Sitting and Watching People - Thoughts on Lack of Standard Practice in Infection Prevention

Guest blogger:  Dr. David Hartley, PhD MPH is a Research Associate Professor in the department of Microbiology and Immunology at the Georgetown University Medical Center. His research interests include the ecology of infectious disease, public health surveillance, hospital infection control, and biological defense. His research applies mathematical modeling methodologies to understand the dynamics of disease in human and animal populations.

Patients who undergo hematopoietic stem cell transplantation are often profoundly immuno-incompetent for months post-transplant. Individuals typically neutrophyl engraft within weeks of the procedure, but in the case of imperfectly matched transplants, complications such as GVHD can make ongoing immunosuppressive therapy necessary in order to achieve t-cell tolerization. During this period, there is potential for infection -- newly acquired and recrudescence, both with attendant potential for emergent drug resistance. The medical management of such individuals can be complex and often results in admissions and tests/procedures in multiple hospitals and departments. In between hospital stays, such patients typically receive long term care in their homes.

As a non-MD epidemiologist who has observed infection control as it's actually practiced in relation to this patient population, I'm left with several impressions:

First, at the individual level, I am struck by the variation between healthcare workers in terms of infection control technique and compliance. Some caregivers can't seem to be bothered to tie their gowns, and I've seen more than a few put the gowns on only up to their elbows. With the gown literally hanging off their forearms, perhaps they don't realize the opportunity for clothes to contaminate or become contaminated with infectious material as they interact patients. Regarding hand washing, the length of soaping and rinsing can range from a few seconds to the time it takes to sing several stanzas of "happy birthday to you".

Second, at the department level, I've noted tremendous heterogeneity in infection control practice between wards within a given institution. The differences between CVL usage and care in post-op versus hematology/oncology units can be stark, not to mention differences in awareness of the importance placed on hand hygiene and isolation of immunosuppressed patients from others.

Third, there are differences in policy and practice between institutions. At some facilities, for example, when indicated, family caregivers and patient advocates must employ contact precautions (i.e., wear gowns and gloves) only when they are in patient rooms, while at other facilities such individuals are required to wear gowns and gloves only when they leave the patient's room (e.g., while going to restrooms or conference/consult areas). In some places the donning or shedding of such garb takes place inside the patient's room, while in other places it happens outside the room.

Lastly, there may be important interactions between the home and hospital environments. Heme-onc and transplant floors are typically controlled, well engineered areas in terms of air handling, environmental cleaning, and visitor access. Home environments, on the other hand, can span many logs of microbial contamination as a function of season, age and type of home, presence of pets, maintenance of HVAC systems, and other factors. Having patients transiting back and forth between these environments further complicates the epidemiologic picture.

This critically fragile patient population needs effective infection control practice in and out of the hospital, better surveillance, and careful epidemiological study. How are we to understand the differences in infection rates between wards or institutions given these and other inhomogeneities in practice? How can studies evaluating practice or intervention be valid when there is so much "noise" in the system? We need evidence-based guidelines and verification of compliance.

Didn't we say not to use ICD-9 codes to track MRSA?

When you're trying to improve epidemiological methods, I guess you have to be patient.  For example, when Yehuda Carmeli and Anthony Harris told us which control group to use when assessing risk factors for antibacterial resistant organisms, it took years for people to regularly follow their advice. However, I'm still a bit surprised when authors and journals keep publishing studies that track MRSA infections using ICD-9 codes. 

A couple years ago, ICHE published our multi-center validation study showing that ICD-9 codes for MRSA have a very poor positive-predictive value: 31%. To quote our conclusion: "In its current state, the ICD-9-CM code V09 is not an accurate predictor of MRSA infection and should not be used to measure rates of MRSA infection." ICHE also published Marin Schweizer and Mike Rubin's excellent editorial summarizing the issues with ICD-9 code based surveillance for MRSA.

