Measurement of Compliance and Resistance of the Lungs and Thorax by the Use of Expiratory Flow-Volume Curves

摘要

Compliance and resistance of the lungs and thorax system were measured in five healthy subjects by a method using relaxed expiratory flow-volume curves. Determinations were made during normal 'shirt-sleeve' conditions and with the subjects suited in ventilated full pressure suits and in anti-G suits inflated to 3 psi. Vital capacity, inspiratory capacity and expiratory reserve volume were also measured under the three conditions. A significant correlation was found between the volume of air inspired above Functional Residual Capacity (FRC) expressed as percentage of normal vital capacity and peak flow reached under normal conditions. No significant correlation was found between the volume of air inspired above FRC and the slope of the V - V curve. Vital capacity and expiratory reserve volume were reduced when the subjects were in pressure suits and anti-G suits, but there was no significant change in inspiratory capacity. A reduction in FRC is implied. (Author)