General anesthesia for cesarean section involves rapid sequence induction with a muscle relaxant and barbiturate followed by endotracheal intubation. Although the use of opioids may blunt haemodynamic responses to endotracheal intubation, they are avoided in pregnant patients due to possible respiratory depressants effects on neonates.Preeclamptic patients response with exaggerated sympathoadrenal reflex to anesthesia induction and intubation. The resulting hypertension and tachycardia may result in cerebrovascular accident, pulmonary edema, arrhythmias, increased myocardial oxygen consumption and fetal hypoxia by uterine vasoconstriction. Several drugs have been used to blunt the hemodynamic disturbances to intubation, but none of them have been implicated for routine use for general anesthesia in preeclamptic patients.~Recently remifentanil has started to be used in general anesthesia of high risk obstetric patients. Remifentanil is a μ-opioid receptor agonist that is metabolized by nonspecific blood and tissue esterase hydrolysis. It has a low distribution volume with a context sensitive half life of 3 minutes. Its elimination half life is 12 minutes even after repeated boli. Previously remifentanil use in pregnant patients with cardiac pathology has been reported with minimal neonatal side effects. A randomized controlled study in normal parturient has shown that remifentanil is transferred through placenta and may cause mild neonatal depression that is easily managed. Umbilical artery and vein remifentanil concentrations has shown that remifentanil is quickly redistributed or metabolized in fetus. Thus, remifentanil may be an appropriate drug for induction and maintenance of general anesthesia in severe preeclamptic patients.
The purpose of this study is to determine whether remifentanil use in preeclamptic patients may blunt hemodynamic response to intubation during general anesthesia for cesarean section.