Opioid withdrawal in critically ill neonates

OBJECTIVE: To determine the occurrence of and risk factors for opioid withdrawal in critically ill neonates receiving continuous infusions of fentanyl. DESIGN: A prospective interventional cohort study was conducted in a university hospital neonatal intensive care unit with 19 neonates who received a minimum of 24 hours of fentanyl by continuous infusion. MEASUREMENTS: Fentanyl total dose, duration of infusion, and peak infusion rate were recorded. Patients were evaluated for withdrawal using the Neonatal Abstinence Scoring System of Finnegan. Patients with a score 8 were considered to have opioid withdrawal. MAIN RESULTS: Withdrawal was observed in 10 (53%) of 19 neonates. The fentanyl total dose (median 525 vs. 168 pg/kg, respectively; p = 0.03) and infusion duration (median 10 vs. 7 d, respectively; p = 0.04) were significantly greater in neonates with withdrawal compared to those without withdrawal. A fentanyl total dose greater than or equal to415 pg/kg predicted Withdrawal with 70% sensitivity and 78% specificity. A fentanyl infusion duration greater than or equal to8 days predicted withdrawal with 90% sensitivity and 67% specificity. The most frequent symptoms of withdrawal were sleeping <3 hours after feeding (81%) and increased muscle tone (55%). In all neonates with withdrawal, onset occurred within 24 hours of fentanyl discontinuation. CONCLUSIONS: Opioid withdrawal occurs frequently in critically ill neonates who receive continuous infusions of fentanyl. Longer infusion duration and higher total dose were associated with withdrawal symptoms.