From Resusci-Anne to Sim-Man: the evolution of simulators in medicine.

Simulators were introduced in education as a tool to make advanced training standardized, less expensive, and without danger to those involved. In 1922 in the United States, Edward Link presented his homemade flight simulator, which became common place in both military and civilian aviation, known as the “Link Trainer.” However, several decades passed before this form of training became accepted in medicine. Already in the early 1960s, Peter Safar had become involved in medical simulation through opportunistic exposure and innovative research. Interested in potential reversal of death from accidents and medical problems causing cardiac arrest, he was disturbed by the poor results of the current resuscitation technique of nonbreathing victims. In discussions with Dr. James Elam, Peter Safar learned that artificial ventilation could be efficiently provided with normal arterial blood gases in anesthetized individuals simply by blowing into the endotracheal tube (1). In the late 1950s, as chief anesthesiologist at Baltimore City Hospital, Dr. Safar undertook his daring experiments on sedated and curarized volunteers. He demonstrated unequivocally the lack of effect of arm lift/chest pressure ventilation efforts, whereas exhaled air provided through mouth-to-mouth ventilation was not only superior but also resulted in both adequate oxygenation and CO2 elimination. This study was published in JAMA in 1958 (2), and Peter Safar reported on his results at an anesthesiology/cardiopulmonary resuscitation congress in Norway. In 1961, Bjorn Lind and other prominent Norwegian anesthesiologists, who participated in this congress, brought the idea of providing appropriate cardiopulmonary resuscitation training equipment to the attention of Asmund Laerdal, a successful entrepreneur in Stavanger, Norway, whose main business was the manufacturing of toys made of soft plastic materials. Laerdal promptly designed a full-size training mannequin for mouth-to-mouth ventilation. The airway could be obstructed, and it was necessary to use hyperextension of the neck and forward thrust of the chin to open the airway before initiating insufflation of air into the mannequin by mouth-tomouth technique as described by Peter Safar. At the recommendation of Dr. Lind, Asmund Laerdal visited Peter Safar in Baltimore for a demonstration of his mannequin. At that time, Kowenhoven, Knickerbocker, and Jude had just published their observation, showing that external chest compression could produce blood flow in cardiac arrest victims. Peter Safar advised Asmund Laerdal to include an internal spring attachment to the chest wall that would permit simulation of cardiac compression; thus, the possibility of training the ABC of cardiopulmonary resuscitation on the simulator was born, with A standing for airway, B for breathing, and C for circulation. This early simulator of a dying victim not breathing and without a heart beat became known as Resusci-Anne, and its utilization rapidly spread around the world. In 1968, Ake Grenvik of Sweden joined Peter Safar’s critical care medicine training program in Pittsburgh. He realized the many problems in training physicians to use proper technique when managing critically ill and injured patients, in whom relatively minor complications could create life-threatening problems leading to death. Through the close collaboration between Peter Safar’s department of anesthesiology and critical care medicine on the American side and the Laerdal Corporation in Norway on the European side, Ake Grenvik, too, became very much involved in the exchange of ideas between Pittsburgh and Stavanger. After Asmund Laerdal’s premature death of cancer in 1981, his son Tore Laerdal became the leader in their Norwegian family business. He continued the traditionally close relations and support of the Safar group. Having used a Link trainer as a former flight surgeon in the Swedish Air Force, Ake realized the need for advanced simulation training in critical care medicine and made repeated recommendations for the Laerdal Corporation to expand into modern computerized simulation technology. The Laerdal Corporation wisely awaited the right opportunity to start this expansion. In 1995, only two, and very expensive, human simulators were available in the United States. At that time, Dr. Peter Winter served as chairman of the department of anesthesiology and critical care medicine after Peter Safar, who had withdrawn into his International Resuscitation Research Center for full-time investigations in the field of reanimatology. Peter Winter had the foresight to acquire one of the available simulators, although at the very high cost of approximately $250,000. Drs. Rene Gonzales and John Schaefer of his Department were appointed director and associate director, respectively, of this simulation center at the University of Pittsburgh. These two ingenious young anesthesiologists designed a far less expensive, much more practical, realistic, and mobile simulation module, which was patented. The Medical Plastics Limited Corporation in Texas assumed responsibility for manufacturing of this new simulator. This company was From the Safar Center for Resuscitation Research (PMK) and the Department of Critical Care Medicine (AG, PMK), University of Pittsburgh School of Medicine, Pittsburgh, PA.