Interpleural or thoracic epidural analgesia for pain after thoracotomy. A double blind study

The analgetic effect of bupivacaine given epidurally or interpleurally after thoracotomy was investigated in a randomized, double blind, placebo controlled study. 32 patients with both an epidural and an interpleural catheter, were randomized to receive either interpleural or epidural analgesia. The interpleural group was given bupivacaine 5 mg ml^-1 with 5 microgram epinephrine as a 30 ml interpleural bolus, followed by a continuous infusion starting at a rate of 7 ml per hour and epidurally a bolus of 0.9% NaCl followed by a continuous infusion of 0.9% NaCl. The epidural group was given bupivacaine 3.75 mg–ml^-1 with 5 microgram epinephrine as a 5 ml epidural bolus, followed by a continuous infusion starting at a rate of 5 ml per hour and interpleurally a bolus of 0.9% NaCl followed by a continuous infusion of 0.9% NaCl. The draining tubes were clamped during the injection of the interpleural bolus and 15 min afterwards. Adequacy of pain relief was evaluated with the Prins–Henry pain scale. Morphine requirement was registered, there was no difference between the groups in painscores or need for additional morphine.