Point-of-care Vascular Ultrasound: Of Fistulas and Flows.

Abstract

Point-of-care ultrasound (POCUS) is increasingly being used in nephrology as a diagnostic tool, and there is a growing interest among physicians and nursing staff to learn how to use POCUS for the evaluation of the dialysis vascular access (DVA). The goal of POCUS is to extend the physical examination and more closely evaluate the DVA at bedside. Typically, POCUS quickly answers yes-no questions (ie, Is the vein too deep? Y/N). It is not the goal of POCUS of the vascular access to extensively investigate the entire fistula or graft. In conjunction with a good physical examination, brightness-mode ultrasound alone can answer most questions regarding the DVA, such as depth and diameter of the vessel. With some additional training, a limited color Doppler can be added to the standard evaluation to check flow direction and pseudoaneurysms. With more extensive training and an understanding of Doppler physics, access flow volumes can also be determined using spectral Doppler-mode ultrasound.