Probability of Pulmonary Embolism
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Wells, P. S., Ginsberg, J. S., et al. (1998). "Use of a clinical model for safe management of patients with suspected pulmonary embolism." Ann Intern Med 129(12).

Important CPR Information

Rates of PE According to Pre-Test Probability

CPR Model used to Calculate Pre-test Probability of PE

Respiratory Symptoms
 Dyspnea or worsening of chronic dyspnea
 Pleuritic chest pain
 Chest pain that is nonretrosternal and nonpleuritic
 Arterial oxygen saturation < 92% that corrects with oxygen supplementation < 40%
 Hemoptysis
 Pleural rub

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Typical Features

Does the patient have any of the following?  Yes   No


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Risk Factors

Does the patient have any of the following risk factors?  Yes   No
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Severe Features

Does the patient have any of the following severe features?  Yes   No
  • syncope
  • blood pressure less than 90mmHg with heart rate greater than 100 beats/min
  • requires oxygen supplementation greater then 40%
  • new onset right heart failure (elevated JVP and new S1,Q3,T3 or RBBB on ECG)

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Calculate Probability of PE

Is the alternative diagnosis (choose one):
 As likely or more likely than PE.
 Less likely than PE.

Result of VQ Scan (choose one):
 Normal
 Low Probability
 Intermediate Probability
 High Probability
     
Pre-test Probability of PE:  
Post-test Probability of PE:

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Critical Appraisal of CPR
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  1. Outcome: Pulmonary Embolism
    • Definition: Patients were considered positive for PE if they had an abnormal pulmonary angiogram, abnormal ultrasound or venogram, high probability VQ scan plus moderate or high pre-test probability, or venous thrombo-embolic event during the 3 months of follow-up..
    • Prevelance: 17.5%
      •
    • Blind assessment
  2. Predictive Variables
    • Blind assessment
  3. Patient Population
    • 1239 patients, no description of average age or gender.
      •
    • Inclusion criteria: Inpatients and outpatients with suspected pulmonary embolism whose symptoms have lasted less than 30 days.
    • Exclusion criteria: 1) Suspected upper extremity DVT as the source of the PE, 2) no symptoms of PE for more than 3 days before presentation, 3) use of anticoagulation for more than 72 hours, 4) expected survival of less than 3 months, 5) containdication to contrast media, 6) pregnancy, 7) age younger than 18 years.
  4. Description of Study Site
    • 5 Canadian centers, both inpatient and outpatient centers
  5. Prospective Validation: Yes
    • Level 2-3
  6. Impact Analysis: No
  7. Results of the Clinical Decision Rule
    8. Pre-Test ProbabilityPrevalence of PE
    Low 3.4% (2.5-5.0%)
    Moderate 27.8% (23-32%)
    High 78.4% (69-86%)
  8. Reproducibility : Kappa statistic for the model was 0.86. Kappa for the individual predictors was not assessed.
  9. Sensibility: Yes
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