Innovations in Veterinary Education
Using the Human Patient Simulator to Educate Students of Veterinary Medicine Jerome H. Modell ■ Shauna Cantwell ■ John Hardcastle ■ Sheilah Robertson ■ Luisito Pablo ABSTRACT Introduction – The human patient simulator has proved to be an effective educational device for teaching physicians and paramedical personnel. Methodology – To determine whether veterinary medicine students would benefit from similar educational sessions, 90 students each took a turn being the patient’s clinician as real-life scenarios were played out on the simulator. The students induced and maintained anesthesia on their patient and monitored vital signs. Several critical events were presented for the students to diagnose and treat as they occurred. All students submitted a written evaluation of the course upon completion. The last 40 students were randomly divided into two groups of 20 students each. The students in Group I experienced the simulator before their clerkship examination, and those in Group II took the examination before their simulator experience. Results – The students rapidly gained confidence in treating their simulated patient. This carried over to the clinical setting, where they appeared to be more confident when anesthetizing live patients. The simulator experience brought together much of the previous didactic material that they had been exposed to so they could appreciate its clinical relevance. The overwhelming response to the simulator experience was positive. The students in Group I had a significantly higher score on the clerkship examination dealing with concepts reviewed by simulation than those in Group II, who engaged in self-study instead of the simulation exercise (p < 0.001). Conclusion – We conclude that the human patient simulator was a valuable learning tool for students of veterinary medicine. It was exciting for the students to work with this simulator, which made them deal with “real-life” scenarios, permitted them to learn without subjecting live patients to complications, enabled them to retrace their steps when their therapy did not correct the simulated patient’s problems, and facilitated correlation of their basic science knowledge with clinical data, thus accelerating their ability to handle complex clinical problems in healthy and diseased patients. Key words – simulation, anesthesia, critical incident training, students, education
INTRODUCTION
THE SIMULATOR
Simulation has been used for decades in the aviation industry to prepare pilots to fly airplanes safely.1 The major advantage of simulation is that a particular scenario can be re-run until the student adequately masters the concept, thus avoiding catastrophes during the learning process. Administering anesthesia to patients frequently requires life-or-death decisions that must be made instantly. In the course of training, several possible adverse events that can occur in the anesthetized patient will not be experienced. Thus, the first time that these events are witnessed, they may not be recognized promptly and treated appropriately, resulting in serious complications to, or death of, the patient.
The simulator consists of a full-sized adult mannequin, a special computer program that controls the values for physiologic parameters, a bar-coded intravenous injection post, and a urinary catheter. The simulator interfaces with a complete clinical anesthesia machine; a mechanical ventilator; and clinical monitors for non-invasive blood pressure, direct arterial blood pressure, electrocardiogram, temperature, pulse oximetry, pulmonary artery pressure, central venous pressure, neuromuscular conduction, cardiac output, inhaled and exhaled concentrations of respiratory and anesthetic gases, and anesthetic system pressures. A special simulator computer program controls the values for physiological parameters and displays them on the monitors for a variety of technical problems and physiologic responses to changing clinical conditions of the patient and to disease states. When medications are given intravenously or by inhalation, the computer processes the dose and adjusts the patient’s response appropriately. One or two instructors control what disease states or physiologic trespasses will be presented to the student, and the simulator adjusts the patient’s response automatically.
In the 1980s, very sophisticated human patient simulators became available for teaching physicians how to administer anesthesia. The emphasis of this equipment was on the unusual critical incidents that may occur during anesthesia. The simulators enabled anesthesiology residents and practicing anesthesiologists to be exposed to these situations in a controlled environment. With time, more common responses were added, and these simulator units are now in wide use. More recent versions have permitted demonstration of clinical manifestations of a wide variety of abnormal pulmonary and cardiovascular conditions. Our study explored whether these simulators were useful in educating students of veterinary medicine.
