Spectral characterization of neonatal arterial blood pressure associated with surfactant therapy for respiratory distress syndrome

The authors´ goal was to characterize the effect of surfactant instillation on arterial blood pressure in premature infants with respiratory distress syndrome to develop prognostic indicators of short term outcome. Twelve infants with birth weights between 500 to 2000 grams were enrolled. All infants received the first dose of surfactant within the first six hours of life. Arterial pressure signals were recorded 30 min. Before and after surfactant administration and later analyzed for spectral composition. The spectral power at the frequency of positive pressure ventilation markedly increased after surfactant therapy in seven patients who survived with the majority demonstrating a significant increase in PaO₂. In the authors´ other five patients spectral power decreased or remained unchanged; these patients died within the first week of life. These findings suggest that the change in the direction of spectral power at the ventilator frequency following the first dose of surfactant may have prognostic significance in infants with respiratory distress syndrome