Clinical pharmacokinetics of carbonated local anesthetics. I: Subclavian perivascular brachial block model.

Fifty healthy adult patients undergoing upper extremity surgery under brachial plexus anesthesia provided by the subclavian perivascular technique were divided into two groups, so that anesthesia provided by 1% lidocaine hydrochloride in one group could be compared with that provided by 1.1% lidocaine carbonate in the other group. Epinephrine, 1:200,000, was added to both solutions just before injection. Carbonated lidocaine reduced the latency of anesthesia by 45% as compared with the hydrochloride salt and produced complete motor block in almost twice as many patients (54 vs 31%). The duration of anesthesia provided by the two agents was virtually identical, as was duration of motor blockade.