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182 PART 2: General Management of the Patient

subclavian and internal jugular venous catheters. These studies showed Several interventions, implemented at the time of catheter insertion,
decreased failure rates, decreased complications, and an increased rate have been shown to reduce the rate of catheter-associated infec-
of successful catheter placement on the first attempt with use of real- tions. Implementation of an evidence-based practice for prevention of
time ultrasound. 43,44 A recent review of CVC complications reported a catheter-associated infections has been shown to be effective when
6% to 10% incidence of mechanical complications with the insertion implemented across multiple institutions. The Keystone ICU project
of subclavian and internal jugular CVCs. Given the frequent use of enlisted over a hundred ICUs in Michigan to monitor and report the
6
CVCs in the ICU and the risk of mechanical complications, it seems number of catheter-associated infections. Clinicians were educated
prudent to utilize real-time ultrasound during the insertion of CVCs if about the evidence-based practice (ie, hand washing, using full-
it is available, especially for patients with coagulation disturbances or barrier precautions, cutaneous antisepsis using chlorhexidine, avoiding
unclear anatomical landmarks. As a result, the British National Institute the femoral site when possible, and removing unnecessary catheters),
for Clinical Excellence (NICE) and American College of Surgeons have provided with central-line carts, and completed checklists to ensure
recently recommended the uniform use of ultrasound guided catheter adherence to infection control practices. At 18 months of follow-up
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placement for elective if not all central access catheters in their respec- the mean rate of infection per 1000 catheter days decreased from 7.7 to
tive guidelines. 45,46 1.4. A subsequent study evaluated the sustainability of this quality
improvement project and demonstrated that the mean rate of catheter-
related infections remained low at 1.1 per 1000 catheter days with the
INFECTIOUS COMPLICATIONS OF CENTRAL ongoing implementation of this evidence-based algorithm. In addition
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VENOUS CATHETERS to institutional quality improvement projects, simulation training not
Catheter-related infections (bloodstream infection, catheter coloniza- only improves competence in placement of CVC insertion, but also
tion, or an exit-site infection) are thought to arise via several different has implications for reducing the rate of catheter-associated infections.
mechanisms: Skin flora from the insertion site can migrate down the A recent study demonstrated that simulation training is superior to
external surface of the catheter; the catheter hub can become infected traditional apprenticeship model or video training alone when assess-
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with repeated manipulation; or hematogenous seeding of the catheter tip ing sterile technique. Interestingly, simulation-based training was also
can result from a distant source of bacteremia. CVC-related infections associated with fewer catheter-related infections when compared to the
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are the most common cause of nosocomial bacteremia in critically ill traditional apprenticeship model (1.0 vs 3.4 per 1000 catheter days) and
patients. The incidence of hospital acquired, CVC-associated blood- others. 23,24 Thus, implementing evidence-based guidelines through qual-
15
stream infections (BSI) is collected by the CDC’s National Nosocomial ity improvement projects and simulation-based training are effective
Infection Surveillance System (NNIS) and is expressed as the number of and sustainable methods in the prevention of catheter-related infections.
in adult ICUs ranged from 2.7 to 5.0 per 1000 catheter days. Diagnosis ■ SKIN PREPARATION
BSI per 1000 CVC days. From 1992 to 2004 the rate of CVC-related BSI
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of a CVC-related BSI requires clinical symptoms of bacteremia (fever The use of antiseptic skin preparations prior to sterile draping and
>38°C, chills, or hypotension) without another apparent source, and percutaneous placement of CVCs is a routine part of the procedure.
isolation of an organism from a peripheral blood culture with either Although povidone-iodine is a commonly used skin antiseptic agent in
a semiquantitative or quantitative culture of a catheter segment that the United States, a meta-analysis reported a 50% reduction in catheter-
yields the same organism and antibiotic sensitivities as the organism related BSI with the use of chlorhexidine-based solutions rather than
cultured from blood. In the semiquantitative culture method the cath- povidone-iodine (risk ratio 0.49 [95% CI 0.28-0.88]). This meta-
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eter segment is rolled on a culture plate and considered positive if there analysis included several different types of chlorhexidine gluconate solu-
are greater than 15 colony-forming units (CFU) of an organism. In the tions for the insertion of central venous, peripheral venous, peripheral
quantitative method the catheter is processed in broth and sonicated, arterial, and pulmonary artery catheters. Subset analyses indicated that
followed by plating the broth on a culture plate. A positive culture the majority of the benefit appeared to come from the chlorhexidine
requires growth of greater than 10 CFU. CVC-related BSI should be gluconate alcoholic solutions rather than chlorhexidine gluconate aque-
3
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distinguished from catheter colonization, which only requires a positive ous solutions. Furthermore it appears that the efficacy of chlorhexidine
semiquantitative or quantitative culture from a catheter segment. In cutaneous antisepsis may be related to the concentration of chlorhexi-
addition to BSI and catheter colonization, a CVC can develop an exit- dine. The 2% aqueous formulation of chlorhexidine has been shown to
site infection defined as erythema, tenderness, induration, or purulence be more effective than 10% povidone-iodine and 70% alcohol in the pre-
within 2 cm of the catheter exit site. 18 vention of catheter-related BSI, but 0.5% tincture of chlorhexidine was
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The majority of pathogens causing CVC-related BSI are skin flora, not more effective than 10% povidone-iodine in preventing bacteremia,
which suggests migration of bacteria down the catheter as the mecha- catheter colonization, or exit-site infections. Current CDC guidelines
26
nism of infection. This notion is supported by a study of pulmonary recommend 2% chlorhexidine skin preparation for cutaneous antisep-
artery catheter (PAC) infections. This study of 297 PACs found that sis prior to CVC insertion. Additionally, a subsequent meta-analysis
1
80% of infected catheters showed concordance with organisms cultu- determined that the use of chlorhexidine for central catheter site care
red from the skin at the insertion site. According to NNIS data from resulted in a 0.23% decrease in the incidence of death, and savings of
5
1992 to 2004, slightly more than 50% of hospital-acquired BSIs were $113 per catheter used. 28
caused by staphylococcal species. The most common organisms isolated In addition to cutaneous antisepsis at the time of catheter insertion,
were coagulase-negative staphylococci (31%), Staphylococcus aureus a meta-analysis of eight randomized control trials suggested that place-
(20%), Enterococcus (9%), gram-negative rods (14%), and Candida ment of chlorhexidine impregnated sponges at the site of vascular and
species (8%). There is also increasing resistance of the isolates— epidural catheters was associated with a trend toward decreased cathe-
16
specifically, methicillin- resistant Staphylococcus aureus (59.5%), ter-related bloodstream or CNS infections. A subsequent randomized
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vancomycin- resistant Enterococcus (28.5%), and third-generation ceph- controlled trial demonstrated that use of chlorhexidine sponges reduced
alosporin-resistant Klebsiella pneumoniae (20.6%). Although these the rate of major catheter-related infections by 60% even when the
16
resistance patterns were isolated from the ICU population, they were baseline infection rate was low. To prevent one catheter-related infec-
30
not risk adjusted or controlled by individual hospital resistance rates. tion 117 chlorhexidine impregnated sponges need to be used at a cost
Therefore, specific institutional resistance patterns must be considered of $2106. Because the management of a single catheter-related infection
when evaluating resistant bacterial infections. Given the frequency and might cost between $8000 and 28,000, use of chlorhexidine impreg-
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cost associated with the treatment of catheter-related infections, there nated sponges may be cost saving. This trial also demonstrated that
has been a great deal of research into reducing the rate of these infections. weekly scheduled dressing changes of clean adherent dressings were not

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