Association of early perioperative stroke after cardiothoracic surgery with intraoperative regional cerebral oxygenation using near-infrared spectroscopy: an observational cohort study comparing affected versus non-affected hemispheres

Purpose Patients undergoing cardiothoracic surgery are at risk of developing perioperative stroke, but residual effects of anesthesia 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 > 20% reduction below baseline) were calculated for each hemisphere. Stroke-affected and non-affected hemispheres were compared using logistic regression analyses to investigate a potential 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. Only the duration of ScO2 < 50% or a > 20% drop from baseline were significantly associated with global ischemia (OR 1.30 (0.95%CI; 1.09-2.30)) when comparing affected (72 [5 to 33] min.) versus non-affected (28 [4 to 44] min.) hemispheres. Conclusion The duration of ScO2 values < 50% or a drop > 20% from baseline were associated with the occurrence of early perioperative global cerebral ischemia within three days after cardiothoracic surgery.