Focused cardiac ultrasound (FOCUS) is sensitive for detecting the presence of PE in those with a HR > 100bpm or systolic blood pressure <90 and highly sensitive for detection of PE in patients with a HR > 110bpm.
Why does this matter?
FOCUS in an insensitive test when looking for PE in the general population. However, when applied to a subset of patients with unstable vital signs, it’s thought that sensitivity is much higher. This may be a viable tool for PE detection in those too unstable or unable to go for CTA.
Getting to the heart of it
This was a prospective observational multicenter cohort study involving a convenience sample of patients from six urban academic EDs. Providers ranging in skill from 3rd year medical student to fellowship trained EM faculty performed FOCUS on patients with suspected PE with a HR >100 or SBP <90 before CTA, the current gold standard for PE diagnosis. FOCUS assessment included right ventricular dilation, McConnell’s sign, septal flattening, tricuspid regurgitation, and tricuspid annular plane systolic excursion (TAPSE). Findings were positive if any one of theses five measures were found. 136 patients were enrolled and FOCUS exam for PE in all patients was 92% sensitive (95%CI 78-98%) and 64% specific (95%CI 53-73%). In a subset of patients with HR >110 FOCUS was 100% sensitive (95%CI 88-100%) and 63% specific (95%CI 51-74%). The most sensitive measure was a TAPSE of less than 2.0cm (93% sensitive; 95%CI 75-95%). In all patients there was substantial interobserver agreement (κ= 1.0; 95%CI 0.31-1.0). My takeaway, with the caveat that the provider is proficient in FOCUS, is that in a patient with contrast allergy, too unstable, too obese, or with too poor renal function for CTA, FOCUS can be used to quickly and reliably expedite disposition and management of those with unstable PEs.
What’s TAPSE? Check out this video to learn how to do it in minutes.
For more, see this emDocs post.
Increased Sensitivity of Focused Cardiac Ultrasound for Pulmonary Embolism in Emergency Department Patients With Abnormal Vital Signs. Acad Emerg Med. 2019 Sep 27. doi: 10.1111/acem.13774. [Epub ahead of print]
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