Relationship Between Cerebral Oximetry Monitoring and Mixed Venous Oxygen Saturation During Cardiopulmonary Bypass and Postoperative Cognitive Impairment

Background: We assessed the relationship between postoperative cognitive impairment and cerebral oximetry (INVOS) and mixed venous oxygen saturation (SvO2) during cardiopulmonary bypass (CPB).Methods: This observational cohort study enrolled 110 patients and divided them into 2 groups of 55 subjects. After the exclusion of 5 patients in the SvO2 group and 3 in the INVOS group, the final analysis was conducted on 50 and 52 patients in the former and latter groups, respectively. The Mini-Mental State Examination (MMSE) score was used to assess cognitive impairment in the patients on the second and third postoperative days. SPSS software, version 24, was used for statistical analysis.Results: On the second postoperative day, the frequency of cognitive dysfunction was 4% in the SvO2 group and 3.8% in the INVOS group (P = 0.73). Three days after surgery, the incidence of cognitive dysfunction in the SvO2 and INVOS groups was 2% and 1.9% (P = 0.49), respectively. No statistically significant difference was observed between the 2 groups concerning the incidence of cognitive dysfunction after surgery with CPB.Conclusions: Our results indicated that cerebral tissue perfusion monitoring by INVOS could be replaced with the SvO2 approach without increasing the incidence of cognitive dysfunction compared with INVOS in adult cardiac surgery using CPB. (Iranian Heart Journal 2024; 25(1): 66-73)