Effects of gestation and prenatal asphyxia on pulmonary surface properties of the foetal rabbit*

Abstract
The pulmonary surface properties of fetal rabbits were studied after delivery by Caesarean section at 26-30 days and after normal delivery at term (31 days). Quasi-static pressure-volume curves were defined for the lungs and the surface properties of the same lungs were further studied both by the bubble-stability method and by means of a surface balance and trough. Results given by each method are compared and discussed. At the 26th day of gestation the pulmonary surface properties, characteristic of the animal at term, were not yet present. These properties were first evident on the 28th day. A period of 16 min intense prenatal asphyxia on the 28th day of gestation failed to produce a change in pulmonary surface properties.