The relationship between cerebral oxygen saturation and quantitative metrics of neurological function after coronary bypass surgery: a feasibility study.

BACKGROUND: It is well-known that patients undergoing coronary artery bypass grafting (CABG) surgery may experience neurological dysfunction following their operation. However, the nature of this dysfunction has not been properly quantified. Furthermore, the relationship between postoperative impairment and cerebral oxygen saturation during surgery has remained unclear. This study aims to define the feasibility of using robotic technology to quantify post-CABG neurocognitive function, and to correlate these objective metrics with intraoperative cerebral oxygenation.

METHODS: Neurological function was tested using robotic technology and a standardized questionnaire before and 3 months after surgery. In addition, frontal lobe cerebral oxygenation was recorded using the FORESIGHT near-infrared spectrometer for the duration of the operation. Pre- and postoperative neurological assessment was performed for 24 participants. Of those 24, 20 participants had cerebral oxygenation recorded during their surgery.

RESULTS: The cerebral oximeter captured 97.2% of the data. Majority of patients experienced no significant decline in overall neurocognitive function. Abnormal postoperative scores were most frequent in a sensorimotor task that involved additional cognitive load. In this reverse visually guided reaching task, postoperative scores significantly correlated with mean and minimum intraoperative cerebral oxygenation values, with lower values being associated with worse performance.

CONCLUSIONS: It is feasible to use robotic technology as a quantitative and objective neurocognitive assessment method for patients undergoing CABG. The relationship between quantitative metrics of neurocognitive function and intraoperative cerebral oxygenation warrants further investigation.