Pain measurement and critical review of analgesic trials: pain scores, functional pain measurements, limits and bias of clinical trials.

Abstract

Randomized clinical trials designed to assess analgesic agents and/or techniques used for postoperative pain control have several limitations, which are addressed in this article. Efficacy of analgesics cannot be limited to the evaluation of pain intensity or the amount of opioid rescue medication, but it also means to evaluate parameters such as the delay and duration of the effect, the number of patients with satisfactory pain control, and side effects. Because combination of analgesics is the standard of care in clinical practice, its value also needs to be documented. Eventually, analgesic treatments have to be considered in the settings of postoperative supportive care and enhanced recovery programmes after surgery.