Effects of remifentanil on cardiovascular and bispectral index responses to endotracheal intubation in severe pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia

Abstract

Background: We examined the effects of remifentanil on cardiovascular and bispectral index (BIS) responses to tracheal intubation and neonatal outcomes in pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia.

Methods: Forty-two women with severe pre-eclampsia were randomly assigned to receive either remifentanil 1 microg kg(-1) (n=21) or saline (n=21) over 30 s before induction of anaesthesia using thiopentone 4 mg kg(-1) and suxamethonium 1.5 mg kg(-1). Mean arterial pressure (MAP), heart rate (HR) and BIS values as well as plasma catecholamine concentrations were measured. Neonatal effects were assessed using Apgar scores and umbilical cord blood gas analysis.

Results: Induction with thiopentone caused a reduction in MAP and BIS in both remifentanil and control groups. Following the tracheal intubation MAP and HR increased in both groups, the magnitude of which was lower in the remifentanil group. BIS values also increased, of which magnitude did not differ between the groups. Norepinephrine concentrations increased significantly following the intubation in the control, while remained unaltered in the remifentanil group. The neonatal Apgar scores at 1 min were significantly lower in the remifentanil group than in the control. However, Apgar scores at 5 min, and umbilical artery and vein blood gas values were similar between the groups.

Conclusions: These results suggest that a single bolus of 1 microg kg(-1) remifentanil effectively attenuates haemodynamic but not BIS responses to tracheal intubation in pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia. However, its use was associated with maternal hypotension and neonatal respiratory depression requiring resuscitation.