Effect of Fentanyl Boluses on Cerebral Oxygenation and Hemodynamics in Preterm Infants: A Prospective Observational Study

Background: Fentanyl is a commonly used off-label medication for pain control and sedation in preterm infants. Yet, the effect of fentanyl on cerebral hemodynamics in preterm neonates remains unexplored. Objective: To evaluate the effect of a bolus dose of fentanyl on the regional cerebral oxygen saturation (RcSO₂), cerebral fractional tissue oxygen extraction (cFTOE) and left ventricular output (LVO) as compared with pre-administration baseline in preterm infants. Methods: This was a prospective observational study conducted in a level III Canadian NICU from September 2017 to February 2019. Preterm infants born <37 weeks of gestation and scheduled to receive a fentanyl bolus (1-2 μg/kg/dose) were eligible. Infants with major congenital anomalies, medically unstable and those who had received fentanyl in the previous 48 h were excluded. Outcomes: The primary outcome was the difference between RcSO₂ measured 5 min prior to and RcSO₂ measured at defined time points after administration of fentanyl. Results: Twenty-eight infants were enrolled during the study period (median gestational age 28 weeks; interquartile range [IQR] 25-29 weeks; median birth weight 1,035 g [IQR 830-1,292 g]; median age 4 days [IQR 3-7 days]). Mean (±standard deviation) baseline RcSO₂ was 73.6% (±11.8), cFTOE was 21.9 (±11.2) and LVO was 380 (±147) mL/kg/min prior to fentanyl infusion. One-way ANOVA showed no statistically significant difference between baseline and any of the post-fentanyl cerebral oxygenation, tissue oxygen extraction or cardiac output measures (p > 0.05). Conclusion: Administration of fentanyl bolus for procedural pain and sedation was not shown to significantly affect cerebral oxygenation, cerebral tissue oxygen extraction or cardiac output in stable preterm infants.