Is there an advantage in using low-dose intrathecal bupivacaine for cesarean section?

Spinal anesthesia for cesarean section is associated with a high incidence of maternal hypotension. The aim of this study was to assess the efficacy of low-dose bupivacaine with fentanyl to reduce the incidence of hypotension in spinal anesthesia for cesarean section.

Forty pregnant women undergoing elective cesarean section were randomly allocated to two groups; those receiving 10 mg bupivacaine to group B (n = 20) and those receiving 4 mg bupivacaine plus 25 microg fentanyl to group BF (n = 20); the agents were given intrathecally with patients in the sitting position, with a combined spinal-epidural technique.

Sensory block was adequate for surgery in all patients. Hypotension occurred in all patients in group B (100%) and in 15 patients in group BF (75%). The incidence of hypotension, number of ephedrine treatments, and need for ephedrine were significantly greater in group B than group BF. Three patients in group BF required i.v. fentanyl supplementation after delivery. In 1 of these patients, i.v. fentanyl was not adequate, and epidural supplementation of 1% lidocaine was required.

The development of hypotension after spinal block in subjects undergoing cesarean section was not prevented despite low-dose (4 mg) bupivacaine plus 25 microg fentanyl, but the severity of maternal hypotension, and the number of ephedrine treatments and the total dose of ephedrine were decreased.