• Home
  • EMCrit-RACC
  • PulmCrit
  • IBCC
  • EMNerd
  • Tox & Hound
  • About
    • About EMCrit
    • About PulmCrit
    • EMCrit FAQ
    • Subscription Options
  • Contact Us

EMCrit RACC

Online Medical Education on Emergency Department (ED) Critical Care, Trauma, and Resuscitation

  • Airway
  • Archives
You are here: Home / EMCrit-RACC / Imaging in Pulmonary Embolism (PE) Algorithm

Imaging in Pulmonary Embolism (PE) Algorithm

July 3, 2011 by Scott Weingart 70 Comments

 

Based on Master Nickson's comments on the PE debate, you could argue this would be an acceptable paradigm. Using Wells as your entry forces gestalt into the equation. Since Wells' low risk arguably gets you somewhere between 1-6% in ED populations, PERC should be acceptable.

Update:

PE DX by Jeff Kline

Clinical Guidelines from ACP include intermediate d-dimers, age-adjusted d-dimer (Ann Intern Med 2015;163:701)

Likely pretest prob patients are ruled out by neg CTA (Safety of multidetector computed tomography pulmonary angiography to exclude pulmonary embolism in patients with a likely pretest clinical probability.  J Thromb Haemost. 2017 Jun 2. doi: 10.1111/jth.13746.)

Normalization of Vital Signs does not reduce probability of PE (https://coreem.net/journal-reviews/vs-normalization/)

  • Author
  • Recent Posts

Scott Weingart

An ED Intensivist from NY. No conflicts of interest (coi).

Latest posts by Scott Weingart (see all)

  • EMCrit 260 – Thoughts on the NEJM Acute Upper Airway Obstruction Review - November 30, 2019
  • EMCrit 259 – Cardiogenic Shock — The Next Level & Mechanical Circulatory Support with Jenelle Badulak - November 13, 2019
  • Letter to the Editor – High-Sensitivity Troponin is not a Myth, and “Myth-busting” is often another Myth to be Busted - November 10, 2019

Share this:

  • Facebook
  • Twitter
  • Reddit
  • Pinterest
  • Email
  • Print

Filed Under: EMCrit-RACC Tagged With: misc

Cite this post as:

Scott Weingart. Imaging in Pulmonary Embolism (PE) Algorithm. EMCrit Blog. Published on July 3, 2011. Accessed on December 11th 2019. Available at [https://emcrit.org/emcrit/imaging-in-pe-diagram/ ].

Financial Disclosures

Unless otherwise noted at the top of the post, the speaker(s) and related parties have no relevant financial disclosures.

You finished the 'cast,
Now get CME credit

Already an EMCrit CME Subscriber?
Click Here to Get CME Credit for the Episode


Not a subcriber yet? Why the heck not?
By subscribing, you can...

  • Get CME hours
  • Support the show
  • Write it off on your taxes or get reimbursed by your department

Sign Up Today!


.

Subscribe Now

If you enjoyed this post, you will almost certainly enjoy our others. Subscribe to our email list to keep informed on all of the Resuscitation and Critical Care goodness.

This Post was by the EMCrit Crew, published 8 years ago. We never spam; we hate spammers! Spammers probably work for the Joint Commission.

70
Comment Here

avatar
We may delete without a full, true name
Your Job (i.e. intensivist, CCRN, etc.)
50 Comment threads
20 Thread replies
0 Followers
 
Most reacted comment
Hottest comment thread
18 Comment authors
PaulPaul rnSeth TruegerDuncanMartin Recent comment authors
avatar
We may delete without a full, true name
Your Job (i.e. intensivist, CCRN, etc.)
newest oldest most voted
Mike
Guest
Mike

Ok Weingart, i’ll bite. Fueled by the fact that i am post shift, it is 3 am and the dogs woke me up and i have had a beer. This algorithm is completely nuts! Maybe i am an ignorant slut but…….. PERC was studied and validated as a stand alone rule to obviate the need for testing AT ALL. Unless Jeff Kline has done a bunch of new, large studies incorporating PERC + dimer or PERC + Wells or PERC + wells+ dimer then all of these new algorithms are just more mental masturbation strewn with unproven assertions and leading us down the garden path. Even Kline, in a recent podcast somewhere advocated the use of PERC + dimer in pregnant women, but he had the decency to say it was based on nothing but his opinion (ah, the glory days oc critical thinking and the fallacy of reference to authority!). Think about it, PERC and Wells overlap so much that the addition of them doesnt gain you much other than a couple more criteria you have to meet to not do the workup. You cannot, nor should you attempt to rule out every PE. The vast majority of PEs… Read more »

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

Mike,

You lost me there. PERC negative in the diagram = stop w/u; no d-dimer or imaging.

