Randomization and Blinding
Eligible participants were randomly assigned to dexmedetomidine or normal saline placebo (control group) using a 1:1 ratio by an online central randomization system. The randomization sequence was based on computer-generated random numbers. Patient clinical management and data collection were sequentially numbered and disclosed by health care practitioners who were not directly involved in this study. Each code was assigned by a random number to 1 of the 2 groups: the placebo group or the dexmedetomidine group. An anesthetic nurse who was not otherwise involved in the study prepared dexmedetomidine and normal saline in advance, which were each kept in syringes labeled only with the patient number. The surgeons, study statistician personnel, research staff who assessed the outcomes, and patients themselves were blinded to the treatment group.