Relationship between alveolar saturated phosphatidylcholine pool sizes and compliance of preterm rabbit lungs. The effect of maternal corticosteroid treatment

The relationship between alveolar saturated phosphatidylcholine pool size and compliance was evaluated in control and maternal corticosteroid-treated 27-, 28-, and 29-day gestational age preterm ventilated rabbits. Surfactant pool sizes below about 0.7 μmol saturated phosphatidylcholine/kg body weight did not alter compliance in either group. Compliance increased to values comparable to surfactant-treated or term newborn rabbits over a narrow range of saturated phosphatidylcholine pool sizes from about 0.7 to 1.2 μmol/kg for corticosteroid-treated rabbits and from about 0.9 to about 2.3 μmol/kg for control rabbits (p < 0.01). When these results are compared with those from surfactant-treated rabbits, almost an order of magnitude less endogenous surfactant than exogenous surfactant is needed to alter compliance in preterm ventilated rabbits.