Spinal anaesthesia for cesarean section with reduced dose of intrathecal bupivacaine plus fentanyl

Abstract

Background and objectives: The hypotension following spinal anesthesia remains common place in cesarean delivery. The combination of reduced dose of local anesthetics with intrathecal opioids makes it possible to achieve adequate spinal anesthesia with minimum hypotension. We investigate whether this synergistic phenomenon could be used to provide less frequent hypotension while incurring adequate spinal anesthesia for cesarean section.

Methods: Forty women scheduled for cesarean delivery (twenty in each group) were divided into two groups of patients who received a spinal injection of either 13.5 mg of standardized isobaric 0.5% bupivacaine or 9 mg of isobaric bupivacaine with 20 microgr fentanyl added. Each measurement of a systolic blood pressure less than 95 mm Hg or a decrease in systolic pressure of greater than 25% from baseline was considered as hypotension and treated with a bolus of 5 to 10 mg of intravenous ephedrine. The quality of surgical anesthesia was evaluated also.

Results: Spinal block provided excellent surgical anesthesia in almost all patients. Peak sensory level was higher (Th 2-3 vs. Th 4-5) and motor block was more intense in the plain bupivacaine group; the patients from standardized bupivacaine group were more likely to require treatment for hypotension (75% vs 15%) and had more persistent hypotension (4.6 vs. 1.0 hypotensive measurements per patient) than patients in the reduced bupivacaine-fentanyl group. Mean ephedrine requirements were 22.0 mg and 3.5 mg, respectively. Patients in the bupivacaine group also complained of emetic effects more frequently than patients in the reduced dose bupivacaine-fentanyl group.

Conclusions: Bupivacaine 9 mg plus fentanyl 20 microgr provided spinal anesthesia for cesarean delivery with less hypotension and vasopressor requirements while ensuring excellent perioperative surgical anesthesia.