The Effect of Maternal Lateral Position or Position Change on Epidural Anesthesia and Plasma Bupivacaine Concentrations

Forty patients scheduled for elective cesarean section were studied. Epidural administration of 0.5% bupivacaine, 95-135 mg, was performed with the patients in right lateral decubitus position. In randomized order, half of the patients remained on the same side for 30 minutes. The other half were turned to the left lateral decubitus position for 30 minutes immediately after the epidural injection. Then all patients were turned to the left lateral “tilt” position for surgery. The spread of analgesia was tested by pinprick, and plasma bupivacaine concentrations were measured from mother and infant. The differences in the spread of anesthesia between the groups and sides (mean maximum cephalad spread was T4-T5) of the patients were small and not significant. Neither were there differences in plasma bupivacaine concentrations between the groups.