Effect of intradialytic change in blood pressure and ultrafiltration volume on the variation in access flow measured by ultrasound dilution

Background: Prospective access flow measurement is the preferred method for vascular access surveillance in hemodialysis (HD) patients. We studied the effect of intradialytic change in blood pressure and ultrafiltration volume on the variation in access flow measured by ultrasound dilution. Methods: Access flow was measured 30 minutes, 120 minutes, and 240 minutes after the start of HD by ultrasound dilution in 30 patients during 89 HD sessions and evaluated for variation. Results: The mean age of the 30 patients was 62±11 years: 19 were male. The accesses comprised 16 fistulae and 14 grafts. The mean access flow over all sessions decreased by 6.1% over time (1265±568 mL/min after 30 minutes, 1260±599 mL/min after 120 minutes, and 1197±576 mL/min after 240 minutes, P