RESUMO
Background: Chest imaging, including chest X-ray (CXR) and computed tomography (CT), can be a helpful adjunct to nucleic acid test (NAT) in the diagnosis and management of Coronavirus Disease 2019 (COVID-19). Lung point of care ultrasound (POCUS), particularly with handheld devices, is an imaging alternative that is rapid, highly portable, and more accessible in low-resource settings. A standardized POCUS scanning protocol has been proposed to assess the severity of COVID-19 pneumonia, but it has not been sufficiently validated to assess diagnostic accuracy for COVID-19 pneumonia. Purpose: To assess the diagnostic performance of a standardized lung POCUS protocol using a handheld POCUS device to detect patients with either a positive NAT or a COVID-19-typical pattern on CT scan. Methods: Adult inpatients with confirmed or suspected COVID-19 and a recent CT were recruited from April to July 2020. Twelve lung zones were scanned with a handheld POCUS machine. Images were reviewed independently by blinded experts and scored according to the proposed protocol. Patients were divided into low, intermediate, and high suspicion based on their POCUS score. Results: Of 79 subjects, 26.6% had a positive NAT and 31.6% had a typical CT pattern. The receiver operator curve for POCUS had an area under the curve (AUC) of 0.787 for positive NAT and 0.820 for a typical CT. Using a two-point cutoff system, POCUS had a sensitivity of 0.90 and 1.00 compared to NAT and typical CT pattern, respectively, at the lower cutoff; it had a specificity of 0.90 and 0.89 compared to NAT and typical CT pattern at the higher cutoff, respectively. Conclusions: The proposed lung POCUS protocol with a handheld device showed reasonable diagnostic performance to detect inpatients with a positive NAT or typical CT pattern for COVID-19. Particularly in low-resource settings, POCUS with handheld devices may serve as a helpful adjunct for persons under investigation for COVID-19 pneumonia.
RESUMO
PURPOSE: The aim of the study was to evaluate for an association between the number of voluntary mannequin simulation sessions completed during the school year with scores on a year-end diagnostic reasoning assessment among second-year medical students. METHOD: This is retrospective analysis of participation in 0 to 8 extracurricular mannequin simulation sessions on diagnostic reasoning assessed among 129 second-year medical students in an end-of-year evaluation. For the final skills assessment, 2 physicians measured students' ability to reason through a standardized case encounter using the Diagnostic Justification (DXJ) instrument (4 categories each scored 0-3 by raters reviewing students' postencounter written summaries). Rater scores were averaged for a total DXJ score (0-12). To provide additional baseline comparison, zero participation students were divided into 2 groups based on intent to participate: those who signed up for extracurricular sessions but never attended versus those who never expressed interest. Scores across the attendance groups were compared with an analysis of variance and trend analysis. RESULTS: The class DXJ mean equaled 7.56, with a standard deviation of 2.78 and range of 0 to 12. Post hoc analysis after a significant analysis of variance (F = 4.91, df = 8, 128, P < 0.001) showed those participating in 1 or more extracurricular sessions had significantly higher DXJ scores than those not participating. Students doing 7 extracurricular sessions had significantly higher DXJ scores than those doing 0 and 2 (P < 0.05). Zero attendance groups were not different. A significant linear trend (R = 0.48, F = 38.0, df = 1, 127, P < 0.001) was found with 9 groups. A significant quadratic effect, like a dose-response pattern, was found (F = 18.1, df = 2, 125, P < 0.001) in an analysis including both zero attendance groups, a low (1-4 extracurricular sessions) group and a high (5-8) group. CONCLUSIONS: Higher year-end diagnostic reasoning scores were associated with increased voluntary participation in extracurricular mannequin-based simulation exercises in an approximate dose-response pattern.
