to a one-response format or pattern. Sirn Two (described later) will have a random-access capability which will provide responses slightly different from each other but all within real-life limits. 8. The use of this form of simulation can save faculty time and/or student time necessary for the teaching and/or learning of the tasks involved.
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anesthesiology residents, Sirn One has been used, with similar results, to teach third- and fourth-year medical students in the anesthesiology clerkship. Indeed, Sim One is an integral part of the curriculum. Later studies of the use of Sirn One by other personnel in performing such tasks as intramuscular injection, intravenous puncture and drawing of blood showed that here, too, the manikin had significant teaching-learning advantages (Abrahamson and Hoffman 1974). The effectiveness of the use of Sim One compared with conventional teaching methods in promoting learning was clearly demonstrated in fifteen out of eighteen experiments involving residents, medical students, inhalation therapists, nurses and ward attendants conducted over a three-year period (Table 1) (Hoffman and Abrahamson 1975). All of these studies involved formal testing and/or certification of skills. Discussion of this form of simulation
Advantages 1. There is a significant reduction in potential discomfort or harm to patients posed by students in the early stages of learning skills. Obviously there is no risk to a real patient during the time that the student is learning on the simulator. And, by the time the student is ready for experience with the real patient, his skills should be significantly improved. 2. Learning with Sim One (or a similar interactive manikin) permits students to learn from mistakes far more readily. If Sim One ‘dies’, a push of a button on the control panel can ‘bring him back to life’ and start the problem over again for the student. 3. Sirn One permits the planned and gradual increase in difficulty of situations faced by the learner. The student
Table 1. Variety of tasks performed by different groups of health professionals using Sirn One. Licensed Interns
Medical students
Nurses
Respirator application
X
X
X
Endotracheal intubation
X
X
Learners
Residents
Nursing students
voca t iona 1
nurses
I n ha la t ion therapists
Paramedical personnel
Tasks
X X
Intramuscular injection
X
Recovery room care
X X
Pulse and respiration measurement Induction of anaesthesia
Medical Teacher V o l 2 No 1 1980
X
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9. Complex tasks can be standardized for effective, objective assessment of student skill level.
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Disadvantages 1. The initial cost of an interactive simulator is usually high. In addition, there are the costs of operation, maintenance, and service. They should not be ignoredthey are a disadvantage; these costs, however, should be amortized over time. While the quoted cost of Sim One was $100,000 in 1974, the present cost is not available because Sim One is not in current manufacture. 2. Teachers tend to have a ‘natural’ reluctance to learn how to use newer educational technology. Teachers must be (a) motivated, (b) orientated, and (c) guided to use such a simulator properly. 3. Introducing this form of technology is like other innovations in that its introduction into and integration with the existing educalional programme(s) of the institution poses a problem. The use of a sophisticated simulation system may require the systematic review of the entire existing curriculum so that implementation and integration can truly capitalize on the advantages available. 4. If the simulation is faulty-or becomes less authentic -it poses the threat of teaching the student to perform the tasks incorrectly. 5 . If the simulation becomes unreliable, both teacher and student will react by losing enthusiasm for this form of teaching and learning.
Comments 1. This form of simulation is best used (i.e., provides biggest benefit) in teaching the use of a combination of already learned individual skills. That is, Sirn One showed greater cost-benefit in the learning of the complex set of skills of intubation and induction than in the simple tasks of intubation or intravenous puncture or intramuscular injection. 2. This form of simulation works best as a training tool because complexity can be gradually programmed into the learning experience, and as an evaluation tool because complex procedures can be standardized for testing purposes. 3. It is best used with individual students or very small groups. 4. It can be used by students alone to practise skills already demonstrated by the teacher and attempted by the student with the teacher present.
Practical Guide for Use of Sirn One Sirn One was used more or less continuously between 1972, when the cost-effectivenessstudies were completed, and 1978. Last year, the steady increase in the number of age-induced problems caused a corresponding increase in those times when the simulator system was unavailable for use because of maintenance problems. We have used 28
Sirn One with a variety of healh-care personnel (e.g., anesthesiology residents (anaesrhetic registrars) interns, (senior house officers), medical students, nursing students, nurses, inhalation rherapisrs. ward attendants) in a number of health-care task (e.g., intubation, induction of anesthesia, intramuscular injection, intravenous puncture and drawing of blood, use of the Bird respirator, checking blood prermre, pulse and respiration), and this has enabled us to draw up a logical sequence of necessary events for the user to derive the maximum benefit. Some of these steps are philosophical, others are quite mechanical. All are clearly indicated. 1. At the outset, there is a familiar first question: what do we want the student to learn? Despite the frequency with which asking this question has been recommended, and the many words that have been written about the need for ‘objectives’,there is still an outrageous tendency for educators to ‘forget’the need to speclfy exactly what it is that students are expected to learn. In the case of simulation exercises, this specification is essential. With so sophisticated a simulator as Sim One, the absence of this statement (of objectives) may lead the student to perform tasks which are not part of the desired learning outcomes. 2. Having stated quite specifically what we want the students to learn, a second question must be asked and answered: what ‘entry behaviour’ is required of students? That is, it is important to specify what knowledge and skills the students must possess in order to be able to master the tasks about to be taught on the simulator. Obviously, there may be a range of prerequisite knowledge and/or skills, but there is probably a minimum level as well -and that must be stated.
