Comparison of Spontaneous and Controlled Breathing During Cyclopropane Anesthesia in Infants

Abstract

Clinical experience has demonstrated that the best way to maintain light surgical anesthesia with cyclopropane in infants, while avoiding exhaustion and cardiovascular disturbances, is to employ a controlled hyperventilation technique. Measurements of end-tidal PCO2, tidal volume and minute volume in a group of infants under three months of age indicate that spontaneous breathing during cyclopropane anesthesia provides effective ventilation for short periods. By employing four rate and pressure combinations of controlled breathing, all of which produced better pulmonary ventilation than present during spontaneous breathing, most effective hyperventilation was achieved at a moderate rate of about 40 minute with a pressure of about 30 cm of water. A change in airway pressure was noted to alter end-tidal PCO2 more than a change in ventilatory rate, at the combinations measured.