Fluxos nas Carótidas e Artérias Vertebrais Extracranianas em Pacientes com Morte Cerebral Extracranial Carotid and Vertebral Artery Flows in Brain Dead Patients

Background: Transcranial Doppler (TCD) is the most widely used method for confirming brain death (BD). Although carotid blood flow also presents a characteristic alteration in BD, this is addressed only superficially in the literature. Objective: To characterize carotid and vertebral artery blood flow types in BD patients through ultrasound. Methods: The carotid and vertebral arteries were assessed in 2 patient groups, one with BD (BDG) and a control group (CG) through the color duplex scanner (CDS). Both groups had 13 patients with no hemodynamically significant stenosis. The flow speed parameters studied were: peak systolic speed, end diastolic speed and the resistance index. As most of the data presented non-parametric distribution, the Wilcoxon and Mann-Whitney U tests were used. Results: Four flow morphologies were found in the inner branches of the carotid and vertebral arteries in the BDG patients: systolic spike, two-phase to-and-fro flow and its variant, oscillatory flow, and three-phase flow. All the morphologies found were similar to those described by the TCD for BD patients. Blood flow in the common carotid varied from normal to the morphologies described for the inner branches of the carotid, vertebral and common carotid arteries. All the BDG velocity parameters presented statistically significant differences from the control group for the inner branches of the carotid, vertebral and common carotid arteries when compared to the CG, with p<0.05.