PERC use already acknowledges that we are not trying to get to zero risk. The diagram is built-in acceptance of the 2% acceptable miss threshold.

Tell me my friend where we have parted ways on our journey????

Vote Up0Vote Down  Reply
8 years ago
Paul rn
Guest
Paul rn

Hi Scott

I’m an rn. Just wondering. Stable looking patient. Absolutely no distress. Reports some recent sob and generalized weakness (has a hard time getting things off the shelf at his job as a dishwasher. Dry cough. Hr 107. 35 male. 101.4. 1 episode of blood tinged sputum “a little bit”.

Was worked up for pneumonia. Cxr normal. WBC nl.

Resident was suspicious for pe. Now is like “ok ctpa for pe”.

Is it ethical to send this patient for a ctpa without sending a d-dimer? I did not protest but it seems like the chances of this pt dying in front of me are extremely low vs the risk and expense of irradiating him for what ended up being a negative ct.

Any thoughts? I feel like I should have spoken up.

Looks like wells criteria makes him a 2.5.

I’ve seen this recently, going straight to ct with no d-dimer on a patient who’s not too far from falling asleep. I’m not sure what difference 45 minutes would make to wait for the test.

Would love your thoughts?

Thanks
Paul

Vote Up0Vote Down  Reply
5 years ago
Paul
Guest
Paul

Perhaps more succinctly: is it ever ok to scan a stable patient without a d dimer?

Vote Up0Vote Down  Reply
5 years ago
Martin
Guest
Martin

You are partly right Mike.
PERC can be used in this setting but after the Well’s moderate arm. Well’s low is low enough, we do not need to double check this one, but if you get a moderate just double check with PERC- if it passes PERC do not bother with a D-dimer.
Personaly I do the opposite- if someone fails PERC, I go on to do a Well’s to see if I can stop doing a D-dimer. This was very elegantly suggested by Dave Newman in his PE talk on smartem.org

Vote Up0Vote Down  Reply
7 years ago
Scott Weingart
Author
Scott Weingart

Martin,

PERC can absolutely not be used after Wells moderate, not sure where you got that. As to Wells low being low enough, that is merely conjecture at this stage. David’s assertion very well may turn out to be true (most of them are), but the evidence is contradictory and you certainly are unlikely to get below 2% unless you are including a bunch of pts who should not get a PE work-up in your cohort.

Your assertion that a moderate Wells can be ruled out with PERC is dangerous and not even suggested by David.

Vote Up0Vote Down  Reply
7 years ago
Haney Mallemat
Guest
Haney Mallemat

If I understand it all correctly, PERC was intended to rule out someone who is low risk for PE by clinical gestalt. Adding Wells to the mix permits an objective way to call a patient low-risk. I completely agree with the point Dr. Jasumback that we should not try to find and treat every single PE, however I do not think that we need a randomized control trial to validate the algorithm above because it makes sense and was built into PERC as clinical gestalt (…aren’t prediction rules simply objective clinical gestalt anyway)?

Haney

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

Haney, absolutely correct! In fact most people are not using the PERC as it was validated, b/c they are supposed to first ask themselves the question of whether they believe the chances of PE are <15% before they even think about using PERC. Unfortunately as Nickson and other listeners have pointed out, this is still not objective b/c the only thing we are using Wells for is to get the gestalt piece.

s

Vote Up0Vote Down  Reply
8 years ago
matt
Guest
matt

S,
Sober and well-rested, and your diagram looks good. in short, PERC helps you find those patients whose pre-test prob of PE is below the d-dimer test threshold. also, of important note, it was validated on patients who stated “Shortness of breath” was the reason they came to the ED (or, of equal importance to cc), so applying it to every misc “chest pain” patient is a bit of an EBM stretch… Although seems to be done on a routine basis. interested in your thoughts…
Matt
EMCC

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

Matt, do you mean Wells or PERC for SOB. Wells has been done on a ton of different ED populations, and in all the low risk is <6% (safe for PERC territory). PERC has also been looked at in a few, though less, ED populations; though as Dr. Newman points out nobody has yet done the study where you use PERC and send the patient home based on it and then follow these patients rather than just collecting PERC and seeing if they have a PE or not.