So, knowing what we know about recent MRSA trends and considering my feelings about ICD-9 codes and MRSA, I was a bit surprised when the August ICHE included a study suggesting that MRSA was increasing in academic medical centers between 2003 and 2008 and it used ICD-9 codes! Sure, they attempted to adjust for the billing code's limited sensitivity.  Unfortunately, sensitivity isn't the key issue. If you say something is increasing, it's more important to know if what you're counting as an MRSA infection is actually an incident MRSA infection from the index admission, and not an MRSA infection from a prior admission, or even newly detected MRSA colonization. Thus positive predictive value and specificity are more important measures. 

Just remember this when you read stuff on the interweb that says "contrary to data from the CDC" or posts saying MRSA has doubled in 5 years.  Stick with the CDC. Fortunately, most of the best evidence suggests MRSA is in decline...at least for now.

Important note: Our validation study included three hospitals and compared ICD-9 to actual culture data, the gold standard.

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Ridiculous Example: What if we wanted to estimate the proportion of 30th Olympiad attendees who were born in England by randomly sampling people walking around the Olympic stadium. We could use a somewhat sensitive test, "is the person wearing a Union Jack t-shirt", and catch many people born in England, but this would be useless (ie very low positive predictive value) since anyone can buy a shirt. We could also use a more specific test like checking their passport. Thus, ICD-9 codes are a bit like t-shirts, while microbiological culture results as used in accurate MRSA estimates are more like a passport.

When is a CLABSI not a CLABSI?

We’ve blogged often about problems with how current NHSN definitions are applied in the era of public reporting and "zero" cheerleading. The results of a recent EIN survey are now available online, and confirm that we all ought to take publicly-reported CLABSI data with a few large grains of salt. When presented with a vignette that clearly meets the NHSN CLABSI definition, fewer than half of respondents reported that they would definitely call a CLABSI when the organism is VRE or Klebsiella, with more than a quarter stating they would classify the case as a secondary bacteremia (secondary, presumably, to gastroenteritis in a patient with diarrhea and fecal leukocytes). Most reported that their hospitals used clinical judgment (e.g. consensus panels, clinician vetoes) in their CLABSI surveillance, and 75% of respondents wanted at least some subjectivity to remain in any CLABSI definition. Needless to say, these findings spell trouble for public reporting and a level playing field for inter-hospital comparisons.

Did the CMS no-payment rule impact hospital HAI prevention practice?

Beginning in October 2008 CMS stopped reimbursing hospitals for excess costs attributable to CLABSI or CAUTI.  While numerous studies and surveys have linked high compliance with HAI prevention bundles for CLABSI and VAP to reduced infection rates, few studies have looked at whether CMS no payment rules improved HAI prevention process measures.

To answer that question, Sarah Krein at the VA Ann Arbor Healthcare System completed surveys of VA and non-VA hospital HAI prevention practices in 2005 and again in 2009.  Their hypothesis was that if adoption of HAI bundles differed between non-VA and VA facilities, some of this difference could be do to the CMS no payment rules since VA facilities aren't directly affected by CMS rules.

The results are pretty interesting and don't really support any impact from the CMS no payment rules.  For CLABSI, both VA and non-VA hospitals reported significant increases in bundle component use with VA having higher use in both 2005 and 2009 (see graph below).

Similar results were reported for VAP and CAUTI.  The authors conclude by saying that "the CMS payment rule is likely not the primary driver of the increased use of infection prevention practices among US hospitals over the past several years."

Source: Krein et al. JGIM July 2012

What does 'antibiotic resistance' mean to patients?

We've all heard a patient or family member claim that "they've become resistant to an antibiotic." Clinicians and public health campaigns often attempt to communicate the importance of appropriate antibiotic use, yet how patients interpret the concept of 'antibiotic resistance' may impede their best efforts. Thus, could patient misunderstanding hinder antibiotic stewardship efforts?

