Cardiology, Cardiology, Critical Care, Improving Outcomes, Improving Throughput, Mythbusting, Pulmonary, Radiology, Radiology

Probing the dyspneic patient.

For undifferentiated dyspnea, how would you like to have an accurate diagnosis in 24 minutes?

I love this study.

Basically, for all dyspneic patients (not trauma related, and over age 18), 10 EP’s were given an H&P, vital signs, and an EKG, as well as access to a Chest X-Ray, Chest CT, cardiologist performed echo, and labs including an ABG.

These same 2,683 patients, in tandem, had point of care ultrasound testing (lung, IVC, echo). Here’s the catch – the ultrasonographers were only provided the H&P, vital signs, and EKG then asked to make a diagnosis. The treating provider was blinded to POCUS diagnosis.

These numbers for diagnostic accuracy of POCUS are astounding.

+LR for acute HF? 22 (-LR 0.12)

+LR for ACS? 105 !!!

+LR for pneumonia? 10.5 (-LR 0.13)

+LR for pleural effusion? 95 (-LR 0.23)

+LR for pericardial effusion? 325!!! (-LR 0.14)

+LR for COPD/asthma? 22 (-LR 0.14)

+LR for PE? 345!!!

+LR for pneumothorax? 4635!!! (-LR 0.12)

+LR for ARDS? 90

Yes, for certain things like pneumonia, the difference in p-values between tradition means and POCUS diagnosis was not significantly different, but what about volume status? I cant imagine blindly giving 30 cc/kg would benefit the patient with a plethoric IVC and pleural effusion. There is some elegance a play here.

Additionally, sure, ED diagnosis for ACS had a higher LR, but they also had a cardiologist performing and interpreting echos in the ED (a rather rare siting in a US ED I would imagine) – without much improvement in their -LR (0.53 vs 0.48). For PE, the -LR of POCUS was predictably mediocre if not outright bad (0.6), while the -LR for ED diagnosis of PE, with the benefit of chest CT, was -0.10.

Now look, I get that these EP’s were quite sono-savvy. They all had 2+ years of experience, over 80 hours of ultrasound lessons & training, with at least 150 lung and 150 ED echo’s under their belt. The diagnosis was made in 24 minutes with POCUS in comparison to 186 minutes for traditional means. And while most of us can not do a year+ ultrasound fellowship, and neither can we all be as savvy with the probe as these authors (or Matt, Mike, Jacob, Resa, Laleh, etc) – it does not mean we shouldnt try. You can still greatly increase your yield just by practicing. To boot, the cognitive offload you experience by saving yourself a few hours by (correctly!) knowing which direction you are heading with a patient is an immense boon to both your mental heath & your patients well being.

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Improving Throughput, Mythbusting, Radiology, Radiology

Whaddaya Mean You Can’t Learn POCUS?

After taking a few one day ultrasound courses, a common theme amongst classmates is something to the effect of, “well, I get it now, but what about next week when the instructor isn’t there to guide me?”

Admittedly, I have wondered about the same thing; and wondered about the retention of knowledge and ability to apply what you have learned at these 1-2 day crash courses.

So you think you cant learn ultrasound? Or that you can not retain it after a weekend course? Well, those damn whippersnappers from Oregon are putting the non-believers to shame.

Medicine interns at Oregon Health & Science University were taught point of care ultrasound 3 months into their first year, as one day of a 5 day medical “boot-camp.” The day-long program consisted of 15-20 minutes of didactic training, and was followed by a 40 minute hands on session. Learners were placed in groups of 2-3 individuals and taught one-hour modules consisting of: the basics (knobology, physics, etc), CLUE protocol, FAST exam, hydronephrosis eval, and aorta & neck anatomy.  The 40 minute hands on portion was divided into 20 minutes for completing modules demonstrating pathology on SonoSim machines and 20 min for facilitator-led hands-on practice with volunteer models. (example- 20 didactic minutes learning FAST, 20 minutes on simulation, then 20 minutes on a real-live person!).  This was followed by two optional 1 hour courses done within 6 months.

A 30 question multiple choice test was administered prior to the course to all 33 interns, testing image interpretation, image acquisition/optimization, and clinical applications of ultrasound. The test was re-administered 6 months later; there was a significant drop out rate (27%), and it was untracked as to whom took the optional one hour courses.

Survey says?