s

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

Updated the diagram with an important first question

Vote Up0Vote Down  Reply
8 years ago
Mike Jasumback
Guest
Mike Jasumback

Scott, I think it was around the 2nd beer that things might have gone south, but perhaps not…… More succinctly this time, then. My understanding of PERC is that PERC negative gets you to no testing. I’d have to go back an look at the derivation and confirmation studies. But basically I think it went something like, I think this pt COULD have a PE. If PERC- then no testing. But now we’ve added stuff. So now it takes WELLS low + PERC – to get to no testing. And I don’t know that that assertion has been tested. With respect to Wells moderate plus d-dimer , your algorithm tells me that a Post op pat, HR>100 and history of PE plus hemoptysis can be ruled out with a neagitve d-dimer and that doesn’t meet the smell test. Haney is right, decision rules are “objectified gestalt”, but I daresay that most of us would not rule out the above pt with a d-dimer (the dimer is going to be positive anyway since he is postop, but maybe not at 4 weeks?). I’m not sure that that helps any, but from our previous emails, THIS IS PRECISELY THE TYPE OF DISCUSSION… Read more »

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

PERC was validated by first asking the clinician what their gestalt is for PE. If you do Wells’ first, all this adds is it forces you to answer this gestalt question. Nothing else in Wells’ is different than PERC (even malignancy alone doesn’t take you away from low). No need for validation, this is just a way to get people to do what they are supposed to do any way.

Not sure of the smell test, but high sens d-dimer is probably superior to most imaging we have available. The numbers are there in countless studies. ACEP’s clinical policy will support you in this practice as well. With the current crack-down on radiation, if your hospital doesn’t have a high-sens d-dimer then they probably should be getting one ASAP.

The d-dimer is going to be positive anyway probably doesn’t ever hold water b/c sometimes in that 85 y/o it actually comes back negative, especially with the higher spec of the newer versions of the high-sens d-dimers.

cheers my friend

p.s. i like you with a few beers in you; you get all fiery.

Vote Up0Vote Down  Reply
8 years ago
Mike Jasumback
Guest
Mike Jasumback

One more thing…

What this illustrates is the problem in all of clinical medicine, the a priori point estimate of probability of disease. This is not, and can never be, objective. Why, because you have to start somewhere.
In your new algorithm, the first box illustrates that. What is that driver, that symptom complex, that gut instinct that gets you to “This patient might have a PE” ? It is from there that you have to generate a point estimate of disease probability, appropriately use a tool of some sort that has been verified in a population (but most likely not using your undefined clinical gestalt), to push your post test probability to an acceptable risk range.

Mike

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

I don’t look at it as a problem, I look at it as the reason for our existence. If everything could be protocolized, what is the point of physicians?

Vote Up0Vote Down  Reply
8 years ago
Burns
Guest
Burns

Scott, I like the thought process and algorithm, but Newman has made the point that PERC and Wells are mutually exclusive and can be used separately; if either is negative the workup can stop. However, I generally use them together as well, though I might move PERC above Wells in the algorithm. i.e.–PERC negative => stop the workup, PERC Positive => Apply Wells criteria as you have written. This makes a little more sense from a binary perspective. I don’t think you need the first question either, since that is already addressed in the clinical gestalt portion of PERC. I think Mike makes some great comments above–I get to reply only because I am equally impaired. I just woke up from the overnight shift, have had only one cup of coffee and am still fuming that there doesn’t seem to be a single hand surgeon in the country taking call on the one day where getting drunk and holding onto firecrackers or as long as possible becomes the national pastime– sorry digression) “It is my belief that espousing these attempts to get to zero risk causes far more harm than good and people advocating this approach are effectively establishung [sic]… Read more »

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

Only reason for the first question is that some have started using PERC and d-dimer as SCREENS for PE, which actually increases imaging rate instead of decreasing it. This is one point that Dr. Newman and I agree on. If you don’t think the patient has a PE, don’t do PERC, Wells, or d-dimer…

Vote Up1Vote Down  Reply
8 years ago
Burns
Guest
Burns

I agree that inappropriate use of D-Dimer (and medical decision make rules in general) is a travesty in medicine, but for the purposes of building an algorithm I’d put clinical gestalt in there only once. I think PERC uses a suspicion of <15% which is probably adequate for the first question.

JB

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

Don’t mean to belabor this, but nope. First question asks you is your pretest < 2% before starting a work-up--if so stop. PERC gestalt question asks you, "Ok, it is >2%, but is it < 15%?" Two very different questions.

Vote Up0Vote Down  Reply
8 years ago
Burns
Guest
Burns

I think it gets hard to quantify gestalt, but I see your point and that does make more sense in the context of the algorithm. . .thanks for the forum.
JB

Vote Up0Vote Down  Reply
8 years ago
Mike Jasumback
Guest
Mike Jasumback

Maybe I misunderstood PERC (and I haven’t gone back and looked at the validation study) but I thought it was stand alone for the low risk pt (<12-15% ), and that's where my hearburn lies. I have always found that the clinical gestalt and Wells rules aligned closely enought that I never applied Wells formally to get to that low risk number.
I have also undestood that the low risk pt (<12-15%) with negative d-dimer got the post-test probability low enough to stop testing.

