Surfactant inhibition by plasma: gestational age and surfactant treatment effects in preterm lambs

Machiko Ikegami, Celso M. Rebello, and Alan H. Jobe Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, California 90502 Received 22 April 1996; accepted in final form 30 July 1996. Ikegami, Machiko, Celso M. Rebello, and Alan H. Jobe. Surfactant inhibition by plasma: gestational age and surfactant treatment effects in preterm lambs. J. Appl. Physiol. 81(6): 2517-2522, 1996. The preterm infant with respiratory distress syndrome has edematous lungs and small amounts of surfactant that do not function normally. We reported that surfactant recovered from preterm lambs after surfactant treatment can have decreased sensitivity to inhibition of surface tension by plasma. We asked whether this augmented resistance to inhibition was dependent on lung development (gestational age) by testing sensitivity to plasma inhibition of 1 ) endogenous surfactant from preterm lambs and 2 ) surfactant from preterm lambs after treatment with an organic solvent-extracted natural sheep surfactant. Surfactant recovered after surfactant treatment of 121- or 128-days-gestation lambs had the same sensitivity to plasma inhibition as did the surfactant used to treat the lambs. Surfactant recovered from 134-days-gestation lambs had decreased sensitivity to inhibition. Lung maturation is a variable influencing surfactant inhibition by plasma. respiratory distress syndrome; surface tension; phosphatidylcholine; lung development; Wilhelmy balance 0161-7567/96 $5.00 Copyright © 1996 the American Physiological Society