Virtual Reality and Simulation: Training the ... - Wiley Online Library

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Reznek et al. • VIRTUAL REALITY AND SIMULATION

SPECIAL CONTRIBUTIONS Virtual Reality and Simulation: Training the Future Emergency Physician MARTIN REZNEK, MD, PHILLIP HARTER, MD, THOMAS KRUMMEL, MD

Abstract. The traditional system of clinical education in emergency medicine relies on practicing diagnostic, therapeutic, and procedural skills on live patients. The ethical, financial, and practical weaknesses of this system are well recognized, but the alternatives that have been explored to date have shown even greater flaws. However, ongoing progress in the area of virtual reality and computer-enhanced simulation is now providing educational applications

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HE INFORMATION age is here and, in an unprecedented fashion, is changing nearly every aspect of our lives. Astoundingly, this evolution promises to accelerate as computer-related advances continue to become available at an exponential rate. Gordon Moore, the cofounder of Intel Corporations, has observed that the power of computer chips doubles every 18 to 24 months. And, Randall Tobias, a former vice-president of ATT, noted that ‘‘over the last 30 years, we have seen a 3,000-fold increase in computing power. If we had had similar progress in the automotive industry, a Lexus would cost $2, it would travel at the speed of sound and go 600 miles on a thimble full of gas.’’1 Almost every profession has learned to adapt to and subsequently exploit this ongoing progress in computing technology. The field of medicine, however, has only just begun to join in and is doing so at a considerably slower pace. The leaders in medical education, in particular, have not taken advantage of the technology that is becoming available, and those of us in emergency medicine (EM) are no exception.

From the Division of Emergency Medicine, Department of Surgery, Center for Advanced Technology in Surgery at Stanford, Stanford University Medical Center (MR, PH, TK), Stanford, CA. Received March 7, 2001; accepted August 27, 2001. Address for correspondence and reprints: Martin Reznek, MD, CATSS Laboratory, Department of Surgery, Stanford University, School of Medicine, 300 Pasteur Drive, H3680, Stanford, CA 94305-5655. Fax: 650-724-3431; e-mail: mreznek@ hotmail.com

that show tremendous promise in overcoming most of the deficiencies associated with live-patient training. It will be important for academic emergency physicians to become more involved with this technology to ensure that our educational system benefits optimally. Key words: virtual reality; simulation; emergency medicine; education. ACADEMIC EMERGENCY MEDICINE 2002; 9:78–87

In EM, as in many other specialties, the traditional training model still exists; for diagnosis, therapeutic intervention, and performing procedures, the live patient remains the cornerstone for teaching. Over the years, many educators have understood there to be significant drawbacks to this system and have searched for other options. These other training tools, including volunteers, plastic models, animals, and cadavers, have shown even greater flaws.2,3 So today, believing there to be no acceptable alternatives, we continue to rely on the patient as the foundation of our clinical education. However, the continuing progress of computing technology is providing us with applications that will challenge this notion and quickly make it outdated. Advances in the realms of virtual reality and computer-enhanced simulation are showing great promise in supplementing our traditional training system of live ‘‘models,’’ and may even eventually replace them.

RATIONALE Traditionally, we have relied on the patient as our primary vehicle for the clinical training of physicians. Unfortunately, this teaching system is not ideal due to the simple fact that the clinical practice of medicine has been refined over the years specifically to improve patient care and not necessarily education. Superior patient care and optimal physician training are often mutually exclusive in the clinical setting, and consequently live-patient training has several significant shortcomings.