As for the clinical assesment question, I agree, that is the reason for our existence as physicians. I've always said, people pay me for my judgement and not much else.

And as for beers, if I make Essentials, I'm buying

Mike

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

Mike,

Absolutely true, you have no need of Well’s before PERC, you can just answer the gestalt question. When you put Wells next to PERC what you will find is the only thing putting it before PERC does is makes you answer the gestalt question. There is no other effect.

Good d-dimer will take your low and

    intermediate patient

to a post-test below test threshold.

as to essentials, sounds good!

Vote Up0Vote Down  Reply
8 years ago
Mike Jasumback
Guest
Mike Jasumback

And by the way, don’t you people have lives? It’s the 4th of July for Gods sake. Go hold a firecracker or something. (just don’t do it in far northern California, I don’t have a hand surgeon either)
At 3 am there were no comments on this now we are at what, 20? We need lives..

oh well, sober, moderately well rested and off to the 4p-1a shift, yippeee

Mike

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

I’m working; I don’t know of the others’ excuses, but remember most of our audience is not in the States and some probably rue the 4th as loss of domain.

Vote Up0Vote Down  Reply
8 years ago
Mike Jasumback
Guest
Mike Jasumback

Scott,

Reference for the Intermediate Probability Pt? I’ve been using dimer for low prob pts. But not brave enough to get into those I’d call intermediate i.e. >12-15% pretest probability

Mike

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

Here are just a few from a quick search, there are quite a few more out there:

Thromb Haemost 1998;79:32–7.

Arch Intern Med 2001;161:447–53.

Hematology. 2009 Oct;14(5):305-10.

AJR Am J Roentgenol. 2009 Aug;193(2):425-30

Systematic Reviews
Thromb Haemost. 2009 May;101(5):886-92.

Vote Up0Vote Down  Reply
8 years ago
matt
Guest
matt

S,
I meant PERC, but mea culpa, while the initial PERC validation was limited to those SOB pts, indeed the larger prospective MCT validation included almost half with cc of CP…
Thnx, lead on,
Matt
(less rested, less sober… Happy 4th!)

Vote Up0Vote Down  Reply
8 years ago
trackback
The LITFL Review 025 - Life in the FastLane Medical Blog

[…] fall in to place, leading to Master Weingart coming up with the following excellent diagram for Imaging in PE Diagram. Well worth listening too!!! Image from: […]

Vote Up0Vote Down  Reply
8 years ago
Minh Le Cong
Guest
Minh Le Cong

Hi Scott et al
I love it when you Yanks get drunk and have a fight!

I had questions about imaging and your proposed algorithim, please. What imaging do you refer to?

And in the Wells criteria HIGH RISK in your algorithim you proceed straight to imaging. If that is reported as negative, what would you do next? Perform a sens D Dimer and back track? Or rely on your gestalt and ignore the imaging report?

thanks and appreciate the debate here for my own learning

Vote Up0Vote Down  Reply
8 years ago
Chris Nickson
Guest
Chris Nickson

Hi Minh and the rest of the EMCrit crowd, This what we do at Charlies once we’ve decided we need to do imaging (i.e. low/int PTP and positive D-dimer OR high PTP based on Wells with D-dimer not indicated): CTPA negative • Rules out PE if low or intermediate PTP on Wells score • If high PTP do CTV or leg USS – if negative then NO PE CTPA positive • PE regardless of low/ int/ high PTP Certain patients we don’t (usually) do CTPAs on: • Female <45y • Pregnant • CTPA contraindicated These patients have VQ SPECT (ideally with no underlying lung disease and a normal CXR for best results): • Negative – rules out PE even if high PTP • Positive – diagnoses PE except if low PTP – then get a leg USS, which if negative may need to be followed up with a PE. Also, we have a highly sensitive D-dimer assay that rules out PE if the Wells score is low or intermediate PTP. Exactly what you do depends on the performance specs and the various types of imaging modalities you have at your disposal at your institution. I agree with all of Scott’s… Read more »

Vote Up0Vote Down  Reply
8 years ago
Casey
Guest
Casey

HI all
I have a neologism for you, one I constantly employ – lets call it “schizogestalt”.
Definition: Schizo`ges`talt
This is when you have a patient referred by helpful nearby doctor who orders a blunder-bust of blood tests including a D-Dimer – which is weakly positive, then sends the patient in for a ?PE workup to ED. The patient looks great, healthy, and maybe has a few risk / Well’s points. However, it all hangs on the big 3 points for: “PE is most likely diagnosis”.

