Independent risk factors for hypoxemia after surgery for acute aortic dissection

OBJECTIVES To determine risk factors associated with postoperative hypoxemia after surgery for acute type A aortic dissection. METHODS We retrospectively analyzed the clinical data of 192 patients with acute type A aortic dissection who underwent surgery in Qingdao Municipal Hospital, Medical College of Qingdao University, Qingdao, China between January 2007 and December 2013. Patients were divided into hypoxemia group (n=55) [arterial partial pressure of oxygen (PaO2)/fraction of inspired oxygen (FiO2) ≤ 200 mm Hg] and non-hypoxemia group (n=137) [PaO2/FiO2 > 200 mm Hg]. Perioperative clinical data were analyzed and compared between the 2 groups. RESULTS The incidence of postoperative hypoxemia after surgery for acute aortic dissection was 28.6% (55/192). Perioperative death occurred in 13 patients (6.8%). Multivariate regression identified body mass index (BMI) > 25 kg/m2 (OR=21.929, p=0.000), deep hypothermic circulatory arrest (DHCA) (OR=11.551, p=0.000), preoperative PaO2/FiO2 ≤ 300 mm Hg (OR=7.830, p=0.000) and blood transfusion > 6U in 24 hours postoperatively (OR=12.037, p=0.000) as independent predictors of postoperative hypoxemia for patients undergoing Stanford A aortic dissection surgery. CONCLUSION Our study demonstrated that BMI > 25 kg/m2, DHCA, preoperative PaO2/FiO2 ≤ 300 mm Hg, and blood transfusion in 24 hours postoperatively > 6U were independent risk factors of the hypoxemia after acute type A aortic dissection aneurysm surgery.