Healthcare-Associated Infections Related to the Use of Intravascular Devices

D. Alexander Perry

Payal K. Patel

Vascular catheters are essential tools in the delivery of medications in a variety of medical settings. Most recently available estimates had about 15 million vascular catheters placed annually in the United States, with 7 million of those being central venous catheters (CVCs).¹ Advancements in placement techniques, infection prevention interventions, and technology have reduced the incidence of intravenous (IV)-related catheter infections, but central line-associated bloodstream infections (CLABSIs) still contribute substantially to patient morbidity and healthcare costs.²^,³ Through the combined work of patient safety efforts from multiple stakeholders, CLABSI rates have decreased by more than 25,000 infections annually from 2001 to 2009.² Despite this national focus on CLABSI and overall improvements, recent surveys have shown that over 20,000 CLABSIs still occur in the United States annually.⁴ It has been estimated that ˜20% of healthcare-associated infection (HAI) deaths are due to bloodstream infections.⁵ In addition to mortality, the mean length of stay can increase by 9 additional days and cost an additional $80,000 per episode.⁶^,⁷^,⁸

Given the cost, both financially and health-related, prevention of CLABSI has become a patient safety priority. At both the state and national level in the United States, CLABSI rates are recorded for interhospital comparison and reported for surveillance from the National Healthcare Safety Network (NHSN).⁹ Starting in 2008, the U.S. Centers for Medicare and Medicaid Services (CMS) stopped reimbursing hospitals due to these infections; however, this was revised in 2014 to the Hospital-Acquired Condition Reduction Program (HACRP) which was developed to reduce payments based on acquisition of certain hospitalacquired infections, including CLABSI.¹⁰^,¹¹ Additionally, the U.S. Department of Health and Human Services has targeted CLABSI for a 50% reduction from the 2015 baseline by 2020.¹² These goals have led to an increase in the development of clinical guidelines, protocols, and innovations to prevent CLABSI.¹³^,¹⁴^,¹⁵^,¹⁶^,¹⁷^,¹⁸^,¹⁹

TYPES OF CATHETERS

Catheters can be used to deliver a variety of medications from benign isotonic fluids to caustic chemotherapeutic agents. Different catheters can be kept in for various lengths of time, and some can be placed in multiple anatomic locations. One of the differences in catheter type is the duration they should remain in place. Short-term catheters usually remain in place for 3 weeks or less, whereas long-term catheters may be in place for weeks to months (Fig. 12-1). Table 12-1 describes different types of catheters currently used in healthcare.

PATHOGENESIS

Short-term Catheters

Infections come from a complex interaction between the microbial factors, the catheter, the infusate, and the host factors. However, with short-term catheters, the two main sources of infection are colonization of the device and contamination of the fluid administered through the device.²⁴ The latter is relatively straightforward as it involves direct inoculation of a microbe to the host, thus leading to an infection. In regard to the former, microorganisms from
the host’s skin track to the extraluminal or intraluminal surface, leading to the creation of a biofilm.²⁴ This can occur by direct invasion, inoculation during the time of insertion or with manipulation, or hematogenous from another infected site.²⁴ Regardless of the mechanism, once microbes gain access to a catheter, they form a biofilm. This biofilm makes treatment of the bloodstream infection difficult without removal of the catheter.

FIGURE 12-1 Location of vascular access. (Chopra V, Flanders SA, Saint S, et al. The Michigan appropriateness guide for intravenous catheters (MAGIC): results from a multispecialty panel using the RAND/UCLA appropriateness method. Ann Intern Med. 2015;163:S1-S40.¹⁴)

Long-term Catheters

Given the specialized function of long-term catheters, the pathophysiology of catheter infection differs from that of short-term catheters. Whereas with short-term catheters the source of infection is more commonly extrinsic to the catheter, with long-term catheters, causes are more commonly intrinsic (ie, within the catheter). Upon insertion of the catheter, host factors involved with inflammation coat the catheter, which serves as foundation for the formation of a biofilm.²⁵ The lumen of the catheter serves as a region of colonization, which leads to biofilm formation. With shortterm catheters, the site of colonization tends to be external to the catheter, but after a period of over 30 days, this process alters, and microbe colonization is predominantly within the lumen.²⁵ The type of microorganism, the host factors, and the type of interventions used with the catheter can all lead to an eventual bloodstream infection.²⁶

