BY SUZANNE MCCAFFREY

Physicians Committee for Responsible Medicine (PCRM) -- "Good Medicine" -- Autumn, 1995

New products that replace live animal labs in medical training are rapidly entering the marketplace. The most impressive new systems incorporate computerized mannequins, complex graphics, and sophisticated operator controls in state-of-the-art patient simulators. Students learn both medical concepts and manual procedures on life-size, interactive equipment that provides the benefits of anatomical correctness, unlimited repetition, scheduling convenience, and variable "health" conditions that prepare students for actual practice.

The Human Patient Simulator was developed by the University of Florida College of Medicine to train anesthesiologists in routine and crisis situations. Its interactive technology provides a realistic learning experience that is adaptable for a wide range of health care practitioners, including medical students, residents, nurses, and medical engineers.

The simulator mannequin has palpable pulses, heart and lung sounds, twitch response to nerve stimulation, and, yes, even a body temperature. Trainees can monitor its heart rate, cardiac rhythms, cardiac output, and blood pressure. Equipped with interface software and an instructor's remote control, the simulator also gives accurate patient responses to over 60 different drugs, mechanical ventilation, and other medical therapies, and allows the instructor to introduce new conditions.

The simulator's drug recognition and response system is particularly useful for replacing animal laboratories in medical school. Some medical schools still use dogs or other animals as laboratory subjects as basic science courses, where students inject the animals with various drugs to observe the change in their blood pressure, respiration, heart rate, etc. The animals are generally killed with a fatal injection at the end of the lab. The simulator allows medical students to observe accurate responses to drugs predicated on human patients without wasting the lives of animals.

The simulator's interactive design allows it to be used with all anesthesia gas delivery systems and mechanical ventilators. It connects to standard monitoring system, including EKG, invasive and non-invasive blood pressure and pulse monitors, and even responds to equipment malfunctions.

Procedures that can be taught on the simulator include inserting artificial airways, taking non-invasive blood pressure measurements, monitoring arterial blood gases, and administering anesthesia. A special curriculum uses a series of clinical scenarios in which students manage the anesthesia and medications for a patient in a diabetic coma, surgical repair of an aortic aneurysm, treatment of end-stage renal disease, and other conditions.

The Human Patient Simulator has been used by the University of Florida system for over eight years. It sells for approximately $180,000, and has been purchased by, among other sites, Mount Sinai Anesthesia Simulation Center, the University of Rochester Strong Memorial Hospital, Vanderbilt University in Nashville, and Santa Fe Community College in Gainesville, where the Florida Department of Education has developed a simulator-based curriculum for health care professionals. More information is available from Loral Data Systems, Medical Products, P.O. Box 3041, Sarasota, FL 34230, 813-378-6702.

Another hands-on, interactive simulator is the Virtual Anesthesiology Training Simulation System, developed from research done by David Gaba and John Williams of Stanford University, and Howard Schwid of the University of Washington. Like the Human Patient Simulator, this product combines a life-size mannequin, computer systems, an operator's console, and monitoring equipment interface. It is appropriate for basic medical instruction in a variety of disciplines, as well as advanced training in anesthesia crisis management, emergency room care, critical care, and advanced cardiac life support.

This simulator is close to the Human Patient Simulator in design and application, and provides similar benefits. Some interesting features include mechanical lungs which ventilate spontaneously and can even simulate blockage of one lung, palpable carotid and radial pulses, points in the arm where intravenous fluids and drugs can be administered, a tongue swelling device, a color graphics workstation which serves as the operator's console, and an interface cart that connects the mannequin to the computers, monitors and anesthesia machine. More information is available from CAE Electronics, Ltd, P.O. Box 957, Binghamton, NY 13902, 607-721-4552.

High-Tech, Not High-Priced

Want a high- quality simulator and don't have $180,000 in loose change? The Critical Care and Anesthesia Simulator programs offered by Anesoft Corporation offer real-time, graphic computer simulations that reproduce patient care in an Intensive Care Unit or an anesthesia environment for a fraction of the cost of a simulator with a mannequin. With the Critical Care Simulator, developed at the University of Washington, students manage twenty different critically ill patients by controlling their airway, ventilation, fluids and medications. The program reproduces the patient's monitors and simulates its responses, including those for boluses and infusions of about seventy drugs, which means it too can be used in place of the traditional dog lab. The simulated cases can be temporarily suspended to provide diagnostic and therapeutic information for optimum management of the clinical situation.