Mean pretest scores – 61%

Mean post-test scores- 85%

Mean 6 month post-test scores – 79%

Great news – We probably intuitively know & retain much more than we think, but just have to continue to pick up the probe to hone our craft.  Bad news, I’m not certain that an ability to retain enough knowledge to improve a multiple choice test score is the same as making a correct clinical decision off of limited ultrasound skills.  Admittedly, POCUS in the wrong hands can be a problem, and making clinical decisions based off limited ultrasound skills and knowledge is a difficult leap to take, but its one we invariably have to make in order to grow as a clinician.

So, yeah, don’t tell me you can’t learn ultrasound.

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Improving Throughput, Mythbusting, Radiology, Radiology

Sono-guided Right IJ? Skip the chest film.

1,322 sono guided IJ central lines. Guess how many pneumothoraces.

One. Exactly one.

Overall success rate – 96.9%.

One percent of the time the catheter required repositioning. So, basically a failed rate of 2%.

Zero arterial placements.

Sure, 1,322 over a one year period is insanity (Henry Ford in Detroit, if you’re curious), and you can easily argue that a hospital that places that many central lines probably has it down cold.

Bottom line, if you are competent enough to place an ultrasound guided right sided IJ central line, you can skip the xray, especially if it is going to delay care. You do not image your femoral lines before usage, do you?

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Improving Outcomes, Improving Throughput, Mythbusting, Neurology, Neurology, Radiology, Radiology

Community EM rejoice- CT within 6 hours safe for SAH rule out.

There is yet another paper to further elucidate who should get the CT / LP work up for subarachnoids. The authors looked at six EDs over 5 years, and encompassed 2,248 patients – of which 1898 had suitable LPs for analysis (insufficient sample, exposed to light [?], blood contamination, incorrect storage or transport [?], or they just plain lost the sample). CT reads were done by on-call radiologists in training (I imagine that means residents), or by board-certified radiologists. Images were then reviewed by a board-certified neuro-radiologist OR by a board-certified general radiologist for a final report. There was no “time limit” from onset of headache for exclusion (ie, patients did not need to be scanned within six hours).

92 patients of the 1898 patients were positive for blood via spectrophotometry – 4.8%. Nine of these positives ended up having a subarachnoid hemorrhage (9.8% of their LPs, or 0.47% of patients). What do these nine patients generally have in common? Six of them had a headache for a week or longer. One had a previously coiled embolism. One had a negative CT performed within 3 hours of onset.  All of these nine patients got coiled or clipped.

So, what do we make of these? If you present within 6 hours with a negative CT (or, dare I say, less than a week!), you have a 0.053% of having a subarachnoid. If you still do the LP in those <6hours from onset (or, <1 week from onset), the baseline risk of a false positive is 10% vs 1.1% chance of true SAH.

Time for some well-informed shared decision making, and perhaps a higher threshold for those that present with a prolonged headache.  Further good news to take away from this study- it does not seem as neuro-radiologists need to make the call and that the <6 hour proposal can be safely extended to the community setting at this point.

 

(First link is to free text of article.  Pubmed did not have a working link to the paper at time of post.  If the first link does not work, try here)

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Improving Throughput, Mythbusting, Radiology, Radiology

Who is really distracted by distracting injuries?

Those that (still) recommend the pan-scan in trauma, it would seem.  Over a once year period, this 803 patient prospective study (451 of which with distracting injuries) evaluated all awake, alert, blunt trauma patients with a GCS of 14-15 to determine the validity of an abdominal exam.  Endpoints were injuries which required the OR and those which required a transfusion.

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A ten percent failure rate of the abdominal exam for an intra-abdominal injury seems rather high, but this is ten percent of all who actually had an injury. When you consider “all-comers,” it’s more like 1.1% of those with a distracting injury and 0.57% for those without a distracting injury.  With that, you would need to scan over a hundred patients to find one intra-abdominal injury that you would have otherwise missed.  Throw in the fact that all five missed injuries in the distracted cohort had solid organ injuries, and that none of them required surgical intervention or blood transfusion, and you can see how the authors come to their conclusion:

These data suggest that clinical examination of the abdomen is valid in awake and alert blunt trauma patients, regardless of the presence of other injuries.”

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Critical Care, Improving Outcomes, Improving Throughput, Mythbusting, Neurology, Radiology, Radiology

Patient Backstabbing in the Age of SDM

11 non-academic hospitals reviewed 760 consecutive patients who had a brain CT for an acute headache that was followed by an LP 12 hrs from the onset of headache from January 2007 to January 2013.  These 11 centers diagnosis roughly 250 subarachnoid bleeds annually.  In this study, the patients presented within 6 hours from onset of the headache, and all had a negative CT read by staff radiologists, and were independently reviewed by two neuroradiologists and one stroke neurologist.  At these 11 centers, of the 760 patients with a negative CT read by staff radiologists, 52 patients had CSF positive for bilirubin (7%).  Of these 52 patients, there was one patient identified to have a non-aneurysmal perimesencephalic SAH on repeat review of the images.  This one patient had a benign outcome.  There were 8 others who had an aneurysm on CTA, DSA, or MRA  (3 of which had been previously coiled).  All of them were deemed as having rupture unlikely for various reasons (RBC <100, no bilirubin on spectrophotometry, etc).