EPIDEMIOLOGY

In order to monitor and report on the incidence of HAIs, the U.S. NHSN collects data reported from various healthcare institutions. The monitoring of nosocomial infections initially started in 1970 with the establishment of the National Nosocomial Infection Surveillance system, which took routinely reported data from a select group of hospitals.²⁷ With the publication of the seminal “To Err is Human” from the Institute of Medicine in 1999, which brought attention to the issue of patient safety, changes have been made to prevent errors that lead to patient harm. In 2014, the CMS developed a method to decrease reimbursements for adverse events the hospital can prevent by following evidence-based guidelines. With various stakeholder interest in decreasing CLABSIs, there has been a significant decrease in infection rates from 2001 to 2011.² In the last several years, the NHSN has changed how CLABSIs are reported nationally, from rates per 1000 central line days to standardized infection ratios (SIRs, See also Chapter 2 on Surveillance of Healthcare-Associated Infections).²⁸ This change was made as comparing rates did not necessarily reflect the differences between hospitals or hospital locations as they may serve a different patient population and made it more difficult to calculate the overall performance of a facility. Additionally, by converting to SIRs, adjustments can be made to account to some degree for those populations at increased risk of infections. According to the NHSN, the SIRs for CLABSI in acute care hospitals are adjusted based on the location where the infection is acquired, the number of beds in the hospital, and whether or not the hospital is affiliated with a medical school.²⁸ According to the most recent NHSN data from 2017, the baseline national U.S. SIR is 0.81, with a 19% decrease in CLABSIs from 2016 to 2019, but 9% of the hospitals had CLABSI burdens that were significantly worse than the national SIR.²⁹

TABLE 12-1 Intravascular Catheter Types Commonly Used in Healthcare

*Catheter type*		*Anatomic locations*	*Recommended duration of use*	*Catheter length*	*Example of complications*
Non-Central Line
–	Peripheral Intravenous	Basilic vein Cephalic vein Brachial vein	Teflon 72-96 h Polyurethane 1-7 d	3-8 cm	Dislocation Infiltration Thrombosis Kinking Phlebitis
–	Peripheral arterial	Radial artery Brachial artery Femoral artery Dorsalis pedis artery Ulnar artery		4-12 cm	Vasospasm Pseudoaneurysm Distal ischemia Vascular injury Infection
–	Midline	Basilic vein Cephalic vein Brachial vein	28 d	8-20 cm	Phlebitis Thrombosis Occlusion
Central Line
–	Peripheral inserted central venous catheters (PICCs)	Basilic Vein Brachial vein Cephalic vein	≥14 d-6 mo	25-60 cm	Dislodgement Occlusion Mechanical Phlebitis Thrombosis Arrhythmia
–	Nontunneled central venous catheters	Internal jugular vein Subclavian vein Femoral vein	7-14 d or ≥3 mo	15-25 cm	Thrombosis Occlusion Infection Pneumothorax
–	Pulmonary artery catheters	Internal jugular vein Subclavian vein Femoral vein		30-110 cm	Arrhythmia Misplacement Knotting Perforation Infarction Thromboembolism Infection Rupture of myocardium, vessel, or valve
–	Tunneled central venous catheters	Internal jugular vein Subclavian vein Femoral vein	≥3 mo	8-40 cm	Thrombosis Occlusion Infection Pneumothorax Pinch-off
Chopra V, Flanders SA, Saint S, et al. The Michigan appropriateness guide for intravenous catheters (magic): results from a multispecialty panel using the RAND/UCLA appropriateness method. Ann Intern Med. 2015;163(6 suppl):S1-S40; Adams DZ, Little A, Vinsant C, Khandelwal S. The midline catheter: a clinical review. J Emerg Med. 2016;51(3):252-258; Cheung E, Baerlocher MO, Asch M, Myers A. Venous access: a practical review for 2009. Can Fam Physician. 2009;55(5):494-496; Galloway S, Bodenham A. Long-term central venous access. Br J Anaesth. 2004;92(5):722-734; Rodriguez Ziccardi M, Khalid N. Pulmonary artery catheterization. StatPearls. Treasure Island, FL: StatPearls Publishing LLC; 2019, Refs.^{14,20,21,22,23}

