Inclusion Criteria:  undergoing unilateral primary THA having the ability to understand the relevant treatment process aged between 18 and 75 years a body mass index (BMI) ≤ 40 kg/m2 hemoglobin ≥ 12g/dL American Society of Anesthesiologists (ASA) physical status classification of I or II no ongoing infection or blood coagulation disorders  Exclusion Criteria:  with a history of coronary artery disease chronic obstructive pulmonary disease arrhythmias untreated obstructive sleep apnea