Impact of needle type on substitution volume during online hemodiafiltration: plastic cannulae versus metal needles

Abstract

Background: Plastic cannulae have attracted increasing interest as an alternative to traditional metal needles with the aim of reducingcannulation-related complications. We investigated whether the substitution volumes during hemodiafiltration differ using thesetwo types of needles in dialysis patients.Methods: An intervention study involving 26 hemodialysis patients was conducted in Korea between March and September in 2021.Patients first received online hemodiafiltration using traditional metal needles, and thereafter plastic cannulae were used in a stepwiseprotocol. Repeated-measures design and linear mixed-effect models were used to compare substitution volumes between thetwo needle types with the same inner diameter.Results: The mean patient age was 62.7 years, and their mean dialysis vintage was 95.2 months. Most patients (92.3%) had an arteriovenousfistula as the vascular access. The substitution volume increased as blood flow and needle size increased for both plasticcannulae and metal needles. The substitution volume was significantly higher with 17-gauge (G) plastic cannulae than with 16-G metalneedles at blood flow rates of 280, 300, and 330 mL/min. Similar results were obtained for 15-G metal needles and 16-G plasticcannulae at a blood flow rate of 330 mL/min. However, the patient ratings of pain on a visual analogue scale were higher for plasticcannulae.Conclusion: Higher substitution volumes were obtained at the same prescribed blood flow rate with plastic cannulae than with metalneedles during online hemodiafiltration. Plastic cannulae are an option for achieving high-volume hemodiafiltration for patients withlow blood flow rates.