2.3. Randomization and masking
The patients underwent single-blind randomization (1:1) into 2 groups (remimazolam group - group R, or propofol group - group P) via the Research Electronic Data Capture (REDCap) computer randomization system stratified by age (75–79 years old or ≥ 80 years old) and body weight (<60 kg or ≥ 60 kg). Patients and operators were blinded to group identification, whereas the attending anesthesiologist could not be blinded to group identification because of the markedly different appearance of the 2 anesthetics.