HOW GOLDEN IS THE STANDARD?MEASUREMENT ERRORS IN THE DETECTIONOF HIGH FLOW ARTERIOVENOUS ACCESS

Citation: 
Kairaitis, L*1, Bek, S2, Oomens, D3
Publication year: 
2019

Introduction: 

The development of a highflow state in a surgicallycreated arteriovenous (AV) access can lead to patient harm as a conse-quence of reduced clearance due to cardiopulmonary recirculation,cardiac failure and vascular steal. Accessflow (Qa) measurement usingsaline indicator dilution has been proposed as thegold standardformeasurement of Qa however has not been validated for accuracy at highISN WCN 2019 ABSTRACTSKidney International Reports (2019)4,S1S437S23 Qa ratesin vivo. A Qa value of>2L per minute has been proposed as amarker of a highflow state at risk of cardiac dysfunction. Previousstudies have indicated close concordance of accessflow (Qa) measure-ments between indicator dilution techniques (IDQa) and volumetricflow doppler imaging of the inflow brachial artery (BAF)when a forearmAVF is in use, however the relationship between these two methods inthe setting of suspected high Qa has not been assessed.

 Methods:

This cross sectional study compared paired measurementsusing the two methods (IDQa and BAF) for patients with an upperextremity AVF found to have a Qa in excess of 2L per minute usingroutine IDQa access surveillance and referred for duplex ultrasoundincluding BAF.

Results:

Paired Qa measurements were obtained in 46 patients ofwhom 31 (67%) had an upper arm AVF and 15 (33%) a forearmAVF. Mean Qa measurements were significantly lower using the BAFmethod compared with IDQa (1590 vs 2677mL/min, p<0.001)withfixed rather than proportional bias demonstrated by Bland Altmananalysis and no correlation between the two measures. BAF returnedQa estimates of greater than 2L per minute in only 10 out of the 46patients (22%).

Conclusions:

These data show that Qa values estimated with the BAFmethod are significantly lower than those estimated by indicatordilution. Given thesefindings, caution should be taken with the use ofthe BAF technique to exclude a highflow state, particularly as the IDmethod has shown to be associated with an increased risk of cardiacdysfunction at Qa values of 2L or more