Comparison of fentanyl and morphine in laser surgery for retinopathy of prematurity

PurposeTo compare complication rates of the analgesics fentanyl and morphine in preterm infants undergoing laser therapy for retinopathy of prematurity (ROP).MethodsIn this observational study, the medical records of consecutive preterm neonates undergoing laser treatment of ROP from June 2007 through September 2010 were retrospectively reviewed. Because a fentanyl-based infusion protocol was initiated in November 2009, there was approximately the same number of treatment sessions with morphine and with fentanyl. In both groups, midazolam was used additionally on a case-by-case basis. Analgesia type, complications, and vital signs were documented at 5-minute intervals for all surgeries. The primary outcome was change in ventilation status. Secondary complications included change in temperature and incidence of apneic, bradycardic, and desaturation events.ResultsA total of 35 patients were included, with 17 in the morphine group (mean gestational age, 24.8 weeks; mean birth weight, 661 g) and 18 in the fentanyl group (mean gestational age, 24.4 weeks; mean birth weight, 681 g). Overall worsening of ventilation status was noted in 29% of patients in the morphine group and 6% of patients in the fentanyl group (P = 0.08; 95% confidence interval, −2% to 48%). Temperature instability (outside of 36.5° to 37.4°C range) was noted in 6% of patients in the morphine group and no patients in the fentanyl group. Apneic events were 3.2 times more common and bradycardic events 1.5 times more common in the morphine group.ConclusionsWe found no difference in safety parameters for fentanyl infusion or morphine for analgesia in preterm infants undergoing ROP laser therapy in the neonatal intensive care unit setting. Although estimates of complication rates suggest that fentanyl may be safer, further study is needed to confirm this premise.