Point-of-care Ultrasound signs of a pulmonary embolism
- Dr. Istrail
- 1 day ago
- 2 min read
When a pulmonary embolism is large enough to obstruct flow, the right ventricle strains against the resistance — and its response is measurable at the bedside with POCUS. In general, the findings are specific but not sensitive. Therefore, their absence does not rule out PE, but their presence is highly informative.
The right ventricle is normally smaller than the left in every cardiac view. RV dilation suggests elevated pulmonary pressures from PE, pulmonary arterial hypertension, or chronic lung disease. An RV to LV ratio ≥1 in the apical 4-chamber view, or RV end-diastolic diameter >3.5 cm, indicates significant dilation.
Tricuspid annular plane systolic excursion (TAPSE) measures RV longitudinal function. A value <1.7 cm is abnormal. In PE patients, TAPSE < 1.5 cm is associated with significantly higher 30-day mortality compared to TAPSE > 2.0 cm. The Age-TAPSE index (Age ÷ TAPSE) adjusts for the age-related decline in TAPSE. An Age-TAPSE index >4.9 in PE patients was associated with:
• HR 3.24 for 30-day mortality (p<0.001)
• HR 2.02 for clinical deterioration within 48 hours (p<0.0001)
The RVOT Doppler waveform provides independent information about pulmonary artery pressure and vascular resistance. As pressures rise, the waveform shifts from rounded and symmetric to peaked and early, eventually developing a mid-systolic notch. The timing and presence of notching helps differentiate pre-capillary from post-capillary pulmonary hypertension.
McConnell's sign — akinesis of the RV free wall with preserved apical motion — was originally described as 77% sensitive and 94% specific for acute PE. A later blinded retrospective study found it was present in 70% of PE patients and 67% of patients with RV infarction, with only 70% sensitivity and 33% specificity for PE in that population.
To learn more about right ventricular assessment and pulmonary hypertension with POCUS, get a copy of The POCUS Textbook — a complete guide to point-of-care ultrasound of the blood vessels, heart, and lungs.
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