Assessment of Reflux From Needleless Connectors: Blinded Comparison of Category Designation to Benchtop Function Using a Venous Simulator

Abstract

Needleless connectors (NCs) for vascular access have limited needlestick injuries, but complications including occlusion, thrombosis, and infections have increased despite reduced needlestick injuries. These complications relate to the ability of an NC design to limit volume fluctuations that can lead to fluid reflux with potential for microbial contamination. Different NC designs requiring specific usage protocols and training, a lack of clarity in NC function relative to manufacturer-designated categories, and confounding results from a limited number of studies comparing different NCs have resulted in confusion, ultimately leading to complications from undesirable fluid movement within the vascular access. The authors therefore quantified the magnitude of reflux with current commercially available NCs using a venous stimulator. Thirteen blinded NC designs spanning the categories of negative and positive displacement, neutral, and antireflux were tested to quantify fluid movement upon disconnection and reconnection from a representative intravenous pressure (3 NCs per design; 10 trials per NC). Trials for each NC tested followed consistent displacement trends leading to tight error bars. Blinded NCs were then characterized according to their function and compared with their category designation after unblinding. All positive and negative NCs functioned in a manner consistent with their respective category designations. Conversely, all NCs categorized as neutral actually functioned with negative displacement (ie, reflux upon disconnection; 4/5 NCs) or positive displacement (1/5 NCs). Only NCs classified as antireflux functioned as neutral, which was confirmed in a blinded bidirectional flow test. These results suggest that the neutral NC-marketed category may be confusing to users unless the particular NC design has an integrated antireflux component.

An In Vitro Evaluation and Comparison of Commercially Available Needleless Connectors with and Without Anti-Reflux Technology

“…However, there have been several in vitro studies evaluating the performance of NCs. Previous studies evaluated reflux volume using a similar venous simulator and included 4 of the 8 NCs tested here [21,24,26]. Additionally, two studies evaluated bi-directional flow control using similar methods duplicated in this study [21,26].…”

“…Previous studies evaluated reflux volume using a similar venous simulator and included 4 of the 8 NCs tested here [21,24,26]. Additionally, two studies evaluated bi-directional flow control using similar methods duplicated in this study [21,26]. Finally, Elli et al evaluated fluid reflux during disconnection of a syringe.…”

“…Negative displacement [21][22][23] • Allows blood to reflux into the catheter lumen during syringe or administration set disconnection NCs that produce low amounts of blood reflux and can control bi-directional fluid flow have been shown to reduce the risk of infection and catheter-related complications [23][24][25][26][27]. Thus, NC performance may be measured based on the amount of blood movement that refluxed into the catheter [24,25,27].…”

“…A venous simulator was used to observe and measure reflux upon connection and disconnection of a syringe as described previously [21,24,26]. The venous simulator was designed to replicate the peripheral venous pressure in the cephalic vein in the middle third of the forearm (111 mm H 2 O or 8 mmHg) [39] and consisted of a vertically positioned glass rod and metric ruler within an acrylic Volume 6; Issue 06 Int J Nurs Health Care Res, an open access journal ISSN: 2688-9501 stand.…”

Controlling peripheral intravenous catheter failure by needleless connector design: A pilot randomised controlled trial

“…There are several reasons for catheter failure; in part, it could be due to the type of NC in use. Currently there are a plethora of NCs, manufactured from various materials and with different structural designs (Gorzek & LaDisa Jr., 2021). Recent novel NCs have features thought to improve patient safety and decrease the risk of CRBSI.…”