The aim of this study is to evaluate the potential usefulness of lung ultrasound to assess the size and perfusion of consolidation and explore their relationships with clinical outcome.

Lung consolidation is one of the most causes of hypoxia in intensive care unit(ICU) settings. A quantitative measurement of consolidation would be extremely benefit for the clinical management in hypoxemia, both as an index of severity and to predict outcomes.In order to quantify the lung consolidation and its effect on clinical outcomes, a simple and quantitative scoring system of the size and perfusion of lung consolidation was proposed by lung ultrasound. Subjects with respiratory failure and lung consolidation proved by chest imaging underwent lung ultrasound examination. The size of consolidation and the richness of blood flow was computed upon lung ultrasound. The sensitivity, specificity and accuracy of the scoring system were calculated and compared to evaluate the diagnostic efficacy.

Inclusion criteria:

1. Admission to ICU( 18yr<age<90yr);
2. Patients presented with acute respiratory failure;
3. Pulmonary consolidation by chest imaging (lung ultrasound, X ray or CT scan).

Exclusion criteria:

1. Hemodynamic instability (i.e., severe hypotension with systolic arterial pressure<60mmHg despite fluid expansion and vasoactive support; systolic arterial pressure>180mmHg; uncontrolled cardiac arrhythmias);
2. Severe thoracic trauma;
3. Coronavirus disease 2019;
4. Pulmonary artery hypertension and pregnancy.

The study population consisted of adult(>18yr) patients admitted to the ICU. Patients presented with acute respiratory failure and pulmonary consolidation by chest imaging (lung ultrasound, X ray or CT scan) were eligible for inclusion. Acute respiratory failure was defined by at least one of the following criteria: PaO2/FiO2<300mmHg, breathing frequencies>30 breath/min, and could involve many potential causes of hypoxemia (e.g., sepsis, atelectasis, pneumonia, acute exacerbation of chronic lung disease).