Spain: Study on Lung Ultrasound Score for COVID-19 Pneumonia

A recent study published in Medicina Clínica has described a lung ultrasound cutoff score that classifies pneumonia's severity for COVID-19.

The study showed lung ultrasound score (LUS) is a good predictor of 28-day mortality and poor outcome in COVID-19. This categorization will help establish an early prognosis for the patient and to guide the most suitable treatment on an individual basis.

• LUS ≥20 cutoff point is linked with severe pneumonia
• LUS 8-20 with moderate pneumonia
• LUS ≤7 with mild pneumonia

The authors note that if a single cutoff point were used, LUS >15 would be the point that better discriminates mild from severe disease.

The usefulness of lung ultrasound has been explored in COVID-19 protocols, an easy-to-learn, nonionizing and repeatable technique. However, the investigators noted that no benchmark points had been addressed as optimal cutoffs for determining pneumonia severity.

Gil-Rodríguez Jaime and colleagues from Spain conducted a literature review to establish different cutoff points based on the Lung Ultrasound Score to categorize COVID-19 pneumonia severity.

For this purpose, the researchers systematically reviewed previously proposed LUS cutoff points. A single-centre prospective cohort study of adult patients with confirmed SARS-CoV-2 infection validated these results. Studied variables included 28-day mortality and poor outcomes (intensive care unit admission, ventilation support or 28-day mortality). 11 articles were included out of 510 reviewed, comprising 1,308 hospitalized patients with COVID-19 pneumonia.

Study Findings

The study revealed the following findings:

• Among the cutoff points proposed in the articles included, only the LUS >15 cutoff point could be validated for its original endpoint, also demonstrating the strongest relation with poor outcome (odds ratio [OR] = 3.636).
• Regarding the cohort, 127 patients were admitted. In these patients, LUS was statistically associated with poor outcomes (OR = 1.303) and 28-day mortality (OR = 1.024).
• LUS >15 showed the best diagnostic performance when choosing a single cutoff point in our cohort (area under the curve 0.650).
• LUS ≤7 showed high sensitivity to rule out poor outcomes (0.89), while LUS >20 revealed high specificity to predict poor outcomes (0.86).

"Our study's findings would help clinicians to predict COVID-19 outcomes better, as an LUS of seven and below can indicate mild pneumonia, while LUS above 20 likely indicate severe pneumonia," the authors wrote. "If a single cutoff point were used, LUS >15 would be the point which better differentiates mild from severe disease."

To conclude, LUS is a good predictor of 28-day mortality and poor outcome in COVID-19.

Reference

Jaime, G., Michel, M., Alberto, B., Pablo, A., Ángel, M. M., José-Antonio, P., Daniel, F., Victoria-Carazo Javier, M. D., Emilio, G., & José, H. (2023). Lung Ultrasound Score severity cutoff points in COVID-19 pneumonia. A systematic review and validating cohort. Medicina Clínica. https://doi.org/10.1016/j.medcli.2023.01.024