Catheter-related bloodstream infections (CRBSIs) are serious infections that occur when germs enter a patient’s bloodstream through an intravenous catheter. These infections are a significant concern in healthcare settings because they can lead to severe health complications and prolonged hospital stays.
Understanding Catheter-Related Bloodstream Infections
CRBSIs occur when bacteria or fungi enter the bloodstream directly through a catheter, a tube inserted into a vein. This provides a direct pathway for microbes to reach the bloodstream, potentially leading to widespread infection. CRBSIs are a common cause of hospital-acquired bloodstream infections and can increase both hospital stay duration and mortality rates.
Several types of catheters are commonly associated with CRBSIs. Central venous catheters (CVCs), which are inserted into large veins in the neck, chest, or groin, carry the highest risk due to their direct access to the central circulation and longer dwell times. Peripherally inserted central catheters (PICCs) are also a type of CVC, inserted through a peripheral arm vein with the tip extending into a central vein. Dialysis catheters, used for hemodialysis, are another type of CVC with a higher infection risk compared to other dialysis access methods. While less common, peripheral intravenous (IV) catheters and arterial catheters also carry some risk of infection.
How CRBSIs Develop
CRBSIs primarily develop through two main pathways. One is contamination at the insertion site, where germs from the patient’s skin enter the bloodstream during the catheter insertion process or by migrating along the external surface of the catheter after insertion. The skin naturally harbors microorganisms, which can be introduced into the bloodstream if proper sterile techniques are not followed.
The second pathway involves contamination of the catheter hub or lumen. This occurs when germs enter the internal opening of the catheter, often during routine use, such as when medications are administered or blood samples are drawn. This type of contamination is more common with long-term catheters, where intraluminal spread from the hub becomes the primary infection mechanism. Common microorganisms include Staphylococcus aureus, coagulase-negative staphylococci, Enterococci, Gram-negative bacilli like Klebsiella species and Pseudomonas, and Candida species. These organisms can form biofilms on the catheter surface, protective layers that make them more resistant to antibiotics and the body’s immune system.
Strategies for Preventing CRBSIs
Preventing CRBSIs involves a multi-faceted approach with strict adherence to infection control protocols. Hand hygiene is foundational, requiring healthcare personnel to thoroughly wash hands with soap and water or use an alcohol-based hand rub before and after any interaction with a catheter or its dressing. This practice significantly reduces the transfer of germs from hands to the catheter.
During catheter insertion, maximal sterile barrier precautions create a sterile field. This includes sterile drapes to cover the patient, along with healthcare providers wearing sterile gowns, masks, caps, and gloves. Preparing the skin at the insertion site with an antiseptic solution, such as chlorhexidine gluconate with alcohol, before insertion eliminates skin microorganisms.
Proper site care and dressing maintenance after insertion are also important. This involves regularly cleaning the insertion site and applying sterile, transparent dressings for visual inspection. Dressings should be changed at least every seven days for non-tunneled CVCs or immediately if soiled, loose, or damp. Continuous review of the catheter’s necessity is also a prevention strategy; catheters should be removed as soon as they are no longer medically required.
Proper catheter maintenance, including disinfecting hubs, needleless connectors, and injection ports before each access, is essential. Some facilities also utilize comprehensive “CRBSI bundles,” sets of evidence-based practices implemented together for the highest level of prevention. In certain situations, antimicrobial-impregnated catheters or dressings, or antimicrobial lock therapy, might be considered, especially for high-risk patients or in units with elevated infection rates.
Identifying and Managing CRBSIs
Recognizing CRBSIs involves observing signs and symptoms. Patients may experience fever, chills, or weakness. Localized signs at the catheter insertion site include redness, pain, tenderness, or drainage. In severe cases, patients might develop systemic symptoms like increased heart rate, confusion, shortness of breath, or clammy skin, indicating sepsis, a serious infection complication.
Diagnosis of a CRBSI usually involves blood cultures to identify the causative microorganism. Samples are typically drawn from both the catheter and a peripheral vein. A “differential time to positivity,” where catheter blood shows microbial growth at least two hours earlier than peripheral vein blood, strongly suggests a CRBSI. Other tests, such as X-rays or CT scans, may rule out other infection sources or assess for complications.
Management of a confirmed CRBSI generally involves removing the infected catheter, especially for short-term ones. If removal is not possible, or in certain situations with long-term catheters, catheter salvage might be attempted, often involving antibiotic lock therapy where a high concentration of antibiotics is instilled directly into the catheter lumen. Administering appropriate antimicrobial medications, such as antibiotics for bacterial or antifungals for fungal infections, is a primary treatment component. Empiric antimicrobial therapy is often initiated after cultures, with adjustments made once the specific organism and its sensitivities are known.