Effect of different sealing caps on the backflow of short-term dialysis catheters: A bench study

Needle-free connectors (NFCs) are recommended as closure systems for peripheral and central vascular catheters to reduce needlestick injuries and infections, while potentially reducing blood reflux. However, their performance in short-term dialysis catheters has never been evaluated. The aim of this study was to evaluate the backflow associated with two NFCs (Neutron™ and Tego™) compared to the standard closure.

In this bench study, the physiological blood pressure of the superior vena cava was simulated. Expert operators performed three sealing sequences for each combination of connector and lumens of the catheter, with and without closing the clamp. After that, the backflow was measured in millimeters using a high-precision digital caliper.

No combination of caps, lumens, or clamping sequences eliminated the backflow. No differences were observed between standard caps and NFCs in both lumens, apart from the Tego™/No clamp combination in the proximal lumen that showed higher backflow (standard cap 15 [11; 17] mm vs Tego™ 23 [19; 25] mm, p < 0.001). Clamping reduced backflow in both the proximal (13 [11; 17] mm vs 20 [13; 25] mm) and distal lumens (12 [11; 16] mm vs 14 [12; 17] mm). No differences were found between standard caps and NFCs in the distal lumen, regardless of clamping. Proximal lumen consistently exhibited larger backflow (14 [12; 22] mm) compared to distal lumens (13 [11; 17] mm, p = 0.005).

NFCs do not seem to introduce any advantage on backflow reduction as compared to a standard cap combined with lumen and clamping. Our data suggest that clamping should become standard practice when NFCs are used in the management of short-term dialysis catheters.