DEVELOPMENT OF PATIENT SIMULATORS

The descriptions given in the following sections are very brief, and the introduction of new or upgraded features in all the simulation systems continues steadily. For up-to-date information about any of the current systems, the reader is advised to contact the manufacturers or authors directly.

In the late 1960s, a mannequin-based simulator—Sim One—was produced by an aerospace company working with anesthesiologists at the University of Southern California. For that era it was a technologic marvel and was years ahead of its time.^{[12] [13] [14]} However, the Sim One project drifted into oblivion, largely because the medical professions were not ready to understand the applicability of simulation to key issues of training, research, and assessment, especially regarding the importance of human factors.

Several patient simulators were developed and introduced in the mid to late 1980s. Each was an independent development, and none had any direct connection with the Sim One project. Several factors led to these advances. Most prominent was the new availability of powerful (comparable to advanced minicomputers of a decade earlier) personal computers (PCs) at a relatively cheap price. The popularity of a variety of simulators for PCs (e.g., flight simulators, driving simulators) demonstrated that simulation of complex systems was possible with a PC, and a screen-based simulator could give users some degree of "feel" that they had been in the environment. For mannequin-based simulators, inexpensive clinical waveform generators became available. These generators produced typical clinical signals for electrocardiographic and invasive pressure monitors, and they allowed waveforms to be selected from an external computer. On the applications side, the public and the anesthesia profession had become more aware of the utility of simulation-based training for military and commercial aviation, space flight, automobile driving, shipping, military command and control, and the operation of nuclear power plants. Media coverage of the space program and corrective responses to the Three Mile Island nuclear accident highlighted the role of simulators. Another pivotal factor was growing interest within anesthesiology in studying the anesthetist's performance and the human factors and ergonomics of the anesthesia work environment.^{[15] [16] [17] [18]}

By the time of this writing, nearly every simulation system has evolved through several generations of improvements. We briefly describe the evolution of some of the simulator systems. Although several "homemade" simulators were developed by different groups in the United States and Europe,^{[19] [20] [21] [22] [23] [24] [25] [26] [27]} only the development of systems that went through commercialization is described because they are the ones that have been installed in a large number of institutions.

Screen-Based Simulators ("Microsimulators")

SLEEPER and BODY

In San Diego, Smith and associates^{[28] [29] [30]} developed a set of linked physiologic and pharmacologic models that accurately reproduced major elements of the patient's clinical behavior. When the models were combined with an appropriate graphic representation of the patient and clinical data on the computer screen and a graphic user interface for the input of clinically relevant actions, the system became a complete screen-based simulator known originally as SLEEPER. ^[31] SLEEPER used a complex transport model to deal with gas exchange and drug distribution. This model provided the opportunity to predict the concentration of drugs in specific anatomic regions (e.g., myocardium, gray matter). In collaboration with Marquette Electronics, Inc. (Milwaukee, WI), the SLEEPER software has evolved into a program called "BODY Simulation." It is distributed by Advanced Simulation Corporation (Point Roberts, WA).

Anesoft Anesthesia Simulator

At the University of Washington, Seattle physician Howard Schwid (formerly a research fellow with Ty Smith) and programmer Daniel O'Donnell developed a screen-based simulator originally called the Anesthesia Simulator Recorder.^{[4] [6] [32]} This simulator then evolved into the Anesthesia Simulator Consultant. This system provides graphic representations of mock monitoring displays and clinical equipment, as well as photographs to display the patient and actions taken on the patient ( Fig. 84-2 ). Interaction with this system also uses a desktop pointing device. The Anesthesia Simulator Consultant uses traditional pharmacokinetic and pharmacodynamic models drawn from the pharmacology literature to track drug levels and the effects of more than 70 drugs, as opposed to the physical transport models used in SLEEPER and BODY Simulation. Schwid's system has built-in debriefing functionalities and is oriented toward critical incident

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Figure 84-2 Computer screen display of the screen-based Anesoft Anesthesia Simulator. The actual screen is in full color. Additional information and actions can be selected by using a pointing device and menus. (Courtesy of Howard Schwid, M.D., Anesoft, with permission.)