Epidural anaesthesia with mixtures of bupivicaine and lidocaine

In a randomized double-blind trial in 30 patients receiving lumbar epidural anaesthesia, the onset and duration of sensory blockade with 0.375 per cent bupivicaine was compared with a mixture of 0.375 per cent bupivicaine and one per cent lidocaine hydrochloride and a mixture of 0.375 per cent bupivicaine and one per cent carbonated lidocaine. Onset (9.3 +/- 1.16 minutes) and complete spread (23.3 +/- 4.8 minutes) for bupivicaine was significantly slower than in the mixtures containing carbonated lidocaine (onset 4.7 +/- 0.48 minutes, complete spread 14.8 +/- 2.49 minutes) and lidocaine hydrochloride (onset 5.0 +/- 0.67 minutes, complete spread 16.3 +/- 3.2 minutes). There was no significant difference in times of onset and complete spread between the two mixtures. The duration of sensory blockade for bupivicaine alone (165 +/- 20 minutes) was not significantly different from the duration in either the mixture containing carbonated lidocaine (161 +/- 51.24 minutes) or lidocaine hydrochloride (143 +/- 33.7 minutes). The results indicate a clinical advantage in speed of onset without significant shortening of duration of action for mixtures of carbonated lidocaine or lidocaine hydrochloride with bupivicaine as compared to bupivicaine alone.