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The simulator is programmed to change vital signs in response to variations in the patient’s medical status or changes induced by drug administration or mechanical therapies performed by the student (Figure 1). The patient’s eyes blink while awake and the pupils respond to light, but the eyes can be closed while anesthetized. The larynx can be
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Figure 1: Students listening to breath sounds on the Human Patient Simulator programmed to demonstrate laryngospasm during an intubation attempt. The simulator breathes spontaneously and has breath sounds that can be changed in character to reflect several different disease states. Compliance of the lungs changes with increases in resistance to gas flow. The simulated patient has a heartbeat and produces heart sounds. It also has radial and carotid pulses that disappear below a critical level of systolic blood pressure. The simulator consumes oxygen and produces carbon dioxide. It can be tested for neuromuscular conduction and produces urine. Normal physiologic function, as well as numerous disease states, can be programmed to produce the appropriate whole animal response. The students have at their disposal a variety of drugs commonly used to produce anesthesia, as well as those used to restore homeostasis in the physiologically compromised patient. More than 50 drugs can be administered intravenously; the simulated patient responds appropriately to the drug and dose administered. A bar code recognition system is used to identify the drug and dose administered (Figure 2). The anesthesia machine is complete with compressed gases, liquid anesthetic agents, a circle absorber system, a mechanical ventilator, and a variety of aids and supplies. The student can select how the patient will be monitored from any or all of the following options: electrocardiogram, non-invasive blood pressure, invasive blood pressure, temperature, pulse oximetry, inspiratory and expiratory oxygen and carbon dioxide tensions, cardiac output, central venous pressure, pulmonary artery pressure, airway system pressure, neuromuscular stimulation, and inspiratory and expiratory anesthetic gas concentrations (Figure 3). Arterial blood gas results are also available upon request.
EDUCATIONAL TECHNIQUE Fifty students participated in our pilot program. We took two to six students at a time during their core clinical clerkship and provided them with a two-hour simulator session. The students were presented with case reports of patients who were scheduled for anesthesia and surgical procedures. The cases that we presented as the patients were a gorilla, which would react almost identically to humans in physiologic response to injury and drugs, and a Labrador retriever, whose reactions would also be similar to those of humans. The students examined their patient and then
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Figure 2: Drug identification and dose delivered is read by a bar code scanner. selected the method by which they would monitor the patient and induce and maintain anesthesia. Then they proceeded to anesthetize their patient. If they did not support the patient’s ventilation as the patient was induced, the patient hypoventilated or, in some cases, became apneic. Unless this was detected by the student and mechanical ventilation performed, either with a bag and mask or via an endotracheal tube, the patient became hypoxic. Subsequently, the cardiovascular changes that are expected to occur with hypoxia took place. During this process, the value of pre-oxygenating the patient prior to intubation was demonstrated. This also provided the opportunity to explain pulmonary gas exchange and oxygen delivery to the students. Almost invariably, at least one student in each group placed the patient in a deep plane of anesthesia. This was rapidly reflected in the patient’s cardiovascular response with hypotension and tachycardia. Different pulmonary states were demonstrated over the course of the two-hour exercise, with production of physiologic changes seen in hypoventilation, apnea, pneumonia, absorption atelectasis, bronchospasm, tension pneumothorax, and endobronchial intubation. Students had the opportunity, both by examining the patient and by interpreting the changes in vital signs, to make the appropriate diagnosis and initiate therapy. If the correct therapy was applied, the patient improved. If not, the patient continued to deteriorate and progressed to a state of ventricular tachycardia, ventricular fibrillation, and/or cardiac arrest, all of which the student was expected to treat. Examples of other scenarios demonstrated included massive blood loss, fluid overload, congestive heart failure, serious cardiac arrhythmias, anaphylactic reaction to antibiotic therapy, equipment failure, and even very rare occurrences such as malignant hyperthermia. During the simulation, in contrast to the situation of anesthetizing live animals in the clinic, if the student missed the correct diagnosis, the scenario could be frozen in time and JVME 29(2) © 2002 AAVMC
Figure 3: (a) Monitor displaying invasive blood pressure, pulse oximeter, electrocardiogram, temperature, and central venous and pulmonary artery pressures. (b) Monitor displaying carbon dioxide, oxygen and anesthetic gas tensions in inspired and expired gas. the problem could be discussed. This enabled the students to “think through” the differential diagnosis and apply physiologic principles to the event, thus facilitating an appropriate conclusion. After the pilot program was completed, 40 additional students were randomly divided into two groups of 20 students each. The students in Group I had the abovedescribed exposure to the simulator three days before taking the clerkship examination. The students in Group II were instructed to spend the same two-hour block of time reviewing respiratory and cardiovascular physiology, as well as anesthesia teaching handouts, before taking the clerkship examination. They were then given the opportunity post-examination to experience the simulator on an elective basis. On the multiple-choice examination, 35 questions were related to the general clerkship and 25 questions dealt with basic physiologic concepts demonstrated by the simulation and previously taught in the didactic curriculum.
