Pulmonary embolism resident survival guide
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Rim Halaby; Pratik Bahekar, MBBS [2]; Chetan Lokhande, M.B.B.S [3]
Pulmonary embolism Resident Survival Guide Microchapters |
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Overview |
Causes |
FIRE |
Diagnosis |
Treatment |
Do's |
Don'ts |
Overview
Pulmonary embolism (PE) is an acute obstruction of the pulmonary artery (or one of its branches). The obstruction in the pulmonary artery that causes a PE can be due to thrombus, air, tumor, or fat. Most often, this is due to a venous thrombosis (blood clot from a vein), which has been dislodged from its site of formation in the lower extremities. It has then embolized to the arterial blood supply of one of the lungs. This process is termed thromboembolism. PE is a potentially lethal condition. The patient can present with a range of signs and symptoms, including dyspnea, chest pain while breathing, and in more severe cases collapse, shock, and cardiac arrest. Pulmonary embolism can be classified based on the time course of symptom presentation (acute and chronic) and the overall severity of disease (stratified based upon three levels of risk: massive, submassive, and low-risk). PE treatment requires rapid and accurate risk stratification before the development of hemodynamic collapse and cardiogenic shock. Treatment consists of an anticoagulant medication, such as heparin or warfarin, and in severe cases, thrombolysis or surgery.
Causes
Life Threatening Causes
Life-threatening causes include conditions which result in death or permanent disability within 24 hours if left untreated.
Common Causes
- Antiphospholipid syndrome
- Antithrombin deficiency
- Factor V Leiden
- Hyperhomocysteinemia
- Long-distance air travel
- Malignancy
- Nephrotic syndrome
- Obesity
- Post surgery
- Pregnancy
- Protein C deficiency
- Protein S deficiency
- Prothrombin mutation
Classification
Pulmonary embolism can be classified based on the time course of symptom presentation (acute and chronic) and the overall severity of disease (stratified based upon three levels of risk: massive, submassive, and low-risk).
Massive Pulmonary Embolism
- An acute pulmonary embolism with:
- Sustained hypotension (systolic blood pressure <90 mm Hg) for at least 15 minutes or requiring inotropic support. This is not due to other possible causes of hypotension such as arrhythmia, hypovolemia, sepsis, or left ventricular dysfunction.
- Pulselessness
- Persistent profound bradycardia (heart rate < 40 bpm with signs or symptoms of shock).[1]
Submassive Pulmonary Embolism
An acute PE without systemic hypotension (systolic blood pressure >90 mm Hg) but with either, right ventricular dysfunction or myocardial necrosis.
- Right ventricular dysfunction: It is defined by the presence of at least one of the following features,
- Echocardiography findings:
- RV dilation (apical 4-chamber RV diameter divided by LV diameter > 0.9)
- RV systolic dysfunction
- CT findings: RV dilation (4-chamber RV diameter divided by LV diameter > 0.9)
- BNP > 90 pg/mL
- N-terminal pro-BNP >500 pg/mL
- EKG findings:
- New complete or incomplete right bundle-branch block
- Anteroseptal ST elevation or depression
- Anteroseptal T-wave inversion.
- Echocardiography findings:
- Myocardial necrosis: It is defined as the presence of either one of the following:
- Elevation of troponin I (>0.4 ng/mL)
- Elevation of troponin T (>0.1 ng/mL).[2] [1].
Low-Risk Pulmonary Embolism
An acute pulmonary embolism without the life threatening clinical markers that define massive or submassive pulmonary emboli. [1]
FIRE: Focused Initial Rapid Evaluation
A Focused Initial Rapid Evaluation (FIRE) should be performed to identify patients in need of immediate intervention. The algorithm below is based on the 2011 AHA Guideline for the Management of Patients With Pulmonary Embolism.
Complete Diagnostic Approach
A complete diagnostic approach should be carried out after a focused initial rapid evaluation is conducted and following initiation of any urgent intervention.
