Effect of Intravenous Paracetamol on Postoperative Morphine Requirements in Neonates and Infants Undergoing Major Noncardiac Surgery

Importance Continuous morphine infusion as standard postoperative analgesic therapy in young infants is associated with unwanted adverse effects such as respiratory depression.Objective To determine whether intravenous paracetamol (acetaminophen) would significantly (Ͼ30%) reduce morphine requirements in neonates and infants after major surgery.Design, Setting, and Patients Single-center, randomized, double-blind study conducted in a level 3 pediatric intensive care unit in Rotterdam, the Netherlands.Patients were 71 neonates or infants younger than 1 year undergoing major thoracic (noncardiac) or abdominal surgery between March 2008 and July 2010, with follow-up of 48 hours.Interventions All patients received a loading dose of morphine 30 minutes before the end of surgery, followed by continuous morphine or intermittent intravenous paracetamol up to 48 hours postsurgery.Infants in both study groups received morphine (boluses and/or continuous infusion) as rescue medication on the guidance of the validated pain assessment instruments. Main Outcome MeasuresPrimary outcome was cumulative morphine dose (study and rescue dose).Secondary outcomes were pain scores and morphine-related adverse effects. ResultsThe cumulative median morphine dose in the first 48 hours postoperatively was 121 (interquartile range, 99-264) g/kg in the paracetamol group (n=33) and 357 (interquartile range, 220-605) g/kg in the morphine group (n=38), PϽ.001, with a betweengroup difference that was 66% (95% CI, 34%-109%) lower in the paracetamol group.Pain scores and adverse effects were not significantly different between groups. Conclusion and RelevanceAmong infants undergoing major surgery, postoperative use of intermittent intravenous paracetamol compared with continuous morphine resulted in a lower cumulative morphine dose over 48 hours.