Graphical Anesthesia Simulators Gain Widespread Use
by 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.