Measurement of hemodialysis access recirculation: a two-needle method at the start of dialysis.

Conventional methods of measuring recirculation in hemodialysis access include a three site method performed during dialysis, and a two site technique conducted at the end of a hemodialysis treatment. This study describes a two site procedure performed at the beginning of a hemodialysis session. Blood samples are drawn from the arterial side of the hemodialysis access immediately prior to hemodialysis (AIPD), and from the same arterial line (A+5) and venous line (V+5) when maximal blood flows are reached 5 min after starting hemodialysis. Blood urea nitrogen (BUN) is measured in these samples, and the results entered into the formula AIPD - A+5/AIPD - V+5 X 100% to calculate the percent recirculation. Percent recirculation calculated by this method compared favorably with, and may hold several advantages over conventional techniques.