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CHAPTER 66: Infectious Complications of Intravascular Access Devices Used in Critical Care 589

chlorhexidine as an antiseptic, the use of transparent dressings (in some
TABLE 66-2 Risk Factors for Device-Related Infection
but not all randomized studies), duration of catheterization of 4 days
Patient-related factors or more, and heavy cutaneous insertion-site colonization all have been
Age (age ≤1 year or ≥60 years) associated with an increased risk of catheter-related bacteremia for cen-
Loss of skin integrity (burns) tral catheters. 12-15,20,28-30 Factors that have been independently associated
with CLABSI include prolonged hospitalization before catheterization,
Presence of neutropenia (absolute neutrophil count ≤1000) prolonged duration of catheterization, heavy microbial colonization at
Chemotherapy and radiotherapy the catheter exit site or hub, use of the femoral or internal jugular sites,
Distant focus of infection neutropenia, prematurity, use of total parenteral nutrition, or substandard
care. In two separate systematic reviews, antibiotic-coated and first-
31
Severity of underlying illness
generation antiseptic-impregnated CVCs have been demonstrated to
Prolonged hospitalization before catheterization reduce catheter colonization and bloodstream infection significantly. 31-33
Use of total parenteral nutrition However, the effects have been modest and the methodologic quality of
the studies was rated as poor and most of the studies were carried out
Device-related risk factors
before the widespread emphasis on infection control bundles for the care
Type of device material (steel, polyurethane, tetrafluoroethylene, and silicone more of central lines. In addition, another meta-analysis suggested that the
33
resistant to bacterial adherence than polyethylene and polyvinylchloride) benefit of the anti-infective catheters was time dependent and evident
34
Frequency of surface irregularities only during the first week after insertion. The use of chlorhexidine-
impregnated sponge dressings has been advocated as an adjunct to
Thrombogenecity of catheter materials (predisposes to bacterial colonization)
reduce vascular catheter-related bloodstream infections but the results
Use of antibiotic- or antiseptic-impregnated catheters (reduces risk) of two randomized controlled studies in the critical care setting are
Microbe-related risk factors disparate, with one large and well-conducted study demonstrating a
significant reduction in catheter-related infections and another smaller
Adherence properties (adherence to fibronectin or directly to polymer materials) study that had low power demonstrating no difference. 35,36 Neither study
Biofilm formation (antiphagocytic and may potentiate pathogenecity by acting as a used alcoholic chlorhexidine-containing products as initial skin antisep-
barrier to antimicrobial penetration) sis prior to vascular catheter insertion, making it difficult to interpret
Host-microbe–device interaction risk factors what impact the chlorhexidine-impregnated sponge dressings would
Type of placement (cutdown higher risk than percutaneous) have in this setting.
Replacement of existing catheters over a guide wire is associated with
Emergent placement (higher risk than elective placement)
a significantly lower rate of mechanical complications than replacement
Site of placement (femoral and jugular sites greater risk than subclavian site) by insertion at a new site but more frequently results in infection of the
Duration of use (longer duration increases the risk) newly placed catheter. 37
Pulmonary arterial catheters (PACs), which are used in the manage-
Use of aseptic technique at the time of insertion (use of maximal barrier precautions— ment of hemodynamically unstable, critically ill patients, carry many
mask, sterile gown and gloves, and large drape—decreases risk)
of the same risk factors and rates of bacteremia as CVCs. Most PACs
Dense cutaneous colonization at device entry site (higher density of bacteria per unit consist of a polyurethane catheter that passes through a percutaneous
area increases risk) indwelling Teflon™ introducer sheath. Prospective studies have identi-
Dressing material (gauze dressing associated with lower risk for central lines) fied several risk factors associated with significant catheter colonization,
including placement with less stringent barrier precautions, internal
Skill of puncturist (greater operator skill decreases risk) jugular vein placement, prolonged catheterization (≥4 days), and heavy
Type of skin antiseptic used for insertion (alcoholic chlorhexidine preparations microbial colonization at the catheter insertion site. 20,38,39 Exposure of a
associated with less risk) PAC to bacteremia from a distant focus of infection, catheterization for
Use of topical antimicrobial ointment (may decrease risk) 4 days or more, and difficulty with insertion also have been found to
Frequency of entry into the system (greater frequency of entry or excessive increase the risk of bacteremia. The incidence of bacteremia from PACs
39
manipulation increases the risk) is about 1%.
PATHOGENESIS
multilumen catheters inserted into either internal jugular or subclavian
sites have found bacteremia rates of 1% to 5% and rates of significant Microorganisms can gain entry (Fig. 66-1) to the intravascular device
colonization of the catheters (≥15 cfu on semiquantitative culture or (usually an intravascular catheter) and the intravenous delivery system
≥10 cfu/mL on quantitative culture) ranging between 5% and 30% 11-18 in several ways to cause device- or catheter-related bacteremia, includ-
3
depending on the use and duration of the catheter plus the patient ing contamination of infusate, contamination of the catheter hub–
population. Peripherally inserted central catheters (PICCs) have lower infusion tubing junction, hematogenous seeding of the catheter tip, and
catheter-related bacteremia rates, ranging between 1% and 2% but this colonization at the cutaneous catheter exit site.
depends on the inpatient versus outpatient setting. In the ICU setting, Contamination of infusate may be intrinsic, occurring at the manu-
6,19
the risk of infection with PICCs is only marginally less than with CVCs facturing level, or extrinsic, occurring via the administration sets, the
placed in the subclavian or internal jugular veins. Many of the factors extension tubing, the use of outdated intravenous solutions, or a break in
19
that may influence the risk of catheter colonization and/or catheter- aseptic technique allowing faulty admixtures. The potential for prolifera-
related bacteremia are listed in Table 66-2. The presence of a distant tion of organisms in various infusate fluids after intrinsic contamination
focus of infection, bacteremia, tracheostomy, loss of skin integrity, has been well documented with strains of Klebsiella, Enterobacter, and
emergent placement, internal jugular or femoral placement, absence of Serratia. 3,40,41 Candida species have a propensity to grow in hypertonic
appropriate barrier precautions, transparent dressings, a high frequency glucose solutions used in parenteral solutions, and the commercially
of entry into the system, and multilumen catheters increase the risk of available lipid emulsions support the growth of most organisms.
42
significant catheter colonization. 1,12-15,18,20-27 Nosocomial bacteremias secondary to contaminated infusate usually
The use of less than maximal barrier precautions, the use of 10% have occurred in epidemics or clusters but with improvement in manu-
povidone-iodine or 70% alcohol alone as compared with alcoholic facturing standards are now exceedingly rare. Extrinsic contamination

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