Anesthesia
nerve block
STERILE
After confirming the inclusion and exclusion criteria in the operating room, all enrolled patients underwent pulse oximetry monitoring (fingertip pulse oximeter YX303, Jiangsu Yuyue Medical Equipment & Supply Co., Ltd., Jiangsu, China), without any analgesic or sedative medications. Sterile preparation was applied to the anesthesia site of the axilla, followed by a systematic ultrasound scan (SONIMAGE® MX1 Portable Ultrasound System with Linear Probe L11-3, Konica Minolta Healthcare Americas, Inc., Wayne, NJ, USA) to determine the optimal location for nerve block placement, and a point was marked for needle insertion. Each patient was instructed to keep the eyes shut and turn the head to the contralateral side during intradermal injection of local anesthesia prior to the nerve block. All anesthetic procedures were trained and conducted by three attending anesthetists. For the intervention group, the compressing disk was applied with projections against the axillary skin centered at the marked point (