RESUMO
BACKGROUND: Current protocols recommend the use of a blunt needle to access the arteriovenous fistula via a buttonhole. This study aims to demonstrate whether a sharp needle can be used at the same buttonhole site without causing complications. GOAL: To measure and compare fistula cannulation failures between the use of blunt and sharp needles. PLAN: Open-crossover randomised controlled trial. PARTICIPANTS: Adult out-patients who had provided consent and were on dialysis with a mature arteriovenous fistula and buttonhole cannulation. OUTCOME MEASURES: Failed cannulation-difficulty in inserting the needle and the trampoline effect; incidence of complications, such as infection and haematomas; times to haemostasis; patients' pain; and patients' preferences. RESULTS: Based on analysis of the data from the 35 patients enrolled, no significant differences were detected in failed cannulation of the fistulae between the use of a blunt needle and a sharp needle for the 335 venous accesses (p = 0.071). However, a significant difference was detected for the 335 arterial accesses (p = 0.001), in which the sharp needle was more effective. Significant differences were also detected in the difficulty of insertion and in the trampoline effect for both venous and arterial access (p < 0.05); the use of a sharp needle was more favourable. CONCLUSION: This study demonstrates an increased incidence of failed cannulation using a blunt needle compared with using a sharp needle, although this was not significant. In addition, the use of a sharp needle did not result in any increase in complications.