Pre-emptive contact precautions of intubated patients: effective??

One of the odd things about contact precautions is that they are typically used to isolate patients colonized or infected with MDROs like MRSA. What this does is protect the healthcare worker from being contaminated with the MDRO but does little to protect the uncolonized patients.  The contact "event" we should MOST care about is contact between the contaminated or colonized healthcare worker and the uncolonized patient. So, current active detection and isolation programs have it all wrong. Please read that paragraph again.

Thus, I read with interest a paper just e-published in the JHI by Matsushima et al.  The authors noticed, using surveillance data, that ventilated patients in their ICU were 8 times as likely to acquire MRSA compared to non-ventilated patients.  Based on this finding they decided to place all ventilated patients on contact precautions throughout their stay to see if it reduced MRSA acquisition.  This intervention is close to a universal contact precautions intervention (or close to the STAR*ICU study that was a study of barrier precautions - gloves or gowns/gloves).

The study was completed in a 19-bed ICU in Osaka, Japan.  A unique (for the US at least) characteristic of this ICU was that only 2 rooms were single-bed rooms while the remaining 17 beds were in a single open ward. There were 2 study periods.  Period 1 occurred during 2004 and period 2 was a 3-year period from 2005-2007. During period 1, contact precautions were only used if the patients was found to be colonized with an MDRO. Surveillance cultures were obtained on all admissions and weekly using sputum, nasal and urine sources. During period 2, the same practices existed as period 1, but all patients who were intubated were placed on contact precautions for their entire stay.  MRSA acquisition occurred when a patient negative for MRSA on admission culture became positive on a subsequent surveillance or clinical culture.  They actually completed segmented Poisson regression looking for changes in slope/intercept of HA-MRSA rates. Woo woo!

The main difference between period 1 and period 2 was that many more people were placed on contact precautions during period 2. In period 1, 2.9% of patients were MRSA+ on admission and isolated while in period 2, 6.1% of patients were MRSA+ on admission, but fully 43% of patients were placed on contact precautions. Importantly, the colonization pressure was 2x greater in period 2.  Keep that in mind...

Interestingly, HA-MRSA infection in all patients declined from 3.6 to 2.3 per 1000 patient-days, p<0.05. The incidence of HA-MRSA in the intubated patients greatly decreased from 12.2% to 1.1%. I have pasted the key figure -->.  What it shows is that while HA-MRSA colonization and infection declined in intubated patients it actually slightly increased in non-intubated patients (who could be considered a non-equivalent control group).  Very cool.

Usual caveats: single center with somewhat unique bed arrangement in the ICU, and of course the control group wasn't random.  However, this is a fairly strong quasi-experimental study with good epi and statistical methods. And it points out that isolating patients actually PROTECTS them, so if there are downsides associated with contact precautions, like fewer visits from healthcare workers, at least the patients isolated directly benefit from the isolation.  This sort of study could actually help flip how we think about contact precautions. Isolate the uncolonized!

Matsushima et al. JHI 2011, doi:101016/j.jhin.2011.02.010

h/t Marin Schweizer

More Chlorhexidine Love

Just in time for Valentine’s Day, another study extols the benefits of the compound we all love, chlorhexidine (CHG). We’ve posted before about the many uses of CHG, including its use as “source control” (bathing patients to reduce bacterial burden, to decrease both transmission and infection risk). The data on source control have to this point been from ICU settings (and, to be fair, not all the data suggest effectiveness, and concerns regarding CHG resistance are valid).

Now, the Rhode Island group has examined the impact of CHG bathing on general wards as well. Using a quasi-experimental study design, the investigators performed daily soap and water bathing of all patients on four general medical wards for one year, and then used daily CHG bathing for the next year (13 months, actually). The composite rate of MRSA and VRE healthcare associated infections (HAIs) was reduced by 64% during the intervention period. Interestingly, nearly the entire difference in infection rates was accounted for by UTIs (10 in the pre- vs. 2 in the post-intervention period). Nosocomial bloodstream infection rates were exactly the same pre and post (5 MRSA and 1 VRE BSI during each time period). Clostridium difficile incidence was unchanged over the time course of the study, serving as a nonequivalent dependent variable (to assess for confounders that might be associated with a general decline in HAI rates).

Given the quasi-experimental design, small size (few HAI events), lack of a concurrent control group, etc., these data require confirmation from a larger controlled trial. I also think the study would be more persuasive if the effect was seen across all body sites, rather than UTI alone. Enough of this unromantic nitpicking—go out and buy your valentine a big bottle of CHG!

Daily chlorhexidine in SICU for CLABSI prevention? Not so much.

A nice report is out in Intensive Care Medicine by Kyle Popovich and collegues from Rush University Medical Center in Chicago. In the RUMC SICU the clinicians decided to start using 2% CHG-impregnated clothes in Fall 2005.  The investigators analyzed CLABSI rates using the time-series data in the before period (Sept 2004-October 2005) and after period (November 2005 - October 2006). 

