Re-designing rooms and re-engineering care to reduce infections

There's an article in the Wall Street Journal on the hospital room of the future. It notes elements of architectural and product design that can reduce the transmission of infection. Take a look at the graphic above. You'll note, for example, that on entering the patient room the sink lights up in red to remind healthcare workers to wash their hands. There are a number of other examples of using design to reduce infection in the graphic. One not specifically designed for infection prevention that may still be useful in preventing infection is the large video monitor on the footwall of the room. Let's say I'm a consultant and I have influenza. I could still interact with the patient without being physically present, not feel guilty about staying home, and not risk transmitting influenza to the patient. Obviously I could not perform all the elements of a physical exam, but not all follow-up visits require an exam, though I have heard rumors that some doctors perform perfunctory exams for billing purposes only. Moreover, does every consultant and medical student need to exam the patient every day? Think of how many contaminated stethoscopes and dirty white coats are touching patients every day with the majority of those interactions adding no value to the care of the patient. Perhaps one physician could examine the patient and the rest skype in.

I've been thinking lately that we really need to carefully exam all the things we do in hospitals and then engineer out the opportunities for transmission of infection. I was reminded of this by a paper in Transactions on Healthcare Systems Engineering, which examines something as simple as how ICU nurses cover patients for each other while on breaks. This paper points out that by providing a structured coverage arrangement the number of unique persons interacting with any given patient are significantly reduced, which potentially reduces transmission of infection. I bet there are many such  examples where re-engineering patient care could reduce the potential for infection transmission.

Graphic:  Wall Street Journal

Preventing Norovirus Transmission in Your Home

Several weeks ago, my son came down with norovirus. There has been a lot of norovirus this year in Iowa, the US and the world. One of the reasons is that there's a new variant of genotype II.4, named Sydney 2012, that was reported through CDCs CaliciNet to be causing 58% of outbreaks in December 2012. So it's likely that none of us are immune to this variant, meaning that the three others in my family were now at high risk of becoming ill with norovirus. To make matters worse, we were about to celebrate my daughter's birthday and I didn't want her to become ill on such an important day. So my wife and I, educated by previous norovirus outbreaks in the family (2005 and 2010), hatched a plan to beat the virus this time. Let me foreshadow a bit, none of us got sick. Let me tell you how we did it.

The enemy
Noroviruses has a very low infectious dose (≥18 viral particles) and infected patients shed 5 billion infectious doses in each gram of feces. The virus is environmentally stable, can survive up to two weeks on surfaces and is resistant to many common disinfectants. Alcohol hand rub, is thought to be a suboptimal form of hand disinfection with soap and water being preferred. The virus is transmitted fecal-orally and is aerosolized, meaning it spreads widely in the environment. Recent evidence even suggests that commercial dishwashers are ineffective in cleaning norovirus off of dishes and silverware. Finally, since 51% of cases caused by Sydney 2012 were caused by human to human transmission, household transmission is a big mechanisms of spread.

Caveats, Limitations and Yes I Know, but Humor Me
Now, as many of you know, I'm an ID physician and epidemiologist and I like to identify limitations in almost anything I read. So, I'll save you some of the trouble and point out the weaknesses in this case report. First, it's a case report. Second, we never tested for norovirus in clinical or environmental specimens. Third, we don't know if we were susceptible to this strain, however unlikely that would be.

Case Report
Our kindergarten-aged son, first expressed norovirus symptoms when strapped into his booster seat in the back seat of our car. The other three of us were in the car at the time. We drove home and he was sick 3-4 more times in the bathroom. We quickly changed his clothes and quarantined him to a bathroom with a TV to watch for the next 24 hours. We then cleaned up the car and hatched a plan to beat back in-house transmission.

The plan
1) We began practicing strict hand hygiene with soap and water. We rarely used alcohol hand rub, if at all.

2) We realized that all dishes in the dishwasher from the morning he became ill were potentially contaminated and double washed them in the dishwasher. We also removed those dishes from circulation for ~7 days.

3) We each began using a unique set of dishes. We each had our own glass, bowl, dish and utensils. We each rinsed and washed those individually so that we couldn't transmit virus to each other. At the time, we didn't know if others were contagious or not.

4) We didn't wash the booster seat, clothes, towels etc that were overtly or potentially contaminated for ~2 weeks; we just kept them in a bag in the corner of the basement.

5) Finally, we were lucky that we have two bathrooms in the house. One was our son's bathroom for one week and the other was for the three "uninfected" family members.

That's it. Most of these steps are easily reproducible in any household. I completely understand that the availability of a second toilet could have made a big difference and not everyone has one available. Although in 2010, we also had a second toilet available and it didn't make a difference since all got sick. Finally, the big change to our infection control in 2013 versus 2010 or 2005 was that we all had our own utensils, glasses and dishes. I suspect that made the difference this time and is probably worth future study.  It would be hard to do a randomized trial of such an intervention (which is why I wrote up this case report), but it could be done.

So good luck out there. Be safe. You never know when norovirus will strike, but don't think you can't beat back this virus. You just gotta use your head, soap and water and your own spoon. Oh, and I know I've now totally jinxed myself. I'll be OK. I'm keeping a bucket next the bed.

reference: Hall AJ, J Infect Dis 2012

We’re doing it wrong—influenza vaccine edition

This prospective cohort study out of University of Michigan demonstrated that influenza vaccine didn’t protect against PCR-documented influenza illness, influenza transmission in households, or medically-attended influenza. Given the good match between vaccine and circulating viruses during the 2010-11 season, and given that the population studied was predominantly healthy young adults and children, these results are pretty shocking (even in the context of other underwhelming data on the effectiveness of influenza vaccination). As John Treanor and Peter Szilagyi opine in the excellent accompanying editorial, “the apparent failure of influenza vaccine under optimal conditions seen in this study is indeed troubling.”

