CEREBRAL BLOOD FLOW VELOCITY (CBFV) IN PRETERM INFANTS TREATED WITH SURFACTANT

Abstract

Intratracheal instillation of exogenous surfactant reduces the severity of respiratory distress syndrome (RDS), but has the potential to affect cerebral blood flow. We measured CBFV in the anterior cerebral artery with 2-D/pulsed Doppler ultrasound in 7 preterm infants treated with surfactant at 2-24 h of age for severe RDS (a/A ratio ≤0.22). Birth weights ranged from 1120 to 2000 g and gestational ages from 28 to 31 weeks. CBFV was measured before and 5, 10, 15, 20, 30, and 40 minutes after the instillation of surfactant. Mean arterial blood pressure was recorded from an indwelling umbilical arterial line, blood gases were obtained by transcutaneous monitoring. Peak systolic, end diastolic, and mean flow velocities increased immediately following surfactant administration with a simultaneous drop in pulsatility index, but returned to pre-surfactant values by 30 min. Mean arterial blood pressure increased and heart rate fell in the immediate post-surfactant period, but recovered quickly. Transcutaneous pO2 rose sharply following surfactant administration, whereas pCO2 remained stable or decreased slightly. These findings indicate that intratracheal instillation of surfactant has short-lived effects on cerebral blood velocity, which are correlated with the simultaneously occurring changes in mean arterial blood pressure.