What is the aim of this review?
The aim of this review was to find out whether people who are critically ill in hospital should be bathed with the antiseptic chlorhexidine, in order to prevent them from developing infections. Researchers from Cochrane collected and analysed all relevant studies to answer this question and found eight relevant randomised trials. Randomised trials are medical studies where people are chosen at random to receive different treatments. This study design provides the most reliable evidence on whether treatments have a relationship with desired or undesired health outcomes.
This review assesses whether using chlorhexidine (instead of soap and water) to bathe patients in an intensive care unit (ICU), or a high-dependency or critical care unit reduces the number of hospital-acquired infections. The evidence available from the studies we analysed was very low quality, meaning that we cannot be certain whether bathing with chlorhexidine reduces the likelihood of critically-ill patients developing an infection, or dying. We are also uncertain whether bathing critically ill patients with chlorhexidine shortens the length of time people spend in hospital, or lowers their risk of developing skin reactions.
What was studied in the review?
People who are critically ill (in an ICU, or a high-dependency or critical care unit) often catch infections during their time in hospital. These infections can lead to longer hospital stays, additional medical complications, permanent disability or even death. Patients in ICUs are particularly vulnerable to infections because the body's ability to fight infection is reduced by illness or trauma. Surgical tubes and lines (for example to help with feeding or breathing) may enable bacteria to enter the body. Chlorhexidine is a low-cost product which is used as an antiseptic and disinfectant in hospitals.
What are the main results of the review?
In December 2018 we searched for studies looking at the use of chlorhexidine for bathing critically ill patients. We found eight studies dating from 2005 to 2018, involving a total of 24,472 people across more than 20 ICUs. Seven studies included people who were adults, and one study included only children. All studies included both males and females. All studies compared bathing with chlorhexidine versus bathing with soap and water or non-antimicrobial washcloths. Four studies received funding from independent funders (government organisations, or from hospital or university departments) or reported no external funding, and four studies received funding from companies that manufactured chlorhexidine products.
The evidence from all eight studies combined is not sufficient to allow us to be certain whether patients bathed in chlorhexidine are less likely to catch an infection during their stay in the ICU. We are also uncertain whether patients bathed in chlorhexidine are less likely to die, because the certainty of the evidence from the six studies that reported on this is very low. We did not pool the evidence from the six studies that reported how long patients had stayed in the ICU, because the results differed widely. We are also uncertain whether patients bathed in chlorhexidine are likely to be in the ICU for less time, because the certainty of the evidence is very low. Reports from five studies provided different evidence about whether chlorhexidine led to more or less skin reactions; we are uncertain whether patients bathed in chlorhexidine are likely to have more or less skin reactions, because the certainty of the evidence is very low.
Quality of evidence
Most studies did not use methods to conceal the type of bathing solution that staff were using, which increases the risk that staff may have treated patients differently depending on whether patients were in the chlorhexidine study group or the soap-and-water study group. Participants in some studies may have already caught an infection before the start of the study and we were concerned that this might have affected our results. We also noticed wide differences in some results, and some outcomes had few reported events. These were reasons to judge the quality of the evidence to be very low.
How up to date is this review?
We searched for studies that had been published up to December 2018.
Due to the very low-certainty evidence available, it is not clear whether bathing with chlorhexidine reduces hospital-acquired infections, mortality, or length of stay in the ICU, or whether the use of chlorhexidine results in more skin reactions.
Hospital-acquired infection is a frequent adverse event in patient care; it can lead to longer stays in the intensive care unit (ICU), additional medical complications, permanent disability or death. Whilst all hospital-based patients are susceptible to infections, prevalence is particularly high in the ICU, where people who are critically ill have suppressed immunity and are subject to increased invasive monitoring. People who are mechanically-ventilated are at infection risk due to tracheostomy and reintubation and use of multiple central venous catheters, where lines and tubes may act as vectors for the transmission of bacteria and may increase bloodstream infections and ventilator-associated pneumonia (VAP). Chlorhexidine is a low-cost product, widely used as a disinfectant and antiseptic, which may be used to bathe people who are critically ill with the aim of killing bacteria and reducing the spread of hospital-acquired infections.
To assess the effects of chlorhexidine bathing on the number of hospital-acquired infections in people who are critically ill.
In December 2018 we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trial registries for ongoing and unpublished studies, and checked reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.
We included randomised controlled trials (RCTs) that compared chlorhexidine bathing with soap-and-water bathing of patients in the ICU.
Two review authors independently assessed study eligibility, extracted data and undertook risk of bias and GRADE assessment of the certainty of the evidence .
We included eight studies in this review. Four RCTs included a total of 1537 individually randomised participants, and four cluster-randomised cross-over studies included 23 randomised ICUs with 22,935 participants. We identified one study awaiting classification, for which we were unable to assess eligibility.
The studies compared bathing using 2% chlorhexidine-impregnated washcloths or dilute solutions of 4% chlorhexidine versus soap-and-water bathing or bathing with non-antimicrobial washcloths.
Eight studies reported data for participants who had a hospital-acquired infection during the ICU stay. We are uncertain whether using chlorhexidine for bathing of critically ill people reduces the rate of hospital-acquired infection, because the certainty of the evidence is very low (rate difference 1.70, 95% confidence interval (CI) 0.12 to 3.29; 21,924 participants). Six studies reported mortality (in hospital, in the ICU, and at 48 hours). We cannot be sure whether using chlorhexidine for bathing of critically-ill people reduces mortality, because the certainty of the evidence is very low (odds ratio 0.87, 95% CI 0.76 to 0.99; 15,798 participants). Six studies reported length of stay in the ICU. We noted that individual studies found no evidence of a difference in length of stay; we did not conduct meta-analysis because data were skewed. It is not clear whether using chlorhexidine for bathing of critically ill people reduced length of stay in the ICU, because the certainty of the evidence is very low. Seven studies reported skin reactions as an adverse event, and five of these reported skin reactions which were thought to be attributable to the bathing solution. Data in these studies were reported inconsistently and we were unable to conduct meta-analysis; we cannot tell whether using chlorhexidine for bathing of critically ill people reduced adverse events, because the certainty of the evidence is very low.
We used the GRADE approach to downgrade the certainty of the evidence of each outcome to very low. For all outcomes, we downgraded evidence because of study limitations (most studies had a high risk of performance bias, and we noted high risks of other bias in some studies). We downgraded evidence due to indirectness, because some participants in studies may have had hospital-acquired infections before recruitment. We noted that one small study had a large influence on the effect for hospital-acquired infections, and we assessed decisions made in analysis of some cluster-randomised cross-over studies on the effect for hospital-acquired infections and for mortality; we downgraded the evidence for these outcomes due to inconsistency. We also downgraded the evidence on length of stay in the ICU, because of imprecision. Data for adverse events were limited by few events and so we downgraded for imprecision.