Category: Screening

Chest X-Ray Utility in Syncope Lost in Translation

Again, straight out of the ACEP Daily News briefing: “Patients Presenting To ED With Complaints Of Syncope Should Still Undergo Routine Chest X-Rays, Research Suggests.”

This accurately reports the lead of the linked lay medical press article: “ED Patients With Syncope Should Undergo Chest X-Rays”

But, it does not accurately reflect the authors’ discussion or conclusions regarding the utility of chest x-ray in syncope.

This is a retrospective evaluation of patients presenting with syncope and having a chest x-ray between 2003 and 2006 – a secondary analysis of the “Boston Syncope Criteria” study. There were 575 patients included in their analysis, 116 of whom had a defined adverse event within 30 days. Of the patients with positive findings on CXR, 15 of those 18 went on to have an adverse event – and I presume this association led to the perpetuation of this headline.

However, in the greater context: only 18 patients out of 575 had abnormal CXR findings, and even the vast majority of patients with adverse events had normal normal CXR findings. Then, an obvious selection bias should be clear with regard to obtaining CXR in those patients with the appropriate clinical indications – such as a suspicion for CHF or pneumonia. Patients go on to have adverse events because of the morbidity associated with concomitant clinical syndromes, of which the findings on CXR are only one small part of their evaluation.

In short, no, CXR is so low-yield it need not be performed anywhere remotely near routinely in syncope. It may be performed to evaluate a specific presenting symptom related to a syncopal event, but, if anything, these data should indicate it ought be performed less frequently.

“Utility of Chest Radiography in Emergency Department Patients Presenting with Syncope”
http://westjem.com/original-research/utility-of-chest-radiography-in-emergency-department-patients-presenting-with-syncope.html

Taking First-Time Seizures Seriously

Last week, I covered a disastrous prevalence study that almost certainly over-estimates the frequency of pulmonary embolism in syncope. Today, something similar – the frequency of epilepsy in patients presenting to the Emergency Department with first-time seizure.

The most recent American College of Emergency Physicians position statement regarding first-time seizures is fairly clear: first-time seizures need not be started on anti-epileptic therapy. The thinking goes, of course, that few patients would be ultimately diagnosed with epilepsy, and most of those initiated on anti-epileptics would be exposed only to their adverse effects without any potential for benefit.

This small study tries to better clarify the frequency of an epilepsy diagnosis. At a single center, during convenience business hours Monday through Friday, consecutive patients with first-time seizure of uncertain etiology were screened for enrollment. During their enrollment period, they were able to capture 71 patients for whom they were able to complete an EEG in the Emergency Department. Of these, 15 (21%) patients were diagnosed with epilepsy based on their ED EEG. All of these patients were then initiated on an anti-epileptic, most commonly levetiracetam. Anti-epileptic therapy was additionally started on two patients with abnormal EEGs and structural brain disease on imaging, one of whom was able to be contacted in follow-up with a repeat EEG showing epilepsy. These authors use these data to suggest potential benefit for EEG performed in the ED.

This is a fairly reasonable conclusion, although the level of evidence from this single study is weak. This is probably another example of the ED filling a gap in outpatient follow-up; it would almost certainly be perfectly safe to discharge these patients without investigation or initiation of therapy if an ambulatory EEG could be arranged within a few days. Further, larger-scale evaluation of the value of an ED EEG would be needed to modify our current approach.

“The First-Time Seizure Emergency Department Electroencephalogram Study.”
https://www.ncbi.nlm.nih.gov/pubmed/27745763

The Impending Pulmonary Embolism Apocalypse

After many years of intense effort, our work in recognizing overdiagnosis and over-treatment of pulmonary embolism has been paying off. With the PERC, with adherence to evidence-based guidelines, and with a responsible approach to resource utilization, it is reasonable to suggest we’re making headway into over-investigating this diagnosis.

Prepare for all that hard work to be obliterated.

