Extradural infusion analgesia for postoperative pain relief

We describe 4-yr experience providing extradural infusion analgesia in a district hospital for treatment of postoperative pain. A total of 770 patients recovering from major surgery were treated on general surgical wards between April 1989 and March 1993. The results of a retrospective audit showed that pain control, assessed with both a visual analogue scale (VAS score (0-10 cm)) and a verbal rating scale (VRS), was good. At rest, more than 80% of patients scored pain as absent or mild (VAS score 0-3) during the first 24 h, with only 4% experiencing severe pain (VAS score 7-10). On movement, 50% of patients had good pain control (VAS score 0-3) while 20% of patients experienced severe pain (VAS score 7-10). Minor complications such as emetic sequelae and pruritus were common; these conditions were mild and rarely required treatment. Hypotension (< 100 mm Hg) occurred in 34% of patients in the first 24 h. Ventilatory frequencies of 8 b.p.m. or less occurred in 2.6% of patients. Four patients (0.52%) developed severe respiratory depression. These patients demonstrated increased sedation but only one had a low ventilatory frequency. Three patients died while receiving extradural infusion analgesia.