Low Intraoperative Cerebral Oxygen Saturation Is Associated with Acute Kidney Injury after Off-Pump Coronary Artery Bypass.

By monitoring the brain as the index organ of global oxygen supply-demand balance including major organs, regional cerebral oxygen saturation (rScO 2 ) may indicate adequacy of renal perfusion. The aim of this study was to investigate the relationship between perioperative rScO 2 and acute kidney injury (AKI) after off-pump coronary artery bypass (OPCAB). AKI was diagnosed according to the Kidney Disease: Improving Global Outcomes criteria. Collected rScO 2 variables were baseline, mean, and lowest value during surgery, maximal percentage decrease from baseline, and areas under the threshold below an absolute value of 50% (AUT 50 ) and of 80% of baseline (AUT 80%base ). Among 580 patients, AKI developed in 143 (24.7%) patients. Patients with AKI had lower baseline, mean, and lowest rScO 2 and higher AUT 50 and AUT 80%base than those without AKI despite routine efforts to restore the rScO 2 values within 20% of the baseline. Among the rScO 2 variables, the area under the receiver operating characteristic curve of mean rScO 2 was the highest (0.636), which was used for the multivariable logistic regression. Multivariable logistic regression revealed mean rScO 2 as an independent predictor of AKI (odds ratio, 0.964; 95% confidence interval, 0.937-0.990; p = 0.008), along with chronic kidney disease and emergency surgery. Low intraoperative mean rScO 2 was independently associated with AKI after OPCAB, which may serve as an early marker of renal injury.