Natural and artificial lung surfactant replacement therapy in premature lambs.
The effect of tracheal instillation of surface-active mixtures in premature lambs was studied as an animal model of exogenous surfactant replacement therapy for the respiratory distress syndrome (RDS). Specific mixtures studied were 7:3 (molar ratio) dipalmitoyl phosphatidylcholine (DPPC):egg phosphatidylglycerol (PG) and extracted mixed lipids (with 1% protein) from cow lung lavage (CLL). Preventilatory tracheal instillation of greater than 15 mg/kg of CLL in 10 ml 0.15 M NaCl to premature lambs gave improved alveolar-arterial O2 gradient and blood gases and increased lung compliance, compared with control lambs over a 15-h period. Lambs receiving 7:3 DPPC:PG dispersions were not improved over controls with regard to pressure-volume characteristics and were worse than controls in arterial oxygenation. In terms of in vitro surface properties, both extracted natural CLL and 7:3 DPPC:egg PG were able to lower aqueous surface tension to 1 dyn/cm under dynamic compression. However, the dynamic respreading of CLL films on successive surface cycles was superior to that of 7:3 DPPC:PG. Moreover, after dispersal in 0.15 M NaCl by vortexing (5 mg/80 ml), CLL adsorbed to surface pressure (tau values of 45 dyn/cm within 10 min. 7:3 DPPC:PG adsorbed to significantly lower tau values after subphase dispersal by a variety of methods.
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D002417:Cattle; D004195:Disease Models, Animal; D005440:Fluid Therapy; D006801:Humans; D007231:Infant, Newborn; D011663:Pulmonary Surfactants / Q000627:therapeutic use*; D012127:Respiratory Distress Syndrome, Newborn / Q000188:drug therapy*; D012756:Sheep / Q000502:physiology*; D013500:Surface Tension; D013501:Surface-Active Agents / Q000627:therapeutic use
D011663:Pulmonary Surfactants; D013501:Surface-Active Agents