So here is what you do – you split your brain in half and try and work out your ‘gestalt’ whilst ignoring the knowledge that the D-Dimer isn’t quite normal. This requires a healthy degree of self-delusion. Cos’ I reckon once we see the + D-dimer we get all iffy about not imaging, no matter how low the Well’s score is.

So work on your schizo-gestalt, you might irradiate less folks!
Casey

Vote Up0Vote Down  Reply
8 years ago
Andy Webster
Guest
Andy Webster

The minefield that is VTE…..so many different pathways so many different views. Should keep researchers in a job for many a year to come. At the same time will mortality and morbidity from VTE actually reduce, or we we just find more small PE that would never cause harm?

Vote Up0Vote Down  Reply
8 years ago
seth
Guest
seth

“At the same time will mortality and morbidity from VTE actually reduce, or we we just find more small PE that would never cause harm?”

This was in the discussion but the Weiner paper in May 2011 in Archives of Internal Medicine answers that pretty definitely as the latter:

http://www.ncbi.nlm.nih.gov/pubmed/21555660

Wiener RS, Schwartz LM, Woloshin S. Time trends in pulmonary embolism in the United States: evidence of overdiagnosis. Arch Intern Med. 2011 May 9;171(9):831-7.

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

great reference, Trueg!

Vote Up0Vote Down  Reply
8 years ago
Andy Neill
Guest
Andy Neill

Great stuff guys enjoyed watching the video till the 60 min mark and my cellphone bandwidth allowance ran out! I’m on holidays and away from the joys of broadband! My two cents (or maybe more than that…) I think Scott’s added question (do you REALLY think it’s a PE) in the image is key – the thing with all the PE studies is that someone has to suspect a PE as a possibility to even get into the study and have the 50 point data sheet used. So the factors that go into why a doc enrolls them in the study are really important. As Master Nickson says, the gestalt is the most important part of the rule. I would argue that the gestalt comes even earlier before the rule is even derived. I have seen multiple cases of truly asymptomatic PE (my own Dad being one!) – incidentally noted in ICU patients and cancer patients picked up on scans for other reasons – these type of patients aren’t even covered in these studies as no one suspected it. Which is why I think we’ll always be a bit buggered when it comes to PEs. Wells and PERC are useful… Read more »

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

First, thank you all for the incredible comments!

To answer some of the questions posed in the thread:
imaging
We use CTPA for pretty much everyone, unless their renal function is crap. My personal belief (and I think Jeff Kline’s as well) is that even in high risk, a well done CTPA negative = done. PIOPED II unfortunately got it totally wrong. I believe an angiogram is no better than CTPA at this point, and a negative CTPA probably predicts pts with a good prognosis without treatment.

I think it is clever to get d-dimer in the high risk pts as well, b/c a neg CT and a neg d-dimer and you are definitely done. If they are high risk, it is also cheap and easy to get a bedside sono of the deep veins. High risk get f/u for formal dvt study as an out-pt.

Andy
David and I discuss points very similar to the ones you discuss in the last 30 minutes–great minds think alike.

Vote Up0Vote Down  Reply
8 years ago
Minh Le Cong
Guest
Minh Le Cong

thanks Scott et al

I am not convinced by your advice to perform a D Dimer in the high risk patient with a negative CTPA. It would seem more logical to do the cheaper , radiation free test first in the high risk group. What would you do if you had a +ve D Dimer and -ve CTPA in a high risk patient?

Could you not assess for Wells criteria and if high risk then do the D Dimer. If positive you treat? If negative then you are done? With safer anticoagulation options already for things such as AF and likely DVT/PE in the near future I imagine empiric therapy is more practical and reduces diagnostic workup

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

Minh,
D-dimer is a non-specific test: positives mean virtually nothing. Certainly not enough to move even a high risk patient above the “treatment” threshold. High risk patient with Neg CTPA and + d-dimer needs a dvt study, whether it is bedside or formal ultrasound or CT leg veins based on the current evidence.

Giving a false + dx of PE has ramifications far in excess of the initial anti-coag. Every time this patient comes to an ED with chest pain, sob, or tachycardia they are going to wind up with a PE w/u. They will have problems getting life insurance and health insurance will be more expensive. And anti-coagulating a 75 y/o is a lot different than a 35 y/o being that the latter may still want to engage in sports, skiing, etc.