The Anesthesia Simulator Consultant reproduces dozens of anesthesia environments in real-time, including anaphylaxis, difficult airway, myocardial ischemia and pneumothorax. The simulated patient responds to management while an automated record-keeping system summarizes the case and an expert system provides immediate consultation. The Critical Care and Anesthesia Simulator software cost about $295 each. More information is available from Howard Schwid, M.D., at Anesoft, Anesthesia and Critical Care Software, 18606 NW Cervinia Court, Issaquah, WA 98027, 206-643-9388, fax 206-643-0092.

Non-Animal Teaching Methods Show Their Superiority

Many medical schools have dropped old-fashioned animal labs. The non-animal methods are cheaper, they don't need to be anesthetized, and students don't object to them. But do they work?

The answer is a resounding yes. Emerging students show that non-animal methods teach as well or better than animal labs and save money in the bargain, not to mention the enormous savings in animal lives.

Researchers at the College of Veterinary Medicine in Auburn, Alabama, tested an interactive video system, assigning students to participate in either an animal laboratory or an interactive videodisc simulation. The two groups scored about the same on a multiple choice/short answer test, but the interactive video program was more time-efficient.

Instructors at the University of Chicago compared student responses to an animal laboratory versus a computer simulation, and found, "the students rated both highly, but the computer-based session received a higher rating." Patient-Oriented Problem Solving (POPS) is a small group teaching tool in which students solve clinical problems as a means of learning medical concepts. A study published by the Association of American Medical Colleges showed it to be effective in conveying principles of pharmacology, doing so at minimal cost.

Assisting in the operating room is the usual way that new surgeons learn their skills. However, some companies have pushed animal surgery laboratories in connection with sales of surgical products. Stephen M. Tsang, M.D., and his colleagues at Tulane University examined surgical complication and mortality rates for gallbladder surgery and found that those who had trained in animal laboratories performed no better than those who had not. In Dr. Tsang's words, "there is no need to attend an expensive and time-consuming classroom and animal laboratory course."

Pioneering heart surgeon Michael DeBakey said, "I gave up surgical training of our students and residents on animals years ago. We used to have a course. I stopped it completely. I said, "I'm not going to do this anymore on animals because we're going to put students in the operating room with humans." Dr. DeBakey went on to point out the ease of using non-animal methods. "You don't have to have a living animal to try to do microsurgery, say, to repair a vessel. You can use fresh cadavers. It's very easy. You just take a piece of tissue out of a fresh cadaver, whether it's an animal that died from some other reason or a human."

Okay, non-human teaching methods work. But will instructors or students find computer simulations, videos, or other methods to be as graphic and engrossing as a live animal laboratory? A method now being explored at Harvard Medical School may be just the answer to that question. Harvard recently allowed medical students to observe heart surgery in the hospital operating room rather than participate in an animal laboratory. In the operating room, a broad range of drugs are used in human patients -- essentially the same drugs used in dog labs -- and their effects on the cardiovascular system can be observed in great detail.

In support of this method, Robert Forstot, M.D., of the division of Cardiothoracic Anesthesia of Washington University in St. Louis, Missouri, wrote, "The demonstration of human pharmacology and physiology that is relevant to the needs of future physicians can be more appropriately achieved by taking medical students into the operating theater under the tutelage of staff anestheologists, rather than using dogs to demonstrate these drug effects. This is especially true if the students can be taken into the cardiac surgery suites, where I practice anesthesia."

In Dr. Forstot's words, the operating room is "an ideal venue from which to teach medical students both pharmacology and physiology that is relevant to their future practice."

Animal laboratories are obviously not essential to medical education, given that many medical schools have dropped them entirely. Happily, scientific studies show that non-animal methods are much less expensive than animal labs, students enjoy them -- and they work.