Mount Carmel Health Partners Clinical Guidelines Pulmonary Embolus

Recommendation for the Evaluation and
Treatment of Pulmonary Embolus
Definition: Pulmonary embolism (PE) is a thrombus, usually originating in a lower extremity vein, that embolizes to the pulmonary arterial circulation.
Depending on the size, location and hemodynamic effects, a pulmonary embolus can have minor, catastrophic or lethal consequences. The majority of
pulmonary emboli are undiagnosed ante-mortem.
Patients present with seemingly typical exacerbations of chronic disease processes such as COPD, asthma or bronchitis which may mask symptoms of
undiagnosed PE. The diagnosis of a PE can be difficult because the signs and symptoms are often nonspecific and subtle. Risk stratification for the pre-test
probability or likelihood of pulmonary embolism is useful in guiding diagnostic testing and algorithms can assist in decision-making. Patient being
evaluated for a PE must be determined to be at either low risk for PE or at moderate to high risk. The PERC algorithm i.e., “Pulmonary Embolus Rule-Out
Criteria” can be applied to low risk patients. Patient’s with a low pretest probability can be safely ruled out for a PE with these decision rules or if testing
with a negative d-dimer test. Patients with high pretest probability however, and a negative D-dimer cannot be ruled out because of negative predictive
value of the D-dimer assay is not sufficient to rule-out a PE. Patients at risk should undergo CT pulmonary angiography or Ventilation/perfusion Scan
(VQ Scan).
Low Probability
Hemodynamically stable
Perform
Quantitative
D-Dimer
PERC Positive
Positive
>500 ng/ml
Negative
<500 ng/ml
PE Excluded
 Chest X-Ray (CXR):
Investigate for alternative
etiologies of symptoms
 Apply the PERC Rule
(see Table 1)
Perform CT pulmonary angiogram (CTPA) or VQ Scan with Chest x-ray
Negative for PE or
low/normal Probability
VQ scan
Positive for PE or
High Probability VQ Scan
Intermediate/
Indeterminate Probability
VQ scan
PE confirmed: Treat
PE Excluded
Perform CT pulmonary angiogram or serial lower
extremity compression ultrasound or magnetic
resonance pulmonary angiogram
Negative for PE
PE Excluded
PERC Negative
Positive for PE
PE confirmed:
Treat unfractionated or
Fractionated heparin
PE Excluded
Quick Guide
 Pulmonary embolus can be a diagnostic
challenge because of its protean
presentations
 Risk stratification at presentation should
guide management
 Besides conventional anticoagulation,
higher-risk patients maybe candidate for
adjunctive therapies; surgical
embolectomy, thrombolysis, or Ekos to
optimize their outcome
 Contraindication to CT angiogram (CTA):
Glomerular Filtration Rate (GFR) < 60ml/
min/1.73m 2 or contrast allergy or morbid
obesity
Table 1: Pulmonary Embolism Rule-out
Criteria (PERC):
 Age > 50 years?
 Heart Rate > 100 bpm?
 O2 Saturation on Room Air < 95%?
 Prior History of DVT/PE
 Recent Trauma or Surgery?
 Hemoptysis?
 Exogenous Estrogen?
 Unilateral Leg Swelling?
If no to all criteria and with clinician’s
pre-test probability < 15%, PERC Rule criteria
are satisfied and no further workup needed
with <2% probability of PE.
December 2016