Remifentanil-induced hyperalgesia in healthy volunteers: a… : PAIN
RF infusion on pain intensity and areas of hyperalgesia and allodynia in healthy volunteers. Nine studies were included. The intervention treatment consisted in RF infusion that was compared with placebo (saline solution). The primary outcome was pain intensity assessment at 30 ± 15 minutes after RF or placebo discontinuation, assessed by any pain scale and using any quantitative sensory testing. Moreover, postwithdrawal pain scores were compared with baseline scores in each treatment. Secondary outcomes included the areas (% of basal values) of hyperalgesia and allodynia. Subjects during RF treatment reported higher pain scores after discontinuation than during treatment with placebo [standardized mean difference (SMD): 0.50, 95% confidence interval (CI): 0.03-0.97; P = 0.04, I2 = 71%]. A significant decrease in pain scores, compared with baseline values, was found in the placebo treatment (SMD: −0.87, 95% CI: −1.61 to −0.13; P = 0.02, I2 = 87%), but not in the RF treatment (SMD: −0.2