Table 1.

Guidelines for clinical diagnosis and definitions and grading system for lung ultrasound and chest radiograph.

Clinical diagnoses
Pneumonia	Difficulty breathing as described by tachypnea, chest indrawing, nasal flaring, or grunting; history of fever, cough, chest pain or abdominal pain; adventitious lung sounds, including rales, rhonchi, crackles, or diminished sounds. Associated CXR findings of interstitial abnormalities or consolidation as reviewed by hospital clinician or on-site radiologist at time of diagnosis [3]. Severity was assessed by presence of chest indrawing, seizures, lethargy, or unconsciousness [4].
Asthma	Presence of wheeze or difficulty breathing on physical exam, history of wheeze and responsive to bronchodilators [5]. Response to bronchodilators assessed clinically without formal pulmonary function testing.
Bronchiolitis	Less than 18 months of age; presence of wheeze or coarse breath sounds, difficulty breathing, and viral symptoms (cough, rhinorrhea); not responsive to bronchodilators if attempted [24].
Upper respiratory infection	Associated with nasal secretions, nasal congestion, sore or red throat or hoarseness without evidence of lower airways involvement (tachypnea and abnormal lung sounds on exam).
Lung ultrasound findings
Lung sliding	Rhythmic movement of pleural line with respiration. It represents sliding of the visceral pleura against the parietal pleura.
A-lines	Horizontal lines equally spaced from pleural line, representing artifact generated by subpleural air, a normal finding.
B-lines	Vertical lines arising from pleura and extending to base of the image.
Pleural abnormality	Disruption of pleural line.
Consolidation	Hypoechoic circumscribed disruption of pleural line extending inferiorly and may contain any of the following; Air bronchogram, Shred sign, Pleural effusion.
Air bronchogram	Punctate or branching hyperechoic images reflecting airways made visible by surrounding fluid/inflammation
Shred sign	Irregular border of consolidation
Pleural effusion	Anechoic space between visceral and parietal pleura.
Sonographic grading
Lung consolidation
Small	Consolidation contained within one intercostal space and extending just below pleural line.
Large	Consolidation extends to more than 1 intercostal space, extends beyond the pleural line, and may be associated with a pleural effusion.
Interstitial abnormality
Focal	Multiple B lines (≥3) present in single view or unilaterally.
Diffuse	Multiple B lines (≥3) present bilaterally.
Radiographic grading
Lung consolidation	Alveolar pneumonia: dense, fluffy consolidation of a portion of a lobe or entire lung. Often contains air bronchograms and may be associated with pleural effusion.
Interstitial abnormality	Linear and patchy densities in a lacy pattern involving both lungs, featuring peri-bronchial thickening and multiple areas of atelectasis. Lung inflation is normal to increased.