Monitoring vascular access flow

Blood flow in peripheral arterio-venous fistulae and grafts as used for hemodialysis access can be derived from measurements of the amount of access recirculation induced by reversing the dialysis blood lines and a knowledge of dialyzer blood flow rates. Furthermore, low or falling access blood flow rates are predictive of access dysfunction from the development of an intraluminal stenosis, which may be reversible, or of access thrombosis. The monitoring of access blood flow rates in hemodialysis populations is therefore suggested. Technologies including ultrasound dilution, hematocrit dilution (or concentration) differential conductivity, and thermodilution used for such monitoring are described. (C) 1999 by the National Kidney Foundation, Inc.