ACADEMIC EMERGENCY MEDICINE • January 2002, Volume 9, Number 1 • www.aemj.org

One can appreciate these deficiencies by considering the simple example of teaching a resident to perform a procedure such as central venous catheterization. Learning curves have been demonstrated for procedures in EM as well as other specialties.4–11 Using the patient as a practice ‘‘model’’ places the patient at an increased risk of complication, but due to a historical lack of satisfactory teaching alternatives, we have had to accept this inherent risk as a ‘‘necessary evil.’’ Even if we can ethically justify allowing a resident to practice inserting a central line in a patient a single time, we certainly cannot allow the resident to repeat the exercise multiple times until he or she has performed it correctly. Even more devastating to the learning process is the fact that an instructor is ethically bound to stop the resident if he or she is making an error. For this reason, the resident will only rarely have the opportunity to experience complications resulting from his or her actions (in other words, pneumothorax or air embolus). In live-patient training, the resident is often denied the luxury of learning from his or her mistakes, a technique that many educators have reported to be highly effective and some even believe to be superior to standard methods of acquiring factual knowledge.12–14 In addition to these ethical issues, live-patientdependent education is also inefficient. In the central line example, the resident is not even guaranteed the opportunity to learn that procedure. The resident is dependent on random chance and must wait for the arrival of a patient who needs a central line before he or she can practice that skill. In fact, for procedures with indications that are less common than those of a central line, such as cricothyroidotomy, the resident may never even get the chance. Even if the resident is fortunate enough to get the opportunity to perform the procedure, significant time constraints exist that will negatively affect his or her learning. When learning on a patient, the resident commonly experiences pressure to ‘‘hurry’’ from the teacher as well as the patient. The attending physician will most likely have limited time due to his or her other duties, and the ‘‘model’’ is likely only to tolerate so much. Central venous catheterization, like any procedure, is designed, of course, from a patient care standpoint and not an educational one and as such impedes learning. For example, sterile draping is required during central line insertion on a live patient. These drapes obscure the important external landmarks that the novice needs to insert the needle properly. The internal anatomy is even more frustrating due to the fact that it cannot be visualized even before draping and must be imagined. Furthermore, with live-patient-based learning,

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standardizing the training of central line insertion is impossible because each educational experience is based on an individual patient with unique anatomy. In addition, recording the exercise, which would allow both the resident and the instructor to review the procedure multiple times and to be more objective in their assessment, is rarely performed because it is difficult and expensive. As a consequence, debriefing the resident after live-patient training is often suboptimal. Recording would also enable the debriefing to be postponed to a time that is more convenient and more conducive to learning. Finally, teaching any procedure on a live ‘‘model’’ is expensive. The instruments are not reusable, and it takes longer for a trainee to perform the procedure.15 Furthermore, an attending observer ideally should be present at all times, keeping him or her from other clinical responsibilities. And due to the learning curve, there theoretically will be a more frequent need for additional medical care due to iatrogenic injuries sustained when an inexperienced physician performs the procedure. It is clear that the live patient ‘‘model’’ is not an ideal instrument for education, especially for the introductory instruction of procedures and most medical management algorithms. Technologic advances in the areas of virtual reality and computerenhanced simulation have introduced a new method of teaching that bypasses each of the ethical, financial, and practical deficiencies of live patient training that have been illustrated in this section.

SIMULATION —BACKGROUND AND HISTORY Simulation is the act of mimicking a real object, event, or process by assuming its appearance or outward qualities.16 In order to be an effective teaching tool, a simulator must provide both educationally sound and realistic feedback to a user’s questions, decisions, and actions.17 Sufficient realism should be present for the user to suspend disbelief; however, it is important to realize that a simulator does not need to be identical to real life to accomplish this.18 Therefore, one does not have to include every detail of the real experience when designing an effective simulator. Both the birth of modern simulation and the majority of advances in this field can be credited to the aerospace industry. Flight simulation was first conceived in 1929 when Edwin Link designed an amusement park ride that gave the sensation of flying a plane. This machine eventually was modified into the Link Flight Simulator.19 Training with this primitive simulator was associated with a 90% reduction in nighttime and bad-weather col-

