Should you use a needleless connector with a continuous infusion?

Needleless connectors are commonly used with continuous infusions, but is this best practice?

Back in the not-so-good ol' days when we knew less about bloodstream infections, we'd quickly wipe the rubber cap with an alcohol wipe before connecting a needle to the secondary line and inserting this into the primary line via the rubber cap. We then applied paper tape to keep it in place for the duration of the medication administration. Needlestick injuries were common!

Needleless connectors were introduced in the 1990s to facilitate quick access to the primary line for intermittent medication administration without risk of needlestick injury. Since then, we've learned a lot about catheter-related bloodstream infection, and we now know that needleless connectors bring their own challenges, particularly related to infection risk.

Unfortunately, there's no evidence to support the use of needleless connectors with continuous infusions compared to direct connection of the administration set to the catheter lumen. Six years after Hadaway (1) called for research in this area, it remains an unresolved issue.

Some staff might believe it is safer to use a needleless connector with a continuous infusion, in case the lines somehow become disconnected. In which case, the needleless connector could prevent opening the lumen to the atmosphere and possibly risking air embolus or bleeding.

However, the INS and CDC guidelines state that the needleless connector should be changed with the administration set, so the catheter lumen will still be opened periodically (2,3). Clamping the line before manipulating the connection should alleviate any risk of air embolus or bleeding.

On the downside, a needleless connector used with a continuous infusion might tempt staff to disconnect a patient's lines for showering or mobilising. Again, this practice is discouraged because every line manipulation brings opportunities for introducing infection (1).

One study found reduced capacity for rapid infusion when a needleless connector was used (4). Blood products in particular should not be infused via a needleless connector because residual blood in the line is an infection risk.

We can all agree that needleless connectors must be changed when visibly contaminated and before drawing blood cultures from a central line, as per organizational policy and manufacturer's guidelines.

Needleless connectors contain the risk of intraluminal contamination (2,3) and they entail an extra financial cost for the organization. If they're not needed for continuous infusions, should they be used? It would be great to have some robust RCT evidence.

References
1 Hadaway, L. Needleless connectors in a continuous infusion system? 7/25/2014
https://hadawayassociates.com/lynns-blog/needleless-connectors-in-a-continuous-infusion-system
2 Infusion Nurses Society Standards of Practice. J Infus Nurs, 2016;39(1S).
3 O'Grady, N. P., Alexander, M., Dellinger, E. P., Gerberding, J. L., Heard, S. O., Maki, D. G., Masur, H., McCormick, R. D., Mermel, L. A., & Pearson, M. L. (2002). Guidelines for the prevention of intravascular catheter-related infections. Pediatrics, 110(5);e51. http://pediatrics.aappublications.org/content/pediatrics/110/5/e51.full.pdf
4 Lehn RA, Gross JB, McIsaac JH, Gipson KE. Needleless connectors substantially reduce flow of crystalloid and red blood cells during rapid infusion. Anesth Analg. 2015;120(4):801-804.