Can Near-Infrared Spectroscopy (NIRS) monitoring prevent post-operative cognitive dysfunction following open-heart surgery

Objective: This study aimed to evaluate the relationship between Post-operative Cognitive Dysfunction (POCD) and regional Oxygen saturation (_rSO_s) determined by NIRS monitoring during Open-heart surgery. Methods: This was a prospective cohort study of all patients about to undergo Open-heart surgery at Cipto Mangunkusumo National Referral Hospital, Jakarta. Subjects who fulfilled the selection criteria underwent cognitive assessment one day before the surgery. Basal rSO₂was registered prior to anaesthetic induction, and this value was reported every 10 minutes throughout the procedure as the lowest rSO₂and total desaturation (drop >20%) duration. On postoperative day 5, cognitive function was reassessed. We declared a drop in the cognitive function if the score dropped to >20% from the baseline in at least two cognitive tests. Results: The incidence of POCD was 51.7%. Basal rSO₂values between POCD and non-POCD subjects were relatively similar. A significant difference was noted in the duration of total rSO₂desaturation between the two groups. Total rSO₂desaturation was longer in subjects with than without POCD. The ROC (receiver operating characteristic) curve showed a cut-off point of 20.5 minutes, with an AUC (area under curve) size of 126.5 minutes %. Conclusion: Absolute rSO₂values did not correlate with POCD. However, a drop in rSO₂value >20% from baseline may correlate with POCD. The use of NIRS in Open-heart surgery may, be beneficial for POCD prevention.