Canadian Journal of Anesthesia, Vol 16, 46-56, Copyright © 1969 by Canadian Anesthesiologists' Society

An Evaluation of Bupivacaine in Epidural Analgesia for Obstetrics

¹ Department of Anaesthesia, McGill University, and Royal Victoria Hospital, Montreal

The new long-acting local anaesthetic, bupivacaine, was compared with tetracaine, using continuous lumbar epidural analgesia for labour and vaginal delivery in 132 patients. Minimal doses were employed, with 1/200,000 epinephrine added as a vasoconstrictor. The 0.5 per cent solutions appeared to be excessively powerful for obstetrical analgesia. There were three cases of prolonged blockade following 0.5 per cent tetracaine and one following 0.5 per cent bupivacaine. The 0.25 per cent solutions appeared to be well suited for obstetrical requirements. Bupivacaine caused very little motor block compared to tetracaine, and yet the incidence of successful sensory analgesia was higher with 0.25 per cent bupivacaine (94%) than with 0.25 per cent tetracaine (84%).

In comparison with results from an earlier series, 0.25 per cent bupivacaine gave a superior performance to equipotent doses of 1 per cent lignocaine hydrochloride, but the success rate was the same as for 1 per cent carbonated lignocaine. Although single doses of bupivacaine had almost twice the duration of lignocaine, during long labours the total dose for satisfactory analgesia required equitoxic amounts of lignocaine, tetracaine, or bupivacaine.