Vascular access devices (VADs) are essential to intravenous (IV) therapy in acute care. The Centers for Disease Control and Prevention recommends using needleless connectors (NCs) to provide IV access and eliminate the need for needles. Approximately 17 NCs are currently available in the United States, with 3 basic designs. The Infusion Nurses Society Standards of Practice established NC classifications of negative, positive, and anti-reflux NCs. Evidence indicates a relationship between NC fluid displacement, blood reflux, and occlusion. A systematic review of the literature was performed to ascertain whether the functional design of anti-reflux NCs results in reduced catheter occlusion. A literature search of design types, function, and incidence of occlusion complications with peripheral and central venous access devices yielded 24 334 publications, with 61 studies meeting inclusion criteria. Results from available in vitro and in vivo evidence suggest using anti-reflux NCs with the lowest levels of fluid displacement may result in fewer complications of occlusion and longer catheter dwell times. This review correlates current research to update scientific knowledge of NC displacement performance and outcomes of NCs.

Moureau N, Gorski L, Flynn J, Johnson K. A Systematic Review of Needleless Connector Function and Occlusion Outcomes: Evidence Leading the Way. J Infus Nurs. 2025 Mar-Apr 01;48(2):84-105. doi: 10.1097/NAN.0000000000000578. Epub 2025 Mar 6. PMID: 40047605.