Computer application for respiratory data processing in closed circuit anesthesia.

A computerized respiratory monitor system for closed circuit anesthesia is described. The system consists of a mass spectrometer, a hot-wire respiratory flow meter, a microcomputer, a central display and a recorder. Respiratory parameters obtained by the computerized system include O2 consumption, carbon dioxide production, expiratory minute volume and respiratory rate. Using this system, closed circuit anesthesia was used in eleven surgical patients. Breath by breath value of carbon dioxide production stayed within the normal range during the procedure, though that of oxygen consumption varied markedly. This system allows anesthesiologists to detect, breath by breath, optimal gas flow and metabolic requirement during the closed circuit anesthesia. Closed circuit anesthesia is being used with increasing frequency in recent years. The patient's condition must be monitored continuously during the closed circuit anesthesia to maintain optimal depth of anesthesia and to prevent hypoxia or hypercarbia; however, monitoring of the respiratory gas exchange is difficult. We have developed a computerized respiratory monitor system for the closed circuit anesthesia.