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Ultrafiltration method for measuring vascular access flow rates during hemodialysis.
D Yarar1, A K Cheung, P Sakiewicz
1Research and Medical Services, Salt Lake City VA Medical Center, and Department of Internal Medicine, University of Utah, USA.
Kidney International
|September 1, 1999
Summary
A new ultrafiltration (UF) method accurately measures vascular access blood flow rate (QA) in hemodialysis (HD) patients. This technique, based on arterial hematocrit changes, offers a reliable alternative for assessing vascular access health.
Area of Science:
- Nephrology
- Vascular Access Monitoring
- Dialysis Technology
Background:
- Vascular access blood flow rate (QA) is a critical predictor of vascular access failure.
- Routine QA measurement is essential for effective vascular access assessment in hemodialysis (HD).
Purpose of the Study:
- To introduce and validate a novel ultrafiltration (UF) method for determining vascular access blood flow rate (QA) during HD.
- To compare the accuracy and reliability of the new UF method against established saline dilution techniques.
Main Methods:
- Developed a new UF method using changes in arterial hematocrit (H) following abrupt UF rate alterations.
- Accounted for cardiopulmonary recirculation without requiring saline injections or precise dialyzer flow rate knowledge.
- Conducted clinical studies in 65 chronic HD patients, comparing UF method QA with saline dilution QA using an ultrasound flow sensor.
Main Results:
- Arterial hematocrit significantly increased with UF rate changes in both normal and reverse configurations (P<0.0001).
- QA values from the UF method were slightly higher (16% ± 25%) than saline dilution (1050±460 ml/min vs. 950±440 ml/min).
- High correlation (R=0.92, P<0.0001) and good reproducibility (approx. 10% CV) were observed between the UF method and saline dilution QA measurements.
Conclusions:
- Changes in arterial hematocrit after UF rate adjustments effectively assess vascular access blood flow rate (QA).
- The novel UF method provides a reliable and accurate means for routine QA assessment in HD patients.