Cerebral Near-Infrared Spectroscopy Monitoring as a Predictor for Postoperative Delirium in Adult Cardiac Surgery Patients: Myth or Reality?

Background: Delirium in the postoperative setting is of clinical importance due to increased morbidity and long-term mortality. Near-infrared spectroscopy (NIRS) has been widely used to measure regional oxygen saturation (rSO₂) in brain tissue during cardiac surgery. We assessed retrospectively the association between duration and severity of perioperative rSO₂ decrease and the occurrence of delirium after cardiac surgery

Method: We enrolled 125 patients over 50 years of age, without previous psychiatric and neurological history, who were scheduled for elective cardiac surgery between December 2019 and December 2020 and among them, 83 patients with sufficient data on rSO₂ in this study. Baseline rSO₂ was measured before induction of anesthesia, throughout surgery and monitored continuously up to 12 hours after operation. Baseline, minimal and average perioperative rSO₂ values as well as areas under the curve (AUCs) at cutoffs of 25% and 50% of the preoperative baseline values were calculated using the analytic tool. The presence of delirium was assessed using the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU).

Results: Of 84 patients (65.57 ± 9.5 years old, 73% male, 27% female), 17 patients (20.4%) presented with delirium during the ICU stay. They had severe absolute rSO₂ decrease in comparison to the patients without delirium (p = 0.004). The duration of rSO₂ reduction was significantly longer in patients with delirium at cutoffs of 25% (adjusted odds ratio [OR]: 6.35; 95% confidence interval [CI]: 2.02; 21.15, p = 0.001) and at cutoffs of 50% (adjusted odds ratio [OR]: 7.12; 95% confidence interval [CI]: 1.98; 25.57, p = 0.004). There was no significant difference regarding sex (p = 0.3), baseline rSO₂ (p = 0.2), and average rSO₂ (p = 0.2), but the patients with delirium were significantly older (p = 0.01), had longer duration of ventilation (p = 0.003), and had longer ICU stay (p = 0.034).

Conclusion: Perioperative cerebral oxygen saturation decrease was associated with postoperative delirium occurrence after elective cardiac surgery, although our results need to be confirmed in a properly sized sample of patients.

Publication History

Article published online:
03 February 2022