OBSERVATIONS In observing the students during these two-hour exercises, we noted that, for the most part, many students were initially intimidated by the fact that this truly looked like a “real patient” treated with “real equipment.” They were concerned that they might make a mistake that could lead to a complication, or even death. Once the ice was broken by the first student participating, the process flowed smoothly and the students truly became immersed in taking care of “their patient.” The students’ faces expressed concern when things went wrong. They were anxious when the vital signs deteriorated, raised their voices when diagnosing problems and administering treatment when impending disaster was realized, and readily jumped in to perform CPR when the patient suffered cardiac arrest.
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STUDENT COMMENTS Following the simulator experience, all students were asked to comment, in narrative form, on their experience and its relevancy to their education. All 90 students submitted evaluations. Their responses were uniformly enthusiastic; examples are given in Table 1. Students reported that this experience brought together much of the didactic and clinical material that had been presented to them previously, but whose relevance to the practice of veterinary medicine they had not realized prior to the simulator exercise. They reported that taking care of a “real patient,” without having to worry about causing complications, was a unique and very rewarding way to learn. The vast majority of the students suggested that the simulator should also be used in their basic science courses. This would show them the relevance to clinical practice of the physiologic and pharmacologic responses they had learned. They also requested additional simulator experience during their clinical assignments. Some suggested that the simulator experience should precede their clinical rotations, others that it should follow them. The first group emphasized that it would better prepare them for the clinics, while the second group emphasized that they would then be more appreciative of the course content and, perhaps, retain more from it. Several students commented that, while an animal mannequin would have been more familiar to them, they felt that the experience was directly applicable to their practice and whether the mannequin was a human or an animal made little difference. Of the 90 responses, only one was negative, as that student was insulted by having to take care of a “human patient” and insisted that we obtain an animal model (which does not exist at present). A second student stated that he or she was stressed by taking care of a human but that, nevertheless, it was a powerful learning experience.
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Table 1: Examples of Anonymous Student Comments about Simulator Session •Excellent with realistic problems chosen. •I thought it did a wonderful job of teaching the methodology associated with diagnosing what is wrong with a patient. •It was a great learning experience! •I was able to focus more on what the physiologic responses were without the added anxiety of knowing it was a live patient. •More problems/time would be even better. •The simulator was realistic in his/her reactions to various treatments and simulations. •Excellent program! •Was great practice to figure out what the complication was and to see your treatment work. •Very good for learning “real life” emergency situations. •Prepares you well for dealing with patient problems. •It is ideal to learn how to think and react quickly and appropriately. •This is a fantastic learning tool! Very realistic. •It is an excellent media for learning anesthesia and its complications in a very short period of time, without risking the life of the patient. •Should definitely have two sessions in 2 days of 3–4 hours. •The simulator is a valuable teaching course, extremely real. •Great for hands on experience without having to sacrifice animals. •Very applicable for practice situations. •Great learning tool! Love it! •Great program! Could be a lot of fun to practice with. •Very applicable, great ability to respond to emergency situations. •This program is excellent! The simulator, although human, is basically the same as our patients. •Because it was so “hands-on,” the treatment will be remembered. •The students are forced to think on their feet and actually treat the patient rather than have someone else step in and fix the problem. •Great session. I highly recommend to continue sessions. •Much needed practical experience to apply all our “book knowledge” to real life. •I would really like to have a simulator in the Veterinary College for the students before they attend the clinics. •Even if a true dog model is never made, the human simulator really made me think and challenge myself. •It was fun and a worthwhile experience. I feel that I learned much more from it than doing a journal review. •Excellent! Well worth the time! Could use more. •This was a great program and I only wish we could have spent more time on the simulator. •Simulator is wonderful.
