Assessment of volume flow rate in arteriovenous fistulas with a novel ultrasound Doppler device (earlybird): Trend analysis, comparison of methods, and inter- and intra-rater reliability.

BACKGROUND

An accessible tool is required to analyze volume flow trends in arteriovenous fistulas for hemodialysis. Earlybird, an easy-to-place ultrasound Doppler device, has shown comparable accuracy to duplex ultrasound. In this study, we compared volume flow measurements obtained with duplex ultrasound and the dilution technique to an enhanced earlybird device, featuring a dual Doppler probe system, eliminating the requirement for a known insonation angle.

METHODS

Nine patients with a distal radiocephalic arteriovenous fistula were monitored for 12 months with regular volume flow measurements. Correlation and inter- and intra-class reliability analyses were conducted.

RESULTS

An overall moderate correlation was observed between earlybird and duplex ultrasound or dilution technique (intraclass correlation coefficient = 0.606 (95% confidence interval 0.064, 0.721) and 0.581 (0.039, 0.739), respectively). Duplex ultrasound compared to dilution measurements, demonstrated an overall moderate correlation (0.725 (0.219, 0.843)). Correlation between earlybird and duplex ultrasound was stronger for the arteriovenous fistula (0.778 (0.016, 0.901)) than the brachial artery (0.381 (-0.062, 0.461)). For earlybird, inter-rater reliability was excellent for the arteriovenous fistula (0.907 (0.423, 0.930)) and poor for the brachial artery (0.430 (0.241, 0.716)). Duplex ultrasound showed a good inter-rater reliability (arteriovenous fistula: 0.843 (0.610, 0.871), brachial artery: 0.819 (0.477, 0.864)). The overall intra-rater reliability was good for duplex ultrasound (rater A: 0.893 (0.727, 0.911); rater B: 0.853 (0.710, 0.891)), while excellent for earlybird (rater A: 0.905 (0.819, 0.928); rater B: 0.921 (0.632, 0.969)).

CONCLUSION

We observed a weaker correlation in the measurements of volume flow rates in arteriovenous fistulas when obtained using earlybird compared to dilution technique, unlike the comparison between duplex ultrasound and the dilution technique. However, inter-rater reliability for the arteriovenous fistula was excellent with earlybird and good with duplex ultrasound, indicating the potential of earlybird as a tool for frequent measurements, enabling trend surveillance and predicting adverse outcomes.

Déclaration de conflit d'intérêts

Declaration of conflicting interestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Holst-Jæger, Emilie: None. Barstad, Marthe: None. Salvesen, Øyvind: None. Torp, Hans: Inventor and shareholder of CIMON Medical ASSeternes, Arne: None. Pettersen, Erik Mulder: None. CIMON Medical AS was not involved in the study design; collection, analysis, or interpretation of data, manuscript writing, or the decision to submit the manuscript for publication.