Preoperative sarcopenic status can affect length of hospital stay and patient outcomes after surgery. The aim of this study was to investigate the impacts of preoperative handgrip strength (HGS) on length of stay (LOS) and outcomes after lumbar fusion surgery. HGS was measured preoperatively, and the cut-off value for low HGS was <28 kg for men and <18 kg for women. Perioperative patient outcomes were compared between patients with low and normal HGS. A total of 225 patients, consisting of 86 and 139 patients in the low and normal HGS groups, respectively, fully satisfied the study criteria for analysis. A longer LOS (median 10 vs. 8 days, p = 0.013) and a higher incidence of serious postoperative complications (15.1 vs. 3.6%, p = 0.002) were observed in the low HGS group. In the multivariate analysis, a low HGS (odds ratio (OR) = 1.917, 95% confidence interval (CI) = 1.046–3.513, p = 0.035) was significantly associated with a longer LOS after surgery. Preoperative HGS below the reference values by sex appeared to be an independent factor associated with longer LOS after lumbar fusion surgery.

By monitoring the brain as the index organ of global oxygen supply–demand balance including major organs, regional cerebral oxygen saturation (rScO₂) may indicate adequacy of renal perfusion. The aim of this study was to investigate the relationship between perioperative rScO₂ 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 rScO₂ 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% (AUT₅₀) 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 rScO₂ and higher AUT₅₀ and AUT_80%base than those without AKI despite routine efforts to restore the rScO₂ values within 20% of the baseline. Among the rScO₂ variables, the area under the receiver operating characteristic curve of mean rScO₂ was the highest (0.636), which was used for the multivariable logistic regression. Multivariable logistic regression revealed mean rScO₂ 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 rScO₂ was independently associated with AKI after OPCAB, which may serve as an early marker of renal injury.