Month: September 2014

EM Physicians Can Accurately Measure Systolic Function… Well Not Really

A guest post by Dr. Andrew Kirkpatrick (@AskEMdoc), an Emergency Medicine resident at the University of Texas Medical School at Houston.

With all of the recent advancement in the field of Emergency Department (ED) ultrasound, you may be tempted to think Emergency Physicians are masters of the bedside cardiac ultrasound and the assessment of systolic heart failure.  Despite the misleading title, the results of this article would suggest that is not the case.   
This is a prospective observational study to determine if E-point Septal Separation (EPSS) measurements made by emergency physicians correlated with calculated Left Ventricular Ejection Fraction (LVEF) measured by cardiologist using comprehensive Trans-Thoracic Echocardiography (TTE). Cardiac ultrasound and TTE were performed on 80 patients between the ages of 22 and 100 years old, of which 71 were included in the final analysis.  The study took place in the academic setting of Denver Health, conducted by 3 ultrasound fellows who had done at least 100 ultrasound scans.  They were given a 10 minute didactic presentation and supervised doing 3 EPSS measurements before they were set loose in the hospital to find patients who had undergone TTE in the last 24 hours. 
Based on their results, the authors conclude that  an EPSS of greater than 7mm is ideal for diagnosing severely reduced LVEF (<30%), with a sensitivity of 100% and a specificity of 51%.  This suggests EPSS is only useful in ruling out severe systolic heart failure – as values over 7mm were poor predictors of actual LVEF.  This inability to provide predictive information is well demonstrated by Figure 2, in which there are 3 patients with EPSS clearly in the range associated with severe systolic dysfunction- 20-22mm – and 2 of these 3 had normal ejection fraction on formal echocardiography.  Put another way, only 31 of the 63 patents with EPSS >7mm had moderate heart failure, calling into question the author’s suggestion the EPSS is a tool to accurately assess for LVEF.  In addition to the previous findings, the authors find that an EPSS of >8mm is a poor predictor of any systolic dysfunction with a sensitivity and specificity of 83.3% and 50.0%, respectively.  The authors also assessed the ability of emergency physicians to visually estimate ejection fraction, and found generally poor correlation with echocardiography and only fair interobserver reliability. 
There are several problems with this paper.  The sample size was small, and generalizability to Emergency Department patients may be limited because a majority of the population studied was inpatient.  More importantly, three ED ultrasound fellows performed all of the EPSS measurements.  These physicians having a special interest in ultrasound are likely more adept at wielding an ultrasound than the average emergency physician.  At best, this article makes a weak case for the clinical relevance of EPSS.  And, ultimately, subtle systolic dysfunction that may or may not be picked up by using a cutoff EPSS of >8 may not be as important as the ejection fraction that is so low it can be seen on the ultrasound screen from across the room. 
“E-point septal separation: a bedside tool for emergency physician assessment of left ventricular ejection fraction”

The 2014 AHA NSTE-ACS Guidelines

One of the best things about Emergency Medicine is the preponderance of guidelines imposed upon our management of patients by non-Emergency Medicine clinicians.  One of the most glorious offenders is the American Heart Association, dictating our care of Stroke and Acute Coronary Syndrome.

But, actually, this most recent update – despite the continued absence of Emergency Medicine from the Writing Committee – contains some interesting subtle shifts.  Out of its 150-odd pages of content and evidence, most of the Emergency Medicine-relevant content is in Section 3: Initial Evaluation and Management.  Many of the guidelines are not controversial – send patients with suspected ACS to the Emergency Department, give aspirin, obtain an ECG, etc.

But, as a Class I recommendation, they note patients with suspected ACS can be risk-stratified based on likelihood of ACS to decide on the need for hospitalization.  They also now include an expanded discussion of tools beyond the old stalwarts TIMI and GRACE, incorporating ED-centric tools such as the Vancouver Rule, the HEART score, and the HEARTS3 score.  This greatly expands guideline-based backing of these rules for shared decision-making with patients, and, frankly, makes the previously “mandatory” observation of patients with chest pain less so.

