To the Editor,
We thank Gil-Rodrigo et al. for their considerations on our manuscript describing the use of a radiography-based triage for COVID-19 in the Emergency Department (ED), published in Medicina Clínica.1 In that manuscript, we described the use of chest X ray (CXR) in patients with mild suspected COVID-19 infection and possible pneumonia as a triage tool to speed up the ED stay and safe discharges.
Gil-Rodrigo et al. describe the potential use of lung ultrasound (LUS) instead of polymerase chain reaction (PCR) for an earlier diagnosis of COVID-19 since laboratory processing might take hours. Furthermore, they considered that detecting COVID-19 patients with LUS would allow to separate them from the rest of the patients quicker, moving them fewer times around the ED. This could reduce the risk of nosocomial spread of the virus. LUS has a fairly better capacity of diagnosing pneumonia compared to CXR. Pneumonia is the hallmark of lung damage and subsequent complications in COVID-19 patients. It is convenient: it can be done at the bedside, no radiations are needed, and it can help to discern which patient would benefit from an extended inhospital stay. Our colleagues propose the integration of LUS in our original COVID-19 ED flow algorithm as a second line test for patients with CXR ruling out pneumonia or for those who could have a contraindication for radiation-based tests.
Our diagnostic approach to COVID-19 has radically changed since 2020. The affordable and quick rapid antigen tests (RAT) have replaced PCR for first line testing, especially in mild symptomatic COVID-19 patients.2 In 15–30 min, we can have a diagnosis, and tests are available in the pharmacies so that patients might come to the ED with a COVID-19 diagnosis already done. Triage for suspected COVID-19 can now be effectively done upon ED admission with RAT and a severity scoring tool like the Andorran triage model. There is almost no role for imaging in COVID-19 infection diagnosis at this point.
Morbidity and mortality secondary to COVID-19 have plummeted. Incidence of pneumonia, hospitalization, or death in the different Omicron variants have decreased compared to previous variants.3 This factor, along with effective vaccination campaigns and treatments, has made less likely the eventual EDs’ COVID-19-related overflow with a great number of patients at risk for complications. We think that in that given setting, limitations including ultrasound machine availability, the need for trained staff in adequate numbers, the inter-operator data interpretation variability, and the time allocated for each exam (5–7 min at best but likely more: e.g. cleaning the device/changing the probe cover, getting the physician to another room, getting the next patient ready) would still pose a serious feasibility issue. CXR can reach an acceptable sensitivity with a very low mortality (0.003%) in patients with no radiologic findings of pneumonia, as we showed. We still think it is the first and most convenient screening tool for COVID-19 pneumonia in patients with mild involvement. LUS can have a paper as an ancillary test.4 It's added benefit in CXR negative patients is nowadays questionable given Omicrons’ generally benign course and the reduction of complications associated to vaccination making them unlikely in general population. Nonetheless, we agree it can have a role in selected patients with CXR contraindications with risk factors for complications, or when CXR is not diagnostic and there is a strong suspicion for COVID-19-related pneumonia.
Funding
None for this specific manuscript.
Conflicts of interest
None for this specific manuscript.
Acknowledgements
None.
Appendix A
Members of the Vall d’Hebron University Hospital COVID 19 ED research group: María Arranz-Betegón, Esperanza Cañas-Ruano, Eva Domingo-Baldrich, Andreu Fernández-Codina, Eloi García-Vives, Albert Gil-Vila, Jordi Llaneras-Artigues, Beatriz Meza, Xabier Michelena, Olimpia Orozco-Gálvez, Iago Pinal-Fernández, Sheila Romero-Ruperto, Francesc Sanpedro-Jiménez, Abiu Sempere-González, and Javier Sarrapio-Lorenzo.
References
- 1.Sempere-González A., Llaneras-Artigues J., Pinal-Fernández I., Cañas-Ruano E., Orozco-Gálvez O., Domingo-Baldrich E., et al. Radiography-based triage for COVID-19 in the Emergency Department in a Spanish cohort of patients. Med Clin (Barc) 2022;158:466–471. doi: 10.1016/j.medcli.2021.05.013. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Dinnes J., Sharma P., Berhane S., van Wyk S.S., Nyaaba N., Domen J., et al. Rapid, point-of-care antigen tests for diagnosis of SARS-CoV-2 infection. Cochrane Database Syst Rev. 2022;7:CD013705. doi: 10.1002/14651858.CD013705.pub3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Wolter N., Jassat W., Walaza S., Welch R., Moultrie H., Groome M.J., et al. Clinical severity of SARS-CoV-2 Omicron BA.4 and BA.5 lineages compared to BA.1 and Delta in South Africa. Nat Commun. 2022;13:5860. doi: 10.1038/s41467-022-33614-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Jari R., Alfuraih A.M., McLaughlan J.R. The diagnostic performance of lung ultrasound for detecting COVID-19 in emergency departments: a systematic review and meta-analysis. J Clin Ultrasound. 2022;50:618–627. doi: 10.1002/jcu.23184. [DOI] [PMC free article] [PubMed] [Google Scholar]