Things we have learned from horror movies: No matter how dead the bad guy looks, he’s not. If an item so much as resembles an egg or a pod, no one in the movie should touch it — it’s surely dangerous. When the main character does something everyone knows is stupid, he’s done for. And there’s no such thing as being “too careful” in a horror movie. We can see the danger coming a mile away, so why don’t the characters on the screen?

Killers are lurking in every hospital in the U.S., and any one of them alone has killed more than all of Hollywood’s crazed, hockey mask-wearing, chainsaw-wielding psychopaths combined. And we have the power to stop them. This module focuses on potentially deadly central venous catheter-associated bloodstream infections (CA-BSIs): the causes, risk factors, and nursing management.

Bundle up!

The Institute for Healthcare Improvement (IHI) recommends five key measures based on best practice guidelines to fight CA-BSI.¹ Together, they are called the “Central Line Bundle,” with “bundle” meaning a group of evidence-based interventions. The nurse’s understanding of CA-BSI and evidenced-based interventions can significantly improve patient outcomes.

In ICUs, an estimated 80,000 patients suffer from CA-BSI yearly, resulting in 28,000 deaths and costing on average $45,000 per incident. About 70% to 90% of BSIs occur in patients with a central venous catheter. CA-BSI has a mortality rate of 18%. Efforts to reduce the rate of CA-BSI are vital to improving quality of health care and promoting patient safety.^2-8

A CVC, or central line, is a catheter that is surgically inserted into the great vessels in patients who require frequent or continuous injections of medications or fluids for nutritional support. A CVC is a vascular infusion device whose tip terminates at or close to the heart or in one of the great vessels (the aorta, pulmonary artery, superior vena cava, inferior vena cava, brachiocephalic veins, internal jugular veins, subclavian vein, external iliac veins, common femoral veins, and, in neonates, the umbilical artery and umbilical vein).²

CVCs play a crucial role in medical practice, particularly in intensive care and during major surgery and resuscitation, providing secure vascular access and reliable hemodynamic measurement. However, central lines also can endanger patients by causing such complications as local infections at the insertion site. Central lines can also cause systemic infections, such as CA-BSI, septic thrombophlebitis, endocarditis, and metastatic infections (microorganisms spreading to distant sites), which include endocarditis, osteomyelitis, or septic arthritis. CA-BSI is the most common of these infection-related complications.

Healthcare clinicians should be aware of the differences between clinical and surveillance definitions of CA-BSI. The clinical definition is physician-driven and based on patients’ clinical signs of sepsis, the presence of a CVC, and the administration of antibiotic therapy. The surveillance definition of CA-BSI is more specific and less subjective and relies on positive blood culture results. According to the CDC’s National Nosocomial Infections Surveillance System, CA-BSI is bacteremia/fungemia in a patient having a CVC when no other site infected with the same microorganism is found. If a patient develops a BSI within the period beginning 48 hours after insertion of a CVC and ending 48 hours after its removal, the BSI is said to be associated with the CVC. If more than 48 hours 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.^1,3,8

Two criteria must be met before a bloodstream infection is classified as CA-BSI: The patient must have both a CVC and a laboratory-confirmed bloodstream infection. The signs, symptoms, and laboratory results must not be related to infection at another site. If the same organism is found at a site other than the bloodstream, this is a secondary BSI rather than a primary BSI. For example, if both blood and wound culture results have shown Pseudomonas aeruginosa, the bloodstream infection is a secondary BSI since microorganism may have migrated from the infected wound into the bloodstream.

The CDC says ...

Using the CDC’s National Healthcare Safety Network surveillance definitions, a laboratory-confirmed bloodstream infection requires that one of the following three criteria be met:²

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 (over 100.4 F [38 C]), chills, or hypotension, and

• Signs and symptoms and positive laboratory results are not related to an infection at another site and
• A common skin contaminant — e.g., diphtheroids (Corynebacterium spp.), Bacillus (not B. anthracis) spp., Propionibacterium spp., coagulase-negative staphylococci (including S. epidermidis), viridans group streptococci, Aerococcus spp., or Micrococcus spp. — is cultured from two or more blood cultures drawn on separate occasions, meaning that the blood draws occur within 48 hours of each other and at least one bottle from each blood draw has the same common skin contaminant.

