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Handheld ultrasound-guided cannulation of difficult hemodialysis arteriovenous access: A randomized controlled trial.

INTRODUCTION
Cannulation of complex arteriovenous fistula (AVF) or graft (AVG) frequently poses challenges to renal nursing practice. Ultrasound (US) guidance on visualizing central and peripheral venous access has been widely adopted in nephrology, reducing vascular intervention complications. Renal nurses could acquire this point-of-care technique to increase the successful cannulation rate while facilitating confidence build-up during practice. We aim to evaluate the use of handheld US on difficult AVF/AVG cannulation in a hospital-based dialysis unit.


METHODS
We conducted a single-center randomized controlled trial from January 2021 to January 2022. Ten renal nurses were trained by an interventional nephrologist before patient recruitment and had completed a pre- and posttraining questionnaire on their confidence level. Fifty hemodialysis patients with complex AVF were randomized to US-guided or conventional cannulation. The total time spent on cannulation and patients' pain scores were also collected.


FINDINGS
Renal nurses increased their confidence level after training (pretraining score 26.6 ± 6.9 vs. posttraining score 36.4 ± 3.0; p = 0.014). There was a higher success rate (only one cannulation attempt required) for US-guided (96%) versus conventional (72.0%) cannulation (p = 0.049). US-guided cannulation had a lower pain score than the conventional method (1.48 ± 0.73 vs. 2.13 ± 0.95, p = 0.012). The pre-cannulation assessment time and time spent on cannulation were comparable between the two groups.


DISCUSSION
Our study showed that US-guided cannulation increased renal nurses' confidence level in difficult cannulation and improved success rate. Larger scale studies are required to further assess the applications of handheld US in AVF cannulation, particularly in different clinical settings (e.g., chronic dialysis centers).