Criteria abstracted from The Users' Guide to Medical Literature, from the Health Information Research Unit and Clinical Epidemiology and Biostatistics, McMaster University

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Article Reviewed:

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Prevention of Central Venous Catheter-Related Bloodstream Infection by Use of an Antiseptic-Impregnated Catheter.

Maki DG, Stolz SM, Wheeler S, et al.

Ann Intern Med 1997;127:257-266. [abstract]

Reviewed by Stephen Schexnayder, University of Arkansas for Medical Sciences/Arkansas Children's Hospital

Review posted January 29, 1998

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I. What is being studied?:

The study objective:

To determine whether the use of a central venous catheter (CVL) impregnated with chlorhexidine/silver sulfadiazine (CH/SSD) will reduce CVL infection and bloodstream infections from CVL's. The study also assessed patient tolerance of the catheter.

The study design:

Single center, randomized controlled trial.

The patients included:

All adult patients in an adult medical-surgical ICU who needed central venous catheters were eligible. Patients were included if no exclusion criteria were met and informed consent was obtained. In the control group there were 195 catheters inserted into 86 patients, and in the treatment group 208 catheters were inserted into 72 patients (some patients received multiple CVLs in both groups). Over 90% of eligible patients agreed to participate.

The patients excluded:

Patients known to be allergic to chlorhexidine, silver sulfadiazine, or sulfonamides.

The interventions compared:

Plain triple lumen polyurethane CVL catheter vs. triple lumen CVL catheter impregnated with CH/SSD. All catheters were 30.5 cm long.

The outcomes evaluated:

Catheter colonization (CC) and catheter-related bloodstream infection (CRBSI). CRBSI was confirmed by restriction-fragment DNA subtyping of the bacterial isolate. Patient tolerance was also evaluated.

CC was defined as a positive semi-quantitative culture of an intravascular catheter segment of >15 colony forming units. CRBSI was defined as a peripheral blood culture positive for a bacterial isolate proven to be the same strain as from a catheter segment, hub, or infusate by restriction-fragment DNA subtyping.

II. Are the results of the study valid?

Primary questions:

1. Was the assignment of patients to treatments randomized?

Yes. Each time a patient needed a CVL, they were randomly assigned from a blinded preset randomization schedule.

2. Were all patients who entered the trial properly accounted for and attributed at its conclusion?

Was followup complete?

Yes. 442 catheters were originally inserted; 403 were analyzed because there were 39 catheters (20 control, 19 CH/SSD) in place for less than 8 hours or that were not cultured upon removal.

Were patients analyzed in the groups to which they were randomized?

Mostly. The same patient had the potential to be analyzed in both groups, as each catheter assigned was randomized, and many patients received more than one catheter. The paper does not address how many were analyzed in both groups.

Secondary questions:

3. Were patients, health workers, and study personnel "blind" to treatment?

Yes. Each time a patient needed a CVL, the catheter selection was randomized. The physicians, nurse, investigator, and research microbiologist were blinded to each study catheter's group. The catheters were not visibly distinguishable.

4. Were the groups similar at the start of the trial?

Yes. Multiple demographic and host risk factors, therapeutic interventions, and catheter sites were the same in both risk groups. Host risk factors evaluated included trauma, recent surgery, azotemia, and diabetes. Therapeutic inventions considered included other intravascular lines, urinary catheters, mechanical ventilation, and corticosteroids. APACHE II scores were not statistically different between groups.

5. Aside from the experimental intervention, were the groups treated equally?

Yes, except more were placed into old sites over a guidewire in the CH/SSD group (53 vs. 41 controls, p = 0.003) than the control group. All catheters were placed using sterile gowns, gloves, and masks. Mean duration of catheterization was also similar (145 +/- 82 hours in the controls vs. 143 +/- 67 hours in the treatment group). No information on concurrent treatment with antibiotics is given.

III. What were the results?

1. How large was the treatment effect?

The relative risk of catheter colonization was 0.56 (95% confidence interval 0.36-0.89) in the CH/SSD group compared to the control group. The relative risk for CRBSI was 0.21 (95% confidence interval 0.03-0.95). The CH/SSD catheters caused more local erythema, but showed less tenderness. Overall composite inflammatory scores were not different between groups.

When measured in infections per 1000 catheter days, there were 1.6 in the CH/SSD group vs. 7.6 in the control group.

2. How precise was the estimate of the treatment effect?

The 95% confidence intervals reported show that we can be 95% confident that the risk of catheter colonization is 11-64% less likely using the CH/SSD catheters. The risk of CRBSI is 5-97% less likely. While this is statistically significant, the CRBSI confidence levels are wide.

IV. Will the results help me in caring for my patients?

1. Can the results be applied to my patient care?

This is not clear. Since the organisms isolated in this study are the most frequent cause of CC in children (coagulase negative staphylcocci), the results may be valid. However, if the major source of catheter infections is from the skin and many infections were in adult males with beards, we may not see such a great benefit. The catheters may cause more local reaction in children than adults, especially in neonates.

These results are supported by one other study (1), but three other studies have found no effect using CH/SSD coated catheters (2,3,4).

2. Were all clinically important outcomes considered?

Yes. Length of stay (LOS) is an important outcome measure that was not assessed. However, CRBSI is usually strongly correlated with increased LOS.

3. Are the likely treatment benefits worth the potential harms and costs?

This depends on the local CRBSI rate. If the local CRBSI rate exceeds 3 per 1000 catheter days, cost savings will be incurred despite the use of a more expensive catheter, based on the authors' cost analysis. These costs are based on adult data from a surgical ICU setting, which may or may not be applicable to pediatric ICU patients. In that study, CRBSI prolonged the ICU stay by an average of eight days (5).

References:

1. George SJ, Vuddamalay P, Boscoe MJ. Antiseptic-impregnated central venous catheters reduce the incidence of bacterial colonization and associated infection in immunocompromised transplant patients. Eur J Anaesthesiol 1997 Jul;14(4):428-431.

2. Ciresi DL, Albrecht RM, Volkers PA, Scholten DJ Failure of antiseptic bonding to prevent central venous catheter-related infection and sepsis. Am Surg 1996 Aug;62(8):641-646.

3. Pemberton LB, Ross V, Cuddy P, Kremer H, Fessler T, McGurk E. No difference in catheter sepsis between standard and antiseptic central venous catheters. A prospective randomized trial. Arch Surg 1996 Sep;131(9):986-989.

4. Logghe C, Van Ossel C, D'Hoore W, Ezzedine H, Wauters G, Haxhe JJ. Evaluation of chlorhexidine and silver-sulfadiazine impregnated central venous catheters for the prevention of bloodstream infection in leukaemic patients: a randomized controlled trial. J Hosp Infect 1997 Oct;37(2):145-156.

5. Pittet D, Tarara D, Wenzel RP. Nosocomial bloodstream infection in critically ill patients. JAMA 1994;271:1598-1601.

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Related Reviews:

Raad D, Darouiche ER, Dupuis J. Central venous catheters coated with minocycline and rifampin for the prevention of catheter-related colonization and bloodstream infections. Ann Intern Med 1997;127:267-274.

• Review, by S. Schexnayder

Darouiche RO, Raad II, Heard SO, et al. A Comparison of Two Antimicrobial-Impregnated Central Venous Catheters. N Engl J Med 1999;340:1-8.

• Review by S. Schexnayder

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