Surfactante pulmonar : avaliação e terapia na bronquiolite viral aguda grave

Abstract

Objectives: To evaluate the response to surfactant of patients with acute bronchiolitis (AB) according the surfactant function and production, measured through the stable microbubble test and the lamellar body count. Study Design: Twenty four patients younger than 1 year of age, with the diagnosis of AB, who were in mechanical ventilation and received 100 mg of surfactant, according with the stablished routine by the pediatric intensive care unit, were studied. Previously to the administration, tracheal secretion was collected for virus identification, stable microbubble test and lamellar body count. Arterial blood gases were obtained. One hour, 6 hours and 24 hours after of surfactant administration arterial blood gases were again collected. Results: There was a 20% increase in PaO2 24 hours after surfactant administration in 2 (14.29%) of 14 patients with lamellar bodies ≤ 60.000 and in 5 (50%) of 10 patients with>60.000 lamellar bodies (p=0.08). Six (46.15%) of 13 patients with ≤13 microbubbles and one (9.09%) of 11 patients with>13 microbubbles had an increase in PaO2>20% after 24 hours of administration (p=0.08). Only 2 patients of 7 who responded to surfactant, had respiratory syncytial virus (RSV) positive. The patients with lamellar bodies ≤ 60.000 had a statistically significant increase in oxygenation after 6 hours of surfactant administration, not associated to a reduction of mechanical ventilation time or hospitalization time. The patients without positive RSV had a substantial increase in PaO2 after one hour after the administration of surfactant, that was maintained for 24 hours. Conclusion: The surfactant administration transiently improved oxygenation in patients with AVB. Patients who had no positive respiratory syncytial virus had an important improvement in oxygenation after administration of exogenous surfactant. LBC and SMT are not sufficiently sensitive and specific to predict who the patients with severe bronchiolitis responding to treatment with exogenous surfactant.