Investigation of the Effect of Variations in the Puncture Site of the Arteriovenous Fistula on Access Blood Flow Measurement by Ultrasound Dilution Method

Background: In assessing vascular access (VA) function, access blood flow (Qa) using the UDM method is more common. However, because of the wide variety of vascular branches in arteriovenous fistula (AVF), Qa measurement may be difficult depending on the puncture position, considering the measurement principle of the ultrasound dilution method (UDM). In this study, we investigated the effect of puncture variation on Qa measurement in AVF. The results were also compared with Qa by ultrasonic Doppler method (Qa (DU)). Methods: The 337 dialysis patients with AVF were divided into 3 groups (Figure1) (Group A:117 patients without a vascular branch between A and V at the puncture site, Group B:112 patients with a vascular branch, and Group C:98 patients with a separate vessel). Qa was measured during dialysis using HD03 dialysis monitor. Qa (DU) was also measured in the brachial artery by the ultrasonic Doppler method. This study protocol was conducted in accordance with the Principle of the Declaration of Helsinki, and was approved by the Ethics Committee of Osaka Metropolitan University (approval No.2021-243). Results: As a result, Qa measurement errors in group A were 28/117 (23.9%), in group B 39/122 (32.0%), and in group C 96/98 (98.0%). Qa (DU) was measurable in all groups in this case. Moreover, group A showed a significant positive correlation between Qa and Qa (DU) (R=0.712, P<0.0001), group B showed a significant positive correlation between Qa and Qa (DU) (R=0.565, P<0.0001), and group C showed no correlation between Qa and Qa (DU) due to many measurement errors of Qa. Conclusion: Based on these results, we believe that the choice of puncture position is important for Qa measurement by UDM, and that if recirculation is not observed or if a vascular bifurcation is present, the puncture position is not suitable for Qa measurement. On the other hand, Qa(DU) could be measured in all cases, which may be a better method of measuring access flow in AVF.