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{{Pulmonary embolism}}
{{PE editors}}


==Overview==
Signs and symptoms of pulmonary embolism are nonspecific; therefore, patients presenting with:
*Unexplained [[dyspnea]]
*[[Tachypnea]]
*[[Chest pain]]
*Risk factors for pulmonary embolism
—should undergo diagnostic tests until the diagnosis is confirmed or eliminated or an alternative diagnosis is made.
== CT equipped hospitals ==
In hospitals having experience in performing and interpreting CT Pulmonary angiography, following flowchart approach can be adopted.
{{familytree/start |summary=PE diagnosis Algorithm.}}
{{familytree | | | | | | | | GMa | GMa='''Determine chances of PE'''}}
{{familytree | | | | |,|-|-|-|^|-|-|-|-|.| | | }}
{{familytree | | |JOE| | | | | | | |SIS| | | JOE='''Low chance'''|SIS='''High chance'''}}
{{familytree | | | |!| | | | | | | | | |!| }}
{{familytree | | |MOM| | | | | | | | |!| |MOM='''[[D-dimer]]'''}}
{{familytree | |,|-|^|.| | | | | | | | |!| }}
{{familytree |GPa| |JOE|~|~|~|~|~|MOM|GPa='''<500 ng/ml'''|JOE='''>500 ng/ml'''|MOM='''[[Pulmonary embolism other imaging findings#Angiography|CT Pulmonary angiography]]'''}}
{{familytree | |!| | | | | | | | | |,|-|^|.| }}
{{familytree |MOM| | | | | | |SIS| | |GMa|MOM='''PE excluded'''|SIS=Negative|GMa=Positive}}
{{familytree | | | | | | | | | | |!| | | | |!| }}
{{familytree | | | | | | | | | |SIS| | |GMa|SIS='''PE excluded'''|GMa='''PE confirmed'''}}
{{familytree/end}}
==CT Non-equipped hospitals==
Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) Study proposed the following for hospitals who do not have sufficient resources to perform or interpret CT Pulmonary angiography.
Wells criteria are used to assess the clinical probability of PE and its graded as Low, Intermediate or High. Later a ventilation-perfusion scan (V/Q) is performed, and based on the result of the scan PE is diagnosed.
'''The following table summarizes the possible outcome of V/Q scan:'''
{| border="1"
|+
! [[Pulmonary embolism ventilation/perfusion scan|V/Q Scan]] !! [[Pulmonary embolism diagnosis#Wells score|Clinical Probability]] !! Diagnosis
|-
| Normal
| any probability
| PE excluded
|-
| Low probability scan
| Low
| PE excluded
|-
| High probability scan
| High
| PE confirmed
|-
| Variable result/Non diagnostic
| Variable
| Serial [[Deep vein thrombosis ultrasound|lower extremity USG]] or [[Pulmonary embolism other imaging findings#Angiography|Pulmonary angiography]]
|}
==Low risk outpatient population==
In populations with low PE prevalence, to avoid unnecessary and costly diagnostic interventions, the following factors were proposed, that formed the PE Rule-out Criteria('''PERC'''):
*Age less than 50 years
*Heart rate less than 100 bpm
*Oxyhemoglobin saturation ≥95 percent
*No hemoptysis
*No estrogen use
*No prior DVT or PE
*No unilateral leg swelling
*No surgery or trauma requiring hospitalization within the past four weeks.
This approach was tested in a multicenter study involving 8138 outpatients with suspected PE.<ref name="pmid18318689">{{cite journal |author=Kline JA, Courtney DM, Kabrhel C, Moore CL, Smithline HA, Plewa MC, Richman PB, O'Neil BJ, Nordenholz K |title=Prospective multicenter evaluation of the pulmonary embolism rule-out criteria |journal=J. Thromb. Haemost. |volume=6 |issue=5 |pages=772–80 |year=2008 |month=May |pmid=18318689 |doi=10.1111/j.1538-7836.2008.02944.x |url=http://dx.doi.org/10.1111/j.1538-7836.2008.02944.x |accessdate=2011-12-19}}</ref> Another study stated that the PERC-approach has a high negative predictive value and sensitivity when combined with a low probability of PE using the Wells criteria, but a low positive predictive value and specificity.<ref name="pmid18272098">{{cite journal |author=Wolf SJ, McCubbin TR, Nordenholz KE, Naviaux NW, Haukoos JS |title=Assessment of the pulmonary embolism rule-out criteria rule for evaluation of suspected pulmonary embolism in the emergency department |journal=Am J Emerg Med |volume=26 |issue=2 |pages=181–5 |year=2008 |month=February |pmid=18272098 |doi=10.1016/j.ajem.2007.04.026 |url=http://linkinghub.elsevier.com/retrieve/pii/S0735-6757(07)00307-5 |accessdate=2011-12-19}}</ref>
Therefore, it can be stated, when combined with a clinical assessment of low risk for PE, this approach can exclude PE without additional diagnostic testing. However, in clinical settings with a higher prevalence of PE (>20%), the PERC based approach has significantly poor predictive value. <ref name="pmid21091866">{{cite journal |author=Hugli O, Righini M, Le Gal G, Roy PM, Sanchez O, Verschuren F, Meyer G, Bounameaux H, Aujesky D |title=The pulmonary embolism rule-out criteria (PERC) rule does not safely exclude pulmonary embolism |journal=J. Thromb.Haemost. |volume=9 |issue=2 |pages=300–4 |year=2011 |month=February |pmid=21091866 |doi=10.1111/j.1538-7836.2010.04147.x |url=http://dx.doi.org/10.1111/j.1538-7836.2010.04147.x |accessdate=2011-12-19}}</ref>
==References==
{{reflist|2}}
[[Category:Hematology]]
[[Category:Pulmonology]]
[[Category:Cardiology]]
[[Category:Emergency medicine]]
{{WH}}
{{WS}}

