Risk Factors of Hypoxemia During Non-cardiothoracic Surgery for Populations at High Altitude in Tibet: A Prospective Cohort Study

  Objective  To investigate the incidence and risk factors of intraoperative hypoxemia in non- cardiothoracic surgery under general anesthesia in high-altitude areas of Tibet, and briefly analyze the impact of intraoperative hypoxemia on the prognosis.

  Methods  The clinical data of patients undergoing non-cardiothoracic surgery under general anesthesia in Tibet Autonomous Region People's Hospital from June 1, 2021 to August 31, 2022 were collected prospectively, including basic preoperative data, surgery information and anesthesia management. The main outcome was intraoperative hypoxemia. Multivariate Logistic regression was used to analyze the risk factors of intraoperative hypoxemia. The perioperative prognosis of patients with or without intraoperative hypoxemia was compared.

  Results  A total of 161 patients having non-cardiothoracic surgery under general anesthesia who met the inclusion and exclusion criteria were included. Among them, 9 patients (5.6%) suffered intraoperative hypoxemia and 152 cases (94.4%) experienced non-intraoperative hypoxemia. Multivariate Logistic regression analysis showed that preoperative oxygen saturation ≤ 85%(OR=4.604, 95% CI: 1.064-19.916, P=0.041), preoperative hemoglobin ≥ 170 g/L (OR=5.396, 95% CI: 1.163-25.035, P=0.031), and preoperative pulmonary artery pressure ≥ 40 mm Hg (OR=11.744, 95% CI: 1.599-86.243, P=0.015) were independent risk factors for hypoxemia during non-cardiothoracic surgery under general anesthesia in people at high altitude in Tibet. The incidence of perioperative adverse cardiac events in patients with intraoperative hypoxemia was significantly higher than that in patients without intraoperative hypoxemia (55.6% vs. 15.1%, P=0.002).

  Conclusion  Preoperative low oxygen saturation, hyperhemoglobin and pulmonary hypertension are the risk factors of intraoperative hypoxemia in non-cardiothoracic surgery under general anesthesia in people at high altitude in Tibet, and intraoperative hypoxemia may have a negative impact on the prognosis of patients.