Category: Quality

Mistakes Were Made

This is a fascinating series in Pediatric Emergency Care in which interesting cases from published medical malpractice verdicts are featured.  Each case – typically ending poorly – is followed by a short editorial on the underlying disease processes, with pearls regarding treatment, diagnosis, and the case outcome.  Reading these cases, hopefully, will not contribute to recency bias, and ideally serve simply as brief reminders of clinical features of the rare sick children lurking in the haystack of walking well.


Medicine – as much as or greater than any other profession – is a delicate mix of confidence, humility, and the recognition of the underlying biases in our cognition and practice.  Most of this blog focuses on practicing based on evidence, applying the rules and probabilities of populations as guides towards the diagnosis and treatment of individual patients.  Therefore, when reading these Legal Briefs, I simply want to reinforce the dangers of anecdote-based medicine.

“Pediatric Emergency Medicine:  Legal Briefs”

When Do Patients Need Blood Cultures?

Another lovely JAMA Rational Clinical Examination article relevant to the Emergency Department – this time regarding the utility of blood cultures.  Blood cultures are frequently requested for febrile inpatients, however, the incidence of false positive ranges between 2.5% and 8%.  This leads, unfortunately, to additional patient harms from additional treatment or observation.


This article is a systematic review of several studies gathering clinical features of patients for whom blood cultures were requested, as well as the clinical outcomes of the cultures, in an attempt to identify features predictive of positive or negative cultures.  They also examine a couple validated clinical decision instruments to determine their potential utility in stratifying the appropriateness of cultures.


Essentially, based on a few pieces of decent evidence and a few pieces of poor evidence, the authors determine a few general categories of infectious etiology with varying pretest probability for bacteremia.  These are:
 • Cellulitis, community-acquired pneumonia, community-acquired fever: low (<14%) probability
 • Pyelonephritis: mid (19-25%)
 • Severe sepsis, septic shock, bacterial meningitis: high (38-69%)


In general, however, no individual clinical feature had a positive or negative likelihood ratio of sufficient magnitude to guide testing.  Combinations of clinical features – such as patients with SIRS – were capable of excellent sensitivity & negative likelihood ratios, but only had specificities of 0.27 to 0.47.


However, the more important clinical aspect of blood cultures and bacteremia is not addressed in this article, which is how frequently the true positives even change clinical management.


“Does This Adult Patient With Suspected Bacteremia Require Blood Cultures?“

www.ncbi.nlm.nih.gov/pubmed/22851117

Empiric Measurement of Bias in Unblinded Trials

This lovely article was passed along to me by David Newman during a discussion of IST-3 – the recently infamous, massive randomized trial of thrombolysis for acute stroke.  There are two ways of thinking about IST-3, and how the results are viewed in the literature seems to depend how much funding you receive from Boehringer or Genentech.  The first way of thinking seems to be accept the results as published, pick apart the subgroups, do statistical contortions, and then either come out in the “pro” camp (Boehringer) or the “con” camp.


The second way of thinking, supported by this article, is “garbage-in, garbage-out”.  The key issue for this approach is that IST-3 is an unblinded, open trial, which introduces bias – treating clinicians and patients who believe TPA is a “promising, yet unproven” treatment (from the uncertainty principle of the study) are perceived as more likely to contribute to favorable reported outcomes when receiving the experimental intervention.  This effect is probably even more pronounced given that much of the follow-up scoring for the Oxford Handicap Scale was performed by mail-in questionnaire, rather than standardized expert evaluation – which has rather poor kappa to begin with.


Page three of this article delves into the empiric analysis of the impact of blinding, and the relative likelihood of unblinded trials to report favorable outcomes.  Essentially, the relative chance of reporting both favorable and unfavorable outcomes are significantly affected.  In clinical terms, this leads to presentation of results in which the benefits are exaggerated and the harms are minimized.  In the context of IST-3, this essentially means the likelihood of any hidden positive effects vanishes, while the poor outcomes are underreported – and it’s more “negative” than “neutral”.


The authors also note they are preparing a systematic review of trials with blind and non-blind outcome assessors, which would be particularly apt to IST-3, as well.