One of the more intriguing findings of this study is that receipt of flu vaccine the previous year seemed to reduce the effectiveness of the vaccine, a finding that is not new. What struck me most after reading these two papers, though, was this statement in the editorial:

"It is frequently stated that evaluation of influenza vaccines in randomized controlled trials is “unethical”, but given that the effectiveness of the vaccine is unclear, the subjects in such studies are typically at extremely low risk of serious disease, and that effective antiviral therapy is available, perhaps this statement should be reconsidered."

When a vaccine’s effectiveness causes experts to consider a return to randomized controlled trials, it’s safe to say that the vaccine in question is pretty awful. We desperately need something better.

In Hospital C. difficile Transmission? Not so much.

There is an important paper in PLoS Medicine by Sarah Walker et al. in the UK that measured the proportion of C. diff cases in hospitalized patients that were acquired during their index hospital stay.  The results are pretty surprising. Using MLST, only ~25% of cases could be linked to inpatient transmission, ranging from 37% in renal/transplant down to 6% in specialist surgery.  Additionally, many of the C. difficile cases linked to in-hospital transmission manifest soon after the index case appeared clinically. In the accompanying editorial, Harbarth and Samore suggest that this means "the hospital environment was not, as has previously been claimed, a long-lasting reservoir for this pathogen."

Sources:

1) Walker AS, et al PLoS Medicine February 2012
2) Harbarth S and Samore MH et al. PLoS Medicine (Editorial)

Disgust and Infection Prevention

That's disgusting! (source: wikipedia)

Just came across this great article in the journal Philosophical Transactions for the Royal Society B, titled "Why Disgust Matters." In the paper Valerie Curtis of the London School of Hygiene and Tropical Medicine argues that the human feeling of "disgust" evolved to motivate infectious disease avoidance. She suggests that a better understanding of disgust could be harnessed to combat the behavioural causes of infectious and chronic disease such as diarrheal disease, influenza and even smoking.

You could imagine that more knowledge around "disgust" or what motivates good behavior (covering your face when you sneeze or washing your hands) could greatly improve infection prevention in hospitals.

Curtis V, Phil. Trans. R. Soc. B 12 December 2011 vol. 366 no. 1583 3478-3490 (abstract) (full text)

Related BBC Article by Health Reporter Philippa Roxby

Trouble in Pittsburgh

The behemoth healthcare system, University of Pittsburgh Medical Center, had its living donor transplant program temporarily shut down after a patient was transplanted with a kidney from a hepatitis C infected donor. The details of the fateful transplant can be found in two well-written articles in the Pittsburgh Post-Gazette (here and here). It's a classic example of the swiss cheese model of complex system failure, where all the holes lined up (in this case the positive lab test was missed on 6 occasions), allowing an adverse outcome to occur. The articles note that UPMC's response was to demote the transplant surgeon and suspend the transplant nurse coordinator. A noted transplant surgeon describes that as an administrator's knee jerk reaction and another stated, "if everyone in transplants got hit for making a mistake, no one would be working." But the journalist probes to unearth how the system fostered the error, and he notes the stresses on the surgeon to increase surgical volume (as well as stressors in his personal life), problems with the electronic medical record, and alarm fatigue. 


I have been intrigued at how physicians who perform the most highly technical procedures in medicine can sometimes be uninterested in details that ultimately can unravel their programs. What infectious diseases physician hasn't been consulted to see a patient who has undergone an amazingly complex surgical procedure, who survived against all odds only due to an enormously talented surgeon, all to be undone by sloppy infection control practices down the line, such as noncompliance with hand hygiene? In the UPMC case, I have to wonder whether a simple tool, such as a checklist, could have prevented this error.

When flu is on your plane...

A study in BMC Medicine uses mathematical modelling to determine the number of infections that result from a single H1N1-infected passenger on a Boeing 747. As shown in the table below, it depends on the duration of the flight and the price of your ticket:

	Number who become infected
Flight duration	1st class	Economy
5 hours	0-1	2-5
11 hours	1-3	5-10
17 hours	2-5	7-17

Soon there'll be a new user fee from the airlines--$100 for lowest risk of H1N1 infection, $75 for moderate risk, and only $25 for highest risk! But wait, for only $150, your flight attendant will sell you a course of tamiflu. Of course, correct change is appreciated. Oh, I kid the airlines....

When flu comes home...

This week's New England Journal of Medicine has a study that looks at transmission of H1N1 flu in the household setting. The investigators studied 216 persons with flu (index cases) and their 600 household contacts over a 7-day follow up period. The attack rate for household contacts developing influenza-like illness (ILI) was 10%. The median age of the secondary cases was 14.5 years (median age of all household contacts was 26). Risk of acquiring ILI was age-dependent (compared to adults aged 18-50 years, children 0-4 years had a 3-fold risk, children 5-18 had a 2-fold risk, while the risk for those over 50 years was one-third that of adults under 50 years). The time from onset of symptoms in the index case to onset of symptoms in a secondary case was a median of 2.6 days.