Key Points
- Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
- Use system-specific risk tools to guide testing and disposition.
- Order high-yield tests first; escalate imaging when indicated.
- Start evidence-based initial therapy and reassess frequently.
Algorithm
- Primary survey and vitals; IV access and monitors.
- Focused history/physical; identify red flags and likely etiologies.
- Order system-appropriate labs and imaging (see Investigations).
- Initiate guideline-based empiric therapy (see Pharmacology).
- Reassess response; arrange consultation and definitive management.
Clinical Synopsis & Reasoning
PE spans from incidental subsegmental disease to obstructive shock. Evaluate pretest probability (e.g., Wells/Geneva), apply age‑adjusted D‑dimer when appropriate, and use CTPA or V/Q based on renal function, pregnancy, and contrast tolerance. Risk‑stratify by RV dysfunction (echo/CT), biomarkers (troponin/BNP), and clinical instability to anticipate decompensation.
Treatment Strategy & Disposition
Anticoagulate promptly when suspicion is high and bleeding risk acceptable; choose DOACs for most stable patients, LMWH in cancer, and UFH if thrombolysis or procedures are possible. Consider systemic thrombolysis or catheter‑directed therapy for massive/submassive PE with deterioration. Assess for precipitating factors and plan duration of therapy (provoked 3 mo; unprovoked often extended). ICU for shock or advanced support; otherwise ward or outpatient pathways for low‑risk cases with reliable follow‑up.
Epidemiology / Risk Factors
- Smoking/chronic lung disease; infections or immobility (VTE)
Investigations
| Test | Role / Rationale | Typical Findings | Notes |
|---|---|---|---|
| CXR | Infection/edema/PTX | Consolidation/effusion/PTX | |
| ABG/VBG | Oxygenation/ventilation | Hypoxemia/hypercapnia | |
| CT chest (indicated) | PE/other | Findings vary |
Risk Category & Initial Therapy
| Category | Features | Initial approach |
|---|---|---|
| High risk (massive) | Hypotension/shock | Reperfusion (systemic or catheter) + anticoagulation |
| Intermediate | RV strain or biomarkers without shock | Anticoagulation; monitored setting |
| Low risk | Stable, no strain | Anticoagulation; consider outpatient |
Pharmacology
| Medication | Mechanism | Onset | Role in Therapy | Limitations |
|---|---|---|---|---|
| Unfractionated heparin (IV) | Antithrombin-mediated Xa/IIa inhibition | Immediate | Initial AC when lysis/cath possible or renal failure | Bleeding, HIT; monitor aPTT |
| Enoxaparin (LMWH) | Xa>IIa inhibition | Hours | Preferred initial AC in many stable cases; cancer VTE | Avoid severe renal failure |
| Alteplase (systemic) | Plasminogen activation (fibrinolysis) | Rapid | Massive PE with shock or arrest | ICH/major bleed; contraindications |
| Apixaban/Rivaroxaban | Direct factor Xa inhibition | Hours | First-line for most stable PE/DVT | Bleeding; interactions |
| Catheter-directed therapy | Localized fibrinolysis/thrombectomy | Rapid | When systemic lysis high risk or ineffective | Bleeding; expertise required |
Prognosis / Complications
- Depends on severity/oxygenation; respiratory failure risk
Patient Education / Counseling
- Explain red flags and when to seek emergent care.
- Reinforce medication adherence and follow-up plan.
Notes
Preferred anticoagulants for most non-cancer patients are DOACs. In pregnancy, use LMWH. Evaluate for contraindications to thrombolysis and bleeding risk.