A silent killer lurks in every U.S. hospital: central line-associated bloodstream infections. CLABSIs affect an estimated 80,000 patients in ICUs each year, and about 250,000 hospital-wide CLABSI are assessed.1 CLABSIs are associated with about 24,000 patient deaths each year.2 They are usually serious infections (e.g., sepsis) and lengthen hospital stay, inflate medical cost and increase the risk of mortality.2 The good news is that CLABSI is preventable,3 and nurses are empowered to reduce these troubling numbers.
This module focuses on potentially deadly central venous catheter-associated bloodstream infections. Patients with CLABSI stay in the hospital about 12 days longer than patients without CLABSI.2 The average CLABSI case costs $18,000.2 One study shows that the estimates of attributable cost for CLABSI ranges from $5,734 to $22,939 per patient, based on the 2007 Consumer Price Index for urban consumers and inpatient hospital services.3 Given this data, efforts to reduce the rate of CLABSI are vital to improving healthcare quality and patient safety.
The Institute for Healthcare Improvement recommends five key measures based on best-practice guidelines to fight CLABSI:4
• Hand hygiene
• Maximal barrier precautions upon insertion of the CVC
• Chlorhexidine skin antisepsis
• Optimal catheter site selection; subclavian vein is the preferred site for nontunneled catheters
• Daily review of line necessity, with prompt removal of unnecessary lines
Together, this group of evidence-based interventions is called the “central-line bundle.”4 The nurse’s understanding of CLABSI and evidenced-based bundle practice can significantly improve patient outcomes.
A CVC, or intravascular catheter or central line, is a catheter that is surgically inserted into the great vessels in patients who require frequent or continuous injections of medications, fluids or nutritional support.5 It is an intravascular infusion device used for infusion, withdrawal of blood or hemodynamic monitoring whose tip terminates at or close to the heart or in one of the great vessels. For the purpose of surveillance reporting CLABSI and counting central-line days in the National Healthcare Safety Network (NHSN) system, the following are considered great vessels: the aorta, pulmonary artery, superior vena cava, inferior vena cava, brachiocephalic veins, internal jugular veins, subclavian vein, external iliac veins, common iliac veins, femoral veins and, in neonates, the umbilical artery and umbilical vein.5
CVCs are crucial to medicine, particularly in intensive care and during major surgery and resuscitation, providing secure vascular access and reliable hemodynamic measurement; however, central lines can cause complications such as local infections at the insertion site. Central lines can also cause systemic infections, such as CLABSI, septic thrombophlebitis and endocarditis, and metastatic infection, which includes lung abscess, brain abscess, osteomyelitis, endophthalmitis or septic arthritis. CLABSI is the most common of these infection-related complications.
Clinicians should understand the difference between clinical and surveillance definitions of CLABSI. The clinical definition is physician driven and based on clinical signs and symptoms of bloodstream infection or sepsis, the blood culture laboratory results and the presence of a CVC. The surveillance definition of CLABSI is more specific and less subjective, and it relies on positive blood culture results and the presence of a CVC. The CLABSI definition in this module was developed by the CDC/NHSN and has been adopted by most healthcare facilities to generate facility-specific CLABSI rates. This definition lists essential criteria for surveillance of CLABSI and succinctly describes the methodology that should be used in CLABSI surveillance systems conducted by healthcare facilities.
According to the CDC/NHSN, CLABSI is a laboratory-confirmed bloodstream infection, such as bacteremia/fungemia, in a patient with a CVC when no other secondary infection source with the same microorganism is found. If a patient develops a BSI within the period beginning two calendar days after insertion of a CVC and ending two calendar days after its removal, the BSI is said to be associated with the CVC.5 If more than two calendar days pass between CVC removal and the onset of infection, convincing evidence must exist before the infection can be classified as related to the central line.5
Two criteria must be met before a bloodstream infection is classified as CLABSI: The patient must have both a CVC and a laboratory-confirmed bloodstream infection. The signs, symptoms and blood culture laboratory results must not be related to an infection at another site. If the same organism is found at a site other than the bloodstream, it is a secondary bloodstream infection rather than a primary bloodstream infection. For example, if both blood and wound culture results have shown Pseudomonas aeruginosa, the bloodstream infection is secondary since the microorganism may have migrated from the infected wound into the bloodstream.5
CDC Says …
Using the CDC/NHSN surveillance definitions, a laboratory-confirmed BSI (LCBSI) requires that one of the following three criteria be met:5
Criterion 1: A recognized pathogen in the blood is found from one or more blood cultures, and the pathogen is not related to an infection at another site.
