Preventing IV Catheter-Related Bloodstream Infection
Special Feature
Preventing IV Catheter-Related Bloodstream Infection
By Jun Takezawa, MD
Approximately 3 million central venous catheters (CVC) are inserted annually in the United States, and an average of 5% of them (150,000 cases) are associated with catheter-related bloodstream infection (CR-BSI).1 Most nosocomial BSIs are related to the use of intravascular devices. CVCs account for an estimated 90% of all CR-BSIs, 45% of which occur in critical care settings.
CR-BSIs are associated with an increased mortality of 10-20%, prolonged hospital length of stay (mean of 7 days), and increased medical costs in excess of $6000 per hospitalization.2 To foster the prevention of CR-BSI, the Centers for Disease Control and Prevention (CDC) guideline for CVC management was developed by the CDC’s Hospital Infection Control Practices Advisory Committee (HICPAC).2 An overview of the content of this guideline is as follows. The organisms most frequently associated with CR-BSI are four pathogens—coagulase-negative staphylococci, particularly Staphylococcus epidermidis; Candida species; enterococci; and Staphylococcus aureus. Among them, BSI caused by vancomycin-resistant enterococci (VRE) have significantly increased and require special attention in terms of drug-resistant nosocomial infection.
Laboratory Test for Diagnosis of Catheter Colonization
Most CR-BSI results from migration of skin organisms at the insertion site into the cutaneous catheter tract, leading to colonization of the catheter tip. Contamination of the catheter hub is also responsible for intraluminal colonization. (See Figure.)
The semiquantitative roll-plate culture method is most widely used for the diagnosis of catheter colonization. In this technique, the catheter segment after removal is rolled across the surface of an agar plate, and growth of 15 CFU or more from a proximal or distal catheter segment is considered to be indicative of catheter colonization. The most sensitive method for the diagnosis of colonization is the quantitative culture. Here, the catheter segment is flushed and immersed in broth or placed in broth and sonicated. Growth of 103 CFU or more from a catheter by quantitative culture is indicative of catheter colonization. Sonication releases microorganisms from both the luminal and external surfaces of the catheter and may be most sensitive for diagnosis of catheter colonization.
Definition of CR-BSI
The CR-BSI is defined as the isolation of the same organism in terms of identical antimicrobial susceptibility and/or DNA fingerprint patterns from the colonized catheter and from the peripheral blood in a patient with clinical manifestations of sepsis and no other apparent source of bloodstream infection.2
Strategy for Prevention of BSI
The following factors should be taken into account in preventing CR-BSI:
1. Strict handwashing and aseptic technique are required in inserting a catheter.
2. A risk of site infection increases as follows: femoral veins > jugular veins > subclavian veins.
3. Teflon and polyurethane catheters are associated with less incidence of CR-BSI than those made of polyvinyl chloride and polyethylene.
4. Routine and scheduled replacement of CVC and infusion sets does not reduce catheter colonization or CR-BSI.
5. Stopcock contamination ranges between 45-50%, and a closed-needle (connecting) port significantly reduces contamination.
6. The effect of transparent dressing on prevention of CR-BSI has been contradictory. However, meta-analysis revealed that CVCs with transparent dressing had a significantly higher incidence of catheter-tip colonization, but no significant increase in CR-BSI.
7. The routine use of inline filter may increase cost, personnel time, and possible infection.
8. The effect of prophylactic antimicrobial administration, either systemically or by continuous low-dose administration through the CVC line, is inconclusive.
9. Two percent aqueous chlorhexidine, which is superior to either 10% povidone-iodine or 70% alcohol, should be used for skin preparation before CVC insertion.
10. Although the application of antimicrobial ointments such as mupirocin to the catheter site during routine dressing changes has been used, the use has not been demonstrated.
Antimicrobial- or Antiseptic- Impregnated Catheters?
Recently, the effect of antimicrobial or antiseptic-impregnated catheters on the reduction of bacterial colonization on the CVC catheter, as well as subsequent CR-BSI, has been evaluated. Kamel and colleagues conducted a randomized control trial (RCT) on catheters coated with cephazolin (CEZ) and reported that CVC coated with CEZ reduced the risk of catheter-related colonization.3 Pemberton and associates conducted a prospective randomized trial evaluating the efficacy of CVC with a surface coating of chlorhexidine and silver sulfadiazine (CCS).4 The control group (40 patients) received a standard CVC and the treatment group (32 patients) received a CVC with a coating of chlorhexidine and silver sulfadiazine (CCS). There was no significant difference in the incidence of site infection and CR-BSI between the groups.
