A simple automatic record of oxygenation and ventilation with a pulse oximeter and a carbon dioxide monitor

Many cases have come to medicolegal attention in which a healthy patient undergoing a routine, elective operation has had an unexpected cardiac arrest attributed to hypoxia or hypercarbia. A simple, objective, automatic, inexpensive record of the adequacy of oxygenation and ventilation was obtained by using the Nellcor N-100 pulse oximeter, the Puritan-Bennett/Datex carbon dioxide monitor, and the Nellcor N-9000 recorder in combination. The required interface is described, and a sample record is presented. A second interface allows the recorder to work with the Puritan-Bennett anesthesia and brain activity monitor (ABM-1). Oxygen saturation can also be displayed on the video screen of the anesthesia and brain activity monitor.