3. Not only must requirements be stated, however, but an assessment must be made to ensure that students possess the necessary traits. Thus, assessment methods must be developed and applied -perhaps involving the use of the simulator itself, perhaps demanding the use of another teaching aid. For instance, before our students began to practise induction of anaesthesia on Sirn One, we had them ‘checked out’ on their skills in intubation, using the Laerdal Company’s static, plastic-skinned manikin consisting of a head and neck accompanied by realistic oral and tracheal anatomy. Moreover, students had to learn about drugs that are used in the induction procedure: what each drugs does, its reaction time, and its proper place in the order in which the agents are used. Students also had to learn how to operate the anaesthesia machine, what gases were available, and how those gases interacted with the drugs given. Finally, the students had to be familiar with taking the blood pressure, listening to heart sounds, and the like. In other words, the simulator’s place in the learning sequence was quite well defined, and a student was not introduced to learning exercises on Sirn One until he was deemed ready for the learning. 4. In addition to ascertaining that students possess the necessary prerequisite skills and knowledge, it is necessary to train them in a protocol for performance of the tasks about to be learned. In the case of induction, we had Medical Teacher V o l 2 No 1 1980
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students learn the procedure step-by-step. That is, they learned what to do first, what to look for in the ‘patient’s’ response, what to do next (depending on the ‘patient’s’ reaction), what the next appropriate step was, and so on. 5 . Once the protocol is understood (and again assessment is needed) the teacher should demonstrate the procedure to be learned. In the case of induction, our teacher would perform a simple, straightforward intubation and induction procedure (Figure 4). Both during and after the demonstration, students should be encouraged to ask questions of the teacher. This question-and-answer period should, of course, be conducted with a small group of students-six or eight at most. 6. Following the teacher’s demonstration, all of the students in the small group should participate in performing the same procedure, each student being responsible for a different task in the overall procedure. For example, in the intubation and induction procedure, we had one student take blood pressure, another check the heart rate, another administer the drugs, while one more maintained the operating-room anaesthesia record, and yet another managed the anaesthesia machine and intubated the patient. In this way, each student is actively involved in some significant phase of the total process. The process can be repeated often enough for each student to perform all of the significant tasks. 7. After each of these joint efforts, students’ performances should be assessed and reviewed with the
Figure 4 : Instructor completing demonstration of simple intubation and induction of anaesthesia.
students. This process can be achieved by the teacher’s observation and comments (Figure 5 ) . In the case of a sophisticated simulation system like Sim One, however, the system itself provides accurate and objective feedback in two forms: an analog recorder’s graphic readout of significant physiological parameters (e.g., respiratory spiral, C 0 2 , anaesthesia level, heart rate, blood pressure) (Figure 6), and a teletype printout of all of the significant events which took place, the order in which they occurred, and the time that elapsed from the beginning of the learning exercise until each of the events took place (Figure 7). 8. It is only at this point that each student should have a n opportunity to perform the entire procedure on his own. For a first individual trial, a teacher and only one or two other students should be present (Figure 8). One student can observe another’s performance and comment and/or make suggestions, after which they change roles. As students and teacher become comfortable with the system, a technician can be used in the role of teacher (thus effecting a saving in valuable teacher time) and the technician can gradually introduce increasingly serious complications for students to confront as the practice sessions continue. In the case of Sim One, we introduced such conditions as cardiac arrhythmias, cardiac arrest, elevated blood pressure, depressed respiration, bucking (an attempt to cough out the tube when the patient becomes too light on the anaesthesia), and the like. 9. At this point, a student may make an appointment to practise on his own according to his needs and so continue until he feels confident in his ability to anaesthetize a patient. 10. The student’s declaration that he is ready to treat a patient should be reviewed by the teacher through the teacher’s observation and/or review records. It is the teacher who should make the final judgement concerning readiness to practise skills involving real patients. Obviously, the student’s skills should be far better developed through practice with the simulator than they would have been with conventional teaching approaches.