“Blinding in Randomized Clinical Trials: Imposed Impartiality”
http://www.ncbi.nlm.nih.gov/pubmed/21993424

Failings of Modern Medicine

A brilliant piece that eloquently states many of the ideas espoused on this blog, focusing on pulmonary embolism as the poster child for over-testing, over-diagnosis, and lack of sound evidence underlying treatment.

These authors, in the Archives of Internal Medicine, accurately describe the chimeric nature of pulmonary embolism – historically described as a dreaded disease, diagnosed clinically from the manifestations of pulmonary infarction, to the modern manifestation of filling defects noted on CTA during an episode of pleuritic chest pain.  They discuss the handful of patients who benefited from the first heparinization for treatment, and argue the disease for which anticoagulation is the treatment is not the disease we are diagnosing today.

This article covers so many excellent points, and ties the clinical problems so tightly into the underlying principles, that it’s almost the sort of must-read article to which medical students should be exposed – in order to bring about that frightening moment of maturity in medicine in which you realize the emperor is distinctly lacking in clothes.

Lovely work!

“The Diagnosis and Treatment – of Pulmonary Embolism: A Metaphor for Medicine in the Evidence-Based Medicine Era”
www.ncbi.nlm.nih.gov/pubmed/22473672

National Quality Measure for Pulmonary Embolism

The overuse of CTA in the Emergency Department and the over-diagnosis of pulmonary emboli of non-physiologic significance has been demonstrated as a significant societal harm.  In response to this, the National Quality Forum has been looking at developing a quality measure aimed at reducing CTA use in the Emergency Department.

The NQF estimated 7 to 25% of CTAs in the ED might be unnecessary.  From Jeff Kline’s shop at Carolinas, they prospectively gathered data on all their potential pulmonary emboli and attempted to determine which scans were “inappropriate.”  For their purposes, a scan was “inappropriate” if it was a low-risk patient with a negative D-dimer assay, or it was a low-risk patient without D-dimer testing.  11% were D-dimer negative and 22% were low-risk without D-dimer testing performed, which sums to 32% potentially avoidable imaging.

Of the 1,205 “potentially avoidable” scans, there were 58 positives.  The clinical significance of these potential misses is uncertain.  Whether this represents an acceptable miss rate for a quality measure in a liability prone environment is another matter entirely.

“Evaluation of Pulmonary Embolism in the Emergency Department and Consistency With a National Quality Measure”
www.ncbi.nlm.nih.gov/pubmed/22664742

News Flash: Diagnostic Tests Take Time

It’s a little more insightful than my cynical title indicates, but it is, essentially an article that tries to quantify what we already know – blood tests, MRI, and CT all add to ED length-of-stay.

While the article isn’t specifically earthshaking, it interests me in the context of patient flow through the Emergency Department and the utilization of finite ED resources.  Every ED has a waiting room – and, if you’re like me, sometimes you look at the board and there are 34 waiting – on a good day.  In that sense, one becomes acutely aware of the value of space in the ED with which to evaluate new patients.  If blood tests and imaging tests are adding over an hour to ED LOS for each of your bed, then it would seem prudent to minimize those tests whenever possible.  It might also, perhaps, even be feasible to consider “standard of care” to be a malleable concept based on a need to ration testing specifically to increase patient flow, balancing the risks of diagnostic uncertainty against the risks of prolonged waiting room times.

Just brought to mind some interesting issues.

“Effect of Testing and Treatment on Emergency Department Length of Stay Using a National Database”
www.ncbi.nlm.nih.gov/pubmed/22594356

Early Steroids Probably Better for Asthma

Not sure if this is the study that proves it – since due to ethical considerations it’s simply observational, and doesn’t control for confounders and introduces a lot of bias – but, it’s a small piece of the puzzle.

This is a cohort in a Montreal pediatric emergency department in which they prospectively collected data on moderate and severe asthma exacerbations as patients progressed through their care pathway.  They see, essentially, a nonsignificant trend in increased odds of hospital admission for patients in whom administration of systemic steroids was delayed.  This is mostly a data mining exercise, so any significant associations should be considered hypothesis generating.  However, considering the patients who received delayed steroids had milder exacerbations overall – yet still seemed to go on to have higher admission rates – it might be tempting to interpret these findings as appropriately confirmatory of physiologic foundations of treatment.

