Effect of previous frequency of headache, duration of fasting and caffeine abstinence on perioperative headache.

We have examined the relationship between perioperative headache and various factors in 219 patients who fasted from midnight and underwent minor surgery under general anaesthesia. Four to six hours after operation all patients completed a questionnaire on previous frequency of headache, daily consumption of caffeine and occurrence of perioperative headache. The duration of fasting, type of surgery, premedication and anaesthetic agents used were obtained from the anaesthetic record. After multivariate logistic regression analysis a significant risk of preoperative headache was found in patients who normally experienced headache more than twice a month (odds ratio (OR): 7.7; confidence interval (CI): 2.9-20.1), had a daily caffeine consumption > 400 mg/24 h (OR: 5.0; CI: 1.6-14.8) and who were anaesthetized after 12:00 (OR: 3.7; CI: 1.4-9.8). The risk of postoperative headache was significantly greater in patients with preoperative headache (OR: 16.9; CI: 6.5-43.8), daily caffeine consumption > 400 mg/24 h (OR: 3.9; CI: 1.5-9.6) and in those patients who received atracurium, which was similar to the risk of tracheal intubation.