This is a prospective study of patients admitted to the hospital for syncope, evaluating each in a systematic fashion for the diagnosis of PE. Consecutive admissions with first-time syncope, who were not currently anticoagulated, underwent risk-stratification using Wells score, D-dimer testing if indicated, and ultimately either CT pulmonary angiograms or V/Q scanning. The top-line result, the big scary number you’re likely seeing circulating the medical and lay news: “among 560 patients hospitalized for a first-time fainting episode, one in six had a pulmonary embolism.”

Prepare for perpetual arguments with the admitting hospitalist for the next several eternities: “Could you go ahead an get a CTPA? You know, 17% of patients with syncope have PE.”

I’d like to tell you they’re wrong, and this study is somehow flawed, and you’ll be able to easily refute their assertions. Unfortunately, yes, they are wrong, and this study is flawed – but it won’t make it any easier to prevent the inevitable downstream overuse of CT.

The primary issue here is the almost certain inappropriate generalization of these results to dissimilar clinical settings. During the study period, there were 2,584 patients presenting to the Emergency Department with a final diagnosis of syncope. Of these, 1,867 were deemed to have an obvious or non-serious alternative cause of syncope and were discharged home. Thus, less than a third of ED visits for syncope were admitted, and the admission cohort is quite old – with a median age for admitted patients of 80 (IQR 72-85). There is incomplete descriptive data given regarding their comorbidities, but the authors state admission criteria included “severe coexisting conditions” and “a high probability of cardiac syncope on the basis of the Evaluation of Guidelines in Syncope Study score.” In short, their admission cohort is almost certainly older and more chronically ill than many practice settings.

Then, there are some befuddling features presented that would serve to inflate their overall prevalence estimate. A full 40.2% of those diagnosed with pulmonary embolism had “Clinical signs of deep-vein thrombosis” in their lower extremities, while 45.4% were tachypneic and 33.0% were tachycardic. These clinical features raise important questions regarding the adequacy of the Emergency Department evaluation; if many of these patients with syncope had symptoms suggestive of PE, why wasn’t the diagnosis made in ED? If even only the patients with clinical signs of DVT were evaluated prior to admission, those imaging studies would have had a yield for PE of 65%, and the prevalence number seen in this study would drop from 17.3% to 10.3%. Further evaluation of either patients with tachypnea or tachycardia might have been similarly high-yield, and further reduced the prevalence of PE in admitted patients.

Lastly, any discussion regarding a prevalence study requires mention of the gold-standard for diagnosis. CTPA confirmed the diagnosis of PE in 72 patients in this study. Of these, 24 involved a segmental or sub-segmental pulmonary artery – vessels in which false-positive results typically represent between one-quarter to one-half. Then, V/Q scanning was used to confirm the diagnosis of PE in 24 patients. Of these, the perfusion defect represented between 1% and 25% of the area of both lungs in 12 patients. I am not familiar with the rate of false-positives in the context of small perfusion defects on V/Q, but, undoubtedly a handful of these would be as well.  Add this to the inadequate ED evaluation of these patients, and suddenly we’re looking at only a handful of true-positive occult PE in this elderly, chronically ill cohort with syncope.

My view of this study is that its purported take-home point regarding the prevalence of PE in syncope is grossly misleading, yet this “one in six” statistic is almost guaranteed to go viral among those on the other side of the admission fence.  This study should not change practice – but I fear it almost certainly will.

“Prevalence of Pulmonary Embolism among Patients Hospitalized for Syncope”

http://www.nejm.org/doi/full/10.1056/NEJMoa1602172

Stumbling Around Risks and Benefits

Practicing clinicians contain multitudes: the vastness of critical medical knowledge applicable to the nearly infinite permutaions of individual patients.  However, lost in the shuffle is apparently a grasp of the basic fundamentals necessary for shared decision-making: the risks, benefits, and harms of many common treatments.

