Exploring Cognitive Changes in High-Risk Cardiac Patients Receiving Dexmedetomidine and Evaluating the Correlation between Different Cognitive Tools: A Cohort Study

Abstract

Background: Mini-mental State Examination (MMSE) is widely accepted clinically for postoperative cognitive dysfunction (POCD) assessment. This study aims to investigate the post-operative cognitive changes among high-risk cardiothoracic patients and establish a standardised approach to post-surgery cognitive assessment. Methods: This is a prospective cohort study, where cognitive assessments were done 1-day before surgery, at discharge, and during 6 weeks of follow-up. Sample size calculation, accounting for an estimated 20% dropout rate, determined a minimum of 170 subjects were required for the study. Reduction of MMSE score of more than 2.5 was considered as having POCD. Score differences between groups were analysed using T-test and analysis of variance (ANOVA), while consistency between tools was analysed using correlation and regression. Results: A total of 188 patients completed the study, with a POCD prevalence of 20.2% and 6.9% at discharge and at the 6 week follow up, respectively. All cognitive tools show a significant difference between preoperative and postoperative scores. All tests show a significant moderate correlation with MMSE. Conclusions: In conclusion, it is imperative to employ a battery of cognitive assessments to evaluate cognitive changes comprehensively.

Keywords

• cognitive dysfunction
• postoperative cognitive dysfunction
• mmse
• high-risk patients
• neuropsychological tests
• cardiac surgery