They found no significant difference in the CLABSI rate after the introduction of CHG clothes (3.81/ 1,000 central line days vs. 4.6/1,000 central line days; p = 0.57). A couple things to note.  The first is that they did a great job identifying their study as a quasi-experimental study and using Poisson regression and segmented regression analyses. They reported the Poisson-regression results after segmented regression did not identify changes in slope or intercept around the time of the CHG cloth introduction.  Nice job!  They also used C. diff, BSI, VAP and UTI rates as "control" variables, as they are thought not to be reduced with CHG bathing.  These 'control' variables are called 'non-equivalent dependent variables' and inclusion of these types of "outcomes" improves the internal validity of quasi-experimental studies since they typically would be reduced by other infection prevention interventions but not the intervention under study. Thus, they help rule out the impact of concurrent interventions that could have biased the study findings.

Previous studies, which were also mostly quasi-experimental studies but in MICUs, have found reduced CLABSIs with CHG.  It's great that the authors spent the time writing up and publishing these results and the journal should also be commended.  There's nothing worse than publication bias; negative studies are just as important as positive ones, even if they make decision making more difficult.  The authors concluded that they would not recommend routine use of CHG baths in SICUs; I would recommend further study.

Popovich, et al. Intensive Care Medicine

Benefits of Universal Gloving

Last but not least in the May issue of ICHE, Gonzalo Bearman and our very own Mike Edmond from VCU in Richmond, completed a nice quasi-experimental study looking at the benefits of universal gloving for all patient contact vs. standard contact precautions in their 18-bed surgical ICU. In phase 1 from September '07 to March '08, only standard contact precautions based on passive (clinical culture-directed) surveillance were used while in phase 2 from March '08 to Sept '08 universal gloving with emollient-impregnated gloves was used without contact precautions. During both phases, admission and every 4 day surveillance cultures were performed for MRSA and VRE but for study purposes only and not shared with the clinical teams.

So what happened? Only good things. Universal gloving compliance was 78% in phase 2 and was associated with higher hand hygiene compliance on entry (5% higher) and exit (12% higher). It also appears that universal gloving was associated with reduced CLABSI and catheter-UTIs, but with p-values = 0.1 for both outcomes. C. difficile was also lower (2.0/1,000 patient-days down to 1.4/1,000) but this finding was not statistically significant, p=0.53. VAP rates were the same (1.0 vs 1.1/1000 device days) The most important finding, in my opinion, was that HCW were less likely to have MRSA and VRE contaminating their hands during the universal glove phase. Despite what the authors state (Mike don't be mad!), the study was not likely powered sufficiently to find reduced acquisition, given that MRSA acquisition was reduced by 50% with universal glove (2.9/1000 patient-days vs. 1.4/1000 patient days) but this had a p=0.2.

I think overall, that these findings suggest that universal gloving shows promise warranting further study. I wonder if they stopped universal gloving after the study period? If they did, this would make for a very epidemiologically sound quasi-study (roll-in and roll-out) which could be analyzed using more powerful segmented Poisson regression,which can detect a change in slope and intercept associated with starting or stopping the intervention.

The June ICHE just appeared online 5 minutes ago...more exciting evidence for us to review!

iPad as a metaphor for the future of infection prevention

I've been doing a lot of thinking lately. This is perhaps because I'm between jobs and have some occasional downtime but it's more likely the result of not actually owning a computer these past two weeks, unless you count my phone. What I've been thinking about is why I ended up in hospital epidemiology in the first place. I mean, who, in their right mind, would choose to go into a profession that is under appreciated, under funded and lacks the proper scientific data to make rational clinical decisions. I could go on, and I'd be happy to if you meet me at the local pub...

What keeps sticking in my head is how little we've advanced since Semmelweis described the benefits of hand disinfection. For one, we're still doing quasi-experimental studies, although Semmelweis's design was at least controlled (midwives). It also seems that most of our contentious debates, including those around active detection and isolation, would be unnecessary if we'd followed his advice and had 100% hand hygiene. As for recent advances, the CLABSI checklist popularized by Peter Pronovost is probably the most important. Why was this advance made by someone who wasn't an ID physician or hospital epidemiologist? I think it's because as a profession we're stuck. Perhaps more clinical trials will advance things, but I have this suspicion we'll just end up proving what we already know - where will the advancement come from?

So, what does this have to do with the iPad? I just came across this article by Daniel Eran Dilger on how Steve Jobs utilizes creative destruction to change the world. The article is a little tech heavy and perhaps Apple biased, but I don't think that detracts from it's main points which I believe have relevance for a potential 'new' future for infection prevention. Dilger's main points are: (1) "Jobs understands death as a creative force better than most people. For society, culture, and technology to progress, old thinking has to die off to make way for fresh new ideas. People who don’t die are dragged kicking and screaming in the future..." and more importantly (2) "When something works, you don’t need to kill it. But in some cases you should."

So what does this mean for infection prevention and what should be "killed off"? I don't know. It's only been two weeks! However, I think we need to discuss what old ideas we are unnecessarily holding on to and we shouldn't back away from killing off things that work. Yes this is easier said than done and is perhaps a useless exercise. I'm just one guy, I don't even own a computer and I'm not even sure I know what a metaphor is.