The relationship between s100β and cerebral oximetry trend in patients undergoing CABG with cardiopulmonary bypass

Background: CABG is among the most common cardiac procedures often done as on pump surgery. There are however, there is always the risk for potential neurologic and neurocognitive insults in CABG. S100β is a biomarker for CNS damage. Cerebral oximetry using NIRS has been developed for CNS monitoring especially cardiac surgery. This study was designed to find the relationship between serum levels of s100β and cerebral oximetry in CABG patients.Methods: in an observational study, 44 adult 40-75 years patients entered the study for elective CABG. Serum levels of s100β were assessed at two times during CPB; i.e. just after aortic clamping and immediately after aortic declamping; while the results were compared with right and left cerebral oximetry readings (NIRS); however, NIRS was measured at baseline, during start of cardiopulmonary bypass (CPB), during aortic clamping, and finally at off-clamping the aorta. Repeated Measures ANCOVA (analysis of covariance), multiple linear regression models and Spearman correlation coefficient with scatter plot were used for data analysis. P value less than 0.05 considered significant.Results: no linear correlation between s100β and NIRS was found according to correlation coefficients. Only among the patients whose s100β was more than 10, the scatter plots demonstrated a positive linear relationship between s100β and right NIRS (spearman correlation coefficient= 0.792; P value=0.006).Conclusions: the study failed to demonstrate a relationship between on-CPB NIRS numbers and serum s100β in adult patients undergoing CABG during the bypass interval; further studies are suggested to evaluate potential predictive value of NIRS in brain ischemia.