Criterion 2: The patient has at least one of the following signs or symptoms: fever (greater than 100.4 F [38 C]), chills or hypotension, and
Signs, symptoms and positive laboratory results are not related to an infection at another site, and
A common skin contaminant — e.g., diphtheroids (Corynebacterium spp. not C. diphtheriae), Bacillus spp. (not B. anthracis), Propionibacterium spp., coagulase-negative staphylococci (including S. epidermidis), viridans group streptococci, Aerococcus spp., or Micrococcus spp. — is identified in two or more blood cultures drawn on separate occasions, occurring within one calendar day of each other with the same skin contaminant found in both results.
Criterion 3: A patient less than 1 year old has at least one of the following signs or symptoms: fever (greater than 100.4 F [38 C], core), hypothermia (less than 96.8 F [36 C], core), apnea or bradycardia, and
Signs, symptoms and positive laboratory results are not related to an infection at another site and
A common skin contaminant — e.g., diphtheroids (Corynebacterium spp. not C. diphtheriae), Bacillus (not B. anthracis), Propionibacterium spp., coagulase-negative staphylococci (including S. epidermidis), viridans group streptococci, Aerococcus spp., or Micrococcus spp. — is identified in two or more blood cultures drawn on separate occasions, occurring within one calendar day of each other with the same skin contaminant found in both results.
A new criterion was added to the 2013 CDC/NHSN CLABSI module: mucosal barrier injury (MBI) LCBSI. This criterion is for patients with allogeneic hematopoietic stem cell transplant within a year or patients with neutropenia, defined as at least two separate days with values of absolute neutrophil count (ANC) or total white blood cell count
The CLABSI criteria do not include catheter tip culture or treatment with antibiotics; therapeutic options are clinical decisions made by healthcare providers.
Blood cultures collected through CVCs can have a higher chance of contamination than blood specimens drawn through peripheral venipuncture. Therefore, cultures should ideally be collected through venipuncture from two to four blood draws from separate sites.5 However, this may be difficult in patients with very poor peripheral venous access. Hospital administrators should work to ensure best practice in specimen collection. Blood cultures obtained from any site (through existing intravascular catheters, arterial lines or venipuncture) must be considered in CLABSI surveillance.
Rating the Risks
Despite associated complications, CVCs remain necessary, especially for managing patients in critical condition. Therefore, clinicians must identify and modify the risk factors of CVC-associated infections.1
Multilumen CVCs are indispensable in managing patients requiring several IV medications, laboratory specimens, frequent blood product transfusions and fluid resuscitations; however, they may be related to a higher rate of CLABSIs than single-lumen CVCs.6 Multilumen catheters are manipulated more frequently, making colonization and bacterial growth at the tip more common. To prevent BSI, patients with multilumen catheters must be assessed daily to determine when to change to single-lumen or peripheral IV catheters.6
Femoral CVCs show increased incidence of deep vein thrombosis and catheter colonization. CLABSI due to gram-negative bacteria (e.g., E. coli and Enterobacter spp.) and yeasts is significantly higher in femoral CVC sites7 because of the proximity of the groin to the genital and perirectal area. The subclavian vein has the lowest rate of BSI, followed by the internal jugular vein. The femoral vein has the highest CLABSI rate. Therefore, the subclavian vein is preferred for inserting nontunneled CVCs (percutaneously inserted into central veins [subclavian, internal jugular, or femoral]).1 Increased risk of CLABSI is seen in patients with femoral intravascular catheters who have a body mass index higher than 28.4.8
CVCs used to administer total parenteral nutrition or lipids and blood product transfusions are associated with increased incidence of BSI. Fungi and polymicrobial infections comprise a large proportion of BSIs in patients receiving long-term TPN. Microorganisms thrive in TPN and high-protein blood products.1
To protect patients, clinicians must use good antiseptic technique before accessing the CVC. Injection ports should be disinfected with an appropriate antiseptic (e.g., chlorhexidine, povidone iodine, an iodophor or 70% alcohol) before accessing the infusion system.1 Also, only sterile devices should be used to access the injection port.1 Injection ports should be allowed time to dry before the infusion system is accessed. Cap all stopcocks when the injection ports are not in use.1
