Cerebral oximetry as a biomarker of postoperative delirium in cardiac surgery patients

Purpose: A promising monitoring strategy for delirium is the use of cerebral oximetry, but its validity during delirium is unknown. We assessed the relationship between oximetry and delirium. We hypothesized that as cerebral oximetry values increased, delirium would resorb. Materials and methods: An observational study was conducted with 30 consecutive adults with delirium after cardiac surgery. Oximetry, delirium assessments, and clinical data were collected for 3 consecutive days after delirium onset. Oximetry was obtained using near-infrared spectroscopy. Delirium was assessed using diagnosis, occurrence (Confusion Assessment Method-ICU), and severity scales (Delirium Index). Results: All patients presented delirium at entry. The mean oximetry value decreased from 66.4 +/- 6.7 (mean +/- SD) to 50.8 +/- 6.8 on the first day after delirium onset and increased in patients whose delirium resorbed over the 3 days. The relationship between oximetry, delirium diagnosis, and severity was analyzed with a marginal model and linear mixed models. Cerebral oximetry was related to delirium diagnosis (P <= .0001) and severity (P <= .0001). Conclusion: This study highlighted the links between increased cerebral oximetry values and delirium resorption. Oximetry values may be useful in monitoring delirium progression, thus assisting in the management of this complicated condition. (C) 2016 Elsevier Inc. All rights reserved.