[Effects of surfactant administration in premature infants with severe respiratory distress syndrome]

Abstract

Background: From January 1992 to June 1993 a study was performed to show whether the administration of surfactant to low birth weight infants with respiratory distress decreased the need for ventilatory support and improved survival.

Method: Twenty three infants born at a single hospital received the surfactant (one dose of a 100 mg/kg divided in four aliquots) and they were eligible for the treatment if they met the following criteria: 1) Weight between 650 g and 2000 g; 2) postnatal age 4 to 24 hours; 3) clinical-radiographic signs of respiratory distress, and 4) need of mechanical ventilation with FiO2 > or = 0.6. The results of the treatment were evaluated comparing the arterial-alveolar oxygenation ratio, maximal inspiratory pressure and the oxygenation index before and after the administration of surfactant. The last consecutive eighteen infants born at our hospital, before our study was started, that met the same criteria were elected as control group.

Results: In the group of infants treated with surfactant the arterial-alveolar oxygenation ratio increased from 0.10 +/- 0.009 before treatment to 0.28 +/- 0.02 six hours after treatment (p < 0.01); the oxygenation index decreased from 37.79 +/- 4.27 to 12.71 +/- 1.17 (p < 0.01) and the maximal inspiratory pressure from 22.13 +/- 0.81 cmH2O to 19.52 +/- 0.76 (p < 0.001) in the same period of time. This improvement was maintained during the following 72 hours. In the group of infants treated with surfactant, mortality decreased (p < 0.01), the frequency of pneumothorax diminished (p < 0.001) and the frequency of pulmonary haemorrhage increased (p < 0.05). The ventilatory time was similar in both groups of infants but the global length of stay of the newborn that received surfactant was longer due to the fact that the non survivors of the control group died before the 72 hours of life.

Conclusions: Treatment with surfactant improves the initial evolution of the respiratory distress syndrome of the newborn and decreases mortality.