Combined spinal-epidural anesthesia for cesarean delivery: dose-dependent effects of hyperbaric bupivacaine on maternal hemodynamics

Abstract

Hypotension remains an important side effect of spinal anesthesia for cesarean delivery. There is limited evidence that reducing the spinal dose has a favorable effect on maternal hemodynamic stability. We designed the present randomized trial to test the hypothesis that reducing the spinal dose of local anesthetics results in equally effective anesthesia and less maternal hypotension. Fifty term pregnant patients were randomly assigned to two study groups. In the HIGH-group combined spinal-epidural anesthesia was performed using 9.5 mg hyperbaric bupivacaine combined with 2.5 microg sufentanil. In the LOW-group combined spinal-epidural anesthesia was performed using 6.5 mg hyperbaric bupivacaine combined with 2.5 microg sufentanil. Demographic data, obstetrical data, visual analog scale score for pain, number of medical interventions for pain, maternal hemodynamics, and neonatal outcome were recorded. Patients in the HIGH-group experienced more pronounced and longer hypotensive periods as compared with the LOW-group. The mean lowest recorded systolic blood pressure was higher in the LOW-group (102 +/- 16 versus 88 +/- 16 in the HIGH-group; P < 0.05). More patients in the HIGH-group experienced hypotension compared with the LOW-group (68% versus 16%; P < 0.05). In the HIGH-group 15 patients required pharmacological treatment for hypotension compared with 5 in the LOW-group. Duration of effective anesthesia (block to cold sensation above or at T3) was longer in the HIGH-group as compared with the LOW-group (95 +/- 25 versus 68 +/- 18 min, respectively, P < 0.05). We conclude that small-dose spinal anesthesia (6.5 mg hyperbaric bupivacaine combined with sufentanil) better preserves maternal hemodynamic stability with equally effective anesthesia that is of shorter duration.