Abstract

AbstractPostoperative respiratory data in eight patients having elective abdominal aneurysmorrhaphy were compared with preoperative measurements to determine the energy cost of respiration in postoperative patients. Oxygen consumption of the muscles of respiration was correlated with mechanical work by these muscles on the lung. Supporting data included respiratory rate, tidal volume, dynamic pulmonary compliance, and functional residual capacity. Postoperative measurements were taken immediately after operation and at 24, 36, 48, 72, 96, and 120 hours. At each of those hours, inspiration was measured for a room air mixture and for a primarily pure oxygen mixture. The study showed a significant increase in the work done on the lung by the respiratory muscles. This increase was associated with a 25% to 50% increase in oxygen consumption by the respiratory muscles. There was no significant change in efficiency in the muscles of respiration. Such increases may lead to respiratory muscle fatigue, and support the need for respirator therapy in the postoperative period.