Volume 11, No. 3 • Fall 1996

Graphical Anesthesia Simulators Gain Widespread Use

Howard A. Schwid, M.D.

Screen-based, graphical anesthesia and critical care simulators reproduce patient care scenarios and dozens of emergency situations from the operating room, ICU, and ER environments to enable health care professionals to improve their response to critical incidents through simulator practice. Three programs developed at the University of Washington Department of Anesthesiology with funding from the APSF, and distributed by Anesoft Corporation, are gaining worldwide use by anesthesia training centers and practicing anesthesiologists.

Graphical, Screen-Based Simulators

Screen-based simulators have been successfully used in training in such diverse areas as radar and sonar systems, weapons systems, and nuclear power plant operation; now, their use in anesthesia training is growing. Full-scale, mannequin-based simulators reproduce the entire patient care environment and can be used for hands-on skills such as airway management, assessment of breath sounds, and interactions with the anesthesia machine and patient monitors. On the other hand, graphical, screen-based simulators concentrate on cognitive skills and display the essential features of the system on a computer screen with mouse or keyboard input to enter commands. Interaction with a mannequin-based simulator is more like the real environment than with a screen-based simulator, but requires significant effort and expense to organize. Graphical simulators can adequately demonstrate principles of physiology and patient management during critical incidents in a format that is very efficient and economical and as readily available as the nearest personal computer.

Anesthesia Simulator Consultant

The Anesthesia Simulator Consultant (ASC) is a screen-based anesthesia simulator that operates on Windows and Macintosh computers. Mathematical models of cardiovascular physiology, respiratory physiology, and pharmacology predict the simulated patient responses. More than 2,500 variables describe the simulated patient’s physiologic state and responses to the more than 80 drugs included in the simulator. Many conditions such as heart failure, valvular heart disease, chronic obstructive pulmonary disease, as well as renal and hepatic disease can be simulated by varying the parameters of the model. Version 2.0 has a library of 80 case scenarios including neonatal, obstetric, and geriatric cases contributed by 25 recognized anesthesia experts (Table I).

The Anesthesia Simulator Consultant can simulate pathophysiologic changes associated with dozens of anesthesia-related critical incidents including myocardial ischemia, arrhythmias, anaphylaxis, and malignant hyperthermia. Emergencies associated with regional anesthesia are also included.

The Anesthesia Simulator Consultant graphical interface (Figure 1) is easy to use by anesthesia personnel, even if they are not experienced computer users. The program produces a detailed anesthetic record allowing students or residents to use the simulator without supervision and later review the case record with an instructor for debriefing. In addition, the Anesthesia Simulator Consultant has an expert system consultant available to highlight cardiovascular and respiratory physiology, drug information and pharmacokinetic plots, and diagnosis and treatment of critical incidents.

Since ASC is easy to use, inexpensive, and operates entirely on Windows or Macintosh computers, virtually any anesthetist can rehearse critical incident management using it anytime. ASC is available in English or Spanish and over 3,000 copies have been distributed.

Critical Care Simulator

The Anesthesia Simulator Consultant concentrates on intraoperative management of patients. The Critical Care Simulator presents problems encountered in the Intensive Care Unit and Emergency Department. With the Critical Care Simulator, physicians and nurses can review hemodynamics and vasoactive infusions and also management of drug overdose, asthma, myocardial ischemia, pneumothorax, cardiac tamponade, trauma, and other medical emergencies.

ACLS Simulator

The ACLS Simulator 3.0 is a software package that allows the user to learn and review management of cardiac arrest. It consists of two modules–Rhythm and Pulse. Rhythm reviews electrocardiogram rhythm recognition and Pulse is a screen-based simulator that uses scripted scenarios to rehearse the American Heart Association Advanced Cardiac Life Support guidelines. The program covers most arrhythmias including ventricular fibrillation, ventricular tachycardia, asystole, supraventricular tachycardias, and heart blocks. The graphical interface is very simple (Figure 2) and most people learn to use the program in five minutes. If the trainee has difficulty resuscitating the patient, an expert system consultant can outline the most important therapeutic interventions, or completely take over case management. The consultant can also debrief the trainee at the end of the simulation highlighting learning objectives, correct interventions, and errors made during the simulated arrest. The ACLS Simulator is available in English, Spanish, and German.

Use of Graphical Simulators

The major goal of the screen-based anesthesia and critical care simulators is to enable every clinician to practice easily the management of medical emergencies. For the past five years anesthesia residents at the University of Washington have been required to complete 14 case simulations using the Anesthesia Simulator Consultant. This guarantees that every resident will be exposed to a case of myocardial ischemia, cardiac arrest, anaphylaxis, malignant hyperthermia, and several other emergencies. Survey of the residents indicates that 92% feel that simulator time is well spent.

These simulators are not just for students and residents; they are also used for Continuing Medical and Nursing Education. Physicians and nurses can earn 40 Continuing Education credits with the Anesthesia Simulator Consultant, 20 credits for the Critical Care Simulator, and 10 credits with the ACLS Simulator. Many have commented that simulator training was more valuable than lectures or reading to prepare for critical incidents and more convenient because they use their home computer rather than travel to a meeting.

In addition to training for medical emergencies, these simulators can be used to review underlying physiologic and pharmacologic principles. The Anesthesia Simulator Consultant and Critical Care Simulator include cardiovascular and respiratory physiology models, and pharmacokinetics for inhalation and intravenous agents. The information is presented in a clinically relevant fashion since it is tied to a simulated case.

New Developments

Graphical simulators will continue to improve as personal computers offer new features. When 256-color graphics became popular, we were able to provide photorealistic patient images that were superior to the cartoon-like images used previously. We are currently adding digitized radiographs, fiberoptic bronchoscopy, and other images. Video clips will provide dynamic transesophageal echocardiograms and now that sound cards are becoming more standardized we are adding audio for the pulse oximeter, breath sounds, and heart sounds.

With CD-ROM and the Internet, we are able to disseminate large amounts of information at a reasonable cost. The Anesthesia Simulator, version 2.0, includes a case library of 80 cases. We hope that version 3.0, on CD-ROM, will have hundreds of cases. It will be possible to simulate several case scenarios for virtually any anesthesia or critical care problem.

The creators of these simulators invite everyone with an interest in anesthesia or critical care to contribute case scenarios, images and video clips to this collection. Case scenarios will be added to the simulator and all other information will be digitized and made available worldwide for lectures and handouts, medical student and resident training, and continuing education. Please write to Anesoft (18606 NW Cervinia Ct.; Issaquah, WA 98027) for information about how to include your materials in the Digital Anesthesia Collection.

Dr. Schwid, a 1990 APSF Research Grant recipient, is a recognized expert in computer simulation. He is Associate Professor, Department of Anesthesiology, University of Washington, and on the staff of the Seattle Veterans Affairs Medical Center.