Regular interval preventive pain relief compared with on demand treatment after hysterectomy.

Eighty otherwise healthy women, aged 22-64 years, admitted for elective hysterectomy were studied in a prospective randomized trial. The aim was to compare two different postoperative pain relief schedules--one with the analgesic given at regular intervals and the other with the analgesic given on demand. All the patients had a neuroleptanaesthesia with fentanyl. Forty patients received an initial dose of buprenorphine 0.3 mg intravenously before termination of anaesthesia and continued with sublingual buprenorphine 0.4 mg 6 hourly postoperatively (regular interval (RI) group). Forty patients received the standard postoperative medication, meperidine 1 mg/kg on demand in the recovery room, followed by ketobemidone 5 mg subcutaneously on demand in the surgical ward (on demand (OD) group). There was no difference between groups concerning pain relief following a single dose of analgesic (P greater than 0.05, type II error 1-5%). In the recovery room 17.5% of the patients in the RI group received an analgesic compared to 87.5% in the OD group (P less than 0.05). Among patients in the RI group who had previously got injections for postoperative pain relief on demand 95% preferred regular interval sublingual buprenorphine for future treatment. The nurses found that 90% of the patients in the RI group were treated adequately compared to 62.5% of the patients in the OD group (P less than 0.05). It is concluded, that regular interval preventive pain relief is superior to conventional on demand analgesic therapy in postoperative pain.