Comparison of rapid bolus instillation with simplified slow administration of surfactant in lung lavaged rats.

The aim of this study was to compare the effects of modified porcine surfactant (Curosurf) given either by a simplified slow delivery technique or by the standard bolus method, on pulmonary gas exchange, lung mechanics, and surfactant distribution in rats with respiratory failure produced by lung lavage. Twelve rats with respiratory failure induced by lung lavage received 200 mg x kg(-1) body weight (b.w.) of tagged porcine surfactant, either by the standard bolus delivery technique or by a simplified 1-min intratracheal infusion method, not requiring interruption of mechanical ventilation. Cardiovascular parameters, arterial blood gases, and pulmonary mechanics were measured repeatedly. Surfactant distribution was also measured by dye-tagged microbead spheres. After surfactant administration, there were no overall major differences between groups in mean heart rate, blood pressure, arterial blood gases, dynamic lung compliance, respiratory system resistance, and pulmonary distribution of exogenous surfactant. However, after 180 min pulmonary gas exchange was better and compliance higher in the bolus than the 1-min infusion group. A transient decrease in blood pressure and heart rate was observed in the bolus group; this side effect was not seen in animals treated with the simplified 1-min infusion method. We conclude that in rats subjected to lung lavage, the infusion of porcine surfactant by a simplified 1-min procedure produced similar short-term effects compared to the same dose of surfactant given by the bolus method. We speculate that tracheal bolus dosing is highly effective and might be the preferable delivery method for porcine surfactant. Dosing by the simplified method described appears less effective, but since no significant differences were observed, and since it produced less acute adverse effects, it could be used when clinical circumstances preclude rapid delivery.

A simplified surfactant dosing procedure in respiratory distress syndrome: the "side-hole" randomized study. Spanish Surfactant Collaborative Group.

The aim of this study was to compare the incidence of acute adverse events and long-term outcome of two different surfactant dosing procedures in respiratory distress syndrome (RDS). The effects of two surfactant dosing procedures on the incidence of transient hypoxia and bradycardia, gas exchange, ventilatory requirements and 28 d outcome were compared. The patients, comprising 102 infants (birthweight 600-2000 g) with RDS on mechanical ventilation with FiO2 > or = 0.4, were randomized at 2-24 h to receive 200 mg kg(-1) of Curosurf; in 56 it was given by bolus delivery, and in 55 by a simplified technique (dose given in 1 min via a catheter introduced through a side-hole in the tracheal tube adaptor. The baby's position was not changed and ventilation was not interrupted). Two additional surfactant doses (100 mg kg(-1)) were also given, by the same method, if ventilation with FiO2 > or = 0.3 was needed 12 and 24 h after the initial dose. The number of episodes of hypoxia and/or bradycardia was similar in both groups. A slight and transient increase in PaCO2 was observed in the side-hole group. The efficacy of the surfactant, based on oxygenation improvement, ventilator requirements, number of doses required and incidence of air leaks, was similar. No differences were observed in the incidence of intraventricular haemorrhage, patent ductus arteriosus, bronchopulmonary dysplasia or survival. In conclusion, a simplified surfactant dosing procedure not requiring fractional doses, ventilator disconnection, changes in the baby's position or manual bagging was found to be as effective as bolus delivery. The number of dosing-related transient episodes of hypoxia and bradycardia was not decreased by the slow, 1 min, side-hole instillation procedure.