Association of Early Perioperative Stroke After Cardiothoracic Surgery with Intraoperative Regional Cerebral Oxygenation Using Near-Infrared Spectroscopy: Comparing Affected Versus Non-Affected Hemispheres

Abstract Purpose Patients undergoing cardiothoracic surgery are at risk of developing perioperative stroke, but residual effects of anaesthesia may hamper timely detection. This study aims to determine if there is an association between intraoperative regional cerebral oxygenation (ScO₂) monitoring using near-infrared spectroscopy (NIRS) and the occurrence of early perioperative stroke within three days after cardiothoracic surgery. Methods We performed a single-center retrospective observational cohort study including all consecutive cardiothoracic surgery patients with routinely perioperative ScO₂ monitoring admitted postoperatively to the Intensive Care Unit (ICU) between 2008 and 2017. Patients with a confirmed stroke in the anterior cerebral circulation on brain imaging were included in the analysis. Intraoperative area under the curve (AUC), duration, and total ScO₂ excursions below predefined thresholds (50% ScO₂ or a reduction of 20% below baseline ScO₂) were calculated for each hemisphere. Stroke-affected and non-affected hemispheres were compared using logistic regression analyses to evaluate if there is an association between ScO₂ values and stroke. Results Of the 2454 cardiothoracic surgery patients with perioperative ScO₂ monitoring, 39 had a anterior stroke on brain imaging. ScO₂ readings of 44 affected hemispheres were compared to 34 non-affected hemispheres. The AUC ScO₂<50% or 20% from baseline (OR 0.99; 95%CI 0.97-1.01), duration (OR 0.99; 95%CI 0.98-1.00), and number (OR 0.99; 95%CI 0.79-1.23) of ScO₂ excursions below predefined thresholds were not significantly different in affected hemispheres compared to non-affected hemispheres. Conclusion Low ScO₂levels during cardiothoracic surgery were not associated with the occurrence of an early perioperative stroke within three days after surgery.