OPIATES AND INTERMEDIARY METABOLISM IN VENTILATED PRETERM BABIES

Abstract

There are few data which indicate benefit from the use of opiates during mechanical ventilation in preterm babies. We have investigated the effect of sedative doses of alfentanil on intermediary metabolism. Ventilated preterm babies were randomised to receive alfentanil (20 ug/kg bolus & 5 ug/kg/hr) or placebo as a pilot study. Samples were taken pre-dose, 1 hour post-dose and twice daily during infusion. No other change in routine management occurred during the trial. Median birthweight of the study group was 1300g (r:726-2352g), gestation: 29 weeks (26-36 weeks). Twelve babies received alfentanil from a median age of 16 hours (r: 12-36) after birth and 12 babies a placebo infusion from 24 hours (r:10-32). No differences in heart rate, blood pressure or pH were seen between the study groups and similar rates of perinatal complications were seen in each group. During the administration of alfentanil, glucose rose by 2.02 mmol/l (sem: 1.67) compared to a fall of 0.87 mmol/l (2.94) in the placebo group 1 hour post-dose, and remained on average 1.27 (1.71) mmol/l higher than baseline over the next 24 hours, compared to 2.64 (1.78) mmol/l less among controls. Similar rises in lactate, pyruvate, glycerol were observed in the alfentanil group which persisted over the next 24 hours, in contrast to the anticipated falt. There were no differences in urinary catecholamine excretion. These data suggest that sedative doses of alfentanil may have no immediate metabolic benefit.