Contribution of lung ultrasound to assess COVID-19 pneumonia in critical care setting: a prospective cohort study

We aimed to describe lung ultrasound (LUS) findings in COVID-19 pneumonia and to analyze the association with initial severity and outcome. Prospective cohort study among intensive care unit (ICU) patients in a teaching hospital in Tunisia. A 20-bed respiratory medical intensive care unit of Abderrahmen Mami Teaching Hospital from January to December 2021. We included all COVID-19 pneumonia patients managed in ICU. LUS examination and chest computed tomography (CT), when possible, were performed during the first 24 h of ICU stay. LUS findings were described and association with severity was analysed for trends. During the one-year study period, 311 patients were included with a median age of 58 IQR [47-67] years. ARDS was diagnosed in 307 patients (98.7%). Median initial PaO₂/FiO₂ was 112 IQR [81-157] mmHg. Median length of stay was 10 IQR [7-14] days and overall mortality was of 45.3%. Median LUS score was 29 IQR [25-32]. LUS score gradients were apico-basal and postero-antero-lateral. There was a significant correlation between ROX index and LUS score with r= -0.146 and p = 0.013. LUS score above 25 was significantly associated with chest CT damage exceeding 75% (NPV = 80.7%). LUS score under 25 was significantly associated with chest CT damage < 50% (NPV = 77.5%). No association was found between the LUS score and mortality or the need for invasive ventilation. In COVID-19 pneumonia, LUS is a good and safe tool for initial severity assessment. LUS score is correlated with ROX index and extent of chest damage on CT scan. However, LUS score does not predict outcome nor need for invasive mechanical ventilation.