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lisions.15 Since that first successful simulator, several major advances have been added to the concept, including motion camera displays and eventually computer-generated displays. The success of this means of training as well as its cost–effectiveness in the aerospace sector has been well documented.20,21 Other industries as diverse as the military, business management, transportation, and nuclear power have also found success in training with simulation.1,16,17 The field of medicine has occasionally incorporated simulation into its training. However, for the majority of applications, the technology has been limited and subsequently so has its success. The one major exception to this has been the use of computer-enhanced mannequins. The first of these simulators, Sim One, was created in 1967 at the University of Southern California. This simulator consisted of a life-size mannequin connected to a computer, an instructor’s console, an interfacing unit, and an anesthesia machine. The Sim One was able to simulate cardiac arrest, blood pressure abnormalities, several arrhythmias, and airway compromise.22 Since then, significant advances in these simulators have been made, and several different commercial models are now available.23 The modern human patient simulators are designed to have more than 40 realistic findings in seven anatomic areas.17 These mannequins have several anatomically correct clinical signs, including breath sounds associated with chest rise, heart sounds, palpable carotid and radial pulses, peripheral blood pressure, pupilary reflexes, and muscle twitch from nerve stimulation. Additionally, the mannequin is able to speak by way of microphone from the operator. The simulators are designed to interface with conventional monitoring devices that can record the mannequin’s electrocardiogram, respired carbon dioxide levels, pulse oximetry signal, invasive pressures (arterial, central venous, and pulmonary artery), cardiac output, and temperature.24 All of the physical findings, as well as the signals to the monitoring devices, can be modified by the operator as needed or automatically by the computer during a scenario. In addition, the simulators are programmed to respond appropriately to approximately 70 medications24 and several physical interventions that include: intubation (unintentional endobronchial or esophageal intubation are possible), chest compression, ventilation, electrocardioversion, cricothyroidotomy (the airway can be automatically altered to make intubation difficult or impossible), chest tube insertion, and insertion of peripheral venous and arterial catheters as well as central venous lines. Modern simulators have approximately 50 available preprogrammed scenarios17 and, if required, new scenarios are easy to design.24 Just a few


examples of available scenarios are: myocardial ischemia/infarction, pneumothorax, pericardial tamponade, hypotension, hypertension, diabetic ketoacidosis, brain injury, blood loss, anaphylaxis, and multiple electrolyte abnormalities. The end result of all the capabilities listed above is that the modern human patient simulator is an extremely realistic and engaging teaching tool.23–25 These simulators have been used primarily in the field of anesthesia and therefore they have been designed mainly for this purpose. However, it has become clear that other specialties, including EM, can potentially benefit from the simulators, and accordingly some initial pilot studies are being performed.

SIMULATION IN MEDICAL EDUCATION The popularity of the human patient simulator in the field of anesthesia is mainly due to the work of Gaba, Fish, and Howard that began in the late 1980s. At that time, it was recognized that 65–70% of all unintentional incidents in anesthesia could be attributed to human error. In an attempt to gain better insight into this problem, they came across extensive research done in the aerospace sector. The airlines and NASA had begun to address human error in their profession and developed a curriculum, called Crew Resource Management (CRM), to educate their pilots in avoiding human error. Gaba, Fish, and Howard adapted the principles of this course to anesthesia and developed a program that they called Anesthesia Crisis Resource Management (ACRM). Forty percent of the course time is used to teach the proper medical responces to specific crises, and 60% is used to teach general principles of teamwork and CRM.26,27 The ACRM course has been well received. Students of the course find the mannequin and scenarios very realistic and believe that they benefit from the crisis resource management and teamwork discussions.23,24,28 A small number of studies have demonstrated construct validity of the patient simulator29 as well as improvement in performance during emergencies after training with the simulator.30 Proper objective evaluation of human performance in any setting, including ACRM, has proven thus far to be difficult. For this reason, few objective studies of ACRM have been undertaken. Despite the lack of objective data however, the subjective response has been positive, and more than a hundred simulator centers are running throughout the world.31 Other fields in medicine also have recently begun to recognize the potential of the patient simulators for teaching in their fields. Surgeons at Penn State University and Stanford University


