New Guideline – POCUS for Acute Dyspnea

Written by Graham Van Schaik

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Adding point-of-care ultrasonography (POCUS) to standard diagnostic pathways for acute dyspnea (AD) led to statistically significantly more correct diagnoses, shorter time-to-correct diagnosis, and, in some studies, shorter time-to-correct treatment than standard diagnostic pathways alone.

Why does this matter?
Acute dyspnea (AD), characterized by subjective distressing breathing discomfort, accounts for >1.2 million ED visits annually. The diagnostic workup of AD can be challenging, particularly in a population of patients with multiple potential causes or new onset of AD. This study sought to examine existing evidence for a Clinical Practice Guideline to determine:

  1. The effectiveness of adding POCUS to the clinical exam to improve health outcomes of CHF, PNA, PE, pleural effusions, or PTX and if there are any potentially harmful health effects of POCUS in terms of false-positives or false-negatives.

  2. The diagnostic accuracy of POCUS to detect the aforementioned etiologies of AD.

For those times when whispering pectoriloquy and egophony just aren’t quite enough…
The authors of this study used methods recommended by the Cochrane Diagnostic Test Accuracy Working Group to conduct a review which identified 5,231 potential studies and ultimately included 49 papers. Of these studies, RCTs, and prospective, cohort-type studies that assessed health outcomes or test accuracy measures in hospital settings were included. Data was generally synthesized narratively and were classified into “parallel” use (adding POCUS to standard workup) or “replacement” use (POCUS entirely replaces one or more diagnostic tests). The study selection and data analyses used in the study were quite intricate and in the interest of space (and your attention span), further summary will focus on the big picture.

Only three out of five RCTs that reported health outcomes (specifically in-hospital mortality) were noted to contain low bias. These 3 studies, n = 1,275, showed a RR of 0.77 (95% CI 0.12 to 5.09) for in hospital mortality in the parallel group when compared to standard work-up (rather than replacement).

Four RCTs with n = 965 were used to evaluate LOS and in the two with larger n and low bias, median LOS was 2.9 vs 3.1 days (not significant) for patients who had parallel use of POCUS rather than standard diagnostic pathways.

Only one study reported on readmission rates (no difference, P = 0.93), and none reported on harmful health effects of POCUS. 

Lastly, and perhaps most interesting for us in the ED, two RCTs and a prospective cohort-type study noted that the addition of POCUS by ED physicians with extensive training led to the correct diagnosis for AD by the 4-hour mark in 88% vs 64% (p < 0.001). Additionally, more participants in the POCUS group had appropriate treatment by 4 hours (78% vs 57%; P < 0.001). Across all studies, adding POCUS also consistently improved sensitivities to detect CHF, PNA, PE, pleural effusion, and PTX when compared to standard work-up alone.

My take-home: While this study is not groundbreaking, nor without its own limitations (heterogeneity, varying reference standards, varying methodological quality, lack of reporting on indeterminate results, questionable generalizability and publication bias), it does seem to indicate that adding POCUS to our ED workup of AD is worthwhile. Personally, from my perspective, anything that allows me to more quickly and accurately diagnose and treat (and thus disposition) someone is worth a look.

Source
Point-of-Care Ultrasonography in Patients With Acute Dyspnea: An Evidence Report for a Clinical Practice Guideline by the American College of Physicians. Ann Intern Med. 2021 Apr 27. doi: 10.7326/M20-5504. Online ahead of print.

Appropriate Use of Point-of-Care Ultrasonography in Patients With Acute Dyspnea in Emergency Department or Inpatient Settings: A Clinical Guideline From the American College of Physicians. Ann Intern Med. 2021 Apr 27. doi: 10.7326/M20-7844. Online ahead of print.

What are your thoughts?

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