Pulmonary Embolism

Key considerations: Massive PE with hemodynamic collapse, Saddle PE, Right heart failure from PE

Cannot miss

history: Risk factors: recent surgery, immobilization, travel >4 hrs, hormonal contraception, cancer, prior VTE; Symptoms: pleuritic chest pain, dyspnea (acute onset), hemoptysis, unilateral leg pain/swelling; Onset: typically sudden; Family history of VTE or thrombophilia; exam: Tachycardia, tachypnea, hypoxia; Unilateral leg swelling, calf tenderness, palpable cord (DVT); JVD, RV heave (right heart strain); Loud P2 (pulmonary hypertension); Clear lung exam is common with PE; labs: D-dimer (age-adjusted: age × 10 for patients >50); Troponin (RV strain marker — prognostic); BNP/NT-proBNP (prognostic); CBC, BMP, coagulation studies; ABG: hypoxia, respiratory alkalosis, increased A-a gradient; imaging: CT Pulmonary Angiography (CTPA) — gold standard; Lower extremity duplex ultrasound if CTPA contraindicated; V/Q scan if contrast allergy or renal impairment; CXR: often normal — Hampton hump, Westermark sign (rare); bedside: ECG: sinus tachycardia most common, S1Q3T3 (classic but uncommon), RV strain, new RBBB; Bedside echo: RV dilation, RV hypokinesis, McConnell sign, D-shaped septum; Compression ultrasound of legs: DVT present in ~50% of PE patients

immediate: Apply Wells PE score or PERC rule to determine pretest probability; If low probability and PERC-negative: PE effectively ruled out; If low probability and PERC-positive: check D-dimer; If moderate-high probability: proceed directly to CTPA; general: Anticoagulation: start immediately if high clinical suspicion, even before imaging; Heparin drip or enoxaparin 1mg/kg BID; Monitor for hemodynamic deterioration; specific: diagnosis: Low-Risk PE (Hemodynamically Stable); steps: Anticoagulation with LMWH or heparin → transition to DOAC; Consider outpatient management with DOAC if low PESI score and reliable follow-up; Duration: 3–6 months minimum, indefinite if unprovoked or recurrent; diagnosis: Submassive PE (RV Strain); steps: Heparin drip; Close monitoring in ICU or step-down; Consider catheter-directed therapy or systemic thrombolysis if deteriorating; Cardiology/pulmonology consult; diagnosis: Massive PE (Hemodynamic Instability); steps: Systemic tPA: alteplase 100mg IV over 2 hours; Bolus heparin; Aggressive IV fluids (500mL bolus — avoid overloading RV); Vasopressors: norepinephrine preferred; Consider surgical embolectomy or catheter-directed therapy if tPA contraindicated

admit: All massive and submassive PE — ICU; First-time PE requiring anticoagulation initiation; Significant comorbidities or poor social support; Elevated troponin or BNP; discharge: Low-risk PE with PESI class I-II; Adequate social support and follow-up; Can take oral anticoagulation; Hestia criteria met for outpatient management; consults: Pulmonology/Hematology: recurrent PE, thrombophilia workup; Interventional radiology: catheter-directed therapy; Cardiac surgery: surgical embolectomy for massive PE with tPA contraindication

PERC rule: if ALL 8 criteria are negative AND low pretest probability, PE is ruled out without D-dimer
Age-adjusted D-dimer cutoff for patients >50: age × 10 ng/mL (e.g., 65yo → cutoff 650)
A clear lung exam with hypoxia should raise suspicion for PE
Massive PE: give tPA even during CPR if PE is the suspected cause of arrest
In pregnancy: CTPA preferred over V/Q scan — fetal radiation dose is lower
Never delay anticoagulation while waiting for imaging if clinical suspicion is high

AHA PE Guidelines 2019, ESC PE Guidelines 2019, ACEP Clinical Policy PE 2018. Last reviewed: 2024-11-01