Comparison of an equal-dose spinal anesthetic for cesarean section and for post partum tubal ligation

Abstract 

Background

We postulated that a spinal dose of hyperbaric bupivacaine 12mg and morphine 100μg administered for cesarean section would yield an equivalent sensory block height and provide sufficient analgesia if administered within 48h of delivery for postpartum tubal ligation.

Method

20 women undergoing postpartum tubal ligation (PPTL) within 48h of vaginal delivery and 20 undergoing cesarean section (CS) were recruited. Spinal anesthesia was induced with intrathecal hyperbaric bupivacaine 12mg and morphine 100μg at L3/4 with patients in the right lateral position.

Results

Baseline demographics of groups were comparable, but tubal ligation patients had greater parity, with a mean±SD 14.5±7.5h from delivery to spinal anesthesia, and shorter duration of surgery, 21.4±7.6 vs. 35.3±11.3 min. Maximal sensory block was higher in group CS than PPTL, T2 (T1-T4) vs. T3 (T2-T5), P=0.001; time to reach maximal level did not differ significantly, (6.9±3.9 vs. 8.7±2.8 min, P=0.091). There was no difference in time for spinal block to recede two segments or to T10, and for motor block recovery to Bromage 2, all P>0.05. More CS patients were hypotensive (80% vs. 45%, P=0.048) and had intraoperative nausea (25% vs. 0%, P=0.047), but mean phenylephrine and ephedrine usage did not differ significantly.

Conclusion

An equivalent dose of hyperbaric bupivacaine 12mg and morphine 100μg for both CS and PPTL resulted in a higher sensory block, more hypotension and nausea in CS patients. The studied regimen might be appropriate for PPTL, but appears excessive for CS.

Keywords: Spinal anesthesia, Cesarean section, Postpartum tubal ligation, Hyperbaric bupivacaine, Sensory block