Current best evidence for clinical care (more info)
STUDY OBJECTIVE: Accurate diagnostic testing to identify severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is critical. Although highly specific, SARS-CoV-2 reverse transcriptase-polymerase chain reaction (RT-PCR) has been shown in clinical practice to be affected by a noninsignificant proportion of false-negative results. This study seeks to explore whether the integration of lung ultrasonography with clinical evaluation is associated with increased sensitivity for the diagnosis of coronavirus disease 2019 pneumonia, and therefore may facilitate the identification of false-negative SARS-CoV-2 RT-PCR results.
METHODS: This prospective cohort study enrolled consecutive adult patients with symptoms potentially related to SARS-CoV-2 infection who were admitted to the emergency department (ED) of an Italian academic hospital. Immediately after the initial assessment, a lung ultrasonographic evaluation was performed and the likelihood of SARS-CoV-2 infection, based on both clinical and lung ultrasonographic findings ("integrated" assessment), was recorded. RT-PCR SARS-CoV-2 detection was subsequently performed.
RESULTS: We enrolled 228 patients; 107 (46.9%) had SARS-CoV-2 infection. Sensitivity and negative predictive value of the clinical-lung ultrasonographic integrated assessment were higher than first RT-PCR result (94.4% [95% confidence interval {CI} 88.2% to 97.9%] versus 80.4% [95% CI 71.6% to 87.4%] and 95% [95% CI 89.5% to 98.2%] versus 85.2% [95% CI 78.3% to 90.6%], respectively). Among the 142 patients who initially had negative RT-PCR results, 21 tested positive at a subsequent molecular test performed within 72 hours. All these false-negative cases were correctly identified by the integrated assessment.
CONCLUSION: This study suggests that, in patients presenting to the ED with symptoms commonly associated with SARS-CoV-2 infection, the integration of lung ultrasonography with clinical evaluation has high sensitivity and specificity for coronavirus disease 2019 pneumonia and it may help to identify false-negative results occurring with RT-PCR.
| Discipline / Specialty Area | Score |
|---|---|
| Emergency Medicine | |
| Hospital Doctor/Hospitalists | |
| Internal Medicine | |
| Intensivist/Critical Care | |
| Respirology/Pulmonology | |
| Infectious Disease | |
The main pitfall is that we do not know the physiological state of the patients on arrival (saturation, respiratory frequency...) which means that we do not really know to which patients these results could be superimposed on our daily practice.
Use of POCUS lung ultrasound resulted in a higher sensitivity than initial RT-PCR COVID-19 testing for patients with suspected COVID-19 infection. However there are some important limitations: 1) it's unclear if these results are generalizable in the hands of less experienced operators; 2) the lack of standardization of what constitutes a positive diagnostic finding on POCUS could lower the sensitivity amongst all POCUS users; 3) this study was done during a time of high prevalence of disease for COVID-19. It's unclear if during other seasons of infectious viral respiratory illness or if the prevalence of COVID-19 were lower would the PPV be as high (likely not); 4) this required a 12-point lung US, which is not commonly used in POCUS. Regardless, it seems clear that POCUS can be an alternative to PCR testing that may in fact be BETTER (or at least more sensitive) for the detection of COVID-19 infection in the hands of expert users. How generalizeable it really is, remains to be seen.
Excellent paper and nice findings!! The only problem is about applicability, as it is necessary to have physicians trained in US at every ED and with clinical experience in Covid-19 patients.
While this initial single-center study had a rather low n value, the findings were more promising than the average clinician might think. This is something that warrants further study. However, at the current stage, it is sound to assume anyone with covid-suspicious symptoms has the virus until proven otherwise, for example with multiple negative rt-PCR tests, rather than rely on the clinical-lung ultrasound composite.