Comparative Study of Spinal Anesthesia with 0.5% Hyperbaric Bupivacaine and 0.5% Hyperbaric Tetracaine in Cesarean Section

Abstract

Background : Marcaine is a recently introduced hyperbaric bupivacaine and may be suitable for spinal anesthetic solution in parturients undergoing cesarean section. Therefore, we have compared bupivacaine with tetracaine mostly used for spinal anesthesia in cesarean section, about maximum level of analgesia, the time taken to reach it, degree of motor block of lower extremities, degree of patient's satisfaction and cardiovascular variables. Methods : Forty eight parturients were allocated to bupivacaine(n=26) or tetracaine(n=22) groups in random order. All patients received an infusion of lactated Ringer' solution(1,000 ml) and no premedication before spinal anesthesia. We used standardized techniques and injected the equal dose(10 mg) in equal volume(2 ml) intrathecally for spinal anesthesia. Maximum level of analgesia and time taken to reach it were checked by pinprick test, and degree of motor block was scored by Bromage scale. Blood pressure and heart rate were measured. Results : There were no differences in maximum level of analgesia, motor block of low extremities, patient's satisfaction, blood pressure and heart rate between two groups. But the time taken to reach maximum level of analgesia was faster in the tetracaine group(8.3±2.3 min) than in the bupivacaine group(10.5±2.1 min)(p<0.05). The incidences of hypotension(systolic blood pressure<30% of preanesthesia value) were fewer in the bupivacaine(1 of 26) group than in the tetracaine group(6 of 22)(p<0.05). Conclusions : 0.5% hyperbaric bupivacaine reaches slower the maximum level of analgesia but induces fewer incidences of hypotension than 0.5% hyperbaric tetracaine. Therefore, hyperbaric bupivacaine is a safe and reliable anesthetic solution for spinal anesthesia in cesarean section. (Korean J Anesthesiol 1997; 32: 219∼225)