Vote Up0Vote Down  Reply
8 years ago
Minh Le Cong
Guest
Minh Le Cong

Scott, I admire your energy for teaching and debate when you are up posting at midnight! I don;t think the issue is as black and white as it may initially appear. Andy is right that this is a grey area of clinical practice. Take the use of gestalt in the decision making. This is so non standardised that its use is hard to define. In essence we are saying gestalt=clinical experience and that as we know is not something uniform nor standard. It is as you say the reason why we still need human brains in point of care medicine. I am aware of gestalt getting docs into a lot of trouble when treating hypotensive, tachypnoeic pregnant women for suspected PE and pushing heparin when it has been a ruptured ectopic or AFE from uterine rupture. AS for the CTPA and imaging I find this even more grey as it depends upon the interpretation and provider. I have had two radiologists report the same CTPA differently and in the end you got to make a clinical call in regard to advising the patient on diagnosis and therapy. In pregnant women we see this all the time where CTPA is not… Read more »

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

Minh-of course we will always need to be clinicians in the gray zones.

I’m not sure how I am contradicting myself. The nature of a sensitive, non-specific test is that a negative can have dramatic effects on your w/u, while a positive doesn’t affect your probability and you continue the w/u as if the test did not exist. If there was no such thing as d-dimer, you would need to proceed to further testing after a negative ct in a high risk patient (at least in the vision of the US organizations), so you do the same in the case of a positive d-dimer.

Vote Up0Vote Down  Reply
8 years ago
Minh Le Cong
Guest
Minh Le Cong

thanks Scott

What if you were in a remote area, like Antarctica? You got someone with High risk Wells presentation and positive D Dimer? Do you wait for the CTPA before starting anticoagulation?

Sure you can get a portable USS for DVT but if that is negative do you still wait for the CTPA in the tachycardic, tachypnoeic, pregnant patient? Even though it will take 3 days to retrieve them to a CTPA machine? And by that time the PE signs may have resolved on imaging?

Vote Up0Vote Down  Reply
8 years ago
Domhnall
Guest
Domhnall

2 things – why would you even bother with a d-dimer in this high risk patient in Antarctica? And secondly, in general the selection of people to head South tends to avoid sending pregnant women…as for what happens when folks get there, well, I have heard some stories…

Vote Up0Vote Down  Reply
8 years ago
Minh Le Cong
Guest
Minh Le Cong

OKay good point, my use of pregnant patient was not the best example. My point really is what would you do if you had to wait a few days, weeks to get your CTPA in that high risk patient. Is it so vital to your diagnostic workup that you simply cannot do anything until you get that CTPA?

Vote Up0Vote Down  Reply
8 years ago
Andy Neill
Guest
Andy Neill

Just watched the last 30 mins of the video, i now see how my comments are kind of redundant!

If you’re so afraid of getting sued in the US over non-diagnosis/treatment of PE then you can do the trial here in Ireland as we’re almost a 3rd world country these days and can’t afford all the CT scans so we’d love a reason not to do them!

Vote Up0Vote Down  Reply
8 years ago
trackback
PE: Pain, Puzzles and PERC - Life in the FastLane Medical Blog

[…] emerging from the blood spattered PE arena, Scott posted a nifty flowchart summarising a reasonable approach to using Wells, the PERC rule and clinical judgement to decide […]

Vote Up0Vote Down  Reply
8 years ago
Mattia Quarta
Guest
Mattia Quarta

Sounds great and reasonable.
Although the starting questionI think is really the key point.
Nonetheless if you really (really!) start thinking about PE in a let’s say young patient healthy looking shound’t you answer yes to the tricky question: PE is the first diagnosis or equally likely?
I guess everyone has felt uncomfortable with this criteria of the Wells’ score in the very beginning of his residency, since the question is cloudy enough to be a test of self confidence. With time I’ve started thinking it was subtly included to solicit cliniacians to wonder whether it is really worth to go on with the work up rather than increasing the risk of the patient yo’ve been evaluating.
Therefore I’m asking wound’t it be more useful to use the Geneva score? It won’t have any overlap with the PERC rule and it’s more objectuve. Proabably the math do not allow this.

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

Mattia,

That is exactly what I used to advocate. Low risk geneva should take you below 15%, which seems perfect for the PERC rule application–it was beautiful! Until Hugli’s article (pubmed link) showed that low risk geneva negative PERC still has a post-test prob that is too high.

Vote Up0Vote Down  Reply
8 years ago
Mattia Quarta
Guest
Mattia Quarta

Definitely have missed that pubblication and maybe quite a lot relevant others. I’ll go through it eagerly, and eventually leave the kids with any excuse to grandma more frequently.

I’ve read all the comments now and I apologize since my post was largely inapt beeing the answer

Vote Up0Vote Down  Reply
8 years ago
Mattia Quarta
Guest
Mattia Quarta

already adressed by Nickson.