The next interesting bit relevant to the ED lay in subsection 3.4.1 – the use of biomarkers.  I’ll just reproduce my favorite bit here:

Class III: No Benefit
1. With contemporary troponin assays, creatine kinase myocardial isoenzyme (CK-MB) and myoglobin are not useful for diagnosis of ACS (158-164). (Level of Evidence: A)

The guidelines also imply, if symptom onset can be reliably determined, a single troponin measurement is reasonable 6+ hours after onset, or, for shorter onset timeframes, a troponin on arrival and a second as few as 3 hours after onset is reasonable to detect rising or falling levels.  And, beautifully, in subsection 3.5.1, all recommendations regarding discharge from the ED are Class IIa, only make weak recommendations for the reasonableness of observation, and acknowledge most patients with chest pain do not have ACS, and most are not at risk of ACS.

There is ample further fodder for the interested reader to pick apart recommendations and conflicts of interest – particularly with regards to the incorporation of newer antiplatelet agents – but, I’m generally pleased with the general direction of this guideline, as it applies to our practice.  However, this does not preclude the need for ACEP to develop its own Clinical Policy, to further guide and protect both patients and Emergency Physicians.

“2014 AHA/ACC Guideline for the Management of Patients With Non-ST-Elevation Acute Coronary Syndromes: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines”
http://circ.ahajournals.org/content/early/2014/09/22/CIR.0000000000000134.full.pdf+html

Alas, Poor (Literally) Detroit

High-quality care can mean many things.  In the ideal sense, it conveys cooperation and coordination between the many facets of healthcare delivery – great physician care, the best possible translation of medical evidence to an individual patient, outstanding nursing, electronic systems that double-check and triple-check for safety, and an army of staff to support patients in all settings to ensure best possible health.

Or, high-quality care can just be a number.  A surrogate number, obliquely related to the ideals of quality care.  And the penalty for bad care can be monetary, a decrease in the level of reimbursement to a hospital.  Reimbursement, that, paradoxically, could be used to increase the quality of care.

And, so we see this paradox playing out in Detroit, as this letter in the NEJM points out.  Detroit, suffering publicly through bankruptcy and infrastructure collapse, simply does not have the resources to support public health.  Thus, its citizens, with poor access to preventative and primary care, and already burdened by the misery of the City, are forced to seek care – repeatedly – in its metropolitan and inner-city hospitals.  And, because of such repeated visits, these hospitals are subject to the Medicare Readmission penalty – and thus, fewer resources with which to care for those lacking adequate support to care for themselves outside the institutional setting.  And around we go again.

Are we truly measuring and encouraging quality?  Or are we punishing those systems who simply cannot afford to be further stressed?

“Medicare Readmission Penalties in Detroit”
http://www.ncbi.nlm.nih.gov/pubmed/25207786

For tPA, Is Delusion the Standard of Care?

Yet again, the tPA apologists dip into their bag of registry data in an attempt to defend tPA – and end up contradicting themselves.

In 2009, neurologists in India published a retrospective case series examining the outcomes following tPA at their institution.  Specifically, they divided up the cases between those with arterial occlusion present on CT angiogram of the cerebral vessels, and those with no demonstrated arterial occlusion.  For patients with demonstrated occlusion, there were significant differences in early NIHSS improvement favoring tPA, but no long term mRS improvements.  Conversely, there were 119 without occlusion present – and the early NIHSS improvement and late mRS improvement outcomes were similar.  There were, however, substantial baseline differences between those receiving tPA and those who did not – and retrospective studies are confounded by many biases – but there was at least a suggestion that some stroke subtypes might not benefit from tPA.

Clearly, that did not sit well with the authors of this study, a handful of whom are paid representatives of Boehringer Ingelheim.  They performed their own retrospective review of a multi-center registry to evaluate outcomes of patients without arterial occlusion demonstrated on initial angiography, but definitive acute stroke seen on follow-up MRI.  They also further subdivided stroke subtypes into lacunar (subcortical, thalamic, and pontine infarct <20mm) vs. non-lacunar (all others).

They identified 154 non-lacunar strokes, 49 of whom underwent thrombolysis, and 102 lacunar strokes, 54 of whom underwent thrombolysis.  Outcomes favored tPA for non-lacunar stroke syndromes, with 51% of tPA patients mRS 0-1 at 90 days, compared with 30% for those who did not receive tPA.  Symptomatic intracranial hemorrhage occurred in 6.1% of tPA patients, compared with 1% without.  Lacunar strokes, however, had identical 90 day mRS outcomes – 65% vs. 63%.  For lacunar strokes, sICH occured in 3.7% of tPA patients vs. 0% without.  The authors still try to statistically adjust their way out of this equivalency for the primary outcome – but fail.

