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

The value of intrapleural analgesia after thoracotomy is still controv ersial. 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/m L in Group TD-. We then performed a placebo-controlled double-blind st udy on 16 patients to evaluate the analgesic effects of an interpleura l infusion of 2% lidocaine using intravenous patient-controlled analge sia (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 a n infusion of 1 mg.kg(-1).h(-1) for 48 h. The VAS score was slightly r educed after the bolus (6.6 +/- 1.0 vs 8.7 +/- 0.3; P < 0.05 vs the pl acebo group) but the cumulative doses of morphine were similar in both groups. There was a slight, but not sustained, improvement in pulmona ry 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.