Under general anesthesia, patients were positioned in the Trendelenburg position with extension of the neck. In the rotated group, the head was rotated to the left at>45°. In the neutral group, the head was placed in the neutral position. Right IJV cannulation was performed using the central approach with the needle angled toward the ipsilateral nipple. The primary outcome variable was the cumulative success rate, which was defined as IJV puncture achieved in the first 3 attempts using a finder needle