Although not reflected in the SIR calculation, CLABSI risk can be influenced by multiple factors including patientrelated factors (comorbidities, severity of illness), catheter-related factors (insertion site, type of catheter) and institutional-related factors.³⁰^,³¹

Patient-Related Risk Factors

Patient-related risk factors are generally considered nonmodifiable as these characteristics are largely immutable as they are intrinsic to the patient. These include such factors as age, gender, and underlying comorbidities (diabetes, end-stage renal disease).³² Retrospective reviews have been performed that investigate how comorbidities within risk models more reflect the impact they can have of risk of CLABSI and allow for better comparison across hospitals when these comorbidities are taken into account for risk adjustment as opposed to the current model.³³^,³⁴

Catheter-Related Risk Factors

As opposed to patient-related risk factors, catheter-related risk factors are in general modifiable but vary in the level of risk involved. Peripheral IVs (PIVs) are the most common
intravascular device but have a relatively lower risk of bloodstream infections compared to other intravascular devices.²⁶ However, given that PIV devices are used in such far greater numbers compared to other vascular access devices, like CVCs, the rate of bloodstream infections likely approaches that of CVCs.²⁶^,³⁵ The risk of infection from peripheral venous catheters largely stems from catheter dwell time.³⁶ Additionally, thrombophlebitis, a known noninfectious complication of PIV insertion, may increase risk for bloodstream infections.³⁶^,³⁷ Recent work has shown that PIVs can serve as a source for Staphylococcus aureus bacteremia and are likely largely unrecognized, and the use of PIV bundles may reduce the incidence of bloodstream infections.³⁷^,³⁸

Midlines catheters and peripherally inserted central catheters (PICCs) are utilized for continual venous access in patients who extend beyond the hospitalized setting. These forms of vascular access are not without risk. Retrospective comparison between these two catheter types noted that midline catheters were more likely to have complications compared to PICCs, but these complications were often non-life threatening. Overall, data are unclear if the overall safety profile of midlines compared to PICC is better. PICC complications are often thought to be more serious, including bacteremia.³⁹ The risk of developing a CLABSI in patients with PICCs has been associated with the number of catheter lumens, length of hospital stay, and use of the catheter for chemotherapy.¹³^,⁴⁰ Within specific patient populations (eg, the acute surgical patient population), PICCs and CVCs have not been shown to have an appreciable difference in infectious complications.⁴¹^,⁴²

Short-term Central Venous Catheters CVCs account for the majority of CLABSIs.⁴³ The following factors have been associated with an increased risk for CLABSI: prolonged hospitalization, prolonged duration of catheterization, heavy microbial colonization at the insertion site or catheter hub, neutropenia, the use of total parental nutrition, excessive manipulation of the catheter and the number of catheters inserted.⁴⁴^,⁴⁵ Data regarding the number of lumens and an increased risk of infection are mixed, with a meta-analysis showing a slight increased risk with multilumen central lines that diminishes when higher-quality studies that control for patient risk factors are examined; however, a more recent prospective study noted that increasing catheter lumens were an independent risk factor for CLABSI.⁴⁶^,⁴⁷ In a multicenter randomized controlled trial of CVC insertion sites, subclavian catheterization was associated with the lowest risk of bloodstream infections and symptomatic thrombosis but higher rates of pneumothorax.⁴⁸ Femoral catheters have been found to have higher rates of infection and thrombosis compared to subclavian and internal jugular catheters, though this may be mitigated if the catheter indwelling time is 4 days or less.⁴⁹^,⁵⁰^,⁵¹ Though data can be mixed, avoidance of femoral site catheter placement and removal of emergently placed lines are frequently part of CLABSI bundles with the goal of reducing CLABSI risk.⁵² Routine replacement of central lines is not recommended and likely only increases the risk of mechanical complication with no reduction in CLABSI risk.⁵³

