Analgésie péridurale après chirurgie thoracique : morphine versus buprénorphine

Abstract

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 μg · kg −1 morphine (group M) or 6.6 μg · 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 FEV 1, adverse effects (euphoria, hallucinations, sweating, facial pruritus, nausea) and atelectasia. 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 FEV 1 in both groups M and B. There was no case of severe respiratory depression ; Pa co 2 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. Fiberoptic bronchoscopy was required for 6 patients in group T, 2 in group M (p < 0.05) and 1 in group B (p < 0.01). The results showed that a single epidural injection of morphine or buprenorphine was a simple, safe and efficient method of analgesia with minimal side-effects after thoracic surgery. Buprenorphine seemed preferable, because of a longer duration of analgesia.