Criterion 3: A patient less than 1 year old has at least one of the following signs or symptoms: fever (over 100.4 F [38 C], rectal), hypothermia (under 98.6 F [37 C], rectal), apnea, or bradycardia, and

• Same as first item under Criterion 2
• Same as second item under Criterion 2

Rating the risks

Despite central venous catheter-associated infectious complications, CVCs remain necessary, especially for managing patients in critical conditions. Therefore, clinicians must identify and modify the risk factors of CVC- associated infections.⁹

Multilumen CVCs are indispensable in managing patients requiring several IV medications, laboratory specimens, frequent blood product transfusions, and fluid resuscitations. However, multilumen CVCs may be related to a higher rate of CA-BSIs than single-lumen central venous catheters.⁹ Multilumen catheters are manipulated more frequently than single-lumen catheters, making colonization and bacterial growth at the tip more frequent. To prevent BSI, patients with multilumen catheters must be assessed daily to determine when to change to single-lumen catheters or peripheral IV catheters.⁹

Femoral CVCs show increased incidence of deep vein thrombosis and catheter colonization. CA-BSI due to Gram-negative bacteria (e.g., Escherichia coli and Enterobacter species) and yeasts is significantly higher in femoral CVC sites than in other catheter sites 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 BSI rate. Therefore, the subclavian vein is preferred for inserting nontunneled CVCs (catheters that are inserted into a vein less than 1 inch from the exit site, in adults.)^1,3,6,10

Research has shown that 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 nutrient-rich TPN and high-protein blood products. To protect patients, clinicians must use good antiseptic technique before accessing the CVC. Injection ports should be cleaned with 70% alcohol or an iodophor before accessing the infusion system.

After infusions of IV solutions that may enhance microbial growth, catheters should be flushed with sterile preservative-free 0.9% sodium chloride according to organizational policies and procedures and the manufacturer’s recommendations for the type of catheter. According to the CDC guideline, tubing that is used to deliver lipid emulsions, blood, or blood products should be replaced within 24 hours of starting the infusion.^1,11,12

Other risk factors include certain patient populations, inexperience of the physician inserting the CVC, and a low nurse-patient ratio. Many groups of patients are vulnerable to BSI, including the elderly, neonates, critical patients, burn patients, neutropenia/oncology patients, dialysis patients, organ transplant patients, and immunodeficient patients.¹³

Getting access

For microorganisms to cause catheter-related infection, they must access the bloodstream via the outside (extraluminal) or inside (intraluminal) surface of the catheter tube.13 Free-floating bacteria in blood adhere to the catheter surface and form a microcolony. This leads to formation of biofilm bacteria, which allows sustained bloodstream infection and hematogenous dissemination (i.e., via the bloodstream). Microorganisms enter by one of several mechanisms: 1) Skin contaminants, likely aided by capillary action, enter the percutaneous tract (through the skin) during catheter insertion or in the days after insertion;  2) microorganisms enter the catheter hub and lumen during catheter insertion over a percutaneous guidewire or during manipulation of the catheter; or 3) microorganisms are carried hematogenously from a distant local infection to the implanted catheter, such as a pneumonia. The most common route of infection is via migration of skin organisms at the insertion site into the cutaneous catheter tract with colonization of the catheter tip.^3,14

The pathogenesis of the bloodstream comprises complex interactions between the invading microorganism and the immune system’s defenses. When infectious agents spread to the bloodstream, the endogenous pyrogen (fever-producing substances) secreted by phagocytes will “turn up” the body’s hypothalamic temperature regulator. Vasodilator substances released from infectious agents trigger widespread vasodilatation and then the reduction of total peripheral resistance. This causes systemic vascular resistance and a decrease in mean arterial pressure. Heart rate is altered as a result of cardiac compensation. As a result, the clinical presentation of BSI includes fever, chills, shaking, tachycardia, and hypotension (systolic pressure at 90 mmHg or less).

