Epidural sufentanil for post-operative pain relief: Effects of adrenaline

The analgesic, respiratory and haemodynamic effects of epidural sufentanil 75 μg (Group 1) or sufentanil 75 μg with adrenaline 75 μg (Group 2) were studied in 20 patients following abdominal surgery in a double-blind randomized trial. Pain relief, assessed on a linear analogue scale, sedation, heart rate (HR), mean arterial pressure (MAP), respiratory rate (RR) and arterial carbon dioxide tension (PaCo2) were recorded before, and for 12 h after, injection. Good post-operative pain relief was obtained after 4 min in Group 1 and 6 min in Group 2. All patients in both groups were pain-free after 30 min. Analgesia lasted for 450 ± 46 min in Group 1 and 690 ± 92 min in Group 2 (P < 0.05). Coughing and active movement was possible with little pain for 6 h post-operatively in Group 1 and 7 h in Group 2. The respiratory rate was significantly decreased from 15 min to 1 h after injection in Group 1 compared with Group 2 (P < 0.05) and in three patients in Group 1 it was necessary to stimulate the patients verbally to maintain adequate respiration. PaCo2 increased significantly in both groups over the first 2 h. The patients in Group 1 showed more marked sedation 1 h after injection. Changes of HR and MAP were similar in both treatment groups. Side-effects were observed more frequently in Group 2, although the differences were not significant. Peak plasma sufentanil concentrations rose to 0.32 ng ml-1 after 4 min in Group 1 and to 0.14 ng ml-1 after 6 min in Group 2. The addition of adrenaline significantly prolonged the duration of analgesia provided by epidural sufentanil. It was accompanied by less hypercapnia and less reduction in respiratory rate. The diminished vascular uptake of sufentanil shown by the lower plasma concentrations in Group 2 might explain the lessened respiratory impairment.SCOPUS: ar.j