Fig. 1From: Analgesia effect of premixed nitrous oxide/oxygen during the rehabilitation after total knee arthroplasty: a study protocol for a randomized controlled trialStudy design framework. TKA total knee arthroplasty, NRS Numerical Rating Scale; KSS Knee Society Score, ROM range of motion. Physiological indices include blood pressure (BP), oxygen saturation (SPO2), heart rate (HR)Back to article page