A Look to the Future
Medical Teacher V o l 2 No 1 1980
For the past decade or more, medical educators concerned with improvement of teaching practices have been consistent in their prediction that simulation is the teaching method of the future. The wide variety of forms of simulation has distracted us from realizing that this variety of teaching-learning is truly growing and being integrated into the mainstream of medical education. In the United States, one cannot find a specialty certification examination that does not make use of the ‘patient-management problem’- a pencil-and-paper form of simulation of a clinical problem to be solved. Many medical schools make extensive use of plastic models and/or manikins; some use non-patients (sometimes actors or actresses) to simulate real patients in interaction with health-care students. Now, interactive manikins are on the verge of making a significant, worldwide entrance into medical education. 29
1. Cardiac arrest and r a t life-threatening arrhythmias. 2. Hypovolemic, cardiac. and sepdc shock. 3. Respiratory distress syndrome. 4. Acute overdose of barbiturate or narcotics. Essentially, the simulation will p-nt the student with the problem of an unconscious went.The student will have to ascertain which of the Me-threatening (if any) conditions the simulated patient is manifesting, stabilize the ‘patient’, and then proceed w i t h resuscitation. The mangement will be considered complete when the ‘patient’ has been returned to consciousness, has been weaned from assisted ventilation. and shows normal vital signs. Figure 5: Assessment of student 2 performance. Med Teach Downloaded from informahealthcare.com by University of Otago on 01/05/15 For personal use only.
Simulation in General Sim Two Plans are underway to develop a new simulation system which will incorporate all of the present capabilities of Sim One and extend them into new areas. Sim Two will be basically an emergency care simulation system potentially of use to a wide variety of health-care personnel. It will be available for use in both training and evaluation of personnel in skills dealing with lifethreatening situations. Initially, Sim Two will include simulation of four life-threatening conditions:
One need only read medical education papers produced during the last few years to see the promise and contribution of simulation of all types. From the simplest form of pencil-and-paper clinical problem-solving exercise to the most complex form of computercontrolled interactive manikin, simulation is assuming an increasingly important role in medical education. The advantages so far outweigh the disadvantages that the case almost need no longer be made in defence of innovative instructional activities of this kind. Moreover, the steady erosion of availability of indigent
Figure 6: Typical graphic readout f r o m an analog recorder
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Medical Teacher V o l 2 No 1 1980
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Figure 8: First individual trial. A teacher and only one or two other students should be present.
expectation that continuous updating of software must accompany each system. Although Sirn Two is still in developmental stages, Applied Biomedical Sciences* of Los Angela is presently engaged in producing, promoting, and marketing the simulation system. According to Michael Chaffee, President of ABS, Sim Two will be functioning in four different settings by the end of 1980, with every indication that this is only the beginning. Those of us who have been working with this form of simulation rejoice that our brainchild seems finally to have come of age. References Abrahamson, S . , Human Simulation of Training in Anesthesiology, in Medical Engineering, Year Book Medical Publishers, Chicago, 1974. Abrahamson, S. and Hoffman, K., Sirn One: a computer-controlled patient simulator, Lf’kartidningen, 1974, 71, 4756.4758. Abrahamson, S., Wallace, P. and Hansen, S., Simulation in medical education: static and interactive manikins, Journal of the Assocation for Programmed Leaning and Educational Technology (VK), 1979, in press. Demon, J. S. and Abrahamson S., A computer-controlled patient simulator, Journal of the American Medical Axsociation, 1969, 208, 504-508.
Figure 7: Typical teletype readout of szgnqicant events in the procedure. (‘Bucking’= attempt t o ‘cough’ out the endotracheal airway).
patients for teaching purposes simply underlines the need for alternative forms of clinical education. What better approach than augmentation of direct clinical experience by simulated encounters -particularly in the early stages of learning clinical skills? The state of the art, furthermore, in the use of plastics, in computer technology, and in electromechanics, is particularly conducive to significant progress. Sim Two is being planned as a ‘system’and not as a ‘simulator’ because of the certainty of continued progress and, therefore, because of the Medical Teacher V o l 2 No 1 1980
Gordon, M. S.. Cardiology patient simulator, T h e AmericanJournal of Cardiology, 1974,34,350-355. Gordon, M. S. and Patterson, D. G . , ‘Haruey’-Cardiology Patient Simuhtor, Progress report from Section of Cardiology, University of Miami, 1977. Hoffman, K. I. and Abrahamson. S., The ‘cost-effectiveness’ of Sim One, Journal of Medical Education, 1975, 50, 1127-1128. (See also Further Study of Computerized Patient Simulator in Medical Education, Educational Resources Information Centre, EDRS, National Cash Register Company, 4936 Fairmount Avenue, Bethesda, Maryland. Contract no. OE-6-10-135.) Knapp, C. F.. A childbirth simulator for training students in maternity patient care, Proceedings of San Diego Biomedical Symposium, 1972, 11, 121-124.
Lane, V. and Knapp, C. F . , The Use and Evaluation of a Dynamic Childbirth Simuhtor, Paper from College of Nursing and College of Engineering, University of Kentucky, circa 1972, 15pp. Maatsch J. L., Hoban, J. D . , Sprafka, S. A., Hendershot, N. A. and Messick, J. R., A Study of Simulation Technology in Medical Education, Office of Medical Education Research and Development, Michigan State University, 1976.
*1885 Kinneloa Canyon Road, Pasadena, California 91 107. 31
