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

BackgroundWe postulated that a spinal dose of hyperbaric bupivacaine 12 mg and morphine 100 μg administered for cesarean section would yield an equivalent sensory block height and provide sufficient analgesia if administered within 48 h of delivery for postpartum tubal ligation.Method20 women undergoing postpartum tubal ligation (PPTL) within 48 h of vaginal delivery and 20 undergoing cesarean section (CS) were recruited. Spinal anesthesia was induced with intrathecal hyperbaric bupivacaine 12 mg and morphine 100 μg at L3/4 with patients in the right lateral position.ResultsBaseline demographics of groups were comparable, but tubal ligation patients had greater parity, with a mean ± SD 14.5 ± 7.5 h 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.ConclusionAn equivalent dose of hyperbaric bupivacaine 12 mg and morphine 100 μg 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.