This study aimed to investigate independent risk factors of postoperative hypoxemia in patients with acute type A aortic dissection (ATAAD). Methods: A single-center retrospective study was conducted with enrolled 75 ATAAD patients following surgery, which were stratified into three groups on the basis of the postoperative PaO 2 /FiO 2 ratio: severe hypoxemia group (PaO 2 /FiO 2 ratio ≤100 mmHg); moderate hypoxemia group (100 mmHg < PaO 2 /FiO 2 ratio ≤200 mmHg); and non-hypoxemia group (PaO 2

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... FiO 2 ratio >200 mmHg). The patient's demography, perioperative laboratory results, operative details, clinical outcomes were collected and analyzed. Univariable and multivariable analyses were performed and logistic regression model was established. Results: The incidence of postoperative severe hypoxemia and hypoxemia was 32% and 52%, respectively. Among the three groups, severe hypoxemia group exhibited a high significance of body mass index (BMI) and preoperative white blood cell (WBC) and main distribution of hypertension; meanwhile, Marfan syndrome was mainly distributed in non-hypoxemia group. On intensive care unit (ICU) admission, severe hypoxemia group exhibited a high significance of Acute Physiology and Chronic Health Evaluation (APACHE II) score of postoperative patients, and more patients would present shock. Moreover, severe hypoxemia group patients had a higher incidence of postoperative acute kidney injury (AKI) and usage of renal replacement therapy, longer length of stay (LOS) of ICU, and shorter 28 days ventilator-free days (VFDs). Conclusions : The incidence of postoperative hypoxemia was high in ATAAD patients owing to comprehensive high-risk factors. Besides, postoperative complications negatively impacted their clinical outcomes. Sang L. Independent risk factors of hypoxemia in patients after surgery with acute type A aortic dissection Ann Palliat Med 2021.