A Prospective Observational Study on Role of Intraoperative Renal & Muscle Oxygen Saturation on Post-operative Serum...

Near-infrared spectroscopy (NIRS), can be used to monitor renal tissue oxygenation (SrO₂), as well as thenar muscle oxygenation (SmO₂). In this study, we have examined the ability of SrO₂ and SmO₂ in predicting cardiac surgery related change in serum creatinine level (ΔsCr) and explored any correlation between these two parameters.

This study included 55 adult patients (18-60 years), who were scheduled for elective cardiac surgery with cardiopulmonary bypass (CPB), having no pre-existing renal impairment, with skin-to-kidney depth of <4 cm at superior lumbar region which was detected by preoperative ultrasonography examination. NIRS sensors were applied on the superior lumber region to measure SrO₂ and on thenar eminence for SmO₂, preoperatively. ΔsCr was investigated at 24, 48 and 72 hours post-operatively. Relative thresholds of SrO₂ and SmO₂ were quantified using the area-under curve; expressed in % min.

Area under the receiver-operating characteristic curve (AUROC) analyses showed SrO₂ decrease >20 % from baseline can significantly predict (AUROC 0.921; p = 0.001) post-operative ΔsCr. SmO₂ decreased 15 % from baseline (AUROC 0.843; p = 0.001) is a better predictor of ΔsCr than its fall >20 % from baseline (AUROC 0.749; p = 0.002). Correlation analysis revealed that the 15 % and >20 % decrease of SmO2 below baseline (Spearman's rho 0.593 and 0.606 respectively) had significant (p = 0.01) positive correlation with decrease of SrO₂ >20 % from baseline.

SrO₂ and SmO₂ have significant predictive values for post-cardiac surgery rise in serum creatinine, and there is strong positive correlation between them.