Lung ultrasound score predicts outcomes in patients with acute respiratory failure secondary to COVID-19 treated with non-invasive respiratory support: a prospective cohort study

BACKGROUND

Lung ultrasound has demonstrated its usefulness in several respiratory diseases management. One derived score, the Lung Ultrasound (LUS) score, is considered a good outcome predictor in patients with Acute Respiratory Failure (ARF). Nevertheless, it has not been tested in patients undergoing non-invasive respiratory support (NIRS). Taking this into account, the aim of this study is to evaluate LUS score as a predictor of 90-day mortality, ETI (Endotracheal intubation) and HFNC (High Flow Nasal Cannula) failure in patients with ARF due to COVID-19 admitted to a Respiratory Intermediate Care Unit (RICU) for NIRS management.

RESULTS

One hundred one patients were admitted to the RICU during the study period. Among these 76% were males and the median age was 55 (45-64) years. Initial ARF management started with HFNC, the next step was the use of Continuous Positive Airway Pressure (CPAP) devices and the last intervention was ETI and Intensive Care Unit (ICU) admission. Of the total study population, CPAP was required in 40%, ETI in 26%, while 15% died. By means of a ROC analysis, a LUS ≥ 25 points was identified as the cut-off point for mortality(AUC 0.81, OR 1.40, 95% CI 1.14 to 1.71; p < 0.001), ETI (AUC 0.83, OR 1.43, 95% CI 1.20 to 1.70; p < 0.001) and HFNC failure (AUC 0.75, OR 1.25, 95% CI 1.12 to 1.41; p < 0.001). Kaplan-Meier survival curves also identified LUS ≥ 25 as a predictor of 90-days mortality (HR 4.16, 95% CI 1.27-13.6) and 30 days ETI as well.

CONCLUSION

In our study, a ≥ 25 point cut-off of the Lung Ultrasound Score was identified as a good outcome prediction factor for 90-days mortality, ETI and HFNC failure in a COVID-19 ARF patients cohort treated in a RICU. Considering that LUS score is easy to calculate, a multicenter study to confirm our findings should be performed.

Combined Noninvasive Respiratory Support Therapies to Treat COVID-19

BACKGROUND

The roles of high-flow nasal cannula (HFNC) and CPAP in coronavirus disease 2019 (COVID-19) are controversial. The objective of the study was to evaluate the impact of the application of a noninvasive respiratory support algorithm on clinical outcomes in subjects with COVID-19 and with acute respiratory failure.

METHODS

We performed a single-center prospective observational study of subjects with respiratory failure from COVID-19 managed with HFNC and with CPAP plus HFNC (combined therapy). The main outcome was the intubation rate, which defined failure of therapy. We also analyzed the role of the ROX index ([[Formula: see text]/[Formula: see text]]/breathing frequency) to predict the need for intubation.

RESULTS

From June to December 2020, 113 subjects with COVID-19 respiratory failure were admitted to our respiratory intermediate care unit. HFNC was applied in 65 subjects (57.52%) and combined therapy in 48 subjects (42.47%). A total of 83 subjects (73.45%) were successfully treated with noninvasive respiratory support. The intubation rate was 26.54%, and the overall mortality rate was 14.15%. The mortality rate in subjects who were intubated was 55.2%. An ROX index of 6.28 at 12 h predicted noninvasive respiratory support failure, with 97.6% sensitivity and 51.8% specificity.

CONCLUSIONS

Data from our cohort managed in a respiratory intermediate care unit showed that combined noninvasive respiratory support was feasible, with favorable outcomes. Further prospective studies are required.