have begun pilot studies in the use of patient simulators for resident trauma and crisis management training. Their initial observations have led them to believe that the use of these simulators in surgical education is promising; however, their findings are yet to be published. Two pilot studies using patient simulators for EM education have been reported in the literature. In New Zealand, a group has developed a course to teach EM trainees ‘‘advanced airway skills.’’32 In this course, the trainees are able to practice practical airway skills as well as hone their general management skills of an emergency. The course creators thought that the patient simulator in conjunction with their curriculum was a very effective teaching tool for EM and reported their intent to further develop their airway course. Another pilot study regarding the potential use of the patient simulator in EM was reported from Boston.33 This group developed several EM scenarios and combined ACRM principles with the MedTeams’ Emergency Team Coordination Course (ETCC) to design their pilot program. The course participants, including EM attendings, residents, and nurses, all regarded the scenarios as highly realistic, and they believed that they benefited from the course as a whole. The most unique aspect of this pilot study is that it appears to be the first to explore the simultaneous use of multiple simulators as well as patient-actors. The human patient simulator is the most impressive of the computer-enhanced medical simulators. However, two others exist that may be useful in EM and deserve brief mention. The first is ‘‘Harvey,’’ a cardiology mannequin simulator released in 1976, which is able to simulate the arterial pulse, blood pressure, jugular venous wave, precordial movements, and heart sounds in normal and diseased states.34 In EM, ‘‘Harvey’’ has been used to determine possible areas of insufficient training of emergency physicians (EPs) in the cardiovascular examination.35 The second simulator with potential applications in EM is a pelvic examination simulator that was recently developed at Stanford University. This pelvic mannequin is equipped with internal sensors that are connected to a computer. By interpreting these signals, the computer is able to provide the user with visual feedback regarding which structures they are palpating and how much pressure they are applying.36

VIRTUAL REALITY —BACKGROUND AND HISTORY The most technologically advanced form of simulation is virtual reality (VR). Jaron Lanier is credited with first coining the term ‘‘virtual reality’’ in the late 1980s; however, the origin of this technol-

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ogy can be traced to work done at MIT and Harvard University by Ivan Sutherland in the mid1960s. Sutherland envisioned a new way for computers and humans to interact and, in 1965, presented his groundbreaking talk entitled ‘‘the Ultimate Display.’’ He proposed a model for a computer display that would simulate the physical world and would allow the user to interact directly with the computer within that world. Five years later, Sutherland’s visions were realized when he invented the first head-mounted display,37 and VR was born. Most believe that it is sufficient to classify VR devices as either immersive or non-immersive. For medicine, however, it is probably more beneficial to use a classification system proposed by Voelter and Kraemer. They classified VR technology into four categories: immersive VR, desktop VR, pseudo VR, and inverse VR. Immersive VR involves a system that completely integrates the human user into the computer’s world, while desktop VR differs in that the user is not totally integrated into the virtual world but is still able to observe and manage the virtual world on a computer screen. For example, modern flight simulators used by the aviation industry and the military would be considered highly immersive. The user sits in the simulator surrounded by the visual display and realistic sounds and the simulator can move. Similar flight simulator programs are available for personal computers; however, these would be classified as desktop VR because the simulation occurs entirely on a computer screen in front of the user. The third type of VR, pseudo VR, refers to a system in which the user can control the computer animation and observe it, but there is no further interaction. For example, a three-dimensional (3-D) anatomic model can be rotated to improve learning, but it cannot be palpated or deformed. Finally, inverse VR describes the integration of a computer into the life of the user as apposed to the reverse. An example of this technology would be a program that allows quadriplegics to use a computer with eye movement-based controls in order to communicate.38 A fifth type of VR, augmented reality, was not mentioned by Voelter and Kramer, but it has been described by other groups in the literature and should be added to the classification to make it complete.39,40 Augmented reality is achieved by presenting virtual images on a see-through headmounted display, thereby superimposing the virtual world on the real one. For example, a program has been created to aid in maxillofacial surgery by enabling the surgeon to view the internal anatomical structures of a patient’s face (based on prior radiographic studies) superimposed on the patient’s surface anatomy.39 In other words, the sur-

