Epidural Low-Dose Morphine and Postoperative Pain: A Controlled Study
A double blind randomized study was undertaken in 14 patients admitted for hysterectomy. After induction of anaesthesia with thiopentone-halothane-N2O-O2-pancuronium, morphine 4 mg in 10 ml of normal saline or 10 ml placebo was injected in an epidural catheter. Postoperatively, the extent of pain was evaluated by means of a visual analogue pain scale (0–10). Each time pain score exceeded 5 points during the 24 hour trial, 10 ml of morphine in saline or placebo was given. If pain score was not decreased at least two points, 10 mg of morphine was injected i.v. and i.m. Control patients received a mean total dose of 35 mg of morphine parenterally with a mean pain score of 3.1. In contrast, the study group received a mean dose of 6.7 mg epidurally with a mean pain score of 1.3. No side effects were observed.