This simple research letter describes a survey distributed to a convenience sample of residents and attending physicians at two academic medical centers. Physicians were asked to estimate the incidence of a variety of effects from common treatments, both positive and negative. A sample question and result:

treatment effect estimates
The green responses are those which fell into the correct range for the question. As you can see, in these two questions, hardly any physician surveyed guessed correctly.  This same pattern is repeated for the remaining questions – involving peptic ulcer prevention, cancer screening, and bleeding complications on aspirin and anticoagulants.

Obviously, only a quarter of participants were attending physicians – though no gross differences in performance were observed between various levels of experience. Then, some of the ranges are narrow with small magnitudes of effect between the “correct” and “incorrect” answers. Regardless, however, the general conclusion of this survey – that we’re not well-equipped to communicate many of the most common treatment effects – is probably valid.

“Physician Understanding and Ability to Communicate Harms and Benefits of Common Medical Treatments”
http://www.ncbi.nlm.nih.gov/pubmed/27571226

High Blood Pressure is Not a Crime

And you don’t need to be sent to “time out” – i.e., referred to the Emergency Department – solely because of it.

This is a retrospective, single-center report regarding the incidence of adverse events in patients found to have “hypertensive urgency” in the outpatient setting.  This was defined formally as any systolic blood pressure measurement ≥180 mmHg or diastolic measurement ≥110 mmHg.  Their question of interest was, specifically, whether patients referred to the ED received clinically-important diagnosis (“major adverse cardiovascular events”), with a secondary interest in whether their blood pressure was under better control at future outpatient visits.

Over their five-year study period, there were 59,535 patient encounters meeting their criteria for “hypertensive urgency”.  Astoundingly, only 426 were referred to the Emergency Department.  Of those referred to the ED, 2 (0.5%) received a MACE diagnosis within 7 days, compared with 61 (0.1%) of the remaining 58,109.  By 6 months, MACE had equalized between the two populations – now 4 (0.9%) in the ED referral cohort compared with 492 (0.8%) in those sent home.  Hospital admission, obviously, was higher in those referred to the ED, but apparently conferred a small difference in blood pressure control in follow-up.

The authors go on to perform a propensity-matched comparison of the ED referrals to the sent home cohort, but this is largely uninsightful.  The more interesting observation is simply that these patients largely do quite well – and any adverse events probably happen at actuarial levels rather than having any specific relationship to the index event.

I appreciate how few patients were ultimately referred to the Emergency Department in this study; fewer than 1% is an inoffensive number.  That said, zero percent would be better.

“Characteristics and Outcomes of Patients Presenting With Hypertensive Urgency in the Office Setting”
http://archinte.jamanetwork.com/article.aspx?articleid=2527389

Triaging Large Artery Occlusions

Endovascular intervention for acute stroke can be quite useful – in appropriately selected patients.  However, few centers are capable of such interventions, and the technology to properly angiographically evaluated for large-artery occlusions is not available in all settings.  Thus, it is just as critical for patients to be clinically screened in some fashion to prevent over-utilization of scarce resources.

These authors retrospectively reviewed 1,004 acute stroke patients admitted to their facility since 2008, 328 of which had large-vessel occlusions: ICA, M1, or basilar artery.  They calculated the accuracy, sensitivity, and specificity of multiple different potential clinical scoring systems, cut-offs.  Unfortunately, every score made some trade-off – either in the rate of false-negative results excluding patients from potential intervention, or in the rate of false-positive results serving to simply subject every patient to advanced imaging.  The maximum accuracy of all their various scores topped around around 78%.

The authors’ conclusions are reasonable, if a little limited.  They feel every patient presenting with an acute stroke within 6 hours of symptom onset should undergo vascular imaging.  These are both reasonable, but ignore one of the major uses for simple clinical scoring systems: prehospital triage.  Admitting none of these are perfect, _something_ must be put to use – and, probably, given the current bandwidth for endovascular intervention, something with the highest specificity.

For what it’s worth, we use RACE to triage for CT perfusion, but CPSSS, ROSIER, or just NIHSS cut-offs around 10 would all be fair choices.

