Quantitative assessment of reflux in commercially available needle-free IV connectors

Abstract

The use of "engineering controls" included the integration of NFCs into the IV access system both for needle safety and for the prevention of central-line associated bloodstream infections (CLABSI) (3-5). NFCs allow for the administration of IV fluids, medications and blood to indwelling venous or arterial catheters without the use of needles. NFCs are also used for the withdrawal of blood samples and for aspiration of blood to check the catheter for patency. While the introduction of NFCs greatly reduced the risk of needle-stick injuries for healthcare workers, their use has been associated with other complications such as an increase in catheter occlusions and CLABSIs (6-11). In response to the increase in CLABSI related to the use of NFCs, medical device companies began designing and developing lower-risk devices (12). Over the past 20 years, 4 categories of NFC designs have emerged (2, 13). While there is no regulatory body that recognizes the categories of NFC as being indicative of function or performance (13), NFCs are typically marketed as being "positive", "negative", "neutral" (6, 12-16) or pressure-activated anti-reflux (9, 13, 17). The characteristics of each category of NFC indicate the mechanism and action of the NFC upon connection/disconnection.

Right Management and Flushing

“…Neutral or antireflux needle free connector technology should theoretically prevent blood reflux from occurring; however, it is suggested by Hadaway and Richardson (2010) that up to 0.02 mL of blood can still be drawn into the catheter tip depending on theneedle free connector design and clamping sequence followed by clinicians (Hadaway and Richardson 2010). Unwanted reflux volumes have also been demonstrated by other researchers (Elli et al 2016;Hull et al 2018). It is therefore rational to conclude that proper flushing techniques can only guarantee the prevention of blood reflux into the catheter tip at the very instant the catheter is being locked (Goossens 2015).…”

“…This association of increased risk of CRBSI with positive pressure NFCs (Ryder 2010) has prevented them from being actively recommended in certain guidelines (Pittiruti et al 2009). Studies have demonstrated that during disconnection of a syringe or intravenous tubing from the NFC, pressure changes within the catheter cause varying degrees of fluid movement or displacement resulting in unwanted blood reflux into the catheter tip (Hull 2018;Elli et al 2016). Improving clinical outcomes for patients by reducing complications such as CRBSI and VAD occlusion has propelled modern NFC design to incorporate an internal mechanism that reduces fluid displacement within the intravascular device (Kelly et al 2017;Hadaway 2012).…”

“…Confusingly there are four different types of NFC. Each has a complex mechanical valve design and are marketed as either negative, neutral, positive displacement or anti-reflux depending on the characteristics of the internal mechanism and action of fluid displacement upon connection and disconnection from a syringe or tubing (Btaiche et al 2011;Elli et al 2016;Hull et al 2018). Hull et al (2018) have published a clear and concise summary (Table 19.1), revealing the details associated with different fluid displacement mechanisms and recommended clamping sequence for each type of NFC.…”

“…Jasinsky and Wuester (2009) demonstrated statistical significance with the reduction of occlusion of CVADs from 30% to 7.6% with use of an anti-reflux NFC; later the study was expanded to include peripheral intravenous catheters, resulting in lower phlebitis rates and longer dwell times (Jasinsky and Wuerster 2009). Recent studies have found anti-reflux connectors are having a positive impact in maintaining patency and reducing occlusion rates and catheter malfunction (Jazinsky and Wuerster 2009, Elli et al 2016, Hull 2018, County Durham and Darlington NHS Foundation trust). A quantitative, in vitro study conducted by Hull et al (2018) demonstrates minimal fluid movement upon connection and disconnection of anti-reflux NFCs and suggests these devices should be considered for incorporation into clinical practice (Hull 2018).…”

“…Recent studies have found anti-reflux connectors are having a positive impact in maintaining patency and reducing occlusion rates and catheter malfunction (Jazinsky and Wuerster 2009, Elli et al 2016, Hull 2018, County Durham and Darlington NHS Foundation trust). A quantitative, in vitro study conducted by Hull et al (2018) demonstrates minimal fluid movement upon connection and disconnection of anti-reflux NFCs and suggests these devices should be considered for incorporation into clinical practice (Hull 2018). The study adds that more research is needed in this area.…”