INTRAVENOUS TRAMADOL VERSUS EPIDURAL MORPHINE FOR POSTTHORACOTOMY PAIN RELIEF - A PLACEBO-CONTROLLED DOUBLE-BLIND TRIAL

Tramadol, an analgesic deriving only part of its effect via opioid ago nist activity, might provide postoperative pain relief with minimal ri sk of respiratory depression. We, therefore, evaluated it for the cont rol of postthoracotomy pain. In this randomized, double-blind study, a single intravenous (IV) bolus dose of 150 mg tramadol (Group T) was c ompared to epidural morphine administered as an initial 2-mg bolus and subsequent continuous infusion at a rate of 0.2 mg/h (Group M). Patie nts in each group could receive morphine IV from a patient-controlled analgesia (PCA) device. Pain scores, morphine consumption, arterial bl ood gases, and vital capacity values were recorded at regular interval s postoperatively until 8:00 AM on the first postoperative day. Both g roups obtained adequate pain relief, and there were no between-group d ifferences in pain scores or PCA morphine consumption. PaO2 was signif icantly higher in Group T at 2 h and PaCO2 significantly higher in Gro up M at 4 h postoperatively. There were no other significant respirato ry differences. We conclude that a single dose of 150 mg tramadol give n at the end of surgery provided postoperative analgesia equivalent to that provided by this dosage regimen of epidural morphine for the ini tial postoperative period.