So, with a negative CT read at a non-academic center by non-neuro radiologists, at the high end, we have a 1 in 760 miss rate if we *only* miss perimesencephalic bleeds on CT.  These types of bleeds account for about 5% of SAH, so, potentially, at the low end, we are looking at a miss rate of 1 in 15,200.  Essentially, the lumbar puncture is not a very useful test to diagnose SAH – with a posttest probability of 1.9% in cases with a positive CSF spectrophotometric result (a previous study reported about 8% PPV for xanthochromia)

Unfortunately, it is not mentioned how SAH was diagnosed throughout the study period.  It would be nice to know if they were made via CT in the ED, as that would help solidify the author’s suggestion that CT/LP is a dinosaur in the age of shared decision making.  Speaking of which…

I’ve had a few colleagues who have said, “show them the needle” as a somewhat subversive way to have patients either sign AMA or a refusal to consent for an LP for a subarachnoid hemorrhage.  Few, if any, have actually said, “tell them the evidence.”

What sounds better to you for well informed shared decision making?

A) “You could die from this. You need a spinal tap. If you don’t do it, you could die.”

B) “Ultimately, I think your risk of a bleed is low, but I want you to understand that there is significant consequences to a subarachnoid and over half of those diagnosed may die.  With that said, studies show that with a normal CT scan, your risk of having this condition is well below 2%.  “Normal” spinal tap results performed 12 hours from the onset of your headache helps to further reduce your risk, but also comes with a significant number of false positives.  While an abnormal spinal tap is concerning for a subarachnoid, it is not specific, and you will likely require admission for further testing if your spinal tap is abnormal.”

 

more reading on this:

http://stroke.ahajournals.org/content/43/8/2031.long

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Improving Throughput, Mythbusting, Radiology, Radiology

Hocus POCUS, legal mumbo jumbo.

First, there was “Failure to Perform”, then the next hot legal topic, “Failure to Perform in A Timely Manner,” took stage.  We are in an age where there is a “Golden Hour” for everything – time to antibiotics, time to lysis, time to cath lab – and if you have been lucky enough to attend the ACEP Scientific Assembly over the last few years, you’ve likely heard that the legal landscape is changing to reflect this.  Legal teams are now privy to the fact that ultrasound training is now mandatory in EM residencies, and we are beginning to see legal outcomes in which POCUS has played a role – though its legal role probably is not what you think.

Like many community ED docs, you are probably uncomfortable doing POCUS.  Perhaps you don’t have the fancy machine you did in residency.  Perhaps you are concerned it increases your liability, and you wonder why you would do it when radiology has a better machine and your institute has radiologists to share the wealth (and the lawsuits!).

First, one previous paper exists examining the liability of point of care ultrasound (POCUS).  Admittedly, this was a 2012 paper looking at 1987-2007, and I would think POCUS has grown exponentially since that time.  Regardless, of the 659 available POCUS cases examined, none were related to misinterpretation- but there was one was for failure to perform POCUS! Now a second study looks at the Westlaw database reviewing cases from January 2008 to December 2012 involving EPs and POCUS.  Here they are:

study

 

Five cases in four years when POCUS is starting to take off.  Without playing armchair quarterback too much, I’ll simply state that one of the central issues was that POCUS was *not* performed in all of the above cases.  There were two other cases in which POCUS was not performed (intra-ocular foreign body after multiple beestings; dyspnea in a patient ultimately found to have acute mitral valve insufficiency on ECHO), but the counterargument was that these indications (intra-ocular FB, valvular evaluation) were not part of ACEP core applications & thus outside of the EPs scope.  So what are ACEP’s Core Applications for Ultrasound? Trauma, IUP, AAA, cardiac, biliary, urinary tract, DVT, soft tissue/musculoskeletal, thoracic, ocular, and procedural guidance.  That’s quite the range, and for a more detailed explanation, ACEP’s clinical policy on sono can be found here (opens pdf, specifics start around page 20)

There you have it.  The precedent has been set. The failure to do POCUS for one of ACEP’s Core Applications in a timely fashion actually puts you at more risk then if you had performed POCUS.  There has yet to be a case on public record to dispute this.  POCUS.  Learn it.  Use it.

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