INTERPLEURAL INFUSION OF 2-PERCENT LIDOCAINE WITH 1/200,000 EPINEPHRINE FOR POSTTHORACOTOMY ANALGESIA

The value of intrapleural analgesia after thoracotomy is still controversial. We investigated the pharmacokinetics of interpleural analgesia in 14 patients with and without thoracic drainage (Groups TD+ and TD-, respectively) to determine the safety of the technique. The infusion led to a high steady-state concentration (C-ss) of 5.91 +/- 2.46 mg/mL in Group TD-. We then performed a placebo-controlled double-blind study on 16 patients to evaluate the analgesic effects of an interpleural infusion of 2% lidocaine using intravenous patient-controlled analgesia (PCA) with morphine and a visual analog scale score (VAS). In both studies an initial bolus of 3 mg/kg of 2% lidocaine was followed by an infusion of 1 mg.kg(-1).h(-1) for 48 h. The VAS score was slightly reduced after the bolus (6.6 +/- 1.0 vs 8.7 +/- 0.3; P < 0.05 vs the placebo group) but the cumulative doses of morphine were similar in both groups. There was a slight, but not sustained, improvement in pulmonary function test. In conclusion, interpleural analgesia by continuous infusion of lidocaine is poor after thoracotomy and may lead to blood levels in the toxic range.