Elastance and resistance of lungs-chest of dogs

¹ Departments of Physiology and Medicine, Northwestern University Medical School, and the Veterans Administration Research Hospital, Chicago, Illinois

Static elastance of the lungs-chest of seven curarized dogs averaged 15.2 ± 4.9 cm H₂O/l. Elastance decreased with time probably because of stress relaxation. The expiratory volume flow rate for five different initial inflations was recorded as a function of time. Nondimensionalized plots were nonlinear, especially with the larger initial inflations, and shifted to the right as a function of initial inflation. A resistance which increases with flow rate because of a turbulent component is the most probable explanation for the complexity of a single free recovery curve. Either an increase in resistance, a decrease in elastance or both could account for the observation that the curves shift to the right with increasing initial volume.