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geon is virtually able to see through the patient’s skin. Functionally, there are four necessary elements comprising a VR system: software, hardware, input devices, and output devices.19 The software essentially is a set of mathematical algorithms and equations that define the virtual environment and its responses to the interactions with the user. The hardware is needed to perform the great number of calculations required by the software to produce the rapidly changing virtual environment. The equations and algorithms used to generate a virtual environment can be based on real-world data from photographs, pathology sections, plain radiographs, computed tomography, magnetic resonance, or ultrasound. From these data, a computer-aided design (CAD) program is used to produce a wire-frame surface model consisting of polygons. These polygons are given texture and coloring by a method called rendering.41 To improve the resolution of an object, the size of the polygons must be decreased and their number increased. However, as the number of polygons increases, so does the number of calculations to produce them. Therefore, there exists a trade-off between the speed of object updating and the image quality,42 both of which are important components of the realism of the virtual environment. Ideally, image frames need to be refreshed from 24 to 30 times per second so the eye cannot distinguish between the frames.43 The virtual environment is then presented to the user through various output devices. Virtual images are projected either on a high-resolution monitor (with or without 3-D capability) or on a head-mounted display. In addition to visual output, there also exist output devices for the other senses. Speakers can be added for audio output and devices have been created to give haptic feedback, including force feedback and tactile touch. Force and tactile feedback remain the most difficult portions of the virtual environment to simulate. The current methods of simulating tactile touch are not optimally realistic. Inflatable bladders covering the hand, vibrating transducers, electrical stimulation, and shape memory alloys that can be altered with an electrical current have all been explored with limited success.41 However, other technologies, including pneumatically-driven pins as well as new inflatable bladders, are being developed. Force feedback simulation has had much greater success. The PHANToM (produced by SensAble Technologies, Woburn, MA) is a computer-driven mechanical arm with a ‘‘wand’’ extension or a thimble at its end that allows its user to sense the position, orientation, shape, and compliance of a virtual object. In the virtual world, just


as in the real world, a person relies on six degrees of freedom of movement to feel an object’s position and orientation in space. The first three degrees of freedom are the Cartesian coordinates X, Y, and Z. Freedom of movement in these three axes is necessary for a person to define an object’s position. The remaining three degrees of freedom refer to the directions of rotation around a point or an object, sometimes referred to as ‘‘pitch,’’ ‘‘yaw,’’ and ‘‘roll.’’19 Rotation in these three degrees is important for establishing an object’s orientation. In combination with a visual display, the PHANToM is able to realistically convey a virtual object’s position and orientation using six degrees of freedom. For force feedback simulation, the PHANToM is able to convey only three degrees of freedom to its user. This limitation is due to the fact that the force feedback at any given instant can be simulated from only a single point on the virtual object’s surface. This is similar to feeling the compliance of an object such as a grapefruit through a pencil; some compliance information can be conveyed but the information is somewhat limited. Despite this hindrance, the force feedback simulation is very realistic when supported by simultaneous visual simulation. The PHANToM has been programmed to simulate the shape and compliance of many objects, including anatomic structures, and programs also exist that simulate the sensation of puncturing one or more layers of varying compliance. The computer’s output or feedback to the user is important for the realism of the virtual experience; however, the input from the user to the computer is also essential in that it makes the experience truly interactive. Conventional input devices, including the keyboard, mouse, and voice recognition technology, can all be useful in VR, but several more advanced innovations have been developed specifically for VR. Tracking devices are used to detect the position and movement of the user’s head, body, and limbs. For most purposes, tracking the hand(s) and head are sufficient for realism; however, full body suits have been developed. Electromagnetic, mechanical, and gyroscopic sensors have been used for positional and movement detection, and biosensors are currently being developed to track muscle and neuronal activity.41 Despite VR technology’s only being in its early stages, it is already impressive and certainly advanced enough to be used in many medical applications. It must be noted that the existing simulation capabilities are somewhat limited in their realism and can be disappointing if one expects too much. However, it is also essential to realize that improvements in all four of the functional portions of VR (software, hardware, input sensors, and output devices) are continually becoming available and the realism will continue to improve.