“Clinical Scales Do Not Reliably Identify Acute Ischemic Stroke Patients With Large-Artery Occlusion”
https://www.ncbi.nlm.nih.gov/pubmed/27125526

The Biomarker for Burnout

I’m tired.  You’re tired.  We’re all tired.  Importantly – performance suffers with exhaustion, unhealthy behaviors at work increase, and cognitive errors at work rise.  Burnout.

And now there might be a test for it.

This is a small study of resident trainees in Turkey, correlating the levels of neurotrophic factor S100 calcium binding protein B with symptoms of Burnout Syndrome – emotional exhaustion, depersonalization, and personal accomplishment.  S100B is a marker of glial activation and brain injury, and seems to fluctuate with stress and depression, although the associations have not been shown to be reliable.

Each resident trainee was asked to complete a questionnaire regarding burnout prior to, and following, a night shift, along with concomitant blood draw.  Unfortunately, the results are primarily grim, and not on account of the primary outcome: 37 of 48 participating residents scored in the severe depression category on the burnout questionnaire.  The remaining 11 scored in the moderate range.

Looking at the actual purpose of the study, however, they did find S100B levels were significantly different between severe and moderate depression, even accounting for the small sample.  The pre- and post-night shift levels were not appreciably different.  Overall, S100B seemed to correlate best with the overall burnout score, in particular the subscore for emotional exhaustion.

It’s a little hard to interpret these data, or envision how they might be applied in a real-world situation.  It does seem a reasonable biomarker to pursue as an objective measure of the stresses of training, and, frankly, it may be the on-shift changes were not detected as a result of most residents already exhibiting features of high stress and burnout even before starting their night.  Then, even assuming S100B were proven valid, the “gold standard” in this case – the burnout inventory – is probably less expensive and certainly less invasive to deploy.

I am not certain the way forward for this line of burnout biomarker research, but it is rather interesting.

“Serum S100B as a surrogate biomarker in the diagnoses of burnout and depression in emergency medicine residents.”
https://www.ncbi.nlm.nih.gov/pubmed/27018399

Let’s Get Inappropriate With AHA Guidelines

How do you hide bad science?  With meta-analyses, systematic reviews, and, the granddaddy of the them all, guidelines.  Guidelines have become so twisted over the recent history of medicine the Institute of Medicine had to release a statement on how to properly create them, and a handful of folks have even gone so far as to imply guidelines have become so untrustworthy a checklist is required for evaluation in order to protect patients.

Regardless, despite this new modern era, we have yet another guideline – this time from the American Heart Association – that deviates from our dignified ideals.  This guideline is meant to rate appropriate use of advanced imaging in all patients presenting to the Emergency Department with chest pain.  This includes, for their purposes, imaging to evaluate nSTEMI/ACS, suspected PE, suspected syndromes of the aorta, and “patients for whom a leading diagnosis is problematic or not possible”.

My irritation, as you might expect, comes at the expense of ACS and “leading diagnosis is problematic or not possible”.  The guidelines weighing the pros and cons of the various options for imaging PE and the aorta are inoffensive.  However, their evaluation of chest pain has one big winner: coronary CT angiograms.  The only time this test is not appropriate in a patient with potential ACS is when the patient has a STEMI.  They provide a wide range of broad clinical scenarios to assist the dutiful reader – all of which are CCTA territory – including as every low/intermediate risk nonischemic EKG and troponin-negative syndrome, explicitly even TIMI 0 patients.

Their justification of such includes citation of the big three – ACRIN-PA, ROMICAT II, and CT-STAT – showing the excellent negative predictive value of the test.  Indeed, the issues with the test – middling specificity inflicted upon low disease prevalence, increased downstream invasive angiography and revascularization of questionable value – are basically muttered under the breath of the authors.  Such dismissive treatment of the downsides of the test are of no surprise, considering Harold Litt, of ACRIN-PA and Siemens, is part of the writing panel for the guideline.  I will, again, point you to Rita Redberg’s excellent editorial in the New England Journal of Medicine, refuting the foundation of such wanton use of CCTA in the emergency evaluation of low-risk chest pain.

