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FOCUS for PE

February 24, 2021

Editor’s note: We covered this article when it first came out. This is a refresher on this important article from the perspective of a POCUS guru. ~Clay Smith

Written by Will Kropf

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In patients with abnormal vitals and suspicion for pulmonary embolism (PE), focused cardiac ultrasound (FOCUS) is highly sensitive (92%), especially for those with a heart rate >110BPM (approaching 100%).


Why does this matter
Can bedside echo guide management when you suspect PE? Immediate CT pulmonary angiogram (CTPA) may not be feasible because of hemodynamic instability, acute kidney injury, contrast allergy, morbid obesity, or practice in a resource-limited setting. A normal FOCUS can significantly reduce suspicion for PE in patients with abnormal vital signs, allowing time to consider other elements of resuscitation.

Matters of the (Right) heart: Knowledge on TAP…SE
This was a multicenter, prospective observational cohort study of FOCUS for PE. Investigators posited that a PE large enough to change vitals should affect the right heart. FOCUS assessed for RV dilation, McConnell’s sign (hypokinesis of the RV with apical sparing), septal flattening (“D-sign”), tricuspid regurgitation, and tricuspid annular plane systolic excursion (TAPSE) less than 20mm. Results were compared to CTPA.

In a sample of 137 patients suspected of having PE with heart rate >100 beats/minute or systolic BP <90 mmHg, FOCUS was 92% sensitive for PE, and in the subgroup of patients with HR >110 (n=98) the sensitivity of FOCUS was 100% (95% CI 88-100%). This is a small sample size with a large confidence interval, so approach these numbers cautiously, especially if pretest probability is high.

Overall, TAPSE was the most sensitive single FOCUS component, with an overall sensitivity of 88%, 93% in the HR >110 subgroup. However, no single FOCUS component was 100% sensitive, and the authors caution against excluding PE in patients with an incomplete FOCUS.

Limitations: Only one component of the exam had to be abnormal to be deemed positive for PE, thus sacrificing specificity for sensitivity. Also, the operators in this study had significant experience in bedside echocardiography, limiting generalizability.

Source
Increased sensitivity of focused cardiac ultrasound for pulmonary embolism in emergency department patients with abnormal vital signs. Academic Emergency Medicine. 2019;26:1212-20.