Surfactant administration acutely affects cerebral and systemic hemodynamics and gas exchange in very-low-birth-weight infants

Abstract

ObjectivesTo determine whether surfactant administration affects cerebral and systemic hemodynamics and gas exchange in very low birth weight infants and to determine the predominant factor influencing changes in mean cerebral blood flow velocity (mCBFv) after surfactant instillation. Study designFourteen very low birth weight infants with respiratory distress syndrome had continuous monitoring of mCBFv, Paco2, mean arterial blood pressure (MABP), and Pao2 before, during, and after the second dose of surfactant. Peak values and relative changes of the 4 variables for 45 minutes after surfactant were calculated. Logistic regression was used to determine the predominant factor influencing changes in mCBFv after surfactant. ResultsBirth weight was 832 ± 162 grams and gestational age was 25.7 ± 1.5 weeks. The time from birth to monitoring was 6.9 ± 1.0 hours. Mean CBFv increased 75.7% ± 51.6% after surfactant and peaked at 14.4 ± 5.9 minutes. Paco2 was highly associated (OR=107.3, P < .0001) with mCBFv; as Paco2 increased, mCBFv increased. In contrast, MABP (OR=6.7, P=.047) had less impact on mCBFv. Pao2 was not associated with mCBFv. ConclusionsThe increases in mCBFv after surfactant administration were predominantly due to increases in Paco2 and not changes in MABP.