CIRCULATORY EFFECTS OF RAISED AIRWAY PRESSURE DURING CYCLOPROPANE ANESTHESIA IN MAN 1

Abstract

This study included observations on 12 patients, before and during anesthesia. Continuous simultaneous measurements of arterial and central venous pressures were made with capacitance manometers. Positive pressure inflation of the lungs produced progressively smaller reductions in arterial pressure as the depth of anesthesia increased, while the decrease of arterial pressure was most marked in the conscious subjects. Cyclopropane anesthesia in man resulted in a marked increase in central venous pressure (up to 30 cm. water) the magnitude of which was related to the depth of anesthesia. Measurements of the proportion of intra-pulmonic pressure transmitted to the right atrium and central veins indicated that this value was decreased by cyclopropane anesthesia. When the increase in central venous pressure produced by anesthesia was greater than the pressure transmitted from the airway to the heart and great veins, reduction in arterial pressure did not occur during positive pressure inflation of the lungs.