Changes in the dynamic compliance coefficient of the lungs and breathing mechanics during administration of diethyl ether and halothane for general anaesthesia with spontaneous respiration.

Changes of the dynamic compliance coefficient of lungs were studied during diethyl ether and halothane anaesthesia. Determining lung compliance at the same time it was possible to show the effect of these agents on changes in the magnitude of breathing work necessary to overcome elastic and non-elastic resistances. The investigations were carried out on 31 patients during general anaesthesia with spontaneous respiration. The determinations revealed that the tidal volume (TV) was decreased in relation to the initial values (before anaesthesia) indicating a depressing effect of these agents on the processes of respiration. Changes in the tidal volume and intrapulmonary pressure decided on the changes of the pulmonary compliance coefficient and the magnitude of breathing work. The coefficient of pulmonary compliance decreased during diethyl ether administration by 18.8% and during halothane by 30.9%. On the other hand the work necessary to overcome respiratory resistances increased mainly during ether anaesthesia owing to a significant rise in the non-elastic resistance (bronchial secretion).