Improved gas exchange and survival after KL-4 surfactant in newborn pigs with severe acute lung injury

Objective: To determine the effectiveness of artificial surfactant therapy using KL-4 surfactant in newborn pigs with hydrochloric acid (HCl)-induced acute lung injury (ALI). Design: After induction of ALI via intratracheal HCl instillation, pigs were randomized to receive 5.8 ml/kg KL-4 surfactant or no surfactant prior to extubation to bubble CPAP. Setting: Clinical laboratory. Subjects: Spontaneously breathing newborn pigs (<1 week of age). Interventions: Treatment with KL-4 surfactant on bubble CPAP with PEEP of 6cmH₂O for 3.5 hr after extubation compared with controls. Measurements: Physiologic parameters and arterial blood gases were measured every 15 min. At the conclusion of the study, the lungs were excised for the analysis of histopathology and morphometric data. Main Results: Pigs treated with KL-4 surfactant had arterial blood gases with less acidosis (P < 0.001), higher P_aO₂ levels (P < 0.001), and lower P _aCO₂ levels (P < 0.001). Pigs treated with KL-4 surfactant had improved survival compared with controls (6/12 KL-4, 2/12 control, P < 0.05). Postmortem morphometric data demonstrated that pigs treated with KL-4 surfactant had larger (P < 0.05) exchange units in the caudal-dorsal lung as compared to relatively atelectatic region in the control animals. Conclusions: In newborn pigs with severe HCl-induced ALI, treatment with KL-4 surfactant resulted in improved respiratory parameters, less dependent atelectasis, and improved short-term survival.