Inhibition of exogenous surfactant in ventilated immature newborn rabbits.

Abstract Immature newborn rabbits were treated at birth by tracheal instillation of porcine surfactant (100 μl, phospholipid concentration 80 mg·ml −1 ), to which [ 14 C]dipalmitoylphosphatidylcholine had been added as a marker. They were kept in a body plethysmograph/pneumotachygraph system at 37°C. During a 120 min period of artificial ventilation with a peak insufflation pressure of 20 cm H 2 O, there was a gradual decrease in tidal volumes (36%·h −1 ). This decrease was correlated to an elevation of minimum surface tension ( r = 0.81; P r = 0.80; P r = 0.56; P r = 0.73; P