At least, there’s no suggestion of harm from early steroid administration in asthma with exacerbation in children.  Perhaps some prospective interventional data with patient-oriented outcomes will surface in response.

“Early Administration of Systemic Corticosteroids Reduces Hospital Admission Rates for Children With Moderate and Severe Asthma Exacerbation”
http://www.ncbi.nlm.nih.gov/pubmed/22410507

How Canada Does Chest Pain

Vancouver, Canada, to be specific.  The 37th most expensive city in the world to live in (ahead of New York and Los Angeles), a jewel on the coast of British Columbia, with breathtaking scenery, evergreens, rugged coasts, and mountains.

This is an observational series of their chest pain algorithm, and it falls into the category of “we do this and we like it” types of articles.  So, they do this, and they like it, and I can see why.

And the first thing you notice is that it is nothing like the United States.  Of the 1,116 patients they enrolled for this follow-up, they send home 25% of their potentially cardiac chest pain after an EKG and a single troponin.  These are patients whose mean age is 43 years old, and have TIMI scores of 0 or 1.  No outpatient stress test is arranged.  None of them had ACS within 30 days.

Another 20% had a negative 2-hour troponin and EKG and were sent home without outpatient stress testing, average age 49 years old and TIMI scores mostly 0 and 1.  None of them had ACS within 30 days.

Finally, at six hours, they were left with a group of 60 year old folks, 30% of their cohort, whose TIMI scores were >1.  They sent them all home, 25% of without an outpatient stress test and 75% with – and none of the no-stress cohort had ACS within 30 days.

Essentially, they send home over half their patients, aged 40 to 60 years old, and a couple cardiac risk factors – and they do fine.  We don’t really know what sort of coronary disease the patients discharged without a follow-up stress test had, and it means they probably have some false negatives in their outcomes at 30 days simply because they don’t receive any sort of additional diagnostic testing.  But, none of them had an unprovoked adverse coronary event, which counts for something.

About 20% of their patients referred for outpatient stress failed, and about half of those ultimately received a diagnosis of ACS – so, even then, in the patients they were most concerned about after negative ED testing, only 10% had ACS.  Seems like there’s room to improve here, as well.

It’s not crazy, it’s Canada.

“Safety and Efficiency of a Chest Pain Diagnostic Algorithm With Selective Outpatient Stress Testing for Emergency Department Patients With Potential Ischemic Chest Pain”
www.ncbi.nlm.nih.gov/pubmed/22221842

Don’t Hold It!

The hidden threat to patient safety in the Emergency Department – impaired cognitive performance secondary to suppressing the extreme urge to urinate!

Of course, this is only eight volunteers who consumed an average of 2.2 liters of water – and, by impaired cognitive performance, I mean to say they were slightly slower – but, it’s certainly suitable for an April Fool’s Day blog post.

This study shared the 2011 IgNobel Prize for Medicine.

“The Effect of Acute Increase in Urge to Void on Cognitive Function in Healthy Adults”
www.ncbi.nlm.nih.gov/pubmed/21058363

The Future of Medicine…is Defensive

At Northwestern University in Chicago, anyway – and probably externally valid to other institutions, as well.

This is a survey of 194 fourth-year medical students and 141 third-year residents regarding whether they observed or encountered “assurance” practice (extra testing of minimal clinical value) or “avoidance” practice (withholding services from patients perceived as high risk).  65% of medical students and 54% of residents completed the survey – decent numbers, but low enough to introduce sampling bias.

The numbers, of course, are grim – 92% of medical students and 96% of residents reported encountering “assurance” practice at least “sometimes” or “often”, while 34% of medical students and 43% of residents had encountered “avoidance” practice at least “sometimes” or “often” – nearly all of those being “sometimes”.  These behaviors are apparently learned from their superiors – approximately 40% of medical students and 55% of residents were explicitly taught to consider practicing defensive medicine.

Interestingly, medical students, internal medicine residents, and surgical residents all reported nearly identical levels of “often”/”sometimes”/”rarely” regardless of the behavior sampled – although surgical residents were more frequently taught to be defensive than medicine residents.

Must be a tough legal quagmire up in Chicago.

“Medical Students’ and Residents’ Clinical and Educational Experiences With Defensive Medicine”
http://www.ncbi.nlm.nih.gov/pubmed/22189882