Prenatal Intraamniotic Surfactant Administration Improves Lung Function at Birth and the Effects of Conventional Postdelivery Treatment in Animal Model. A Randomized Controled Trial

Abstract

Introduction: Surfactant diluted in the pulmonary fluid at birth promove airway formation and prevents lung injury, for this reason some investigators have proposed that actual surfactant prophylaxis in high risk preterm deliveries, should be done before the first breath, perhaps in-uteri. Objetive: to evaluate if intraamniotic surfactant plus conventional neonatal instillation improves respiratory outcome outcome compared with only conventional neonatal instillation. Materials and Methods: randomized, controlled and double blinded protocol in a model of very immature born lambs. 125 days pregnant ewes received, with ultrasound guide, an intraamniotic injection of 240 mg of natural bovine surfactant or normal saline solution. After one hour of fetal breathing movement's stimulation with aminophylline the premature lamb’s fetuses were delivered by C-section, and a 3-mm endotracheal tube was placed by tracheotomy. Heart rate, aortic blood pressure, central temperature, respiratory rate and hemoglobin saturation, as well as mechanical ventilator settings, were continuously monitored. Variables under study were: Peak Inspiratory Pressure (PIP), Mean Airway Pressure (MAP), Oxygenation Index (OI) and Arterio-Alveolar Ratio (a/A). Conclusion: Prenatal intraamniotic surfactant instillation improves short-term respiratory outcome compared with conventional postpartum treatment in this animal model.