After infusions of IV solutions that may enhance microbial growth, catheters should be flushed with sterile, preservative-free 0.9% sodium chloride according to organization policies and procedures and the manufacturer’s recommendations for the type of catheter. According to the CDC guideline, tubing used to deliver lipid emulsions, blood or blood products should be replaced within 24 hours of starting the infusion.1 The tubing used to administer propofol infusions should be replaced every six to 12 hours, when the propofol vial is changed, per the manufacturer’s instruction.1 Replace administration tubing sets not used for blood, blood products or lipids at intervals not longer than 96 hours.1,8
Other risk factors include prolonged hospitalization before CVC insertion, prolonged duration of catheterization, heavy microbial colonization at the insertion site, heavy microbial colonization of the catheter hub, certain patient populations, inexperience of the physician inserting the CVC and a low nurse-to-patient ratio. Hospitals should keep nurse-to-patient ratios at least 2:1 in ICUs where nurses manage patients with CVCs and minimize the use of floating nurses in the ICU.8 Many groups of patients are vulnerable to BSI, including the elderly, neonates, critical patients, patients with severe medical conditions, burn patients, oncology patients, immunodeficient patients, neutropenia patients, organ transplant patients, immunocompromised patients and dialysis patients.
Getting Access
To cause catheter-related infection, microorganisms must access the bloodstream via the outside (extraluminal) or inside (intraluminal) surface of the catheter tube.9 After accessing the bloodstream, free-floating bacteria adhere to the catheter surface and form a microcolony. This leads to a biofilm, which allows sustained BSI and hematogenous dissemination (i.e., via the bloodstream). Microorganisms can enter by one of several mechanisms. Skin contaminants, likely aided by capillary action, enter through the skin during catheter insertion or in the days after insertion. Microorganisms can enter the catheter hub and lumen during catheter insertion over a percutaneous guidewire or during manipulation of the catheter. They can also be carried hematogenously to the implanted catheter from a distant local infection, such as pneumonia. The most common route of infection is migration of skin organisms at the insertion site into the cutaneous catheter tract with colonization of the catheter tip.1
Complex Interactions
The pathogenesis of the bloodstream comprises complex interactions between the invading microorganism and immune system defenses. When infectious agents spread to the bloodstream, the fever-producing substances secreted by phagocytes will “turn up” the body’s hypothalamic temperature regulator. Vasodilation substances released from the mediators of the inflammatory process in response to overwhelming BSI trigger widespread vasodilation and the reduction of total peripheral resistance. This causes reduced systemic vascular resistance and a decrease in mean arterial pressure. The heart rate is altered because of cardiac compensation. As a result, clinical presentation of BSI includes fever, chills, shaking, tachycardia and hypotension.
The microbial profile of healthcare-associated infections, including BSI, has changed over the past decades. From 2009 to 2010, the species of bacteria most frequently isolated from blood cultures were, in rank order, coagulase-negative staphylococci, Staphylococcus aureus, Enterococcus faecalis, Candida spp. or NOS, Klebsiella pneumoniae/oxytoca and Enterococcus faecium.10 Coagulase-negative staphylococci and Staphylococcus aureus were by far the most common, comprising 20.5% and 12.3% of CLABSIs, respectively.10 From 2009 to 2010, 54.6% of blood cultures testing positive for Staphylococcus aureus were found to be resistant to oxacillin/methicillin.10 In 1999, for the first time, more than half of all S. aureus infections in ICUs were resistant to oxacillin. When S. aureus resists oxacillin, it is classified as methicillin-resistant S. aureus, which has become endemic in many locations and often causes outbreaks. MRSA contributes significantly to increases in morbidity, mortality and healthcare costs.1,11
All Together Now
The central-line bundle correlates with the CDC’s BSI prevention guidelines.1,4,8 Used as a whole, the central-line bundle results in better outcomes than the five measures used individually. Use of the central-line bundle dramatically reduces the incidence of CLABSI, and the reduction is sustainable.12,13 The following is a description of the five key components in more detail.
