No abstract

A retrospective study of serious non-fatal complications of extradural block in obstetric practice was carried out using a postal questionnaire. Two hundred and three obstetric units in the United Kingdom (responsible for 2,580,000 deliveries from 1982 to 1986 inclusive) responded. A total of 505,000 extradural blocks were performed, 84% for relief of pain in labour and 16% for Caesarean section. Of 108 events reported, five were associated with permanent disability. Neuropathy involving a single spinal nerve, acute toxicity from the local anaesthetic, and problems associated with accidental dural puncture were the commonest complications. This investigation indicates the need for a prospective study. Although rare, serious complications could be reduced further by meticulous technique, while early diagnosis and treatment of untoward events would reduce the incidence of permanent disability.

Etidocaine given by intravenous infusion has been compared, using a double-blind technique, with bupivacaine and lignocaine in respect of toxic symptoms and signs. The degree of toxicity is affected considerably by the rate of drug infusion. At 10 mg/min subjects could tolerate twice the dose of etidocaine as bupivacaine. Tolerance to etidocaine was less at 20 mg/min but still compared favourably with bupivacaine at 10 mg/min. Considering the difference in potency of the two agents it was considered that the therapeutic ratios would not be substantially different. Lignocaine at 20 mg/min was better tolerated than etidocaine. Venous plasma concentration during these experiments showed a more rapid decrease in the case of etidocaine compared with bupivacaine, but the concentrations were unhelpful in predicting the toxic effects. Similarly electroencephalography revealed no abnormalities in spite of marked subjective and objective signs of toxicity.