In July's JGIM (abstract free here), Lucy Brookes-Howell and colleagues from nine European countries completed semi-structured interviews of 121 patients with a recent lower respiratory tract infection, in order to determine their understanding of 'antibiotic resistance'. The most common theme that emerged from this study was that patients conceptualized antibiotic resistance as being 'the resistant human body' with 43 of 121 expressing this idea. Only 28 patients correctly understood that resistance was a property of the bacteria. Thus, substantial confusion was present in the majority of patients.

With almost two-thirds of patients not understanding the basics of antibiotic resistance, it is unclear if current public health campaigns that suggest that individual misuse promotes resistance can ever be effective. The authors of this study correctly wonder whether a community focus might be a better approach and also mention that using terms like 'superbug' might improve patient understanding. Maryn McKenna might be onto something...

Image source: (here)

Addendum: Really nice editorial by Timothy Edgar accompanies the study.

Intrigued by the plot of Kent Sepkowitz’ perspective piece on antibiotic stewardship in the NEJM

This is a guest-authored piece by Dr. Tom Gottlieb (Senior Specialist in Microbiology and Infectious Diseases, Concord Hospital, New South Wales, Australia), wherein he discusses Kent Sepkowitz's latest commentary in the NEJM.

This is writ in the genre of a thriller in which a new generation of ID physician villains (the previous heroic ID generation’s illegitimate offspring, it seems ) abound as ‘fervent’ ‘chastisers of antibiotic overuse and abuse’. These ‘self-pitying’, ‘inept’, ‘feckless’ ‘prohibitionists’, ‘gnawed with regret’, indeed ‘deranged’, threaten to undermine and disenfranchise the orderly world of antibiotic prescribing, by seeking to banish miracle antibiotics forever from the world. Indeed their quest, (in cahoots with the loonies of the anti-vaccination lobby), is so dangerous, it is spelt out in the more sophisticated French; “an idée fixe”. These antibiotic nihilists cannot appreciate the true contribution antibiotic chemotherapy has made to individual patient care and also to the global well being of humanity.

Now I too enjoy debunking zealotry, and would not deny that there is plenty about antibiotic stewardship that is worth challenging in a balanced discourse. And stewardship, (or is it shepherd-ship?) can be clearly problematic. As ID physicians, we are frequently left in a schizoid situation where, as on one hand we attempt to control unnecessary use, on the other, in individual care we often contribute to broad-spectrum prescribing. Moreover some clever contrarianism never goes astray. But Sepkowitz’ pendulum swings beyond healthy scepticism, past contrarianism, to something akin to denialism.

Damn it, I too need to reach for the French dictionary. Un agent provocateur? Peut-être, saboteur? Because there is significant damage caused when worthwhile attempts, not as suggested by Sepkowitz to deny antibiotics for patients, but to preserve antibiotics into an uncertain future, are derided by ID doyens. But without him providing us with any cogent examples of groups or policies that would support the existence of these villanous ‘antibiotic prohibitionists’. And the very simplistic, polemical, good versus evil like vision he paints, creates a disservice to the antibiotic debate. (Or is it that for the sake of a good argument, as Oscar Wilde wrote, Sepkowitz feels that “in matters of great importance, style, not sincerity is the vital thing”)

I agree with Sepkowitz that “just in case” prescribing, often saves the day in settings of uncertainty. But one of the banes of our clinical existence is ‘just in case’ prolonged orthopedic prophylaxis, ‘just in case’ ceftriaxone in heart failure, ‘just in case’ stat gentamicin dose pre catheter removal, just in case treatment in case confusion is caused by a urine infection, or a few more days of treatment ‘just in case’, etc..; situations in which antibiotics are used to treat the prescribers’ anxieties rather than the patient’s condition.

I find Sepkowitz’s piece in the NEJM more a diatribe than a commentary. But it is a very useful piece too. It is a wake-up call that if we fail to convince other ID physicians regarding the merits of prudent antibiotic use, we have a long way to go to change attitudes amongst medical peers or in the community.

