An evaluation of the effect of a kinked cannula on intravenous cannula flow rates

Abstract EN

-Objective : To determine to what extent a kink would affect rates of saline flow through different gauges of intravenous cannulae.

Design : An Observational Study.

Setting : RCSI-MUB Laboratory.

Method : The flow rates of normal saline through Becton Dickinson (BD) Venflon cannulae sizes 22, 20, 18, 16 and 14 gauges (G) were measured.

A kink was introduced in all cannulae immediately proximal to the catheter hub, and the flow rates were measured again.

Result: Statistical analysis showed a confidence interval overlap for flow rates in non-kinked versus kinked catheters sizes 14 G, 16 G and 18 G indicating that kinking does not significantly alter flow rate in these catheters.

Ambiguity in the 20 G catheter data suggests that a greater sample size should be examined.

Analysis of the 22 G catheter data showed a statistically significant decrease in flow rate when kinked.

Conclusion: Kinking was shown to have negligible effect on flow rates in 14 G, 16 G and 18 G catheters.

No definitive conclusion could be drawn from 20 G data, although it was found that kinking decreased 22 G catheter flow by 9.94 % on average