RESULTS OF THE CLERKSHIP EXAMINATION The students who experienced the simulator before taking the clerkship examination scored higher (59.4 ± 8.2%; mean ± SD) than those who took the examination after selfstudy but before experiencing the simulator (48.0 ± 8.7%; 114
p < 0.001 using unpaired Student’s t-test) on the concepts demonstrated with simulation. There was no difference in scores between the groups on the questions related to the general clerkship exclusive of simulation (73.7 ± 10.1% vs. 73.8 ± 11.1%; p = 0.966). JVME 29(2) © 2002 AAVMC
DISCUSSION Simulation, although first introduced in the airline industry, has now become a popular way to teach critical incidents in human medicine. In veterinary medicine, increasing emphasis is being placed on the use of alternatives to live animals in teaching. The advantage of simulation is that if the student does not respond properly to a critical incident that occurs, the scenario can be re-run until it is better understood and mastered by the student, with no harm to a patient. Many of the physiologic responses that occur during anesthesia are considered common and routine. Other responses, however, both mechanical and biological, are infrequently seen and, if not recognized and treated within minutes or, in some cases, within seconds, can result in irreversible damage to or death of a patient. In the course of training as a specialist in anesthesiology, several possible adverse events that can occur in the anesthetized patient may not be experienced. Thus, the first time that these events are witnessed in patients, they may not be recognized promptly and treated appropriately. It was this concern that led to the initial development of a computer-controlled patient anesthesia simulator by Denson and Abrahamson in 1969.2 Not much additional progress was made until the 1980s, when two independent groups of investigators developed more sophisticated human simulators. One of these groups was led by Gaba at Stanford University,3 and the other by Good and Gravenstein at the University of Florida.4–6 The original emphasis was on the unusual critical incidents that can occur during anesthesia and the ability to expose anesthesiology residents and practicing anesthesiologists to these situations in a controlled environment. As the technology developed, however, it became possible to incorporate into a single model the common physiologic responses to different drugs, combinations of drugs, changes in organ function, and mechanical mishaps that occur during anesthesia and surgery.7 One of these simulators, originally developed at the University of Florida and known as the Gainesville Anesthesia Simulator, is now available commercially as the Human Patient Simulator.a In our institution, this simulator is used to educate medical students, anesthesiology residents, other physicians, critical care and post-anesthesia care unit nurses, emergency medical technicians, physician assistants, engineers who design medical equipment, and respiratory therapists. Courses are currently being expanded to teach high school students the dangers of drug abuse in a simulated real-life scenario. It is an updated version of this University of Florida–built simulator that was used in this project. At the University of Florida College of Veterinary Medicine, all veterinary students receive a 15-hour didactic series on anesthesia in their second year and a two-week core clinical clerkship during their third year, during which they anesthetize cats, dogs, horses, and, occasionally, other species. Following this, in the second semester of the third year or in the fourth year, approximately 70% elect a second didactic course in either small or large animal anesthesia, while 60% elect a second two-week clinical clerkship experience. This training is the background for graduates to provide anesthesia to their patients. But it may not provide sufficient expo-
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sure to critical situations to enable graduates to immediately recognize and appropriately treat such incidents in their patients. For this reason, we conducted a pilot program that provided the veterinary students with a limited experience using the human patient simulator. During this time, the students experienced several unusual scenarios that might occur in their patients during anesthesia. We believe that after experiencing these critical incidents and actually participating in the care of the simulated patient, students have a better background for treating their patients successfully should they see these critical incidents in the future. We have observed that when our students return from the simulator session, they seem to be more confident in taking care of their patients in the operating room theater and respond much more rapidly to changes in the patient’s condition. We are quite enthusiastic about the future of patient simulators to teach veterinary medicine. We were concerned that although an evaluation tool to quantify the improvement in learning resulting from using the simulator would be desirable, this would be difficult to come by because the simulator experience at our institution does not replace other educational experiences. However, students who had had a two-hour simulator experience scored significantly higher on the portion of the clerkship examination that related to concepts