STATIC VOLUME-PRESSURE RELATIONS OF EXCISED LUNGS OF INFANTS WITH HYALINE MEMBRANE DISEASE, NEWBORN AND STILLBORN INFANTS

Abstract

Comparison was made of virtually static volume-pressure relations of excised lungs obtained from 10 infants with hyaline membrane disease, 5 newborn infants dying from other causes, and 5 stillborn infants. To eliminate the influence of size on these measurements, volume was expressed as milliliter of gas per gram of tissue. Special emphasis was given to the volume-pressure relations during deflation from a peak airway pressure of 35 cm H2O. At all pressures the lungs with hyaline membranes contained less gas per unit of weight than the control lungs; in addition, the slope of their entire volume-pressure curve was depressed. From these volume-pressure relations estimates were made of the magnitude of differences in functional residual capacity and compliance that might have been present during life. The differences compared closely with direct measurements made by other investigators. The low compliance in membrane-containing lungs was thought to be due to a reduction in number of units participating in ventilation. The relative importance of changes in surface forces that might lead either to a collapse of units or to increased resistance to inflationary pressures and of mechanical plugging could not be determined from these studies.