Concerns about the frequent need for access revision have stimulated inquiry into techniques for the early detection of access complications before symptoms develop. Most techniques concentrate on intradialytic monitoring of flow, pressure, dialysis efficacy, or a combination of these. The advantage of intradi-alytic monitoring is that it minimizes the need for extra hospital resources for these ill patients. Each technique has its proponents, and the techniques mentioned are not mutually exclusive.
The DOQI guidelines state, "Access flow measured by ultrasound dilution, conductance dilution, thermal dilution, Doppler or other technique should be performed monthly. The assessment of flow should be performed during the first 1.5 hours of the treatment to eliminate error caused by decreases in cardiac output related to ultrafiltration. The mean value of three separate determinations performed at a single treatment should be considered the access flow. If access flow is less than 600 mL/ min, the patient should be referred for fistulo-gram. Access flow less than 1000mL/min that has decreased by more than 25% over 4 months should be referred for fistulogram."
This is a counsel of perfection and some centers would advocate duplex ultrasound prior to fistulography. Where there is evidence of a stenosis of >50%, there is a significant subsequent thrombosis rate. Such fistula should undergo endovascular or surgical revision as appropriate. Juxta-anastomotic stenoses are often best dealt with by surgery, with endovas-cular dilatation being reserved for those in the body of the access.
Was this article helpful?