Chlorhexidine-Impregnated Sponges Reduce Catheter-related Infections
Abstract & Commentary
By Robert Muder, MD, Hospital Epidemiologist, Pittsburgh VA Medical Center, Section Editor, Hospital Epidemiology , is Associate Editor for Infectious Disease Alert.
Dr. Muder does research for Aventis and Pharmacia.
Synopsis: In a randomized, multicenter trial, chlorhexidine-impregnated sponges used in the dressing of intravascular catheters reduced catheter-related infections by 60%. Increasing the interval of catheter-related dressing changes from 3 to 7 days did not increase the rate of infection.
Sources: Timsit J-F, et al. Chlorhexidine-impregnated sponges and less frequent dressing changes for prevention of catheter-related infections in critically ill adults. JAMA. 2009;301:1231-1241.
Timsit et al conducted a 2x2 randomized, controlled trial comparing chlorhexidine-impregnated sponges in the dressing of vascular catheters with control dressings. They simultaneously compared a three-day dressing change interval with a seven-day interval. The study was conducted in seven adult critical-care units in five French hospitals, and included medical and surgical units. Both arterial and central venous catheters were included; none of the catheters were impregnated with anti-microbial agents. All centers used maximal sterile barrier precautions for catheter insertion. The skin disinfectant used was povidone-iodine in alcohol.
There were two major endpoints. Catheter colonization, defined as a quantitative catheter tip culture yielding > 1000 colony forming units, was the major endpoint for evaluation of dressing change interval. Major catheter-related infection (CRI) was the primary endpoint for evaluation of the efficacy of the chlorhexidine impregnated sponge. Major CRI was defined as either catheter-related sepsis without bacteremia (clinical signs of infection, catheter colonization, and no other focus of infection) or catheter-related bloodstream infection (BSI; positive blood culture with catheter colonization or differential time to positivity > 2 hours). Secondary endpoints were catheter-related BSI and insertion-site skin colonization at the time of catheter removal. Although ICU staff were not blinded to patient assignment, the clinical evaluators and microbiology staff were.
In the intention-to-treat analysis, there were 1,636 patients with a total of 3,778 catheters and 28,931 catheter days. The rate of major CRI among patients assigned to chlorhexidine impregnated dressings was 0.60 per 1,000 catheter days, compared to 1.40 per 1,000 catheter days in the control group (p = .03). There was a similar reduction in catheter-related BSI: 0.4 per 1,000 catheter days compared to 1.3 per 1000 catheter days. Insertion-site colony counts were significantly lower in the chlorhexidine dressing group. Use of chlorhexidine dressing did not lead to an increase in the isolation of chlorhexidine-resistant organisms. Severe adverse events were uncommon; eight patients developed severe contact dermatitis, requiring discontinuation of the chlorhexidine dressing.
Catheter colonization occurred at a rate of 10.4/1000 patient days in the three-day dressing change group and 11.0/1000 patient days in the seven-day group (p = .95). There was no significant difference in major CRI, catheter-related BSI, or catheter colonization between the group assigned to three-day dressing changes and the group assigned to seven-day dressing changes. However, 45% of dressing changes were performed before the scheduled date due to dressing leakage or soiling. Only 10% of the dressing changes scheduled for seven days were actually performed at that time.
Commentary
This study is notable for a number of reasons. It is a very large, multicenter, randomized trial with a high rate of enrollment and adherence to protocol. The endpoints are well defined and clinically relevant. It's notable that the incidence of major CRI in the reference group, patients who were assigned to standard catheters and a three-day dressing change interval, was quite low at 1.6/1000 catheter days. Despite this, the use of chlorhexidine-impregnated sponges led to a 60% decrease in infection rate. The catheters included both arterial (46%) and venous (54%) catheters. Timsit et al state that the effect size was similar for both catheter types, but don't provide specific data. This would have been useful, as arterial catheters generally have lower rates of infection than venous catheters.
Although the results satisfy the study's prospective criteria of non-inferiority of seven-day dressing changes compared with three-day dressing changes, it should be noted that unscheduled dressing changes were very common and that very few (10%) dressings actually remained in place for seven days.
The reduction in catheter-related infections resulting from the use of chlorhexidine-impregnated sponges is similar to that reported in randomized trials of antimicrobial catheters. In a meta-analysis, Casey et al found that minocycline-rifampin catheters and 2nd generation chlorhexidine/silver sulfadiazine catheters led to a significant reduction in CRI compared with standard catheters.1 These trials were relatively small, and in several of them, the rate of infection for control catheters was significantly higher than that observed by Timsit et al.
One important implication of this study is that it demonstrates that even if CRI rates in a unit are low, presumably due to high compliance with aseptic insertion techniques, further significant reductions are possible by use of chlorhexidine-impregnated dressings. Although Timsit et al did not perform a cost-effectiveness analysis, they estimate that 117 catheters would need to be treated in order to prevent one major CRI. This is likely to be cost effective, as the dressings cost approximately $6 each. They estimate the cost of prevention as $2100, which is certainly much less than the cost of a CRI.
Whether chlorhexidine-impregnated dressings are effective in units with higher CRI rates, or more effective than antimicrobial catheters, remains to be determined.
References
- Casey AL, et al. Antimicrobial central venous catheters in adults: A systematic review and meta-analysis. Lancet Infect Dis. 2008;8:763-776.
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