Regional Cerebral Oxygen Saturation Decreases During Primary Hip Arthroplasty: An Analysis of Perioperative Regional Cerebral Oxygenation (rSO2), S100 Calcium-Binding Protein B (S100B) and Glial Fibrillary Acidic Protein (GFAP) Values. A Pilot Study.

BACKGROUND The incidence of postoperative cognitive dysfunction (POCD) after major joint arthroplasty is high. In the etiology of POCD, many factors have been cited, including thromboembolic complications. The incidence of cerebral embolization after lower extremity arthroplasty may be as high as 40-60%. The potential events of cerebral embolization could lead to a decrease in the regional cerebral oxygenation (rSO2) and increased serum levels of biochemical markers of brain damage. The objective of the study was to test whether there are any changes in the rSO2 values and serum markers of brain damage in patients who underwent total hip arthroplasty. MATERIAL AND METHODS Fifteen patients who underwent primary hip arthroplasty under spinal anesthesia were analyzed. The rSO2 was monitored using infrared spectroscopy. Biochemical analyses of S100 calcium-binding protein B (S100B) protein and fibrillary acidic protein (GFAP) serum concentrations were performed using immunoassay methods. RESULTS The values of rSO2 decreased during the surgery, but this was not related to mean arterial pressure variations or hemoglobin saturation. The concentration of S100B was increased compared to its preoperative values, and there were no changes in GFAP values. The changes in rSO2 readings correlated with the biomarkers' levels just after the surgery. CONCLUSIONS Our results suggest that S100B may be a more specific marker of astroglial damage in patients after primary total hip arthroplasty. The decrease in rSO2 readings may be due to micro-thromboembolic events that occurred during the surgery. However, the results of this study are preliminary, and further studies are needed to establish its clinical efficacy.