Sevoflurane versus isoflurane in normal and preeclamptic parturients undergoing cesarean delivery

Abstract EN

Background: This study was designed to compare the efficacy, maintenance, recovery profiles, and neonatal outcome after general anaesthesia using either sevoflurane or isoflurane in normal pregnancies and pregnancy complicated by severe pre-eclampsia undergoing elective caesarean section.

Method: One hundred and twenty pregnant women were randomly assigned to receive either isoflurane (two groups) or sevoflurane (two groups) using an open (non-blinded) study design.

Anesthesia was maintained with either isoflurane 0.5% end tidal or sevoflurane 1% end tidal in combination with nitrous oxide (N20) 50% in oxygen.

The following data were measured and recorded; liver functions, kidney functions, complete blood count and coagulation profile.

Pharmacokinetic study included serum inorganic fluoride concentration and kinetics of serum inorganic fluoride.

Also, blood pressure, heart rate, central venous pressure (CVP) monitoring, ECG, estimation of intra-operative blood loss, uterine tone, recovery profile and urine output in 24 hours were also studied.

Infant outcome was also evaluated by Apgar score, neurologic adaptive capacity score (NACS), umbilical artery blood gas, acid base status and serum fluoride level.

Results: HR, Bl.P, CVP and ECG changes proved haemodynamic stability for all groups.

Slight insignificant increase observed in liver and kidney functions in pre-eclamptic groups who showed prolonged stay in ICU compared to normal pregnancy groups.

Estimated blood loss and uterine tone were nearly similar for both inhalational anaesihetics.

Sevoflurane groups of patients showed significantly shorter emergence times.

Postoperative nausea and vomiting.

(PONV) showed significantly higher incidence in sevoflurane groups.

Significant difference was observed in FDPs value when pre-eclamptic groups were compared to normal pregnancy groups (P<0.05).

Pharmacokinetic study proved significant increase in serum fluoride levels in all groups.

Postoperative peak drug concentration (Cmca) was higher in sevoflurane compared to isoflurane groups.

The time to peak drug concentration (Tmax) was at 12 hours and 6 hours in isoflurane and sevoflurane groups respectively.

The terminal elimination rate constant (KJ and the* elimination half life (T0.s) were lower in isoflurane groups.

Volume of distribution (Vj) was smaller in pre-eclamptic groups of patients.

Inhalational anaesthetics used did not affect the neonatal outcome parameters measured but NACS was slightly decreased in neonates of pre-eclamptic mothers.

Conclusion: Sevoflurane appears to be similar to isoflurane with a few exceptions.

It appears similar to isoflurane in its effect on regional blood flows including the hepatic and renal circulation.

The use of sevoflurane resulted in faster emergence than after isoflurane.

The high serum fluoride levels associated with administration of sevoflurane anesthesia were not dangerous because it did not reach the level that cause nephrotoxicity.

Neonatal outcomes were similar after anesthesia with either isoflurane or sevoflurane.

So, sevoflurane 1.0% is a suitable alternative to isoflurane 0.5% for maintenance of anesthesia in such cases, but in this era of cost containment and rationing of health resources, it remains to be seen whether sevoflurane will supplant isoflurane for obstetrical anesthesia.