Figure 2.

Correlation between LUS‐score and oxygen demand defined as SpO₂/FiO₂‐ratio. Cut‐off values (dotted lines) for mild, moderate and severe respiratory failure are defined as SpO₂/FiO₂‐ratio 315, 235 and 148, respectively. Data presented prior to intubation (IMV‐group) and on the day with highest oxygen demand (non‐IMV‐group). For the reference group data were collected within 48 hours after hospital admission. Correlation coefficient and p‐value given for Pearson correlation. See Figure 1 legend for definition of groups. LUS = lung ultrasound; IMV = invasive mechanical ventilation; SpO₂ = peripheral oxygen saturation; FiO₂ = inspired fraction of oxygen.