WHAT ARE THE MAIN CAUSES OF INFECTION OF THE EXIT-SITE OF CENTRAL VENOUS CATHETERS?

10 Jan WHAT ARE THE MAIN CAUSES OF INFECTION OF THE EXIT-SITE OF CENTRAL VENOUS CATHETERS?

Edited by: Dr. Maurizio Alberto Gallieni, Associate Professor of Nephrology at the University of Milan. Since 2018 Director of the Complex Operational Unit of Nephrology and Dialysis of the ASST (Local healthcare area) Fatebenefratelli Sacco of Milan. Author of over 200 scientific publications, indexed in the PubMed database of the National Library of Medicine. He is a member of various Scientific Societies, also has coordination positions and is the Editor for Italian and foreign journals of Nephrology.

In another article by Prof. Gallieni, we talked about venous vascular accesses and the diseases for which they are carried out.

CVCs are delicate points that require proper cleaning and hygiene to maintain them, in order to avoid infections that could compromise the success of the treatment. Below, the Professor summarises the main causes of exit-site infection of central venous catheters (CVC): correct information is the basis for good practices and reduces the risk of CVC infections.

CVC exit-site infections are a serious medical problem and can have various origins. Bacteraemia can originate from the extra-luminal route, i.e. enter the bloodstream following an infection of the exit-site and/or the subcutaneous path via the CVC. They can also originate from endoluminal contamination, for example when handling the CVC when administering infusions or when carrying out dialysis treatment. It is also possible that the CVC becomes contaminated via the hematogenous route after bacteria have entered the bloodstream from elsewhere. In this case, the CVC spreads the infection because a contaminated CVC can make it difficult to eliminate it.

Here we focus on two main types of extra-luminal CVC infections:

HOW DO YOU RECOGNIZE CVC INFECTIONS?

An exit-site infection can cause erythema, infiltrates, and/or softening within 2 cm of the catheter exit-site with or without positive culture. This type of infection can be associated with other signs and symptoms such as fever or pus discharge from the exit-site, with or without bacteraemia.

Tunnel infection can cause erythema, infiltrate and/or softening beyond 2 cm from the catheter exit-site, along the subcutaneous tract of a tunnelled catheter, with or without concomitant bacteraemia.

The causes of these types of CVC infection are linked to a loss of balance between the body’s ability to fight infectious diseases and the invasiveness of bacteria that come into contact with and colonize the exit-site. The frequency of these infections is usually higher in immunosuppressed patients, even if they keep a good level of hygiene; or in immunocompetent patients, if the bacterial load exceeds the limits, and therefore the capacity of the individual patients’ immune system to combat inflection.

The bacteria that cause infections are more frequently bacteria that live in the skin, in particular Gram-positive bacteria, such as Staphylococcus Epidermidis and Staphylococcus Aureus. However, infections from Gram-negative bacteria and other pathogenic microorganisms, such as Clostridium difficile, viruses or Candida albicans, are also possible.

The hands of the operators and the patient are the main vehicle for microorganism infection. This is why the guidelines insist on frequent hand washing, using an appropriate technique, and on the use of alcohol-based antibacterial hand gels. Hand hygiene is essential before and after contact with a patient with a CVC. In addition to hand hygiene, the use of protective barriers such as gloves, masks and sterile sheets is also extremely important, both when the needle is inserted and in the daily management of the CVC.

Lastly, it is essential to carry out CVC medication properly, with suitable materials and have the appropriate amount of time to dedicate to the patient.