demonstrated by simulation than those who had spent that time in directed self-study. The fact that scores on the general clerkship portion of the exam were identical for the two groups indicates that the random division of the students was appropriate and was not skewed by prior knowledge base. Our results are consistent with studies conducted at a medical school that have shown that simulator instruction for teaching advanced cardiac life support is superior to standard methods and that students have increased retention from simulator exercises than from book review.8 Our very positive observations of the students’ response to the simulator, the increased confidence they show in caring for their patients, and their enthusiastic critique of the experience has been rewarding. In the future, we will explore the possibility of expanding the simulator experience to construct both a basic science course and clinical science course to take advantage of the breadth of experiences possible using this educational tool. We recently converted our human mannequin to a gorilla to remove the emphasis on the human for our veterinary students. We also are in the process of exploring the economic feasibility of developing a dog mannequin that can be used specifically for veterinarians. We realize that it would be difficult to program the simulator for all of the different species that veterinarians must deal with in their practice; however, the basic physiological principles used in this exercise should be transferable to most veterinary patients. Further, if an animal mannequin is developed, the software can be reprogrammed to make it species-specific for the more common species. We believe that, just as was the case in the human arena, the use of the simulator can be beneficial in providing for continuing medical education courses for practicing veterinarians or for technicians who perform anesthesia under their direction.9 We conclude that simulators offer an excellent educational tool for the teaching of veterinary sciences. Rather than hav-
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ing to completely retool or reinvent a simulator for veterinary students, the human patient simulator can be easily adapted for training students of veterinary medicine. This education modality is exciting for the students to work with, permits them to learn without subjecting live patients to complications, enables them to retrace their steps when conditions are not treated properly, and facilitates correlation of their basic science knowledge with clinical data, thus accelerating their ability to handle complex clinical problems in healthy and diseased patients. ■
ACKNOWLEDGMENTS
6. Good ML, Gravenstein JS. Anesthesia simulators and training devices. Int Anesth Clin 27:161–168, 1989. 7. Van Meurs WL, Nikkelen E, Good ML. Pharmacokinetic-pharmacodynamic model for educational simulations. IEEE Trans Biomed Eng 45:582–590, 1998. 8. Schwid HA, Rooke GA, Ross BK, Sivarajan M. Use of a computerized advanced cardiac life support simulator improves retention of advanced cardiac life support guidelines better than a textbook review. Crit Care Med 27:821– 824, 1999.
The authors thank Ms. Kelly Spaulding and Mr. Bruce Ruiz for their technical assistance and Dr. J.S. Gravenstein, Dr. Eleanor Green, and Ms. Anita Yeager for their editorial assistance.
9. Lampotang S, Good ML, Westhrope R, Hardcastle J, Carovano RG. Logistics of conducting a large number of individual sessions with a full-scale patient simulator at a scientific meeting. J Clin Monit 13:399–407, 1997.
NOTE
AUTHOR INFORMATION
a
Medical Education Technologies, Inc., Sarasota, FL.
REFERENCES 1. Ruffell-Smith HP. A Simulator Study of the Interaction of Pilot Workload with Errors, Vigilance, and Decisions. Washington, DC: National Aeronautics and Space Administration, 1979 p1–54. 2. Denson JS, Abrahamson S. A computer-controlled patient simulator. J Am Med Assoc 208:504–508, 1969. 3. Gaba DM, DeAnda A. A comprehensive anesthesia simulation environment: Recreating the operating room for research and training. Anesthesiology 69:387–394, 1988. 4. Good ML, Lampotang S, Gibby GL, Gravenstein JS. Critical events simulation for training in anesthesiology, abstracted. J Clin Monit 4:140, 1988. 5. Good ML, Lampotang S, Ritchie G, Heffels J, Miller B. Hybrid lung model for use in anesthesia research and education, abstracted. Anesthesiology 71:A982, 1989.
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Jerome H. Modell, MD, Department of Anesthesiology, University of Florida College of Medicine, and Department of Large Animal Clinical Science, University of Florida College of Veterinary Medicine, Gainesville, FL. Address correspondence to Dr. Modell at the Department of Anesthesiology, PO Box 100254, Gainesville, FL 32610-0254. E-mail:
[email protected]. Shauna Cantwell, DVM, Department of Large Animal Clinical Science, University of Florida College of Veterinary Medicine, Gainesville, FL. John Hardcastle, BSE(ES), Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL. Sheilah Robertson, BVMS, PhD, Department of Large Animal Clinical Science, University of Florida College of Veterinary Medicine, Gainesville, FL. Luisito Pablo, DVM, Department of Large Animal Clinical Science, University of Florida College of Veterinary Medicine, Gainesville, FL.
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