Use of opioids in asphyxiated term neonates: effects on neuroimaging and clinical outcome

Perinatal asphyxia is a common cause of neurologic morbidity in neonates who are born at term. Asphyxiated neonates are frequently treated with analgesic medications, including opioids, for pain and discomfort associated with their care. On the basis of previous laboratory studies suggesting that opioids may have neuroprotective effects, we conducted a retrospective review of medical records of 52 neonates who were admitted to our neonatal intensive care unit between 1995 and 2002 and had undergone magnetic resonance imaging (MRI) of the brain. Our review revealed that 33% of neonates received morphine or fentanyl. The neonates who received opioids also had experienced hypoxic/ischemic insults of greater magnitude as suggested by higher plasma lactate levels and lower 5-min Apgar scores. It is interesting that the MRI studies of neonates who were treated with opioids during the first week of life demonstrated significantly less brain injury in all regions studied. More important, follow-up studies of a subgroup of opioid-treated neonates whose MRI scans were obtained in the second postnatal week had better long-term neurologic outcomes. Our results suggest that the use of opioids in the first week of life after perinatal asphyxia have no significant long-term detrimental effects and may increase the brain's resistance to hypoxic-ischemic insults.