Image: Nicolas Poussin's Adoration of the Golden Calf. "The Golden calf of Stewardship" paraded in front of idolatrous ID physicians?

Rory

In this morning's New York Times, Maureen Dowd's op-ed piece is about Rory Staunton, the 12-year old boy who recently died from an invasive group A strep infection. Rory's story was chronicled in the New York Times earlier this week in a lengthy piece by Jim Dwyer. I have thought a lot about this case over the past several days. It's a tragedy for all involved.

Ironically, over the past few weeks I've been reading the new edition of Bob Wachter's text, Understanding Patient Safety. I plan to review the book on this blog in the near future. The issues at play in Rory's case are all described in Wachter's book. There were both systems issues (e.g., laboratory data that were not acted upon because they arrived after the patient had been discharged from the emergency department) and medical decision-making issues. When the case is laid out in the well-written piece by Mr. Dwyer, it seems fairly obvious that this boy was critically ill and should never have been discharged. Yet what we can't see is what else was happening at that time that may have influenced the physicians' decision making. Many potential explanations are put forward in the 1,500 comments on the New York Times online edition.

In my conversations with Mr. Dwyer as he was writing the article, I questioned him about whether the child had a necrotizing soft tissue infection. Though no diagnosis was made (at least antemortem from what we know), this appears to be a classic story for such. Two hallmarks of necrotizing soft tissue infection were present--pain (typically in a limb) out of proportion to what you would expect from visual inspection of the area and toxicity out of proportion to what you would expect. Often these cases occur after relatively minor trauma, so minor that patients often don't think to initially tell physicians about it. In Rory's case, I suspect that the traumatic injury to his leg occurred when he dived for a ball during gym class.

In my experience, the diagnosis of necrotizing fasciitis or necrotizing myositis is not considered early in the presentation as the findings on the skin over the deeper infection are initially subtle. Often the infectious diseases physician is the first to consider the diagnosis, but the consultation may occur after critical time has passed. Importantly, severe pain in a limb with Group A strep growing in blood cultures is a necrotizing soft tissue infection until proven otherwise. However, the disease needs to be considered before the blood cultures turn positive (which often takes 12 hours or so). The natural tendency is to obtain imaging of the limb to look for the cause of pain. However, plain x-rays do not provide useful information and CT scans typically do not help either. Often, clinicians will falsely conclude that necrotizing infection is not present because imaging shows no gas in the soft tissues; however, group A strep does not produce gas. MRI can be useful but at most hospitals MRIs are difficult to obtain promptly as schedules are tight, and additional time can be lost. Diagnosis can be made quickly by having the surgeon make an incision over the suspected area, visually inspect the muscle and probe the fascia. If a necrotizing infection is found, debridement of devitalized tissue is then performed. The critical issue is that the diagnosis of group A strep necrotizing infection is often delayed and even when suspected by an astute clinician, other physicians involved in the patient's care may not act quickly to establish the diagnosis. Thus, the infectious diseases consultant may spin his wheels trying to convince other physicians of the suspected diagnosis.

My hope is that Rory's case will raise awareness of invasive group A strep infections for clinicians, and prompt hospitals to examine the systems issues at play in this case. His family has already established a website focused on raising awareness. 

Rory's story is a reminder that medicine remains a human endeavor fraught with peril and that even well-trained physicians practicing in sophisticated settings err. When I read a story like this, I get a sick feeling in the pit of my stomach as I think but for the grace of God that could have been me making similar clinical decisions that led to a terrible outcome. I continue to find the practice of medicine a humbling experience as I am reminded often of how rapidly the corpus of medical knowledge is expanding.

The two pieces about Rory in the New York Times paint a picture of a really good kid who wanted to make a difference in this world. And I suspect that in the sharing of the story of his final days, he has.


Photo: New York Times