Doppler Ultrasonography Assessed Vascular Changes Before and After Radial Artery Puncture

Inclusion Criteria: * Patients were included in the study if they were ethnic Chinese, between 18 and 65 years old, American Society of Anesthesiologists (ASA) physical status I or II,candidates for general anesthesia undergoing thoracic surgery Exclusion Criteria: * Patients were excluded if they do not want to cooperate with the test, had a history of upper extremity arteriosclerosis obliterans or thromboangitis obliterans,had a history of radial artery puncture or coronary artery bypass grafting,had acute vessel trauma,or had been diagnosed with Raynaud' disease,had suffered from mental or neurological disorders