Comparison of lidocaine CO2, two per cent lidocaine hydrochloride and pH adjusted lidocaine hydrochloride for caesarean section anesthesia.

Lidocaine can be prepared in a variety of ways which may affect the characteristics of neural blockade achieved. Experimental evidence is equivocal as to the clinical impact of the use of different lidocaine preparations. A randomized, double-blind study was performed to investigate the differences in epidural anaesthesia for Caesarean section using three different lidocaine solutions: lidocaine CO2, two per cent lidocaine and two per cent lidocaine with its pH adjusted by the addition of bicarbonate. No differences were found among the groups in time of onset of neural blockade, quality or duration of neural blockade, time to delivery of the infant or volume of anaesthetic solution injected into the epidural space. A significant difference was found between the pH's of the solutions used. It is concluded that all three solutions are equally efficacious in epidural anaesthesia for Caesarean section.