Episode 214: Acute Pulmonary Embolism

We review the diagnosis, risk stratification, & management of acute pulmonary embolism in the ED.

Hosts:

Vivian Chiu, MD

Brian Gilberti, MD

https://media.blubrry.com/coreem/content.blubrry.com/coreem/Acute_Pulmonary_Embolism.mp3

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Tags: Pulmonary

Show Notes

Core Concepts and Initial Approach

Definition: Obstruction of pulmonary arteries, usually from a DVT in the proximal lower extremity veins (iliac/femoral), but may be tumor, air, or fat emboli.

Incidence & Mortality: 300,000–370,000 cases/year in the USA, with 60,000–100,000 deaths annually.

Mantra: “Don’t anchor on the obvious. Always risk stratify and resuscitate with precision.”

Risk Factors: Broad, including older age, inherited thrombophilias, malignancy, recent surgery/trauma, travel, smoking, hormonal use, and pregnancy.

Clinical Presentation and Risk Stratification

Presentation: Highly variable, showing up as anything from subtle shortness of breath to collapse.

Acute/Subacute: Dyspnea (most common), pleuritic chest pain, cough, hemoptysis, and syncope. Patients are likely tachycardic, tachypneic, hypoxemic on room air, and may have a low-grade fever.

Chronic: Can mimic acute symptoms or be totally asymptomatic.

Pulmonary Infarction Signs: Pleuritic pain, hemoptysis, and an effusion.

High-Risk Red Flags: Signs of hypotension (systolic blood pressure < 90 mmHg for over 15 minutes), requirement of vasopressors, or signs of shock → activate PERT team immediately.

Crucial Mimics: Think broadly; consider pneumonia, ACS, pneumothorax, heart failure exacerbation, and aortic dissection.

Workup & Diagnostics

History/Scoring: Ask about prior clots, recent surgeries, hospitalizations, travel. Use Wells/PERC criteria to assess pretest probability.

Labs:

D-dimer: A good test to rule out PE in a patient with low probability. If suspicion is high, proceed directly to imaging.

Troponin/BNP: Act as RV stress gauges. Elevated levels are associated with increased risk of a complicated clinical course (25-40%).

Lactate: Helpful in identifying patients in possible cardiogenic shock.

EKG: Most common finding is sinus tachycardia. Classic RV strain patterns (S1Q3T3, T-wave changes/inversions) are nonspecific.

Imaging:

CXR: Usually normal, but quick and essential to rule out other causes.

CTPA: The usual standard and gold standard for stable patients. High sensitivity (> 95%) and can detect RV enlargement/strain.

V/Q Scan: Option for patients with contraindications to contrast (e.g., severe contrast allergies).

POCUS (Point-of-Care Ultrasound): Useful adjunct for unstable patients.

Bedside Echo: Can show signs of RV strain (enlarged RV, McConnell sign).

Lower Extremity Ultrasound: Can identify a DVT in proximal leg veins.

Treatment & Management

Resuscitation (Reviving the RV):

Oxygenation: Give supplementally as needed (nasal cannula, non-rebreather, high flow).

Intubation: Avoid if possible; positive pressure ventilation can worsen RV dysfunction.

Fluids: Be judicious; even the smallest amount can worsen RV overload.

Vasopressors: Norepinephrine is preferred as first-line for hypotension/shock.

Anticoagulation (Start Immediately):

Initial choice is UFH or LMWH (Lovenox).

Lovenox is preferred for quicker time to therapeutic range, but is contraindicated in renal dysfunction, older age, or need for emergent procedures.

DOACs can be considered for stable, low-risk patients as an outpatient.

Escalation for High-Risk PE

Systemic Thrombolytics: Consider for very sick patients with shock/cardiac arrest (e.g., Alteplase 100 mg over two hours or a bolus in cardiac arrest). High risk of intracranial hemorrhage; weigh risks versus benefits.

PERT Activation: Engage multidisciplinary teams (usually including ICU, CT surgery, and interventional radiology).

Interventions: Consult specialists for catheter-directed thrombolysis or suction embolectomy. Surgical embolectomy can also be considered.

Bridge to Care: Activate the ECMO t