Measurement and control of postoperative pain.

Continuous intravenous infusion of morphine in a dosage varied according to the changing needs of the patient is proposed as an ideal method of controlling postoperative pain and reducing postoperative respiratory complications. An original technique for the measurement of pain is described which, when used in conjunction with measurement of serum levels of free morphine, has demonstrated the superiority of this method of pain control. Preoperative psychological tests are considered as possible predictors of pain experienced after operation, and extra counselling is suggested for patients indicated to be at risk.