Effects of morphine on the electroencephalograms of neonates: a prospective, observational study

Objectives: Although opiates have been reported to profoundly alter the EEG and cause seizures in full-term and premature newborn babies, no prospective study has systematically studied the effects of morphine on the EEG of normal neonates. Methods: A prospective observational study was conducted on 20 neurologically and metabolically normal newborn babies of ≥26 weeks post-conceptional age, with EEG recordings performed while on and off morphine infusions. Results: The recordings performed while the babies were on morphine were all abnormal; the principal abnormalities consisted of prolonged periods of electrical quiescence (PPEQs) and excessive interictal epileptiform activity. After the morphine was discontinued, the PPEQs resolved and the EEG background rhythms were normal for age, but 5 continued to have excessive sharp transients. All babies did well clinically and did not require anti-epileptic drug therapy. Conclusions: Morphine produces a profound, largely reversible alteration of all neonatal EEGs at various post-conceptional ages. The study has implications for caution in formulating conclusions regarding the clinical significance of EEGs of critically ill neonates on morphine infusions.