Maternal and neonatal effects of a new short acting opioid analgesic remifentanil

ABSTRACT

Remifentanil is a new potent opioid analgesic. This study was to determine the placental transfer of remifentanil and its effects on mother and neonate when given as an intravenous [IV] adjunct to epidural anaesthesia for cesarean section [C.S]. 20 pregnant women 37-40 weeks, underwent non emergent C.S. with epidural anaesthesia received 0.1 or 1.0 micro g/kg / minute remifentanil IV, which was continued until skin closure Maternal arterial [MA], umbilical arterial [UA] and umbilical venous [UV] blood samples were obtained immediately after delivery to evaluate the blood gases and concentrations of remifentanil. Maternal blood pressure [B.P], heart rate [HR] and respiratory rate [RR] were monitored. The results of blood gases analysis showed slight increase of MA. Partial carbon dioxide tension [PaCo2], UAPaCo2, and UVPaCo2 in both doses of remifentanil treatment. This study also showed a significant degree of placental transfer of remifentanil detected by determination of remifentanil concentration in maternal and neonatal blood samples and we found that the foetal remifentanil concentration was about 1/4 of the maternal concentration but there were no-adverse effects on the neonates [Apgar score > 7]. This was referred to its rapid metabolism and short duration of action. The present study also showed significant decrease of maternal blood pressure, heart rate and respiratory rate. Also, the sedation score was < 4 in all cases