Daily Chlorhexidine Bathing in the CCU: Should You Do It?

This is Andy Shorr from Washington, DC, with the Pulmonary and Critical Care Literature Update.

Today I want to discuss an article in the January 27, 2015, issue of JAMA by Noto and colleagues.^[1] These authors investigated the impact of daily chlorhexidine bathing on the prevention of catheter-associated bloodstream infections, catheter-associated urinary tract infections, ventilator-associated pneumonias (VAP), and Clostridium difficile infections in patients in critical care units (CCUs).

These authors sought to replicate or refute the findings of an earlier study published in the New England Journal of Medicine by Climo and colleagues.^[2] In that study, the investigators showed that chlorhexidine bathing substantially reduced the risk for hospital-acquired infection, primarily bloodstream infections, which was their focus, and the acquisition of certain resistant pathogens, namely methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE).

The study by Climo and colleagues was not limited to CCUs, however. That study was criticized for including patients in a bone marrow transplant unit. In addition, they conducted active surveillance looking at acquisition, which also was criticized because that is not always done. Finally, in that study, it was unclear whether the bloodstream infections that were prevented were real bloodstream infections or skin contaminants causing blood culture contamination. Hence, although chlorhexidine bathing has been widely adopted because of the first study, questions remain about its actual efficacy.

Perhaps more important, chlorhexidine bathing is associated with direct costs and the potential for promoting resistance. For example, certain organisms that produce carbapenemases can become resistant to chlorhexidine, and the use of chlorhexidine could create selection pressure to produce more carbapenem-resistant Enterobacteriaceae (CREs), for which we have very few treatment options.

New Study Finds No Benefit From Chlorhexidine Bathing

The group from Vanderbilt University in Nashville, Tennessee, conducted a pragmatic randomized controlled trial.^[1] They randomly assigned, in a crossover fashion, five CCUs to use chlorhexidine bathing or bathing with a non-antimicrobial-impregnated device. Then they looked at a composite endpoint of central line-associated bloodstream infections (CLABSIs), catheter-associated urinary tract infections (CAUTIs), VAP, and C difficile infections

The study was very well done. Obviously, the investigators could not blind the CCU providers or the people recording data, and the unit of randomization was the CCU. However, each CCU crossed over from antimicrobial disinfection to regular bathing, back and forth three times, and the study included CCUs of various types (a neurology CCU, a medical CCU, etc) but only focused on CCUs.

The study included about 9000 patients overall. They excluded the patients who were only enrolled during the washout period when patients were bathed with non-antimicrobial disposable cloths. Again, they measured a pooled endpoint.

This study found no impact of chlorhexidine bathing on their combined endpoint of CLABSI, CLAUTI, VAP, and C difficile infection. Pooling those four complications may not make biologic sense because no evidence has suggested that chlorhexidine bathing will affect anything but CLABSIs. However, if the rate of all of these events is low in a given CCU, it is important to pool these infections to see whether you have missed something, or whether there is a signal you might not have otherwise seen.

Overall, these investigators saw absolutely no difference with chlorhexidine bathing vs without. In one of their specified subgroup analyses, the rate of VAP was doubled during one period of chlorhexidine bathing. They conducted several analyses, adjusting for a number of variables. In terms of their secondary endpoints, which were hospital length of stay, mortality, and other important considerations, they found no difference.

This important study should lead us to question the practice of chlorhexidine bathing, which we all leapt to doing after the publication of the initial study.^[2] I believe we should go back and decide whether we really want to use a universal decontamination approach with chlorhexidine considering the potential risks. The true benefits are not clear. In the end, this is a very thought-provoking article in the January 27, 2015, issue of JAMA.

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