So, again, this is a retrospective study confounded by many biases.  However, the authors have nicely demonstrated support for a hypothesis some stroke subtypes – particularly those for whom no arterial occlusion is demonstrated on angiography – might not benefit from tPA.  Thus, the conclusion:

“In conclusion, this retrospective study demonstrates the efficacy of intravenous thrombolysis in patients with ischemic stroke who have no radiographically demonstrated arterial occlusion at presentation. Both subgroups, nonlacunar and lacunar strokes, were found to have had better clinical outcome after receiving r-tPA.”

Or, the opposite of what their data suggests.

Is it really so impossible conceive tPA might not be magical?

“Thrombolysis in Ischemic Stroke Without Arterial Occlusion at Presentation”

Sedation May Not Always Be the Answer in Shoulder Reduction

A guest post by Dr. Andrew Kirkpatrick, an Emergency Medicine resident at the University of Texas Medical School at Houston.

What happens when you combine Ultrasound guided nerve blocks and shoulder reduction?  In the hands of experienced operators, not surprisingly, great things!

This is a randomized control trial of 41 patients out of Turkey that compared shoulder reduction utilizing procedural sedation versus an ultrasound guided suprascapular nerve block.  Using the modified Kocher method for reduction, the authors found that the nerve block leads to a statistically significant decrease in pain quantified by a Visual Analog Score.  There was also non-significant trend toward first attempt success using the Ultrasound guided nerve block, which may have been significant if the authors had bothered to calculate the appropriate sample size.  No side effects were noted in the group receiving regional anesthesia, while the sedation group predictably suffered nausea/vomiting in 15%, hypoxia in 10%, and agitation in 15%.  Time to discharge in the nerve block group was 100 minutes less than the procedural sedation group, a finding which reached statistical significance.   Lastly there was no significant difference in patient or physician satisfaction between the two groups, although trends in both cases favored the nerve block group.

Despite all of its short-comings – including small sample size, no blinding, and no clear primary outcome – the paper makes a case for using a suprascapular block to avoid the risks associated with procedural sedation for the reduction of this common dislocation.  The authors show shoulder reductions can be done in the Emergency Department without the use of procedural sedation.  True, there are some patients that cannot tolerate shoulder reduction without being fully disassociated from the event, but in the appropriately selected patient, the technique outlined in this article could decrease patient discomfort and decrease the risk to the patient undergoing shoulder reduction all without starting an IV.  In the world of emergency medicine where we are pressured to “treat and street” patients as quickly as possible while attempting to minimize risk to the patient, the ultrasound guided suprascapular nerve block seems like a great addition to the shoulder reduction armamentarium.

“A Comparison of Suprascapular Nerve Block and Procedural Sedation Analgesia in Shoulder Dislocation Reduction”
http://dx.doi.org/10.1016/j.ajem.2014.02.014

Ondansetron vs. Metoclopramide in Hyperemesis

I hate to say it, but this is one of the first randomized trials I’ve stumbled across from Obstetrics and Gynecology – so, even though it’s not terribly profound, I felt compelled to cover it.

This is a double-blind, randomized trial of women admitted to observation with hyperemesis gravidarum.  They received either 4mg of ondansetron or 10mg of metoclopramide every 8 hours for 24 hours, and patient were tracked for vomiting episodes and self-reported nausea.  With regard to these co-primary outcomes, there was no difference between study drugs – most had full resolution, and most in each group had 2 episodes of vomiting or fewer.  However, secondary outcomes and adverse effects – drowsiness, xerostomia, and persistent ketonuria – favored ondansetron.

The authors therefore conclude ondansetron ought probably be favored – all else being equal.  But, for these authors, all else is not equal – ondansetron is markedly more expensive.  Therefore, the ultimate conclusion of these authors is rather in favor of metoclopramide, considering their similar efficacy.

Of other interesting note, one patient, despite admission and supportive care, had 23 episodes of vomiting during the study period.  Oy.

