Evaluation of the brain hemodynamic response by means of near-infrared spectroscopy (NIRS) monitoring in patients with atherosclerotic carotid disease undergoing endarterectomy

BACKGROUNDS: Near-infrared spectroscopy (NIRS) is non-invasive technique that detects hemodynamic alterations in tissues. It enables continuous monitoring of intracerebral vascular physiologic information. Due to its portable nature, NIRS may be used bedside or in the operating room. OBJECTIVES: To evaluate use of NIRS for intraoperative monitoring of the brain hemodynamic response, during carotid endarterectomy. METHODS: 10 patients with atherosclerotic carotid disease scheduled for endarterectomy were evaluated. After patients had been selected, they answered a questionnaire on epidemiological data and information about comorbidities and then carotid disease was confirmed with diagnostic methods. NRIS monitoring was used during the surgical procedure. The variables analyzed before, during and after carotid clamping were oxygen saturation (SatO(2)), total hemoglobin (THb), reduced hemoglobin (RHb), and oxyhemoglobin (OHb). A p value of <0.05 was considered statistically significant. RESULTS: The results obtained from NIRS show that RHb and SatO(2) vary during the different stages of surgery. RHb levels are higher during clamping, when compared with the other two surgical stages. On the other hand, SatO(2) is lower during clamping. CONCLUSIONS: During carotid endarterectomy, NIRS is a feasible, real-time, and non-invasive intracranial monitoring method that accurately and reliably measures the changes in intracerebral capillary hemodynamic conditions.