Needleless connectors are widely used in clinical practice. The purpose of this study was to determine the difference between microorganisms entering six different connectors (three neutral displacements, one negative displacement and two anti-backflow connectors).


Initially connect the needleless connector to the catheter hub to reduce the risk of needle stick injury. Manufacturers have classified needleless connectors based on the type of fluid displacement that occurs when the male luer connector is disconnected. The negative displacement device will return blood to the lumen of the catheter, so a positive pressure technique is needed to avoid obstruction. Neutral displacement devices do not allow blood backflow when disconnected (if they are indeed neutral), and positive displacement devices push blood out of the catheter lumen through the reservoir. All three types of equipment connected to an empty liquid container will allow blood to flow back into the catheter. Therefore, pinless connectors that use anti-backflow technology are now also available. These devices differ from positive displacement needleless connectors in that they contain bidirectional fluid control valves. The valve prevents accidental blood flow back into the intravascular catheter during infusion (for example, when the gravity infusion bag runs out of fluid), connection, disconnection, and changes in the patient's chest pressure.

Activation of the device is usually done through a male Luer connector, which may involve a variety of designs, including opening a cracked septum or depressing the seal in the inlet.

However, subsequent reports indicate that the use of different types of equipment increases the incidence of blood infections. For example, after changing from a needleless joint without a cracked diaphragm to a mechanical positive displacement valve and a negative displacement valve, the ensuing blood infections increased. When using needle-free systems, septum valves may be preferable to some mechanical valves. Do not use positive pressure needleless connectors with mechanical valves until after a comprehensive assessment of risks, benefits, and education about appropriate methods. After this, there are reports that using specific positive displacement connectors can reduce the increased risk of infection. Affecting the updated SHEA / IDSA guidelines, which pointed out that the best design of the needleless connector used to prevent infection is not yet clear. Indeed, it has been suggested that the risk of infection may not be related to the device category (ie negative displacement, positive displacement or neutral displacement), but to the device (ie brand).

The purpose of this study was to determine whether different types of pinless connectors (three neutral displacement connectors, one negative displacement connector, and two anti-reflow connectors) provide similar physical barriers to prevent entry after microbial invasion Challenged by microorganisms under simulated controlled clinical conditions. The main outcome indicator is the number of Staphylococcus aureus through the connector. This is determined by collecting the liquid flowing through the device. In addition, with the passage of time and two different purification schemes, the risk of microorganisms entering the connector was evaluated.


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