The Relationship Between Upper and Lower Extremity Blood Pressure in Thyroid Surgery Patients Under General Anesthesia

Inclusion Criteria: * Patients having elective thyroid surgery under general anesthesia * Aged between 20 to 80 years old * American Society of Anesthesiologist(ASA) Physical Status Class I or II * Individuals who have voluntarily given written consent to participate in this clinical study Exclusion Criteria: * Patients with Diabetes Mellitus or Peripheral vascular disease * Patients with a history of Heart disease; Myocardial infarction, Heart failure, etc. * Patients with Arrhythmia * Patients with musculoskeletal abnormalities * Patients for whom the placement of a non-invasive blood pressure cuff is contraindicated: inflammatory diseases or wounds causing pain at the cuff site, severe edema, thrombophlebitis, etc. * Other cases deemed unsuitable for the study by the researcher: absence of appropriately sized blood pressure cuffs, placement of a pressurized blood pressure cuff expected to affect the induction and maintenance of general anesthesia, history of mental illness, etc.