A randomized study of the effects of perioperative i.v. lidocaine on hemodynamic and hormonal responses for cesarean section

Purpose  Intravenous infusion of lidocaine attenuates the stress response to surgery. We aimed to evaluate the effects of perioperative lidocaine on the hemodynamic and hormonal responses for cesarean delivery. Methods  After the gaining of ethical approval, 90 patients scheduled for elective cesarean delivery were randomly allocated to receive either lidocaine 1.5 mg·kg⁻¹ i.v. bolus 30 min before induction, followed by an infusion of 1.5 mg·kg⁻¹·h⁻¹ until 1 h after surgery (n = 45), or saline placebo (n = 45). Anesthesia was maintained with 50% nitrous oxide in oxygen with 0.7% isoflurane. Hemodynamic variables, plasma cortisol, maternal and neonatal lidocaine concentrations, Apgar scores at 1 and 5 min, neonatal acid-base status, and the neurologic and adaptive capacity score (NACS) were recorded. Results  After induction, patients receiving lidocaine had a smaller increase in heart rate and mean arterial blood pressure (P < 0.02) and lower plasma cortisol concentrations (31.1 ± 9.91 vs 45.6 ± 8.43 μg·dL⁻¹; P < 0.001). There were no differences between the two groups in Apgar scores, NACS, or neonatal acid-base status. After delivery, maternal and umbilical venous concentrations and umbilical vein-to-maternal vein ratios of lidocaine were 2.05 ± 0.42 μg·mL⁻ and 1.06 ± 0.31 μg·mL⁻¹, and 0.52 ± 0.07, respectively. Conclusion  Perioperative lidocaine is safe and effective in attenuating the maternal stress response to surgery for cesarean delivery.