WHAT WOULD YOU DO? · CASE 02
The case
During a crowded ED shift, a woman arrived from a family medicine clinic after about a week of cough and breathlessness. She was sitting comfortably, using her phone. Her lungs were clear and she had no fever. SpO₂ was 97–98% on room air, BP 110/70 mmHg, and HR 120/min. The ECG showed sinus tachycardia. There was no recent surgery or long-distance flight.
The clue
Focused bedside echo suggested a right ventricle larger than the left. The tachycardia remained unexplained.
What would you do next?
Which is the most appropriate immediate approach?
- Observe and repeat vital signs; investigate PE only if hypoxaemia or hypotension develops.
- Repeat cardiac POCUS to confirm RV enlargement before beginning a PE investigation.
- Assess PE probability and promptly follow the indicated D-dimer or CTPA pathway.
Reveal the answer and reasoning
C — Investigate according to clinical probability now. If PE is likely, arrange urgent CTPA; if unlikely, use an appropriate D-dimer pathway. Normal oxygen saturation does not exclude PE.
RV enlargement can have other causes and can be misjudged on an off-axis view. It cannot confirm PE, and a normal limited echo would not exclude it. Waiting for desaturation (A) or repeating POCUS before initiating the diagnostic pathway (B) risks delay.
What happened? CTPA was requested, but approval was delayed. After discussing the concern with the patient, enoxaparin was given while awaiting imaging. About three hours later, CTPA confirmed bilateral pulmonary embolism. If PE is clinically likely and imaging is delayed, interim therapeutic anticoagulation may be appropriate after assessing bleeding risk and contraindications.
Reassess heart rate, blood pressure, breathing and perfusion; escalate promptly with clinical deterioration.
Bedside takeaway: A normal SpO₂ does not explain away persistent, unexplained tachycardia.
Sources
- NICE NG158 — Venous thromboembolic diseases: diagnosis and management.
- 2026 AHA/ACC Multisociety Guideline for Acute Pulmonary Embolism.
Related: Suspected pulmonary embolism — a practical ED diagnostic algorithm →
Educational case for healthcare professionals; apply clinical judgment and local pathways.
