Bupivacaine overdose eNS toxicity

Evidence of CNS toxicity was noted in 2 patients who underwent extradural analgesia lor Caesarian section.

Case , : A 22-year-old primigravid patient in spontaneous labour received lumbar extradural analgesia with 0.375% bupivacaine plain solution 2 hours after admission. Over the next 8 .5 hours she received an additional 69ml of bupivacaine injected in divided doses. At this point delivery by Caesarean seclion was decided and Ihe patient was given 9ml of 0.375% and 13ml of 0.5% bupivacaine for extension of extradural analgesia. 20 min after the bU'pivacaine there was a sudden onset of a grand mal convulsion which lasted 90 sec. No cardiovascular abnormalilies were noted, and the infant was subsequently delivered by Caesarean section. The total dose of bupivacaine administered was 357.5mg over a 10-hour period and of this 98.5mg were given during the last 60 min.

Case 2: Two hours after admission a 23-year-old primigravida with spontaneous onset labour had extradural analgesia wit" 0.375% bupiv8caine solution. Over the next 9 hours she received an adoitional 35m1 of bupivacaine in divided doses followed by 45ml of 0.5% bupivacaine in a period of 70 min to extend the extradural block for Caesarean section. Soon after delivery the patient became drowsy, cyanosed and showed convulsions. As in Case 1, there were no cardiovascular abnormalities and recovery was rapid . Over a 9·hour period a lotal dose of 356.25mg of plain bupivacaine solution had been administered of which 225mg were given within the last 70 min. The evidence presented here suggests that the total dose of bupivacaine injected should not exceed Ihe manulacturer's recommended maximum dose of 2 mgt kg for an adult weighing 65-70kg in a 4· hour period. In view of the increased popularity Of extradural anaesthesia for Caesarean section, it may be advantageous to use the more dilute solutions of bupivacaine 10 provide pain relief in labour as tl1is will reduce the total dose required lor extension of extradural analgesia if necessary. Thorburn. J and Moir. DO. Bri/Jsh Journal of Anaesthesia 56.' 551 (May 1984)

6 Reactions 8 Ssp 1984 0157·7211 /84/0908-0006/0S01.00/0 © ADIS Press