Randomisation and blinding
RECRUITMENT, BLIND
The patients were randomized at 1:1 ratio to receive total intravenous anesthesia (TIVA group) or total inhalation anesthesia (TIHA group) by using the SPSS software. The center for Evidence-Based Medicine provided sequentially numbered opaque sealed envelopes to achieve allocation concealment. These sealed envelopes were kept by the screener who was not implementation of the interventions. The envelopes corresponding to the patient’s serial number were sent to the anesthesiologist after recruitment. Then the anesthesiologist opened the envelope and administered the appropriate anesthesia protocol (TIVA or TIHA) according to the card.The randomization allocation schedule was blinded to the outcome evaluators who were not involved in the implementation of the interventions. Participants were blinded to the allocation and did not know the anesthetic protocol they received. It was impossible to blind anesthesiologists from the interventional schemes. However, anesthesiologists were not involved in the measurement or statistical analysis of outcomes and were required not to reveal the details of the anesthetic protocol to outcome evaluators or participants. The statistician was blinded to the group allocation until completion of the statistical analyses. The randomization allocation schedule was also blinded to the outcome evaluators, participants and statisticians until completion of the study.