2.3. Type of outcome measures
Our primary outcomes were postoperative pain intensity at rest at 24h and the incidence of PONV. Postoperative pain intensity was evaluated by pain scores scaling from 0 (no pain) to 10 (worst possible pain). Intensity scores reported on a visual analogue scale (VAS: 0: no pain to 100: worst possible pain) were transformed to a 0-to-10 scale. PONV, the most common adverse event with an incidence as high as 80% in high-risk cohorts[16], contribute to the highly distressing experience and severe patient dissatisfaction[17, 18].
Our secondary outcomes include pain thresholds at 24h after surgery, cumulative morphine consumption over the 24h, the time to first postoperative analgesic requirement and the incidence of shivering.