#406 Scan, See, Decide: POCUS in the Evaluation of Dyspnea
CLINICAL QUESTION
Is point-of-care ultrasonography (POCUS) helpful for the evaluation of undifferentiated dyspnea?
BOTTOM LINE
For patients presenting to the emergency department (ED) with dyspnea, adding POCUS to conventional work-up improves the diagnostic accuracy of decompensated heart failure from ~87% to ~93%, and may improve diagnostic accuracy of other conditions. Length of ED stay is not different.
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EVIDENCE
- Results statistically significant unless indicated.
- Two systematic reviews past 5 years, 5-7 randomized controlled trials (RCTs), 1483-1535 patients.1,2 Focus on three largest RCTs due to different protocols/outcomes. Diagnostic accuracy determined by masked chart audit.
- 518 patients randomized after clinical evaluation to POCUS or chest X-ray/N-terminal pro-B-type natriuretic peptide.3 ED physicians, accredited training and >40 scans. Focus: B-line artifact (for decompensated heart failure diagnosis, present in ~43%).
- Diagnostic accuracy: 95% (POCUS) versus 87%.
- Sensitivity: 94% (POCUS) versus 85% (no statistics available).
- Specificity: 96% (POCUS) versus 89% (no statistics).
- Time to diagnosis: 5 minutes (POCUS) versus 105 minutes.
- 442 patients randomized to conventional work-up alone (clinical evaluation, ECG, blood tests, most received CXR, with optional CT scans and formal echocardiography) or conventional workup plus POCUS.4 ED physicians, 4 hours of training and 10 practice scans. Focus: B-line artifact (decompensated heart failure, present in ~30%).
- Diagnostic accuracy: 93% (POCUS) versus 87%.
- Sensitivity: 88% (POCUS) versus 83% (no statistics).
- Specificity: 95% (POCUS) versus 88% (no statistics).
- Length of ED stay: Not different.
- 315 patients randomized to conventional workup alone or conventional workup plus single expert physician-performed POCUS.5 Multiple views of cardiac/lung/deep veins for identifying any relevant diagnosis (most common: chronic obstructive pulmonary disease, pneumonia or heart failure).
- Diagnostic accuracy: 88% (POCUS) versus 64%.
- Appropriate treatment at 4 hours: 78% (POCUS) versus 57%.
- Limitations: Various POCUS expertise and “diagnostic accuracy” definitions, CXR results in chart audit could bias final diagnosis determination.
CONTEXT
- POCUS: Typically 8-view anterior and anterior/lateral lung, screening for increased tissue density (“B line artifact”), pleural effusion.3,4
- POCUS: Positive likelihood ratio~20 (very good at ruling in heart failure), negative likelihood ratio ~0.1 (very good at ruling out heart failure).3,4
- Training options examples: https://cpocus.ca; https://emergdoc.com.
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Good to know
Checking IVC with POCUS has been valuable in my experience: collapsed IVC in intra-vascular depletion and plethoric in volume overload states. This can guide management decisions: do I give fluids or administer diuretics?