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

Abstract

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 an exact hypothesis tests for binomial random variables. We also measured LUS diagnostic performance using computed tomography as the gold standard. Results We reviewed 77 charts; 62 met inclusion criteria. Vital signs were normal in 31 patients; 10 (32%) of these patients had LUS consistent with CoVid-19. We rejected the null hypothesis (p-value for bitest <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 emergency department 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.

Fig 1.

Patient flow through the study.