Long-term Central Venous Catheters There are fundamental differences between infection rates and risk between short- and long-term catheters. The average infection rate for long-term CVCs ranges from 0.1 to 1.2 to 1.5 episodes per 1000 catheter-days, much less than that noted in short-term CVCs, which ranges from 1.2 to 2.9 per 1000 catheter days.²⁶ The data comparing CLABSI rates between long-term catheters and ports in a prospective randomized study of 100 cancer patients found no difference in infection rates between the two catheter types.⁵⁴ However, an observational study compared tunneled cuffed silicone catheters, PICCs, and ports, and identified an increased rate of catheter infections in tunneled cuffed silicone catheters compared to PICCs and ports. Patients with ports had almost no catheter infections in this study.⁵⁵ Additional comparison studies have noted that there is an overall decreased likelihood of infectious complications with ports versus other long-term catheter types.⁵⁶^,⁵⁷ Studies comparing the infection risk of other types of long-term catheters are mixed. In a prospective randomized study of 212 patients, no difference in infections rates was noted between patients with tunneled and nontunneled subclavian CVCs.⁵⁸ Additionally, another study of 84 patients found no difference in infection rates when comparing cuffed and noncuffed CVCs.⁵⁹

In looking at factors that increase bloodstream infections in long-term CVCs: age >65, cancer type, previous bloodstream infection, increased number of catheter lumens, multiple catheter manipulations, neutropenia, hematopoietic stem cell transplant, and receipt of total parental nutrition have all been noted in clinical studies to be associated with increased risk.⁶⁰^,⁶¹^,⁶²^,⁶³^,⁶⁴

Institution-Related Risk Factors

As mentioned previously, the Centers for Disease Control and Prevention (CDC) uses risk adjustment though the SIR to compare CLABSI rates across hospitals. Initially, only adjustment by type of intensive care unit (ICU) was included in the risk model, but in 2017, hospital size by beds and medical school affiliation were added.⁶⁵ Notably, there has been some controversy in the decision to include these criteria in the SIR calculation. A study found no association of medical school affiliation or hospital size with risk adjustment, but rather the use of patient comorbidities showed better discrimination between facilities.³⁴ The effect of staffing on CLABSI risk has shown mixed results with no significance noted between nursing and physician staffing and HAIs, but did find an increase in HAI rates with increased use of nonpermanent staff and mixed results with increased infection control personnel staffing.⁶⁶ The geographic location (ie, hospital unit) where the central line is placed has been associated with an increased risk of CLABSI. Placing a central line in an emergency room or an ICU has been associated with increased CLABSIs, but this likely reflects the patient who is in urgent need of vascular access, as well as more comorbidities with these patients.⁶⁷ While central lines placed in the ICU are associated with an increased risk for CLABSI, CLABSI rates outside ICUs have been assumed to be similar to those within ICU.³ This is controversial as there have been data to show the rates have been higher, and there has been less research on the rates and prevention of CLABSIs in non-ICU settings.²^,⁶⁸

SPECIAL CATHETER TYPES

Pulmonary Artery Catheters

Pulmonary artery (PA) catheters are intravascular devices used to monitor hemodynamics in critically ill patients that are inserted into one of the main large veins (internal jugular, subclavian, or femoral) through the right atrium and ventricle of the heart and into the PA. A previous meta-analysis found that the average catheter-related bloodstream infection (CRBSI) rate was higher with PA catheters compared to nontunneled CVCs (3.7 per 1000 catheter days vs 2.7 per 1000 catheter days).²⁶ An older prospective study of cardiac surgery patients found a higher incidence of colonization (11.6% or 17.7 per 1000 catheter days) compared to bacteremia (0.6% or 0.93 per 1000 catheter days).⁶⁹ A recent retrospective cohort of patients awaiting heart transplant found an infection rate of 5.46 per 1000 PA catheter days with coagulase-negative Staphylococcus as the predominant causative organism.⁷⁰ Studies indicate risk of developing PA catheter-related infection increases with the duration of catheterization (particularly over 7 days), skin colonization at the insertion site, insertion into the internal jugular vein, and insertion in the operating room or emergently if there are less stringent barrier precautions.⁷¹^,⁷²

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