“Ondansetron Compared With Metoclopramide for Hyperemesis Gravidarum
A Randomized Controlled Trial”
http://www.ncbi.nlm.nih.gov/pubmed/24807340

Farewell, CT Stone Protocol

Ureterolthiasis has become a poster child for over-utilization of advanced imaging.  Despite the relative level of distress kidney stones cause our patients, the use of computed tomography has never been associated with improved outcomes – yet, CT is widespread for its diagnostic utility, contributing substantially to $2 billion in annual healthcare expenditures for this condition in the U.S. alone.

This, however, is a comparative effectiveness evaluation promoting ultrasound for the diagnosis of ureterolithiasis in the Emergency Department, a three-pronged evaluation comparing CT, formal ultrasonography by radiology technicians, and bedside Emergency Department ultrasonography.  Essentially, the objective of this study was to compare safety – regarding, in a sense, whether the additional information supplied by CT was valuable for the detection of life-threatening alternative diagnoses.  And, with respect to this outcome all strategies had, essentially, the same number of “misses” during the follow-up period – mostly acute cholecystitis, one case of appendicitis, and a smattering of other thoracoabdominal diagnoses.  And so – ultrasonography, even our amateur sort in the ED, is “just as good”.

Of course, there are a few oddities associated with this publication.   There are, bizarrely, three “primary outcomes”, and the authors explicitly choose to report only two of them.  Total costs of care was intended to be an outcome, but the authors simply state those results will not be reported in this paper.  This study also has an interestingly low incidence of ~33% confirmed ureterolithiasis – which may result from their lack of a “gold standard” for diagnosis of stone, relying on patient-reported stone passage or follow-up for stone removal.  Or, it could be enrollment of a population with an oddly low incidence of hematuria – only ~63% of enrolled patients exhibited this common finding with a sensitivity of >80%.  I’d be curious to see the incidence of hematuria in the cases with alternative diagnoses, although there would likely be too few to draw any substantial conclusions.

There was also substantial crossover from the ultrasonography cohorts.  40.7% of those randomized to ED ultrasonography and 27.0% randomized to radiology ultrasonography ultimately underwent CT.  And, this crossover reveals the limitation of ED ultrasonography: a “sensitivity” of 54%, compared with a “sensitivity” of 88% for CT (the unreliable gold standard for diagnosis limits test characteristic calculations).  There was also a major exclusion relevant to the U.S. population: women over 250 lbs and men over 285 lbs.  Unfortunately, a substantial portion of the U.S. exceeds such superlative mass – and the generalizability of these results to that population is open to reasonable variability.

The take home point, however, is a little less reliable.  Yes, if you select patients for imaging similarly to these authors and visualize unilateral hydronephrosis in the setting of suspected ureterolithiasis, it is fair to terminate your diagnostic pathway.  However, the primary fallacy of this study design is predicated on the debatable necessity of performing imaging for all suspected ureterolithiasis.  One can make a very reasonable argument ureterolithiasis can be adequately diagnosed on clinical grounds, and advanced imaging is required only in the minority of cases, regardless of the findings on bedside ultrasound.  The vast majority of ureterolithiasis carries a relatively benign prognosis of recurring and remitting pain of a few weeks duration, and return precautions or outpatient follow-up for persistent symptoms is likewise a reasonable course of action.

“Ultrasonography versus Computed Tomography for Suspected Nephrolithiasis”
http://www.nejm.org/doi/full/10.1056/NEJMoa1404446

Are a Third of Research Conclusions Wrong?

As I covered last year, half of what you’ve been taught in medicine is wrong – we just don’t know which half.

And, it turns out, sometimes even the same authors taking a second look at the same data as before, can come up with new – and wildly different – conclusions.

This is a review of 37 randomized-controlled trials published after 1966 paired with 37 “re-analyses” of the same data.  These trials span the entire medical domain, from mycophenolate therapy after cardiac transplantation to homeopathy for fibrosis.  Of these 37 re-analyses, 32 of them involved authors from the original research group.  These re-analyses differed by changing statistical techniques, outcome definitions, or other study interpretation methods.

Following re-analysis, 13 (35%) changed the original conclusions – either suggesting more, fewer, or even entirely different patients should be treated.  The implication regarding the reliability of our evidentiary basis for medical practice is obviously profound – if even just the original authors and data can result in conflicting conclusions.