One more thought if you allow me: do we all have the perception that a certain amount of episodes of small PE occurs probably with no or subtle symptoms all life long. As if it might be a sort of physiological process as much as atherosclerosis is for the non pulmonary circle? After all centuries of natural bleeding selection should have favoured thrombophilic profiles.
Consequently

Vote Up0Vote Down  Reply
8 years ago
Mattia Quarta
Guest
Mattia Quarta

A small amount of small PE that cause some pleuritic discomfort whether or not accompanied by mild dispnea could be tolerated as just overnatural events without any anticoagulation therapy?

Scott Keep going with the PE brain-storming it’s just great!

Mattia

Vote Up0Vote Down  Reply
8 years ago
Scott Weingart
Author
Scott Weingart

Thanks Mattia!

Vote Up0Vote Down  Reply
8 years ago
Domhnall
Guest
Domhnall

In response to Mattia’s penultimate comment above, the AHA’s March 2011 paper speaks to the concept of CTEPH (Chronic Thromboembolic Pulmonary Hypertension) which appears to be fairly nebulously attributed to “one or more” previous PEs, despite stating that “up to 63% of patients with CTEPH were not previously aware of having had a PE.” I have a few doubts about the breadth of this link to begin with, and one wonders if there is a bit of a backlash in the “establishment” to the idea that perhaps we shouldn’t be panicking so much about finding every last tiny little subclinical (and even physiological) PE. I am prepared to accept that a couple of big PEs is going to end up giving you pulmonary HTN, but I struggle with the “63% not knowing they had a PE” that is quoted in the paper, which would suggest that CTEPH could come from subclinical PEs – There doesn’t appear to be any real evidence for this on my reading, but I must admit I did lose interest in what is a fairly tedious and involved document. (Management of Massive and Submassive Pulmonary Embolism, Iliofemoral Deep Vein Thrombosis, and Chronic Thromboembolic Pulmonary Hypertension –… Read more »

Vote Up0Vote Down  Reply
8 years ago
Steve
Guest
Steve

Pretty late to this discussion but I’ll throw in my 0.02…I think this diagram is the way that we all have been practicing for a while…however I love the first step…”Do you think it’s a PE” and if the answer is no, stop there. That way we don’t even mess with Well’s or PERC or anything else- we just say NO and move on.

I haven’t been explicitly using Well’s to risk stratify people before using PERC but in reality I have been doing that on a subconscious level. I agree with the use of the d-dimer- if you have someone who is otherwise low risk but PERC positive (usually its tachycardia or on OCPs) then that is where a d-dimer comes in. Otherwise, don’t order that $%$#! test.

Don’t get me wrong, I love PERC…if we could find other variables to replace OCPs and tachycardia then we could avoid testing on even more people.

Vote Up0Vote Down  Reply
8 years ago
trackback
“Time trends in pulmonary embolism in the United States: evidence of overdiagnosis..” Archives of internal medicine 171 (9) (May 9): 831–837 | Emergency Medicine Ireland

[…] Found this via a chap who commented on Weingart’s now famous PE episode. […]

Vote Up0Vote Down  Reply
8 years ago
trackback
Medical Decision Tree for PE | Med Algorithms

[…] followed by the PERC rule to decrease the risk to less than 2%.  The algorithm below from emcrit.org best illustrates such an […]

Vote Up0Vote Down  Reply
8 years ago
trackback
Decision Tools: PERC, NEXUS and CURB-65 - ercast.org

[…] a pretest probability rather than guessing. Although guessing/gestalt works pretty well too. Here is a link to Scott’s algorithm.Click Here for the NEXUS […]

Vote Up0Vote Down  Reply
7 years ago
andyb
Guest
andyb

How can you use two rules in a row? Its similar to using likelihood ratio in series, and that has never been validated, yet it makes sense.

Vote Up0Vote Down  Reply
7 years ago
Scott Weingart
Author
Scott Weingart

Andy which two rules in a row do you mean?

Vote Up0Vote Down  Reply
7 years ago
andyb
Guest
andyb

If you use the wells criteria to lower your pretest prob to less then 15% then using the perc to then again lower your pretest prob im not sure thats kosher? i mean the wells is essentially plugging a prior pretest prob and using the wells to generate a post test prob which then becomes your next pretest prob right? Is this like using the wells as a negative likelihood ratio and then again using the PERC as another -LR and i did not think LR tests used in series had ever been validated… however it makes theoretical sense.

Vote Up0Vote Down  Reply
7 years ago
andyb
Guest
andyb

Scott, im not sure if i am making myself clear, you are using the wells criteria as a predictive rule to generate a negative predictive value , and i understand you can choose which rule you want to use. You could use either the perc or the wells and which ever one got you a lower value …yes you could use that! however i am not sure you can use one to generate a post test prob and then call it a pretest prob for another test ( the PERC )…?

