UMEM Educational Pearls

Category: Vascular

Title: Ruling out Pulmonary Embolism during the holidays?

Keywords: Pulmonary Embolism (PubMed Search)

Posted: 12/24/2007 by Rob Rogers, MD (Updated: 2/18/2020)
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The PERC Rules revisted

How can I rule out PE without ANY testing, you ask? Do I have to get a d-dimer on that low risk patient?

Do these things keep you up at night like they do me?

Consider using the PERC rule (Pulmonary Embolism Rule Out Criteria)

This set of rules was mentioned in an earlier pearl, but there are now 3 large studies (and one on the way) that validate the use of these rules.

So, if you have a patient who is LOW risk for PE but you would like to document something in the chart that proves you thought about the diagnosis and clinically ruled it out:

If the patient is LOW risk for PE by your clinical gestalt and if the answer to ALL of the following questions is YES, then the patient is considered PERC negative:

  • Age < 50 years
  • Pulse < 100 bpm
  • SpO2 > 95%
  • No unilateral leg swelling
  • No hemoptysis
  • No recent trauma or surgery
  • No prior PE or DVT
  • No hormone use

PERC negative + Low Risk clinical gestalt = PE ruled out

Caution!

  • Most people are comfortable with: LOW risk + negative d-dimer = PE ruled out but use of the PERC rules has not gained wide acceptance yet. Experts in this area predict this will change.
  • Clinical gestalt must be used and the patient must be LOW risk for PE
  • The PERC rule is not intended for use in moderate risk patients or in patients without an alternative diagnosis.
  • The rule is really only intended to avoid testing in the patient you were really not thinking about PE in the first place. Some experts agree that writing "PERC negative" in the chart is defensible.

Jeff Kline, PERC rule. Journal of Thrombosis and Hemostasis. 2007/2008