Hand hygiene: Good hand hygiene is the cornerstone of infection prevention. Wearing sterile gloves does not eliminate the need for hand hygiene. Cleaning hands before inserting or manipulating a CVC helps prevent contamination of central line sites and resultant BSIs. (Hands should be washed with antibacterial soap and water with adequate rinsing or cleaned with a waterless, alcohol-based hand sanitizer.) Hand hygiene has the lowest adherence rate of the five components of the central line bundle (62%).14 Every healthcare facility should develop strategies to improve hand hygiene.
The World Health Organization’s key moments to perform hand hygiene:15
• Before touching a patient
• Before clean/aseptic procedures
• After body fluid exposure/risk of exposure (and after glove removal)
• After touching a patient
• After touching patient surroundings
Maximal barrier precautions upon insertion: The operator inserting the CVC should wear a cap (with all hair tucked under the cap), mask, sterile gown and sterile gloves. The mouth and nose should be covered tightly by the mask. The patient should be covered from head to toe with a sterile drape. The adherence rate for sterile draping of patients is 85%.14 If a full-size drape is unavailable, use two small drapes to cover the patient. A sterile dressing must be applied to the insertion site before the sterile barriers are removed. Hand hygiene is also a part of maximal barrier precautions.4
Chlorhexidine skin antisepsis: Evidence suggests that antiseptic 2% chlorhexidine gluconate in 70% isopropyl alcohol provides better antisepsis than povidone-iodine.4 To prepare the site, press the applicator against the insertion site and apply the antiseptic solution using a back-and-forth friction scrub for at least 30 seconds. Allow the solution to air dry completely before CVC insertion (about two minutes). Never wipe or blot to dry.4 According to the CDC, no recommendation can be made for using chlorhexidine-based skin antisepsis on patients under 2 months of age.1
Optimal catheter site selection: A subclavian vein is preferred for nontunneled catheters.1 Subclavian venous access has a lower rate of CLABSI than internal jugular or femoral vein access. Subclavian placement may be associated with mechanical complications (e.g., pneumothorax). Patient-specific medical risk factors (e.g., subclavian vein stenosis, coagulopathy, anatomic deformity) should be carefully evaluated when the insertion site is selected.1,4
Daily review of line necessity with prompt removal of unnecessary lines: The risk of CLABSI is closely related to the length of time that a CVC is in place. When physicians and nurses conduct a daily review, unnecessary CVCs are more likely to be removed promptly. A daily review of CVC necessity can be incorporated into multidisciplinary rounds and daily goal reports.4
Ultrasound scanners (designed for guiding vascular access to reduce mechanical complications due to multiple sticks) are not a part of this bundle.
Beyond the Bundle
The central-line bundle focuses on the insertion of the catheter rather than later management of the catheter site. Following are recommendations and guidelines for issues that emerge after the catheter is inserted.
Guidewires: Replacing a malfunctioning catheter or exchanging a pulmonary artery catheter for a CVC over a guidewire has become common practice. According to the CDC, guidewires should not be used when replacing catheters in patients suspected of having an infection.1 The CDC does not recommend routinely replacing CVCs to reduce BSI.1
If no evidence of CLABSI is present, use a guidewire exchange to replace a malfunctioning nontunneled catheter as appropriate. Clinicians should wear sterile gloves before handling the new catheter.1
Maximal sterile barrier precautions (including a cap, mask, sterile gown, sterile gloves and a large sterile full-body drape) must be applied during guidewire exchanges for intravascular catheters.1
Pulmonary artery catheters: During insertion of a pulmonary artery catheter, use a sterile sleeve to protect the catheter. Sterile sleeves should be used for all pulmonary artery catheters.1
Prophylaxis: Do not routinely administer intranasal or systemic antimicrobial prophylaxis before or during an intravascular catheter insertion to prevent catheter colonization or development of BSI.1
Catheter and insertion-site care:1,16
• No recommendation can be made regarding the designation of a lumen to use for parenteral nutrition.
• Apply sterile gauze or sterile, transparent, semipermeable dressing to cover the catheter insertion site.
• If the patient is diaphoretic or if the site is bleeding or oozing, apply gauze dressing until this is resolved.
