Ultra-low dose combined spinal-epidural anesthesia with intrathecal bupivacaine 3.75 mg for cesarean delivery: a randomized controlled trial

• Published in: International journal of obstetric anesthesia 2006-10, Vol.15 (4), p.273-278
• Main Authors: Teoh, W.H.L., Thomas, E., Tan, H.M.
• Format: Article
• Language: English
• Subjects: Adult; Anesthesia, Epidural; Anesthesia, Obstetrical - methods; Anesthesia, Spinal; Anesthetics, Combined - administration & dosage; Bupivacaine - administration & dosage; Cesarean; Cesarean Section; Combined spinal-epidural; Dose-Response Relationship, Drug; Double-Blind Method; Feasibility Studies; Female; Fentanyl - administration & dosage; Humans; Hypotension; Low dose spinal anesthesia; Morphine - administration & dosage; Pregnancy; Regional anesthesia
• ISSN: 0959-289X; 1532-3374
• DOI: 10.1016/j.ijoa.2006.03.004

We wished to investigate the feasibility of an ultra low-dose combined spinal-epidural technique in providing surgical anesthesia for uncomplicated cesarean deliveries in a randomized, double-blind controlled trial. Forty-four normotensive, non-obese patients were randomized to receive either intrathecal hyperbaric bupivacaine 3.75 mg (low dose group, n = 22) or 9 mg (conventional group, n = 22), in addition to intrathecal fentanyl 25 μg, morphine 100 μg, and epidural 1.5% lidocaine 3 mL. Sensorimotor anesthesia and hemodynamic data were assessed at 2.5-min intervals for the first 15 min. The maximal sensory block achieved in the low-dose group was significantly lower than that in the conventional group (median T3, [range T2-T6] vs. T2 [C2-T6], P < 0.001) with a longer time taken to reach maximal sensory block. The low-dose group had less motor block, faster sensory regression to T10 dermatome and faster motor recovery to Bromage 0 (all P < 0.001). The block failed to reach T6 bilaterally within 10 min in one patient in the low-dose group and two in the conventional group, with no significant difference in the need for epidural supplementation before or after delivery of the baby. The low-dose group experienced less hypotension (14% vs. 73%, P < 0.001) with less ephedrine usage (0.68 vs. 17.5 mg, P < 0.001). There was no difference in operating conditions and other side effects (shivering, pruritus). We conclude that this technique results in a significantly lower incidence of maternal hypotension and has a role in high-risk parturients in whom maintenance of stable hemodynamics is imperative.