Intraoperative mild hyperoxia may be associated with improved survival after off-pump coronary artery bypass grafting: a retrospective observational study

• Published in: Perioperative medicine (London) Vol. 11; no. 1; pp. 1 - 27
• Main Authors: Ju, Jae-Woo, Choe, Hyun Woo, Bae, Jinyoung, Lee, Seohee, Cho, Youn Joung, Nam, Karam, Jeon, Yunseok
• Format: Journal Article
• Language: English
• Published: London BioMed Central Ltd 19-07-2022; BioMed Central; BMC
• Subjects: Analysis; Anesthesia; Cardiac patients; Cardiac surgery; Cardiovascular disease; Catheters; Coronary artery bypass; Coronary artery bypass grafting; Coronary vessels; Creatinine; Electronic health records; Extubation; Heart surgery; Hemodynamics; Hospital patients; Hyperoxia; Intubation; Kidneys; Medical records; Medical research; Medicine, Experimental; Mortality; Observational studies; Outcome; Oxygen; Oxygen saturation; Oxygen therapy; Patient outcomes; Patients; Pulmonary arteries; Regression analysis; Renal replacement therapy; Surgery; Ventilators; United States > US
• ISSN: 2047-0525; 2047-0525
• DOI: 10.1186/s13741-022-00259-y

Background The effect of hyperoxia due to supplemental oxygen administration on postoperative outcomes in patients undergoing cardiac surgery remains unclear. This retrospective study aimed to evaluate the relationship between intraoperative oxygen tension and mortality after off-pump coronary artery bypass grafting (OPCAB). Methods The study included adult patients who underwent isolated OPCAB between July 2010 and June 2020. Patients were categorised into three groups based on their intraoperative time-weighted average arterial oxygen partial pressure (PaO.sub.2): normoxia/near-normoxia (< 150 mmHg), mild hyperoxia (150-250 mmHg), and severe hyperoxia (> 250 mmHg). The risk of in-hospital mortality was compared using weighted logistic regression analysis. Restricted cubic spline analysis was performed to analyse intraoperative PaO.sub.2 as a continuous variable. The risk of cumulative all-cause mortality was compared using Cox regression analysis. Results The normoxia/near-normoxia, mild hyperoxia, and severe hyperoxia groups included 229, 991, and 173 patients (n = 1393), respectively. The mild hyperoxia group had a significantly lower risk of in-hospital mortality than the normoxia/near-normoxia (odds ratio [OR], 0.12; 95% confidence interval [CI], 0.06-0.22) and severe hyperoxia groups (OR, 0.06; 95% CI, 0.03-0.14). Intraoperative PaO.sub.2 exhibited a U-shaped relationship with in-hospital mortality in the non-hypoxic range. The risk of cumulative all-cause mortality was significantly lower in the mild hyperoxia group (hazard ratio, 0.72; 95% CI, 0.52-0.99) than in the normoxia/near-normoxia group. Conclusions Maintaining intraoperative PaO.sub.2 at 150-250 mmHg was associated with a lower risk of mortality after OPCAB than PaO.sub.2 at < 150 mmHg and at > 250 mmHg. Future randomised trials are required to confirm if mildly increasing arterial oxygen tension during OPCAB to 150-250 mmHg improves postoperative outcomes. Keywords: Cardiac surgery, Coronary artery bypass grafting, Mortality, Outcome, Oxygen