Revision as of 18:32, 27 April 2012

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Editor(s)-In-Chief: The APEX Trial Investigators, C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]

Overview

Signs and symptoms of pulmonary embolism are nonspecific; therefore, patients presenting with:

—should undergo diagnostic tests until the diagnosis is confirmed or eliminated or an alternative diagnosis is made.

CT equipped hospitals

In hospitals having experience in performing and interpreting CT Pulmonary angiography, following flowchart approach can be adopted.

 
 
 
 
 
 
 
Determine chances of PE
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Low chance
 
 
 
 
 
 
 
High chance
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
D-dimer
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
<500 ng/ml
 
>500 ng/ml
 
 
 
 
 
CT Pulmonary angiography
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
PE excluded
 
 
 
 
 
 
Negative
 
 
Positive
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
PE excluded
 
 
PE confirmed

CT Non-equipped hospitals

Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) Study proposed the following for hospitals who do not have sufficient resources to perform or interpret CT Pulmonary angiography.

Wells criteria are used to assess the clinical probability of PE and its graded as Low, Intermediate or High. Later a ventilation-perfusion scan (V/Q) is performed, and based on the result of the scan PE is diagnosed.


The following table summarizes the possible outcome of V/Q scan:

V/Q Scan Clinical Probability Diagnosis
Normal any probability PE excluded
Low probability scan Low PE excluded
High probability scan High PE confirmed
Variable result/Non diagnostic Variable Serial lower extremity USG or Pulmonary angiography

Low risk outpatient population

In populations with low PE prevalence, to avoid unnecessary and costly diagnostic interventions, the following factors were proposed, that formed the PE Rule-out Criteria(PERC):

  • Age less than 50 years
  • Heart rate less than 100 bpm
  • Oxyhemoglobin saturation ≥95 percent
  • No hemoptysis
  • No estrogen use
  • No prior DVT or PE
  • No unilateral leg swelling
  • No surgery or trauma requiring hospitalization within the past four weeks.

This approach was tested in a multicenter study involving 8138 outpatients with suspected PE.[1] Another study stated that the PERC-approach has a high negative predictive value and sensitivity when combined with a low probability of PE using the Wells criteria, but a low positive predictive value and specificity.[2]

Therefore, it can be stated, when combined with a clinical assessment of low risk for PE, this approach can exclude PE without additional diagnostic testing. However, in clinical settings with a higher prevalence of PE (>20%), the PERC based approach has significantly poor predictive value. [3]

References

  1. ↑ Kline JA, Courtney DM, Kabrhel C, Moore CL, Smithline HA, Plewa MC, Richman PB, O'Neil BJ, Nordenholz K (2008). "Prospective multicenter evaluation of the pulmonary embolism rule-out criteria". J. Thromb. Haemost. 6 (5): 772–80. doi:10.1111/j.1538-7836.2008.02944.x. PMID 18318689. Retrieved 2011-12-19. Unknown parameter |month= ignored (help)
  2. ↑ Wolf SJ, McCubbin TR, Nordenholz KE, Naviaux NW, Haukoos JS (2008). "Assessment of the pulmonary embolism rule-out criteria rule for evaluation of suspected pulmonary embolism in the emergency department". Am J Emerg Med. 26 (2): 181–5. doi:10.1016/j.ajem.2007.04.026. PMID 18272098. Retrieved 2011-12-19. Unknown parameter |month= ignored (help)
  3. ↑ Hugli O, Righini M, Le Gal G, Roy PM, Sanchez O, Verschuren F, Meyer G, Bounameaux H, Aujesky D (2011). "The pulmonary embolism rule-out criteria (PERC) rule does not safely exclude pulmonary embolism". J. Thromb.Haemost. 9 (2): 300–4. doi:10.1111/j.1538-7836.2010.04147.x. PMID 21091866. Retrieved 2011-12-19. Unknown parameter |month= ignored (help)

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