Step 1: Establish The Diagnosis Of Pulmonary Embolism
In hospitals that have experience in performing and interpreting CT pulmonary angiography, the following flowchart approach can be adopted.
Identify cardinal findings that increase the pretest probability of pulmonary embolism ❑ Dyspnea at rest or with exertion | |||||||||||||||||||||||||||||||||||
Does the patient have any of the following findings of massive pulmonary embolism that require urgent management? ❑ >2- Pillow orthopnea ❑ Hypotension ❑ Jugular venous distension ❑ Right-sided S3 ❑ Parasternal lift | |||||||||||||||||||||||||||||||||||
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 | ||||||||||||||||||||||||||||||||
Note: If there is a high clinical suspicion of pulmonary embolism, then anticoagulation can begin with a parenteral agent such as unfractionated heparin during the process of performing the diagnostic studies.
Treatment
Step 2: Use A Risk-Stratified Approach to Treat the Patient with Pulmonary Embolism
Confirmed PE | |||||||||||||||||||||||||||||||||||||||||||||||
Assess Clinical Stability | |||||||||||||||||||||||||||||||||||||||||||||||
Unstable | Stable | ||||||||||||||||||||||||||||||||||||||||||||||
Blood pressure ≦ 90mm Drop in BP ≧ 40mm for > 15 min | Assess RV function Biomarkers of injury | ||||||||||||||||||||||||||||||||||||||||||||||
Thrombolysis Catheter embolectomy Surgery | No Dysfunction + No injury | Dysfunction + No injury | Dysfunction + Injury | ||||||||||||||||||||||||||||||||||||||||||||
Anticoagulation Early discharge | Anticoagulation Ward admission | Thrombolytics ICU admission | |||||||||||||||||||||||||||||||||||||||||||||
Step 3: Assess Treatment Response and Need for Device Based Therapy
Acute PE confirmed | |||||||||||||||||||||||||||||||||||||||||||||||
Anticoagulation contraindicated ? | |||||||||||||||||||||||||||||||||||||||||||||||
Yes | No | ||||||||||||||||||||||||||||||||||||||||||||||
IVC filter | Risk stratification | ||||||||||||||||||||||||||||||||||||||||||||||
Low-risk PE | Submassive PE | Massive PE | |||||||||||||||||||||||||||||||||||||||||||||
Anticoagulation | Anticoagulation | ||||||||||||||||||||||||||||||||||||||||||||||
Assess clinically for evidence of increased severity | |||||||||||||||||||||||||||||||||||||||||||||||
Evidence of shock (SBP <90 mmHg) or respiratory failure | Is thrombolytic contraindicated? | ||||||||||||||||||||||||||||||||||||||||||||||
Yes | No | ||||||||||||||||||||||||||||||||||||||||||||||
Surgical emblectomy or catheter based interventions | Hold anticoagulation, give thrombolytics then resume anticoagulations | ||||||||||||||||||||||||||||||||||||||||||||||
Patient shows clinical improvement | |||||||||||||||||||||||||||||||||||||||||||||||
No | Yes | ||||||||||||||||||||||||||||||||||||||||||||||
Surgical emblectomy or catheter based interventions | Continue anticoagulation | ||||||||||||||||||||||||||||||||||||||||||||||
Do's
Don'ts
References
- ↑ 1.0 1.1 1.2 Jaff MR, McMurtry MS, Archer SL, Cushman M, Goldenberg N, Goldhaber SZ; et al. (2011). "Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: a scientific statement from the American Heart Association". Circulation. 123 (16): 1788–830. doi:10.1161/CIR.0b013e318214914f. PMID 21422387.
- ↑ Cannon CP, Goldhaber SZ (1996). "Cardiovascular risk stratification of pulmonary embolism". Am. J. Cardiol. 78 (10): 1149–51. PMID 8914880. Retrieved 2011-12-21. Unknown parameter
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