Dexmedetomidine vs. Remifentanil for Pre-eclampsia During Caesarean Delivery

Preeclampsia is a pregnancy-specific, multisystem disorder that complicates approximately 5 % of pregnancies. Tracheal intubation in the women with severe pre-eclampsia is usually associated with exaggerated transient increases in blood pressure, heart rate and maternal plasma catecholamine concentrations. These changes may lead to maternal cerebral oedema, haemorrhage, left ventricular failure, pulmonary oedema or mortality, and reduce uterine blood flow which may adversely affect the neonatal wellbeing. Therefore, the attenuation of the haemodynamic responses to tracheal intubation in this unique group of patients is demanding for the best of both mother and foetus. The use of single remifentanil boluses of 0.5 to 1 µg/kg reduces effectively the haemodynamic and catecholamine responses to laryngoscopy and tracheal intubation in severe pre-eclamptics during Cesarean delivery under general anesthesia. Unfortunately, the use of 1 µg/kg doses are associated with more maternal hypotension and neonatal respiratory depression requiring resuscitation. Moreover, the use of preinduction remifentanil bolus of 0.5 µg/kg followed by a continuous infusion at 0.15-0.2 µg/kg/min is associated with significant attenuation of the maternal stress response to tracheal intubation with variable degree of neonatal depression in non-pre-eclamptic women. Whereas, the use of infusion rates of 0.1 µg/kg/min or less is less likely to produce neonatal depression. In our previous study, we demonstrated that the preoperative administration of dexmedetomidine 0.4 and 0.6 µg/kg/h, a specific alpha 2-adrenoceptor agonist, blunts the maternal haemodynamic and hormonal responses to Caesarean delivery under sevoflurane anaesthesia without adverse neonatal effects. However the use of 0.6 µg/kg/h doses is associated with higher postoperative sedation scores.