Does pregnancy protect against intrathecal lidocaine-induced transient neurologic symptoms?

We investigated the incidence of transient neurologic symptoms (TNS) after the use of hyperbaric lidocaine as compared with hyperbaric bupivacaine in patients undergoing cesarean delivery under spinal anesthesia. Two hundred women scheduled for cesarean delivery were randomly allocated to receive spinal anesthesia with 75 mg hyperbaric lidocaine 5% (n = 100) or 12 mg hyperbaric bupivacaine 0.75% (n = 100). Spinal anesthesia was administered to all patients in the sitting position with a 25-gauge Whitacre needle. The level of sensory blockade, time to full recovery, and intraoperative hemodynamic profile were noted in all patients. The patients were interviewed postoperatively for three consecutive days to detect the occurrence of TNS. The incidence of TNS was zero (95% confidence interval 0%-3%) in both the Lidocaine and the Bupivacaine Groups. Our results indicate that the frequency of postoperative TNS does not exceed 3% in patients undergoing cesarean delivery at term using hyperbaric lidocaine 5% or hyperbaric bupivacaine 0.75%.