• Immediately replace soiled, loosened or damp dressing. Replace dressing when inspecting the site.
• Perform site care for nontunneled CVCs in adolescents and adults with a chlorhexidine-based solution, and replace gauze site dressings every two days (seven days for transparent dressings). For some pediatric patients, risk of dislodging the catheter may outweigh benefits associated with dressing changes. Institutional CVC site care policies should address frequency of dressing changes.
• Until the insertion site has healed, replace dressings used on tunneled or implanted CVC sites no more than once per week.
• Avoid the use of topical antibiotic creams or ointments on insertion sites other than for dialysis catheters; such creams and ointments may promote antimicrobial resistance and fungal infections.
• Avoid submerging the catheter in water. Precautions should be taken to protect the catheter from the introduction of organisms during showering.
• If the CLABSI rate remains higher than the institutional goal despite other strategies (e.g., education and the central-line bundle), use of antiseptic- or antibiotic-impregnated short-term CVCs and chlorhexidine-impregnated sponge dressings in patients older than 2 months is recommended.
Nurses in Charge
Nurses should be trained on the indications of IV catheterization, proper insertion procedure, standardized care of CVCs based on institutional policy and the prevention of CLABSI. A hospital’s senior leadership is responsible for ensuring support for the nursing department and an infection prevention and control program that prevents CLABSI. Healthcare providers are responsible for ensuring that optimal CLABSI prevention practice is followed at all times.8
To implement the central-line bundle and ensure adherence, nurses should be empowered to supervise the insertion procedure. Nurses should have the authority to terminate procedures if they observe violations of hand hygiene, sterile technique or evidence-based guidelines for the prevention of intravascular catheter-related infections.
Healthcare providers should be educated to increase their awareness of evidence-based infection prevention practice. Insertion kits, maximum barriers and 2% chlorhexidine gluconate in 70% isopropyl alcohol applicators should be kept in one location, such as on a single cart, so clinicians will be able to obtain all central-line insertion supplies easily. A CVC insertion checklist should be developed to document adherence, and data should be collected for benchmarking.8,16 Nursing administrators should provide feedback to the appropriate healthcare providers on unit trends in the incidence and prevalence of CLABSIs and on the strategies to prevent them.
More and more patients are discharged with CVCs. Patients and families must be educated before discharge on caring for the catheter and preventing CLABSI. Providing written material can help the patient retain information. The Society for Healthcare Epidemiology of America and the Infectious Diseases Society of America collaborated with the CDC on a compendium of practice recommendations to prevent healthcare-associated infections, including CLABSIs. Clinicians can use this compendium as a reference.17
Joining Efforts
The Centers for Medicare & Medicaid Services no longer pay for the costs of treating CLABSI.18 In addition, hospitals accredited by The Joint Commission have to establish practices to prevent CLABSI.19 Prevention of CLABSI has become a national patient safety goal (NPSG) NPSG 07.04.01. Use proven guidelines to prevent infection of the blood from central lines. This Joint Commission requirement covers short- and long-term CVC and peripherally inserted central catheter lines.19 Hospital administrators and the public are more aware than ever of the need to prevent healthcare-acquired infections.
CLABSI is associated with increased medical expenses, morbidity and mortality. It is largely preventable with evidence-based guidelines and an increasing awareness of the role of nurse. A CLABSI rate of zero is the goal; patient safety is the No.1 priority.
May Mei-Sheng Riley, RN, MSN, MPH, ACNP, CCRN, CIC, is an infection prevention and control specialist at Packard Children’s Hospital at Stanford Medical Center and formerly clinical epidemiologist at University of California Los Angeles Medical Center. Riley holds two masters degrees, an MSN from the UCLA School of Nursing and an MPH from the UCLA School of Public Health. Her work in nursing has included medical/surgical, organ transplant and critical care nursing. Her experience in infection prevention/hospital epidemiology includes work both with adult and pediatric patient populations.
The author thanks David Pegues, MD, for allowing concepts from his physician’s CVC insertion training module to be used in the test for this module. Pegues was an infectious disease physician, the director of the epidemiology department at UCLA Medical Center and a clinical medicine professor of UCLA’s David Geffen School of Medicine.
