Cognitive function improvement after bilateral carotid endarterectomy. Are low rSO(2) values an indication for oxygen therapy?
Abstract
Many physiological functions including cognition are decreasing with ageing. Cognitive function reduction disturbing functioning in activities of daily living is called dementia.
In seniors, performing a cognitive assessment using short screening instruments is strongly recommended during preoperative evaluation. In the case report I describe a case of an 80-year old lady with bilateral carotid stenoses resulting in insufficient brain oxygen delivery with pathologically low rSO(2) values on near infrared spectroscopy (NIRS) and decreased cognitive performance.
She underwent carotid endarterectomy on both sides. With oxygen inhalation during the surgery, these very low rSO(2) values normalized completely so that introducing shunts was unnecessary during carotid clamping.
Would such brain hypoxia be an indication for longer oxygen therapy? Brain hypoxia before the first surgery could be explained by decreased cerebral blood flow caused by carotid stenoses, because rSO(2) values as well as cognitive functioning using Clock-In-the-Box test improved significantly after the endarterectomy. Short cognitive assessment during preoperative evaluation is feasible and with NIRS monitoring in carotid surgery it can facilitate perioperative management and make risk assessment easier.