Point-of-care Lung Ultrasound Is Useful to Evaluate Emergency Department Patients for COVID-19

Abstract

Introduction: Coronavirus disease 2019 (COVID-19) can be a life-threatening lung disease or a trivial upper respiratory infection depending on whether the alveoli are involved. Emergency department (ED) evaluation of symptomatic patients with normal vital signs is frequently limited to chest auscultation and oro-nasopharyngeal swabs. We tested the null hypothesis that patients being screened for COVID-19 in the ED with normal vital signs and without hypoxia would have a point-of-care lung ultrasound (LUS) consistent with COVID-19 less than 2% of the time.

Methods: We performed a retrospective, structured, blinded ultrasound review and chart review in patients 14 years or older with symptoms prompting ED evaluation for COVID-19. We excluded those with known congestive heart failure or other chronic lung conditions likely to cause excessive B-lines on LUS. We used a two-sided exact hypothesis test for binomial random variables. We measured LUS diagnostic performance using computed tomography as the gold standard.

Results: We reviewed 77 charts; 49 met inclusion criteria. Vital signs were normal in 30/49 patients; 10 (33%) of these patients had LUS consistent with viral pneumonitis. We rejected the null hypothesis (p-value <0.001). The treating physicians' interpretations of their own point-of-care LUS had a sensitivity of 100% (95% confidence interval (CI), 74%, 100%), specificity 88% (95% CI, 47%, 100%), likelihood ratio (LR) positive of 5.8 (95% CI, 1.3, 25), and LR negative of 0.05 (95% CI, 0.03, 0.71) when compared to CT findings.

Conclusion: LUS had a meaningful detection rate for pneumonitis in symptomatic ED patients with normal vital signs who were being evaluated for COVID-19. We recommend at least LUS be used in addition to polymerase chain reaction testing when evaluating symptomatic ED patients for COVID-19.

Figure

This figure shows patient flow through the study. Given the clinical context of evaluating suspected COVID-19 the presence or absence of lung ultrasound findings consistent with viral pneumonitis was interpreted as consistent with COVID-19. COVID-19, coronavirus disease 2019; US, ultrasound; CHF, congestive heart failure.