Effects of an inflatable lumbar pillow on phenylephrine dose for spinal hypotension in cesarean delivery: an unblinded randomized controlled trial.

Background: Aortocaval compression by the gravid uterus in the supine position may exacerbate spinal hypotension during cesarean delivery. We developed an inflatable lumbar pillow (ILP) to elevate the uterus in the supine position. The aim of this study was to evaluate the effect of the ILP on the dose of phenylephrine to prevent hypotension after spinal anesthesia in cesarean delivery.

Methods: One hundred and twenty-three healthy women undergoing elective cesarean delivery under spinal anesthesia were randomized to the ILP ( = 61) or control group ( = 62). After anesthesia, all women received a phenylephrine infusion started at 25 μg/min and titrated in response to changes in systolic arterial pressure until delivery, and after the woman was positioned supine, the ILP was inflated until uterine incision in the ILP group. The primary outcome was the dose of phenylephrine per minute during the study period.

Results: The dose of phenylephrine per minute (27.9 ± 3.8 μg/min vs.36.7 ± 8.3 μg/min, < 0.001) and the incidence of hypotension (11.5% vs. 25.8 %, = 0.042) and nausea (4.9% vs. 22.6%, = 0.005) were significantly lower in the ILP group than in the control group. There were no significant differences in other maternal side effects or neonatal outcomes between the two groups.

Conclusion: ILP reduces the dose of phenylephrine and the incidence of hypotension and nausea after spinal anesthesia for cesarean delivery. Further studies are needed to morphologically validate the effect of ILP on aortocaval compression.