Vote Up0Vote Down  Reply
7 years ago
andyb
Guest
andyb

https://emcrit.org/blogpost/a-debate-on-pe-decision-rules/

AMAZING DEBATE!!! this answers ALL my questions!! Thanx for posting this.

Vote Up0Vote Down  Reply
7 years ago
Mattia Quarta
Guest
Mattia Quarta

I totally agree on this one. I was about to post a similar comment. I guess what Martin ment to say is that in Kline’s 2008 validation study even just PERC negative patients independently from clinical judgment had very good outcomes (only about 1% had VTE/death at 45 days). I guess this is what David Newman might have mentioned in his podcast. I think though this is not surprising since the profile of a PERC negative patient almost matches the one of a Wells low score one. Almost inevitably low risk patient HAD NO CLOTS!

Vote Up0Vote Down  Reply
7 years ago
Duncan
Guest
Duncan

I know this is an old thread but… I use the algorithm at the top of the page and it makes sense to me. I also know that we still overinvestigate. But I had a clinical scenario that still made me a little uneasy (there’s Gestalt creeping in again…) when I chose NOT to investigate. Well’s score 1.5 or 4.5 depending on the subjective question (I would go for 4.5), high sensitivity D-dimer negative. Stop investigating. Easy. However, this was a young patient, on the OCP, with a long haul flight (UK to Australia) four weeks before, with a story that could have easily been PE or not PE but with a persistent tachycardia up to 140-150 with normal axis and ST-T. There was no other convincing explanation for her tachycardia. My decision to stop investigating her for PE was made easier by the fact that she was admitted for her persistent tachycardia and I’d already given her LMWH (locally here, she’d get admitted for V/Q even if we kept pursuing it, so it would have no effect on her ED treatment), but I was wondering what others thought about the worrying tachycardia with Gestalt that favoured PE over cardiac… Read more »

Vote Up0Vote Down  Reply
7 years ago
Scott Weingart
Author
Scott Weingart

if your gestalt is high, spin, spin, spin

Vote Up0Vote Down  Reply
7 years ago
trackback
Essential Evidence #8 – The PERC rule | EM Basic

[…] EmCrit on PE workup […]

Vote Up0Vote Down  Reply
6 years ago
trackback
“Time trends in pulmonary embolism in the United States: evidence of overdiagnosis..” Archives of internal medicine 171 (9) (May 9): 831–837 - Emergency Medicine Ireland

[…] Found this via a chap who commented on Weingart’s now famous PE episode. […]

Vote Up0Vote Down  Reply
6 years ago
Seth Trueger
Guest
Seth Trueger

Here’s my (not really) modified version: http://mdaware.blogspot.com/2013/09/how-to-pe.html

Vote Up0Vote Down  Reply
6 years ago
trackback
Emergency Medicine - a risky business part 1 - St Emlyns

[…] the reasons why I like the way Scott Weingart wrote the rule out PE pathway at EMCRIT. The one from Scott Weingart is not typical in that respect as the end point is ‘stop work up’ as opposed to PE […]

Vote Up0Vote Down  Reply
4 years ago
trackback
emDOCs.net – Emergency Medicine EducationPE and Evaluation of Risk: Pik Mukherji (AllNYCEM6) - emDOCs.net - Emergency Medicine Education

[…] Dr. Mukherji concluded that we over-workup patients with suspected PE. He then mentioned the algorithm posted at emcrit.org, which begins with: “Do you think this could be a PE? No really. No really, do […]

Vote Up0Vote Down  Reply
2 years ago
trackback
PE: Pain, Puzzles and PERC • LITFL

[…] emerging from the blood spattered PE arena, Scott posted a nifty flowchart summarising a reasonable approach to using Wells, the PERC rule and clinical judgement to decide […]

Vote Up0Vote Down  Reply
3 months ago

Follow EMCrit Everywhere

Click for More Subscribe Options


Other Stuff

  • Have a great idea for the next podcast? Share it here!
  • Tough Questions. Maybe you have an answer!
  • When you're done listening to the podcast,
    check out these great sites.

Who We Are

We are the EMCrit Project, a team of independent medical bloggers and podcasters joined together by our common love of cutting-edge care, iconoclastic ramblings, and FOAM.

Like Us on Facebook

Like Us on Facebook

Subscribe by Email

EMCrit is a trademark of Metasin LLC. Copyright 2009-. This site represents our opinions only. See our full disclaimer, our privacy policy, commenting policy and here for credits and attribution.

wpDiscuz
loading Cancel
Post was not sent - check your email addresses!
Email check failed, please try again
Sorry, your blog cannot share posts by email.
You are going to send email to

Move Comment