Effects of Aerosolized Synthetic Surfactant in a Canine Model of Wood Smoke Inhalation

Abstract

BACKGROUND: Pulmonary surfactant replacement therapy is beneficial for premature infants with surfactant deficiency, and preliminary studies indicate that it may also be beneficial for the treatment of the surfactant deficiency associated with the acute respiratory distress syndrome (ARDS). Surfactant deactivation is an important factor in the pathophysiology of wood smoke inhalation. In this study, we examined the effects of surfactant replacement with aerosolized ExOSURF on smoke-inhalation injury in dogs. METHODS: All dogs were anesthetized and placed on a ventilator with provision for airway pressure measurement. Vascular access was established for sampling, pressure measurements, and cardiac-output determinations. Smoke was delivered to the animals at 26 breaths/min for 5 minutes. The treatment consisted of either aerosolized surfactant (experimental group, n = 6) or aerosolized saline (control group, n = 6). We measured PaO2, carboxyhemoglobin, lung compliance, and pulmonary shunt at 30-minute intervals for 4 hours. Following sacrifice of the animal 4 hours after smoke exposure, we determined the wet-dry lung-weight ratio and dynamic function of pulmonary surfactant with a Wilhelmy balance. RESULTS: There was no statistically significant difference for any of the measured variables between the control and experimental groups. CONCLUSION: ExOSURF does not ameliorate the acute pulmonary pathophysiology of severe smoke inhalation within 4 hours of injury.