EBQ:PERC Rule Validation
- 1 Clinical Question
- 2 Conclusion
- 3 Design
- 4 Population Studied
- 5 Interventions
- 6 Outcomes
- 7 Discussion
- 8 Funding
- 9 CME
- 10 Related Publications
- 11 Sources
- 12 Further Reading
Can risk stratification to low risk for pulmonary embolism (PE) in combination with a negative Pulmonary Embolism Rule Out Criteria (PERC) score reduce the probability of PE to less than 2%?
The combination of gestalt estimate of low suspicion for PE and PERC(-) reduces the probability of VTE to below 2% in about 20% of outpatients with suspected PE.
This was a prospective, non-interventional, multicenter study of patients presenting to the emergency department (ED) in 12 hospitals in the USA and one in Christchurch, New Zealand. Investigators were trained in applying the PERC Rule
8138 patients from 12,213 eligible patients
Inclusion was triggered by an order for a test to establish objective evidence of a PE, written by or under the supervision of a board-certified emergency physician. The decision to order this test was based upon information obtained from the initial history and physical examination, and medical records immediately available in the ED. Objective Evidence included:
- Pulmonary vascular imaging study (CT angiography or VQ scan)
- D-dimer assay ordered to evaluate for possible PE
tests to simply exclude a deep venous thromboembolsm did not trigger patient enrollment
- Knowledge of a diagnostic positive pulmonary vascular imaging study performed within the previous 7 days.
- The patient indicated that the enrollment hospital was not his or her hospital system of choice for follow-up.
- Any circumstance that suggested that the patient would be lost to follow-up
- Average age: 49 years old
- Sex: 67% Female
- Symptoms: Dyspnea (51%) > Pleuritic CP (44%) > Substernal CP (34%) > Cough (29%) > Syncope (6%) > Hemptysis (3%)
- Comorbid Conditions: Current smoker (35%) > Immobility (25%) > Active malignancy (15%) > Known CAD (13%) > Prior PE/DVT & estrogen use (11%) > Pregnant/Post-partum (10%)
- 72-field, web-based date form completed at the time of test order, which included gestalt pretest probability.
The PERC rule was derived in 2004 with the
- Is the patient older than 49 years of age?
- Is the pulse rate above 99 beats min)1?
- Is the pulse oximetry reading <95% while the patient breathes room air?
- Is there a present history of hemoptysis?
- Is the patient taking exogenous estrogen?
- Does the patient have a prior diagnosis of venous thromboembolism (VTE)?
- Has the patient had recent surgery or trauma? (Requiring endotracheal intubation or hospitalization in the previous 4 weeks.)
- Does the patient have unilateral leg swelling? (Visual observation of asymmetry of the calves.)
Supported by Grants from the National Institutes of Health R41HL074415 and R42HL074415, K23HL077404 and R01 HL074384, and a Medical Student Award from the Emergency Medicine Foundation
- ACEP clinical policy; Ann Emerg Med 2011; 57:628-650.
- Kline JA, Mitchell AM, Kabrhel C., Richman PB, Courtney DM. Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism. J Thromb Haemost 2004; 2: 1247–55
- Radecki, R. The PERC Rule Mini-Review. Emergency Medicine Literature of Note. August 23, 2011. Available at: http://www.emlitofnote.com/2011/08/perc-rule-mini-review.html