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 pain scores or need for additional morphine.