Point of care lung ultrasound is useful when screening for CoVid-19 in Emergency Department patients

Walsh, Paul; Hankins, Andrea; Bang, Heejung

BACKGROUND: 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) screening in symptomatic patients with normal vital signs is frequently limited to 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: SUBJECTS: Subjects were identified from ED ultrasound logs. INCLUSION CRITERIA: Age 14 years or older with symptoms prompting ED screening for CoVid-19. EXCLUSION CRITERIA: Known congestive heart failure or other chronic lung condition likely to cause excessive B lines on LUS. INTERVENTION: Structured blinded ultrasound review and chart review ANALYSIS: We used a two-sided exact hypothesis test for binomial random variables. We also 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 CoVid-19. We rejected the null hypothesis (p-value <0.001). The treating physicians’ interpretation of their own point of care lung ultrasounds had a sensitivity of 100% (95% CI 75%, 100%) and specificity of 80% (95% CI 68%, 89%). CONCLUSION: LUS has a meaningful detection rate for CoVid-19 in symptomatic ED patients with normal vital signs. We recommend at least LUS be used in addition to PCR testing when screening symptomatic ED patients for CoVid-19.