Bupivacaine Dosing for Cesarean Delivery in Parturients of Short Stature: A Retrospective Case-Control Study.

The ED50 and ED95 of spinal bupivacaine for cesarean delivery has been well described in the literature; however, parturients with extremes of stature have been excluded. Parturients of short stature are a height of ≤ 148 cm. This retrospective, case-control study evaluated anesthetic outcomes for parturients of short stature and controls who underwent cesarean delivery over a 10-year period. Women were matched for anesthetic type and body mass index. Data extracted included patient demographics and obstetric and anesthetic information. The primary outcome was dose of intrathecal bupivacaine. Categorical data were compared using a chi-squared test, continuous data were compared using a t-test or Mann-Whitney U test. Data for 26 women of short stature and 52 controls were evaluated. The mean dose of bupivacaine used for spinal anesthesia in parturients of short stature was 9.8 ± 1.0 mg (P <.0001). The mean intrathecal bupivacaine dose used in combined spinal epidural anesthesia was 10.5 mg (interquartile range, 9-10.9) in parturients of short stature (P = .002). All but one patient of short stature achieved an adequate surgical level; there were no instances of high spinal blockade. Adequate surgical anesthesia was achieved with reduced dosing of spinal bupivacaine in parturients of short stature without an increase in adverse outcomes.