The microbial profile of BSI has changed over the past decades. January to December 2002 data from the Surveillance Network Database-USA show that the five species of bacteria most frequently isolated from culture are coagulase-negative staphylococci, S. aureus, Enterococcus faecalis, E. coli, and Klebsiella pneumoniae. Coagulase-negative staphylococci and S. aureus are by far the most common, comprising 37% and 12.6% of hospital-acquired bloodstream infections, respectively. According to National Nosocomial Infections Surveillance System, in 1999, for the first time, more than half of all S. aureus infections found in ICUs were resistant to oxacillin. When S. aureus resists oxacillin, it is classified as methicillin-resistant S. aureus. MRSA has become endemic in many locations and frequently causes outbreaks. MRSA contributes significantly to increases in morbidity, mortality, and the cost of health care. ^3,15

All together now

The IHI’s five-part Central Line Bundle to fight CA-BSI correlates with the Guidelines for the Prevention of Intravascular Catheter-Related Infection from the CDC. ^1,3 Implemented as a whole, the IHI’s Central Line Bundle results in better outcomes than do the five measures individually. Use of the central line bundle dramatically reduces the incidence of CA-BSI, and that reduction in CA-BSI is sustainable.^4,5,7,8 The five key components are:

Hand hygiene: Good hand hygiene is the cornerstone of infection prevention. Poor hand hygiene contributes significantly to a greater bacterial burden and subsequent spread of organisms in the healthcare environment. Wearing gloves does not eliminate the need for hand hygiene. Washing before inserting or manipulating a CVC helps prevent contamination of central line sites and resultant bloodstream infections. (Hands should be washed with antibacterial soap and water with adequate rinsing or with a waterless, alcohol-based hand sanitizer.) However, hand hygiene has the lowest adherence rate of the five components of the central line bundle (62%).^1,7 This indicates an urgent need to stress hand hygiene in the interest of patient safety. Every healthcare facility should develop strategies to improve hand hygiene.³

Maximal barrier precautions upon insertion: Maximal barriers reduce CA-BSI during catheter insertion. The operator inserting the CVC should wear a cap, mask, sterile gown, and sterile gloves. All hair should be tucked under the cap. 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%. 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.^1,7

Chlorhexidine skin antisepsis: Povidone iodine has been the most common antiseptic for skin preparation before central line insertion. But evidence suggests that antiseptic 2% chlorhexidine gluconate in 70% isopropyl alcohol provides better antisepsis than iodine. 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. According to the CDC, no recommendation can be made for using chlorhexidine-based skin antisepsis on patients under 2 months of age.^1,3

Optimal catheter site selection: A subclavian vein is preferred for nontunneled catheters. Subclavian venous access has a lower rate of CA-BSI than internal jugular or femoral vein access.⁴ 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.

Daily review of line necessity with prompt removal of unnecessary lines: The risk of CA-BSI is closely related to the length of time the CVC is in place. When physicians and nurses conduct a daily review of CVC necessity, unnecessary CVCs are more likely to be removed promptly. A daily CVC review can be incorporated into multidisciplinary rounds and daily goal reports.^1,3

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 bacteremia since colonization of the skin tract at the insertion site is usually the source of infection. The CDC does not recommend routinely replacing CVCs to reduce BSI.³

The Central Line Bundle focuses on the insertion of the catheter rather than later management of the catheter site. Ultrasound scanners (designed for guiding vascular access to reduce mechanical complications due to multiple sticks) are not a part of this bundle.

Nurses in charge

To implement the Central Line Bundle and achieve the highest adherence rate, 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. Healthcare providers should be educated to increase awareness of evidence-based infection prevention practice. Insertion kits, maximum barriers, and 2% chlorhexidine gluconate in 70% isopropyl alcohol applicators should be kept in a single location, such as on a single cart, so that clinicians can obtain all central line insertion supplies easily. A CVC insertion checklist should be developed to document adherence. Data should be collected for benchmarking.⁷

More than a decade of research has shown increasing rates and risks of CA-BSI, a significant nosocomial infection. CA-BSI is closely associated with morbidity and mortality; however, it is largely preventable with evidence-based guidelines and an increasing awareness of the role of nurse. A CA-BSI rate of zero is the goal; patient safety should be our No.1 priority.