VIRTUAL REALITY IN MEDICAL EDUCATION Basic Science. Several VR projects are currently under way for basic science education. One system, called the Anatomic VisualizeR, is being developed at the University of California, San Diego. This program contains several 3-D anatomic models that are based on data from the Visible Human Project. A student is able to virtually dissect these 3-D models while simultaneously accessing other supporting 2-D resources, such as diagrams, text, and videos. The program also allows the user to adjust the size, opacity, and orientation of the various organs in order to better reveal the adjacent and deeper structures. This function of the program provides the user with an extremely effective method for learning the anatomic relations of organs.44,45 Another virtual anatomy program, called the ‘‘3D Human Atlas,’’ has been developed in Japan. This program facilitates students’ understanding of anatomic cross-sections and how they relate to the anatomy of the entire body. Cross-sections, based on magnetic resonance imaging (MRI) scans of a live model, are shown simultaneously alongside a 3-D computer rendering of the entire body of that model. An opaque plane through the 3-D model indicates the orientation of the MRI crosssection, thereby enabling the student to better understand how the cross-section relates to the entire body. Additionally, the external and internal structures of the 3-D whole-body rendering have varying opacities, allowing the user to develop a better understanding of the anatomic relationships of these organs.46 A VR program has also been designed for teaching brain anatomy to medical students. This program includes 2-D modules of gross brain sections, histology, and neuroradiology, in addition to a 3-D anatomic model of the brain. The user can adjust the views of the brain, and variable opacities exist to allow better understanding of deeper structures and their relative positions.45,47 Clinical Scenarios. The number of programs that have been created for basic science education is limited; however, more applications have been developed for advanced levels of medical training. The military, likely due to its success with VR in aviation and combat training, has been interested in using VR for training its medical personnel in battlefield trauma management. Accordingly, a military group in Germany has produced a desktop VR program that facilitates the training of medics in casualty triage, resuscitation, and evacuation.48 In this system, 30 different injuries can be simulated, multiple interventions can be performed,

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and the condition and vital signs of the patients are dynamic and respond appropriately to the specific injuries and interventions. This program incorporates an educational module, as well as practice modules and a testing module for each injury. There are text and graphic feedback as well as audio and visual feedback in the form of a realistic virtual patient; however, there is no haptic feedback. Similar VR medic trainers have also been developed by other groups.49,50 One trainer developed at the University of Pennsylvania differs slightly from the others in that a virtual medic has been added to the animation. In this program, users are able to watch the virtual medic perform the examinations or procedures that they have selected.49 In addition to out-of-hospital patient care, a virtual emergency department (ED) program has also been created.51 This system is in an early stage of development and is limited in the current number of procedures and interventions that are programmed; however, the graphics are very realistic and multiple patient types are possible (including newborns, males and females). In addition to increasing the number of available disease/injury scenarios and medical interventions, the designers intend to enhance the program in other ways to make it more realistic. One anticipated upgrade is to enable multiple users to interact in the virtual ED at the same time. A group in Norway also has begun to address this issue.52 It is their intention to use their program to facilitate the continued medical education of EPs in remote locations. The outlook for the multiple user virtual EDs is promising because a similar project in neonatology has shown initial success.53 A virtual delivery room has been programmed with a newborn that has variable breathing, movement, crying, heart rate, and skin color. These five parameters are controlled from a command computer that can be networked to other computers by local cables or an internet connection. This allows multiple users, even if separated by a great distance, to simultaneously observe the changing condition of the virtual neonate. The individual users are able to communicate with each other in real time through headphones and a microphone at each console. Currently, users can only observe the virtual baby; however, further development of the software is currently under way that will allow the users to perform virtual medical interventions on the baby. Eventually, this interesting VR setup will allow several users to care for the virtual neonate simultaneously much as nurses, residents, and attendings do in the real world. Medical Procedures. The greatest amount of work to date in VR for medical education has come in the arena of medical procedures. Virtual reality

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trainers have been developed for several different examinations, invasive procedures, and surgeries. These trainers use haptic as well as visual feedback, and most of them have been well received. Virtual reality simulators have been developed for abdominal trauma surgery, laparoscopic cholecystectomy, neurosurgery, endoscopic sinus surgery, temporal bone dissection, arthroscopic surgery of the knee and shoulder, and vascular anastamosis.54–61 In general, the minimally invasive surgeries are easier to simulate due to the limited visual and haptic feedback. The surgical field is viewed on a screen, away from the patient, and the haptic feedback is transmitted through the surgical instruments. Several of these simulators have multiple interactive modules, including educational, practice, and testing. All of these simulators have been well received and are considered to have great potential; however, most of them have not yet been adequately tested for validity or their effectiveness as teaching tools. In addition to the surgeries listed in the previous paragraph, several non–operating room invasive procedures also have been simulated using VR technology. Again, most of these use haptic as well as visual feedback, and the more advanced programs have multiple modules for education, practice, and testing. Similarly to the surgical VR programs, these have also been well received, but most presently lack significant testing. Simulators have been developed or are currently under development for: intravenous catheter insertion, skin suturing, lumbar puncture, epidural anesthesia, bone marrow biopsy, leg trauma assessment and treatment, cardiac catheterization, inferior vena cava filter placement, pericardiocentesis, cricothyroidotomy, diagnostic peritoneal lavage, and emergency thoracotomy.62–73 The emergency thoracotomy program is unique in that it previously has been studied in the EM literature.73,74 Investigators found that the program was a reliable and valid evaluation tool; however, it remained inferior to porcine animal models. Another study documented that it ‘‘showed promise’’ as a teaching tool; however, no concrete conclusions were drawn. When interpreting these results, it is important to understand that this thoracotomy program is an innovative but early simulator. It is not as interactive as many newer simulators and does not use haptic feedback. It is the only one of the simulators listed above that would be classified as pseudo VR. Therefore, generalizing the results from these two studies to other VR simulators is not appropriate because the thoracotomy program differs in its level of interaction and potential realism. A number of VR programs have also been developed to simulate minimally invasive or noninva-


