Management of postoperative pain in abdominal surgery in Spain. A multicentre drug utilization study

Postoperative pain is common in hospital-admitted patients. Its management is determined by different therapeutic traditions and by the attitudes of health professionals in each hospital. The aim of this study was to describe the patterns of prescription and administration of analgesic drugs used for postoperative pain after abdominal surgery in Spanish hospitals, to know the prevalence and the severity of postoperative pain, and to determine the extent of variability in the management of postoperative pain among the participating centres.

The study was a multicentre descriptive cross-sectional drug utilization study in 12 Spanish hospitals. The subjects were an unselected sample of consecutive patients undergoing abdominal surgery, admitted between October 1994 and January 1995. For each patient, information about the surgical procedure and the use of analgesics was prospectively collected. The severity of postoperative pain was assessed during the first day after surgery by means of a six-category (none, mild, moderate, severe, very severe, and unbearable) rating scale and a visual analogue scale (VAS).

Nine hundred and ninety-three patients (547 men) were included. The most common surgical procedures were inguinal hernia repair (315, 32%), cholecystectomy (268, 27%), appendectomy (140, 14%), bowel resection (137, 14%), and gastric surgery (58, 6%). Fifty-nine percent of patients (587) received nonopioid analgesics only, 9% (89) received opioid analgesics only, and 27% (263) received both opioid and nonopioid analgesics. The most frequently administered drugs were metamizole (667 patients) and pethidine (213 patients). Although in the majority of medical orders the administration of analgesics was scheduled at regular time intervals, the majority of actual doses were given 'as-needed'. The average administered daily doses of all analgesics were lower than those prescribed. Thirty-eight percent (371/967) of patients rated their maximum pain on the first day as severe to unbearable. Wide interhospital variability was recorded in the surgical procedures which had been performed, in the analgesics used, and also in the pain scores referred by patients. The percentage of patients in each centre who suffered severe to unbearable pain varied from 22 to 67%.

In Spain many patients still suffer severe pain after abdominal surgery, and this seems to be due to an inadequate use of analgesics. Wide interhospital variability in the management of postoperative pain and in its prevalence was also recorded.