Impact of Tubing Colonization on the Incidence of Central Venous Catheter Infection

Central venous catheters (CVCs) are essential devices in the care of critically ill patients, with approximately 63% of patients admitted to intensive care being exposed to them. While they provide a safe access route for administering catecholamines or other substances unsuitable for peripheral veins, they are also associated with complications, including thrombotic and infectious events. CVC-related infections rank as the third most common nosocomial infections in the intensive care unit, representing a major public health challenge. According to the latest surveillance report on nosocomial infections in France, the incidence density is 0.61 infections per 1,000 catheter-days and 0.49 catheter-related bloodstream infections per 1,000 catheter-days. Approximately 10% of cultured catheters are found to be positive, indicating colonization. These infections are associated with an increased risk of mortality in the intensive care unit, estimated between 4% and 20%, as well as a prolonged length of stay (5-20 days) and an additional cost of approximately €10,000 per episode. Although catheter colonization has limited clinical impact, it remains a major concern due to its role as a precursor to infection. CVC infection is defined by the presence of microorganisms on the internal and/or external surface of the catheter, causing local and/or systemic infection with or without bacteremia. There are several mechanisms of infection, it is well accepted that infection begins with cutaneous colonization of the CVC, which can then spread to the intravascular part of the catheter. Another source of infection may be the colonization of infusion pathways leading to catheter colonization and infection through the "endoluminal" route. Factors associated with CVC infection include the frequency of line manipulations and the infused products. Therefore, it is recommended to minimize line manipulations, adhere to strict aseptic measures when accessing infusion lines, and regularly change (every 4 days) the infusion systems (ramps). Placing injection sites further away from the insertion site reduces the risk of contamination. The first connector tubing is never changed throughout the entire duration of CVC placement. However, there is limited data to confirm the link between infusion pathway colonization (particularly ramps used in intensive care) and catheter infection. The equipment used as infusion systems has evolved with the introduction of new devices, such as multi-lumen devices. One of these devices consists of five injection ports, each equipped with one-way valves, connected to a separate compartment in the tubing system, allowing simultaneous intravenous administration of five different active substances without mixing. This device is left in place for the entire duration of CVC placement (compared to current systems that are changed every 4 days). The objective of this study is to investigate whether there is a relationship between the colonization of infusion systems (ramps and/or multi-lumen devices) and the occurrence of CVC infection/colonization, and if this relationship varies depending on the type of device used (ramps vs. multi-lumen devices).

All adult patients hospitalized in the ICU with a CVC in place for an expected duration >2 days will be proposed to participate, in absence of oral refusal, ramps of the tubing systems will be swabed at each changes (scheduled every 4 days) and at catheter removal, in case of multi-lumen devices (edelweiss system), swabbing will be only performed upon catheter removal at the level of the one-way valves.

After catheter removal, a flush (1 mL of 0.9% NaCl) of the midline is performed and cultured to assess for endoluminal colonization. The distal end of the CVC is sent for culture, following the usual practice of the department to monitor catheter colonization and infections.

Colonization of the tubing system (ramps or multi-lumen device) will be defined as a positive culture of a swab, colonization and infection of the catheter will be defined using the CDC definitions (positiive cultutre defined as ≥10p3 CFU/ml).

Rates of catheter colonization will be compared in colonized (positive culture of a swab) or not colonized (no positiive swab culture) tubing systems. A sensibility analysis will be conducted taking into acount only the ramps and catheter colonized with the same bacterial strains.