Tennenberg and associates5 reported another RCT on CCS. The CCS group (137 patients) had a significantly decreased rate of catheter site colonization in comparison with the standard group (145 patients), with incidences of 49% and 28%, respectively. CR-BSI was less in the CCS group than the standard CVC group (3.8% vs 6.4%, respectively); however, this difference was not significant. Tennenberg et al speculated that these negative results were due to a relatively greater importance of catheter hub contamination rather than catheter site infection, or alternatively to the short duration of catheterization (5.2 days).
Maki and colleagues6 reported an additional RCT in the blinded fashion on prevention of BSI by CCS. Catheter colonization was found in 47 CVCs (triple-lumen 16-G polyurethane catheter) in the control group (n = 195) as compared with 25 CVCs (out of 208) in the treatment group. Relative risk (RR) of catheter colonization for CCS was 0.56 (95% CI 0.36-0.86). The CR-BSI was identified in nine and two catheters in the control and treatment groups, respectively, and RR of BSI for CCS was 0.21 (95% CI 0.03-0.95).
Heard and associates7 also reported a similar RCT, with a similar result. Patients were divided into two groups and received either a standard CVC or a CCS. Although the catheter colonization rate was significantly less in the CCS group, no significant difference was found in the incidence of CR-BSI in the two groups.
Raad and colleagues,8 in a blinded RCT carried out at five university-based medical centers, evaluated the efficacy of CVC coated with minocycline and rifampin (CMR). One hundred fifty-one catheters were used as controls, and 147 catheters coated with minocycline and rifampin was used for the treatment group. Colonization occurred in 36 uncoated catheters and 11 in CMR (P < 0.001). CR-BSI occurred in seven patients in the control group and no CR-BSI occurred in the treatment group (P < 0.05).
The latest RCT comparing the efficacy of prevention of both catheter colonization and BSI between the CCS and CMR was reported by Darouiche and associates.9 This study was an open trial at 12 university-affiliated hospitals. The patients in whom CVC were expected to be placed for more than three days were randomized to receive either CCS (n = 382) or CMR (356). In this large-scale study, catheter colonization was significantly less (P < 0.001) in the CMR group (28 vs 87, CCS vs CMR, respectively). The incidence of BSI was also less (P < 0.002) in the CMR group (13 vs 28, CMR vs CCS, respectively). Although this study looks promising for routine use of antibiotic-impregnated catheters in ICU settings, several concerns are present. The manufacturer that developed CMR also funded the study, and the patents of the CMR belong to some of the authors of the current paper. Additionally, the study was carried out as an open trial. Thus, it is quite difficult to eliminate Darouiche et al’s bias confounding the result of the study. It is strongly recommended to conduct another blinded RCT to confirm this result.
According to the recent statement of Durbin,10 the cost of a conventional CVC is about $20. Additional costs for CMR and CCS were $66 and $50, respectively. It is also recommended to evaluate the overall hospital cost in taking both additional costs due to the nosocomial CR-BSI and the excessive cost of newer antimicrobial- or antiseptic-impregnated catheters into account.
Summary
In summary, antimicrobial- or antiseptic-impregnated catheters look promising in preventing CR-BSI in critical care settings. However, further study is needed to confirm their efficacy using a cost-benefit analysis. Even in the absence of such further investigations, however, CVC management should be strictly observed following the CDC guideline.2 This should be especially emphasized because actual practice of intravascular site care varied significantly among hospitals and between units in a given same hospital.11
References
1. Raad II, et al. Clin Infect Dis 1992;15:197-208.
2. Pearson ML. Am J Infect Control 1996;24:262-277.
3. Kamel GD, et al. JAMA 1991;265:2364-2368.
4. Pemberton LB, et al. Arch Surg 1996;131:986-989.
5. Tennenberg S, et al. Arch Surg 1997;132:1348-1351.
6. Maki DG, et al. Ann Intern Med 1997;127:257-266.
7. Heard SO, et al. Arch Intern Med 1998;158:81-87.
8. Raad II, et al. Ann Intern Med 1997;127:267-274.
9. Darouiche RO, et al. N Engl J Med 1999;340:1-8.
10. Durbin Jr, CD, et al. Crit Care Alert 1999;6:93-94.
11. Roach H, et al. Heart Lung 1996;25:401-408.
Which of the following is recommended by the CDC to prevent IV catheter-related intravascular infections?
a. Use of strict handwashing and aseptic technique on insertion
b. Routine use of inline filters
c. Routine use of topical mupirocin ointment at catheter insertion sites
d. Routine administration of systemic antibiotics as prophylaxis
e. Routine and scheduled replacement of all central venous catheters.
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