A Correlation Study of Internal Jugular Vein Variability Under Deep Inhalation and Propofol-induced Hypotension

Inclusion Criteria:

• age over 60 years

• American Society of Anesthesiology (ASA) status Ⅱ-Ⅲ

• Surgery with radial artery puncture

• Propofol induction

Exclusion Criteria:

• BMI≥30kg/m2

• People with short necks;

• Previous hypotension (systolic blood pressure <90mmHg or mean arterial pressure <65mmHg)

• Previous poorly controlled hypertension

• Cardiac insufficiency , EF value<50%

• Upper limb deep vein thrombosis

• History of radiotherapy or neck surgery

• Inability to maintain a supine position for necessary measurements

• Mechanical ventilation status or inability to take deep breaths patients

• gastrointestinal surgery

• patients allergic to propofol.