sive procedures and examinations. These include: occular examination, ultrasound, hysteroscopy, sigmiodoscopy, ureteroscopy, brochoscopy, and upper GI endoscopy.75–82 The ultrasound and endoscopic simulators have been found to be very realistic. In both cases, the simulated medical instruments and visual output appear very real. Both use tracking devices that allow the computer to sense the actions of the user, and the endoscopic simulators use a robotic interface to provide the appropriate force feedback on the scope. These tracking and feedback devices are hidden from the user so they do not take away from the realism of the simulators. Only a few of these simulators have been formally studied to date. The ultrasound simulator has been examined for its potential in training surgical residents. Investigators concluded that it was equally as effective as live patient training but superior in its convenience.77 The sigmoidoscopy simulator has been shown to improve performance, but it has not been compared with the current standard of training, the live patient.79 Clearly all of these simulators, including the few that have been subjected to initial review, require further investigation.

COMBINED VIRTUAL REALITY AND SIMULATION IN MEDICAL EDUCATION Members of the department of EM at the University of Michigan have created an immersive training environment, called the Medical Readiness Trainer (MRT), that simultaneously uses both VR and computer-enhanced mannequin simulation.83 The MRT uses a mannequin simulator for haptic feedback and a CAVE system for the visual and auditory feedback. The CAVE system is essentially a room with computer-generated stereoscopic (3-D) images projected onto its walls. The participants wear stereoscopic glasses that enable them to see the wall images in three dimensions but do not otherwise distort their vision of the real world. The MRT allows participants to care for the mannequin simulator in a variety of virtual environments, including an injury scene in the field, an ED, a sick bay on a rocking naval vessel, a rescue helicopter, an ambulance, and even a battlefield. There are currently no reports of formal testing of the MRT, but its creators are hopeful that this combination of mannequin simulation and VR will prove to be an excellent training tool.

DISCUSSION Virtual reality and computer-enhanced simulation represent the future of medical education. Despite


this technology’s only being in its infancy, several applications have already shown themselves to be effective teaching tools. Given this early success and the certainty that computer and engineering technology will continue to advance at an exponential rate, it is clear that the potential of VR and simulators for medical education is astounding. We predict that once they have reached a sufficient level of sophistication and cost-efficiency, VR applications and simulators will be broadly accepted into medical education. One can easily envision an educational system in which medical students and residents will first learn procedures and other elements of patient care on simulators or in the virtual world. Once these trainees have safely mastered certain basic skills, they then can begin to hone these skills with patients in the real world. Despite the tremendous potential of simulators and VR, it is important that we do not prematurely accept them solely due to the positive subjective responses that they receive (sometimes referred to as the ‘‘wow’’ factor). Evaluation of these new teaching tools, based on sound scientific and educational principles, should be performed before they are incorporated into medical curricula. It will benefit the medical community greatly to develop a standardized methodology of evaluating these new teaching instruments. However, we remain confident that these studies will, in fact, prove the future simulators and VR programs to be more efficient, more economical, and more ethical than our current teaching methods. Following the incorporation of VR and computer-enhanced simulation into medical education, we also predict that a less tangible but equally important benefit of this technology will come to light. We believe that their use in medical education will actually improve the patient–physician relationship. Under our current system of education, the doctor in training often removes himself or herself from a patient when using that patient to learn medical skills. This naturally occurs because the trainee must focus on the learning task at hand and also because, for many of us, it is difficult to accept that we may be causing additional pain or harm to a person for our own gain. If the skills to be performed by a trainee were practiced on a simulator prior to his or her introduction to the patient, the advantage would be twofold. The doctor in training could focus more of his or her attention on developing a relationship with the patient, and the patient would be much more trusting and receptive. The potential of VR and computer-enhanced simulation in medical education has been well recognized by anesthesiologists and surgeons. Up to this point, they have been the pioneers in the field and emergency physicians rarely have been in-