In his editorial, Harlan Krumholz argues the solution is clear: open the data.  Independent verification of findings – whether by erasing bias or undesired mathematical pathology – is critical to ensuring the most complete understanding of the evidence base.  If our highest duty is to our patients, we must break down the barriers created by self-interest and institutional policies in order to promote data sharing – and serve patients by improving the clarity and transparency of medical practice.

“Reanalyses of Randomized Clinical Trial Data”
http://www.ncbi.nlm.nih.gov/pubmed/25203082

Emergency PCI for STEMI is Dead?

This somewhat befuddling study tries desperately to create a problem where there probably truly wasn’t – but as soon as the conflict-of-interest disclosures come up, it’s clear why.

This is the 1-year outcomes from STREAM, a prospective, open-label, parallel-group trial enrolling participants with acute STEMI, but unlikely to undergo primary PCI within 1 hour of diagnosis.  Participants were then randomized to either still undergo emergency PCI, or to fibrinolysis followed by urgent or emergency rescue PCI.  The initial 1-month composite outcome, despite an excess of deaths secondary to intracranial hemorrhage in the fibrinolysis group, did not demonstrate any disadvantage to fibrinolysis with delayed PCI.  There was actually a 2% absolute decrease in the composite outcome favoring fibrinolysis – and thus the 1-year follow-up, hoping this small advantage in morbidity would translate into a measurable mortality advantage.

This was, however, not the case – as cardiac mortality was 4.0% with fibrinolysis vs. 4.1% with PCI.  Adding in the ICH and other non-cardiac deaths, the all-cause mortality rose to 6.7% with fibrinolysis vs. 5.9% with PCI.  Baseline characteristics probably favored the fibrinolysis group, so there’s actually a reasonable chance the mortality disadvantage owed to the fibrinolysis strategy might indeed be durable if properly powered and balanced.

Ostensibly, the authors claim to be addressing a problem of resource scarcity.  Using their fibrinolysis strategy, they seem to suggest, allows elimination of the expensive healthcare delivery models predicated on timely PCI.  However, a full 36% of patients failed to re-establish flow and still required emergency rescue angiography.  Then, all remaining patients still underwent urgent angiography, with greater than 95% receiving a stent.  So, in essence, the trade-off for increased flexibility in the timing of angiography is the added expenditure of tenecteplase – and possibly an increase in long-term mortality.

Certainly, there are many remote or resource austere settings where revascularization by thrombolysis is appropriate.  However, Boehringer Ingelheim and their sponsored collaborators have produced this scientific work simply in a transparent attempt at promoting an expansion of the pharamacoinvasive group (read: sell more tenecteplase) – and, frankly, failing.

“STEMI Patients Randomized to a Pharmaco-Invasive Strategy or Primary PCI: The STREAM 1-Year Mortality Follow-Up”
http://www.ncbi.nlm.nih.gov/pubmed/25161043

Why Should Patients Be Denied Access to Results?

Interestingly, even though patients have long had full access to their medical record – laborious as it might be to obtain – just recently the Department of Health and Human Services issued a ruling stating patients could directly obtain their laboratory results from medical laboratories.

The real question – why did this take so long?  Are lab results, excepting a few exceptional cases, truly dangerous?  And, are patients not essentially the true owner of their medical testing?  Certainly, where the patient has directly purchased diagnostics, there should be no obstacle in providing them with information.  One can make a technical case that, when the results are purchased by a third-party – government or health insurance provider – those entities are the true owner of the result, but that hardly holds up to ethical scrutiny.

Regardless, this step is just one part of what is increasingly a growing movement towards transparency in medicine.  I think this is a good thing – patients ought be involved at each step of testing and interpretation, and, ideally should be provided with their results in real time.  It is outdated paternalism in medicine patients cannot be trusted with their own test results; is it reasonable to expect patients are a “threat” to themselves by using alternative information sources to self-educate?  If this is truly so, the answer is not to hide the results – but rather to improve how we as professionals educate patients, and improve the lines of communication.

“Direct-to-Patient Laboratory Test Reporting”
http://jama.jamanetwork.com/article.aspx?articleid=1882585 (free fulltext)