2.4. Randomization and masking
The patients were randomly assigned to the intervention (DEX and NCD, DEX-NCD) or control (DEX and normal saline, DEX) groups using sealed opaque envelopes on the morning of surgery. A computer-generated random allocation sequence was created using Excel 2019 (Microsoft) with a 1:1 allocation and random block sizes. For double-blindness, 1 researcher (S.K.), who did not manipulate the study data, confirmed the group assignment and administered the NCD or saline at a fixed infusion rate.