Surfactant Treatment of Full-Term Newborns With Respiratory Failure

Surfactant inactivation has been shown to be a significant factor in animal models of lung injury and may also be important in some forms of respiratory failure in full-term newborns. Fourteen full-term newborns with respiratory failure associated with pneumonia (7 patients) and meconium aspiration syndrome (7 patients) were treated with 90 mg/kg of a calf lung surfactant extract, given intratracheally up to every 6 hours for a maximum of four doses. The group mean fraction of inspired oxygen (Fi02) before treatment was 0.99 ± 0.01 SEM, and the mean airway pressure (MAP) was 14.6 ± 1.0 cm H2O. Patients showed significant improvement in oxygenation after initial surfactant treatment, with the arterial-alveolar oxygenation ratio (a/A ratio) rising from 0.09 ± 0.01 before surfactant treatment to 0.22 ± 0.05 by 15 minutes (P = .03) and remaining improved for 6 hours. The oxygenation index, incorporating MAP as well as oxygen variables, also improved significantly from 26.2 ± 3.1 to 11.2 ± 1.7 at 15 minutes (P < .001), with improvement sustained for more than 6 hours. Chest radiographs were blindly scored from 0 (normal) to 5 (severe opacification), and these improved with marginal significance after initial surfactant treatment (from 2.9 ± 0.2 to 2.5 ± 0.2, P = .05). Eight patients subsequently met retreatment criteria (Fi02 ≥ 0.5 and MAP ≥ 7 cm H2O) and received a second surfactant dose, with a/A ratio rising from 0.124 ± 0.02 before treatment to 0.26 ± 0.07 after 45 minutes (P = .03) and remaining improved for more than 4 hours; the oxygenation index was also significantly improved over similar times by the second surfactant dose. Six patients received a third surfactant dose, with no increase in a/A ratio and a less prominent improvement in oxygenation index. There were no significant improvements in oxygenation in the three patients who received a fourth surfactant dose. Of the 14 patients treated, none died, required extracorporeal membrane oxygenation, had tension pneumothorax after study entry, required oxygen supplementation for more than 14 days, or required oxygen supplementation at discharge. These findings suggest that surfactant supplementation may provide therapeutic benefits for newborns with respiratory failure due to pneumonia or meconium aspiration and that expanded controlled trials of this therapy are indicated.