Impedance Threshold Devices Are Useless

So, supposedly, impedance threshold devices installed inline for ventilation during CPR potentially improve hemodynamics via negative intrathoracic pressure.  This is a prospective, randomized, multi-center, placebo-controlled sham study that really meets a very high standard for internal validity.  Over 4000 patients in the ITD group, the sham ITD group, and the not-enrolled comparison cohort.

Short summary:
 – Minimal differences between groups.
 – 27.8% sham vs. 27.1% active device ROSC in the ED.
 – 8.2% sham vs. 8.2% active device discharge from the hospital.
 – No apparent harms from the ITD device, but no benefits either.

The most important point from this article is that we have gotten sloppy in our rush to implement supposedly new and beneficial therapies in medicine.  Hypothermia, TPA for stroke, Factor VIIa, direct thrombin inhibitors, etc. and we should add impedance threshold devices to the list.  The AHA has had ITD as a class IIa recommendation to improve hemodynamics since 2005 – six years of useless therapy and costs based solely on a theoretical model without proof of improved outcomes.  Hammering this point home never gets old.

“A Trial of an Impedance Threshold Device in Out-of-Hospital Cardiac Arrest.”
www.ncbi.nlm.nih.gov/pubmed/21879897

Against Medical Advice

This is a nice review article that shows a mix of different issues associated with signing a patient out AMA.  It’s a strange practice environment we have here, where EM is turning into an increasingly customer-centric practice specialty – yet unless we have airtight documentation, our customers can litigate against us for the choices they make.

In principle, our patients have the autonomy to make their own decisions – but our cultural values have drifted away from accepting responsibility for our actions.  To best protect ourselves, the authors recommend using a specific AMA form – not because having the patient’s signature on a form confers any extra legal protection, but because it’s a structured document that helps remind clinicians to document the two key elements of the AMA:  that the patient had medical capacity to make the decision, and that the patient was adequately informed of the risks.   After you satisfy both those conditions, the key is simply complete documentation in the medical record, and you should be afforded some protection given the patient has now terminated the legal duty to treat and assumed the risk for further poor outcomes.

“The Importance of a Proper Against-Medical-Advice (AMA) Discharge”
www.ncbi.nlm.nih.gov/pubmed/21715123

Regression To The Mean

To bias is to be human, and this is a nice review of some of our own intrinsic publication biases.  It’s fun to get excited about a new biomarker promising more sensitive or specific identification of disease, promising to streamline our medical decision making.  And then you get stuck with something like d-Dimer or BNP that gives us information people rarely use appropriately.

These authors pulled “highly-cited” articles evaluating biomarker utility, examined the reported findings, and then pooled the results of subsequent, larger follow-up studies and meta-analyses.  83% of their “highly cited” studies had effect sizes larger than the corresponding meta-analyses, and only 7 of the 35 biomarkers they reviewed even had RR estimates greater than 1.37 in the meta-analyses.

Jerry Hoffman likes to say on Emergency Medical Abstracts that if you just sit back and skeptically critique everything – you’ll end up being right most of the time.  This article demonstrates just how frequently you’ll look smart by not getting overexcited by the most recent fantastic discovery.

“Comparison of Effect Sizes Associated With Biomarkers Reported in Highly Cited Individual Articles and in Subsequent Meta-analyses.”
http://www.ncbi.nlm.nih.gov/pubmed/21632484

Public Insurance Places Children At Risk

Determining proper payment for healthcare services is a fascinating problem of substantial complexity, and, with the “Affordable Care Act” and various past and future movements towards public insurance, there is a great deal of uncertainty regarding physician payment – both in the amount (public vs. private insurance) or whether (uncompensated care in hospitals, emergency departments).

This is a very interesting study out of NEJM that is applicable to the 70 to 80% of emergency departments we send home with instructions to “follow-up with X”.  They nicely demonstrate that, in Chicago, at least, “follow-up with X” is nearly trivially easy with private insurance, and much more difficult if funded by one of their Medicaid providers for children.  Excepting child psychiatry – which is in shortage – when calling a specialist for follow-up claiming to have private insurance, their research assistants could schedule an appointment well over 90% of the time.  Alternatively, when stating they had public insurance for their child, ability to follow-up ranged from 20 to 57%, depending on the specialty.

Not only that, public insurance patients waited a mean of 42 days for their appointment versus 22 days for private insurance, when they looked at clinics that would even accept that insurance option.

And, the clinical scenarios they presented for follow-up were not just routine new patient appointments – they were pediatric patients with legitimate uncontrolled morbid disease with the potential to significantly worsen and impact their overall health.

I don’t have a solution to a complex social, financial, and political problem with complex social, financial, and political obstacles – but the more good articles like this are published, the more likely smart folks will start working on solutions.

“Auditing access to specialty care for children with public insurance.”
http://www.ncbi.nlm.nih.gov/pubmed/21675891

Physician Perception of Ethnicity Preferences at End Of Life

I’m not sure what this paper definitely adds to the body of literature, but it’s been awhile since I read anything on this topic, so I thought it was interesting.

I will give the disclaimer that this has been my limited anecdotal experience during my time in MICU, SICU, PICU etc., that certain ethnic groups were less likely to be amenable to withdrawal of care discussions, transitions to comfort care, hospice, etc., much to our absolute frustration that we were expending inordinate resources to torture some poor ventilated husk of person with no chance of functional recovery.  This study, in a small single-center sample, more or less confirms that we all share that same perception – but, in theory, it doesn’t change our practice.

This study surveyed physicians regarding their perceptions of black vs. white end-stage cancer patients, and they tended to believe that a black person would be more likely to want continued aggressive treatment at the end of life.  The remainder of their article, which is a little more difficult to interpret, basically said that regardless of the perceptions, they still recommended the same (in statistical aggregate) treatment to the black vs. white hypothetical cohorts.

While this study didn’t find any measurable treatment differences, we’ve seen all throughout the literature that perception tends towards reality, and that there are many cases of measurable outcomes differences for different ethnicities.  This study just leaves me with a sour taste and more questions than answers.

http://www.ncbi.nlm.nih.gov/pubmed/21460710

More Conflicts of Interest

I don’t know if I’m the only one who gets depressed by these sorts of articles.  You have the progression through medical school and residency, you finally start feeling up-to-date on current treatment, your Grand Rounds invited speakers present results from some trials, and you think you’re fully armed to provide the best care modern medicine can provide.

And, then you discover that it’s all a stack of cards predicated on results influenced by pharmaceutical funding.

This article is from JAMA, again, very important topic given studies performed with pharmaceutical funding have a fourfold greater chance of reporting positive results.  They looked at meta-analysis, one of the techniques we try to use to increase statistical power in our reading of the literature.  They discovered that nearly no meta-analyses included comment on whether the included studies were funded by pharmaceutical literature – even though 60% of the studies reported funding sources, and 70% of those studies reported receiving funding from the pharmaceutical industry – and the same sort of dismal reporting for author conflicts of interest.  What it means – it’s another cautionary tale regarding how pervasive the masking of conflicts of interest really is, and how easily it creeps into the medical literature without our knowledge.

http://www.ncbi.nlm.nih.gov/pubmed/21386079