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volved. A search for virtual reality and simulation in EM in the medical, computer, and engineering literature revealed only 13 publications. Of the 13, just six were published in the EM literature, and of those, two dealt with only pseudo VR and one was an editorial.84 Because the involvement of EPs has been limited, most of the VR programs as well as the mannequin simulators have not been designed with EM in mind. It is fortunate for us that many of these simulators are still useful for EM education; however, in many cases their designs could be improved for our specific needs. By EPs assuming an active leadership role in this area, we will be able to ensure that future VR and simulation technology will be steered in a direction that will most benefit education in our field. References 1. Krummel TM. Surgical simulation and VR: the coming revolution. Ann Surg. 1998; 228:635–7. 2. Nelson MS. Models for teaching emergency medicine skills. Ann Emerg Med. 1990; 9:333–5. 3. Totten VY. Ethics and teaching the art of emergency medicine. Ethical Issues Clin Emerg Med. 1999; 17:429–39. 4. Shackford SR, Rogers FB, Osler TM, Trabulsy ME, Clauss DW, Vane DW. Focused abdominal sonogram for trauma: the learning curve of nonradiologist clinicians in detecting hemoperitoneum. J Trauma. 1999; 46:553–62. 5. Delaney KA, Hessler R. Emergency flexible fiberoptic nasotracheal intubation: a report of 60 cases. Ann Emerg Med. 1988; 17:919–26. 6. Smith JE, Jackson AP, Hurdley J, Clifton PJ. Learning curves for fiberoptic nasotracheal intubation when using the endoscopic video camera. Anaesthesia. 1997; 52:101–6. 7. Watson DI, Baigrie RJ, Jamieson GG. A learning curve for laparoscopic fundoplication. Ann Surg. 1996; 224:198–203. 8. Martin KR, Burton RL. The phacoemulsification learning curve: per-operative complications in the first 3000 cases of an experienced surgeon. Eye. 2000; 14:190–5. 9. Carmody BJ, Otchy DP. Learning curve of transrectal ultrasound. Dis Colon Rectum. 2000; 43:193–7. 10. Vrancic JM, Piccinini F, Vaccarino G, Iparraguirre E, Albertal J, Navia D. Endoscopic saphenous vein harvesting: initial experience and learning curve. Ann Thorac Surg. 2000; 70: 1086–9. 11. Gates EA. New surgical procedures: can our patients benefit while we learn? Am J Obstet Gynecol. 1997; 176:1293–8. 12. Wu AW, Folkman S, McPhee SJ, Lo B. Do house officers learn from their mistakes? JAMA. 1991; 265:2089–94. 13. Short D. Learning from our mistakes. Br J Hosp Med. 1994; 51:250–2. 14. McIntyre N, Popper K. The critical attitude in medicine: the need for a new ethics. Br Med J. 1983; 287:1919–24. 15. Haluck RS, Krummel TM. Simulation and virtual reality for surgical education. Surg Technol Int VIII. 1999; 8:59–63. 16. Gorman PJ, Meier AH, Krummel TM. Simulation and virtual reality in surgical education: real or unreal? Arch Surg. 1999; 134;1203–8. 17. Issenberg SB, McGaghie WC, Hart IR, et al. Simulation technology for health care professional skills training and assessment. JAMA. 1999; 282:861–6. 18. Jones K. Simulators: A Handbook for Teachers. New York: Nichols Publishing Co., 1980. 19. Ahmed M, Meech JF, Timoney A. Virtual reality in medicine. Br J Urol. 1997; 80(suppl 3):46–52. 20. Lessons learned. Army devises systems to decide what does, and does not, work: the real value of experience. Wall Street J. May 23, 1997, p A1.

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