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 (rSOs) 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 rSO2 was registered prior to anaesthetic induction, and this value was reported every 10 minutes throughout the procedure as the lowest rSO2 and 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 rSO2 values between POCD and non-POCD subjects were relatively similar. A significant difference was noted in the duration of total rSO2 desaturation between the two groups. Total rSO2 desaturation 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 %. CONCLUSIONS: Absolute rSO2 values did not correlate with POCD. However, a drop in rSO2 value >20% from baseline may correlate with POCD. The use of NIRS in Open-heart surgery may, be beneficial for POCD prevention.