The “leading diagnosis is problematic or not possible” category is just baffling.  Are we really trying to enable clinicians to be so helpless as to say, “I don’t know!  Why think when I can scan?”  The so-called “triple rule-out” is endorsed in this document for this exact scenario – so you can use a test whose characteristics for detection of each entity under consideration are just as degraded as your clinical acumen.

Fantastically, both the Society of Academic Emergency Medicine and the American College of Emergency Physicians are somehow co-signatories to this document.  How can we possibly endorse such fragrant literature?

“2015 ACR/ACC/AHA/AATS/ACEP/ ASNC/NASCI/SAEM/SCCT/SCMR/ SCPC/SNMMI/STR/STS Appropriate Utilization of Cardiovascular Imaging in Emergency Department Patients With Chest Pain”
http://www.ncbi.nlm.nih.gov/pubmed/26809772

Patients Packin’ Heat

Does your Emergency Department have a metal detector?  No?  Then, read on.

These authors describe the installation of a typical arch-style metal detector at a single, Midwest, urban teaching hospital.  Between 2011 and 2013, security personnel screened all walk-in guests during hours of operation, ranging from 8h per day at initiation to 16h by the end of the study period.  In just two years of limited operation, they collected:

  • 268 firearms
  • 4,842 knives
  • 512 chemical sprays
  • 275 other weapons (brass knuckles, stun guns, box cutters)

Hospital maintenance also reported finding additional discarded weapons in the landscaping just outside the Emergency Department after the implementation of screening, while triage personnel also anecdotally noted some potential visitors turned away whence they came upon the security station.

Thus, the authors reasonably speculate their findings are representative – or even under-representative – of the weapons present, and concealed, inside their Emergency Department when security screening was absent.  The authors do not simultaneously evaluate any change in reduction in violent events in the Emergency Department, but it’s a fair conclusion their department is now a much safer workplace.

“Weapons retrieved after the implementation of emergency department metal detection.”
http://www.ncbi.nlm.nih.gov/pubmed/26153030

SIRS – Insensitive, Non-Specific

In what is almost certainly news only to quality improvement administrators, this newly published work out of Australia and New Zealand confirms what most already knew: the Systemic Inflammatory Response Syndrome criteria are only modestly associated with severe sepsis.

This is a retrospective evaluation of 13 years of data from the Australia and New Zealand Intensive Care Society Adult Patient Database, comprising routinely collected quality-assurance data.  Of 1,171,797 patients admitted to adult ICUs, 109,663 were identified as having both an infection and organ failure – the general, clinical definition of severe sepsis.  First, the good news:  over the 13 year study period, mortality dropped substantially – from over 30% down to close to 15%.  Then, the bad news:  12.1% of patients in the severe sepsis cohort manifested 0 or 1 SIRS criteria.  Mortality was lower in SIRS-negative severe sepsis, but hardly trivial at 16.1% during the study period, compared with 24.5% in the SIRS-positive patients.

So, the traditional SIRS-criteria definition of severe sepsis, previously thought to have at least sensitivity at expense of specificity will miss 1 in 8 patients with organ failure and an underlying infection.  Considering only approximately 1/3rd of patients with two or more SIRS criteria in the Emergency Department have an underlying infection, the utility of these criteria is substantially less reliable than previously thought.  Sadly, I’m certain many of you are suffering under SIRS criteria-based alerts in your Electronic Health Record – and, if such alerts are introducing cognitive biases by decreased vigilance and alert fatigue, it ought to be obvious we’re simply harming ourselves and patients.

“Systemic Inflammatory Response Syndrome Criteria in Defining Severe Sepsis”
http://www.nejm.org/doi/full/10.1056/NEJMoa1415236