Unilateral versus bilateral cerebral oximetry in delirium prevention during CABG and valve surgery

Abstract

Background: Cerebral oximetry is a non-invasive tool for identifying silent desaturation during cardiac surgery. Peri-operative desaturation may require rapid interventions to avoid adverse events, including delirium. Most desaturations during cardiac surgery occur in both hemispheres. Our objective was to evaluate the difference in applying a single cerebral oximetry sensor versus a dual sensor for preventing delirium in coronary artery bypass grafting and valve surgery. Methods: We conducted a single-center, retrospective study of all patients undergoing coronary artery bypass grafting and valve surgery between January 2016 and December 2017. Before surgery, we identified any cerebral low flow state by transcranial Doppler ultrasound and either restored cerebral flow prior to surgery or, if that was not possible, waived surgery and offered the patient alternative non-surgical therapies, such as coronary angioplasty. In 2016, patients undergoing cardiac surgery were monitored with bilateral oximetry sensors (control group), whereas a single sensor was used in 2017 (study group). Results: Bilateral sensors were used in 508 patients and a single oximetry sensor in 498 patients. The use of a unilateral sensor did not influence the delirium rate. Regression analysis confirmed our null hypothesis. The primary outcome delirium rate was not significantly different between the control (bilateral sensors) group (6.4%) and the study (unilateral sensor) group (5.4%) (p = 0.472, OR 1.21 [95%CI 0.72 – 2.05]). Conclusions: Using a single cerebral oximetry sensor instead of bilateral sensors may reduce both the cost of monitoring and the threshold for applying cerebral oximetry during cardiac surgery without influencing the delirium rate.