The relationship between regional brain tissue oxygen saturation and early postoperative cognitive dysfunction after heart valve replacement

Objective To investigate the relationship between the occurrence of post-operative cognitive dysfunction (POCD) after heart valve replacement (HVR) and the changes of regional brain tissue oxygen saturation (rSO₂). Methods this study, 82 patients with elective HVR were enrolled. After entering the operating room, cerebral oxygen saturation was monitored. The baseline value of rSO₂(rSO_2base), the minimum value of rSO₂ (rSO_2min) and the maximum percentage of decrease relative to the baseline (rSO_2%max), and the area enclosed by threshold line below 20% of the baseline value and the curve (AUT_20%) were recorded. The cognitive function was assessed by the neuropsychological test methodsbefore and 7 dafter operation. The patients were divided into POCD group and non-POCD group by the results. The differences of rSO₂ between the two groups were compared. Results There were 34 patients in the POCD group and 48 patients in the non-POCD group. The incidence of POCD was 41.5%. The rSO_2%max and AUT_20% of the POCD group were higher than the non-POCD group(P＜0.05). Conclusions Early cognitive dysfunction after HVR has a certain correlation with regional brain tissue oxygen saturation. Minimizing the exposure time of rSO₂ below baseline by 20% may help reduce the incidence of POCD.