Morphine and Stress Hormone Levels in Ventilated Newborns

Abstract

In a previously reported uncontrolled study we have shown that morphine reduces stress hormone levels in ventilated preterm babies. We now report a randomised double blind placebo controlled trial.41 preterm babies who qualified for Curosurf (A/a ratio < 0.22) were enrolled in the study 20 received 5% dextrose infusion (group P) whilst 21 received morphine (100 ugs/kg/hr × 2 hrs then 25 ugs/kg/hr infusion) in 5% dextrose (group M). Plasma catecholamine levels were measured on entry and after 24 hours. Blood pressure was documented on entry and after 6 hours. The two groups showed no differences with respect to method of delivery, Apgar scores, birth weight, gestation and catecholamine levels on enrolment. Group M showed a small but significant (P=0.01) reduction in adrenaline levels ([median (range) change -0.4 nmols/L (-34.7 to +0.06)], compared with group P [median (range) change +0.2 (-13.5 to + 19.0)]. There were no significant changes in noradrenaline levels. Group M treated babies showed a slight reduction (median: -4 mmHg) in blood pressure There were no differences between the groups for the incidence of intraventricular haemorrhage, patent ductus arteriosus, pneumothorax, the number of ventilator days and death.We conclude that morphine reduces adrenaline levels in ventilated preterm babies and appears to have no significant adverse effects.