The Mechanics of the Respiratory System During Anesthesia

Abstract

The flow resistance, static compliance, kinetic compliance and pressure stress relaxation of the total respiratory system were measured by the method of constant flow rate inflation of the lungs. The term kinetic compliance is introduced to distinguish a nonstatic compliance from the conventional dynamic compliance. Results for 20 supine apneic anesthetized patients prior to operation are presented. Atropine (0.012 mg/kg intravenously) caused a 33% fall in flow resistance and a 4% rise in static compliance. The addition of CO2 to the hypo-capnic subject was associated with a 29% decrease in flow resistance and no change in static compliance. A possible dual action of CO2 on flow resistance is discussed. Pressure stress relaxation was decreased by 14 per cent with the addition of CO2.