[Epidural analgesia after thoracic surgery: morphine versus buprenorphine]

A double-blind study was carried out to assess the efficiency and possible side-effects of a single epidural injection of either morphine or buprenorphine at equipotent doses after elective thoracic surgery. The series included 24 patients aged 53.7 +/- 11.4 years; 13 underwent a lobectomy and 11 a pneumonectomy. 6 h after the last intravenous injection of fentanyl, the patients were randomly allocated to one of three equal groups. They received an epidural injection at T8-9 or T9-10 level of either 100 micrograms.kg-1 morphine (group M) or 6.6 micrograms.kg-1 buprenorphine (group B) or a subcutaneous injection of 0.1 ml.kg-1 normal saline placebo at the same level (group T). The following parameters were measured 20 and 60 min, and every 6 h up to 48 h after the injection: patient wakefulness, respiratory rate, blood gases, pain (according to a verbal scale), FVC and FEV1, adverse effects (euphoria, hallucinations, sweating, facial pruritus, nausea) and atelectasis. The duration of surgery, the anaesthetic protocol, the age, weight and height, as well as all the parameters before injection were similar in all three groups. There was a fall in pain intensity from the 20th min to the 24th hour in group M and from the 20th min to the 36th hour in group B, significant for both groups when compared with group T. Similarly, there was a prolonged increase in FEV1 in both groups M and B. There was no case of severe respiratory depression; PaCO2 was increased at the 1st hour (+0.3 +/- 0.6 kPa) in group B and at the 6th hour (+0.5 +/- 0.7 kPa) in group M.(ABSTRACT TRUNCATED AT 250 WORDS)