Table 3 Definition of VetALI/VetARDS: Veterinary Acute Lung Injury and Acute Respiratory Distress Syndrome [25]

1. Acute onset (72 h) of tachypnoea and laboured breathing at rest.

2. Known risk factors (inflammation, infection, sepsis, SIRS, severe trauma, multiple transfusions, smoke inhalation, near-drowning, aspiration of stomach contents, drugs and toxins).

3. Evidence of pulmonary capillary leak without increased pulmonary capillary pressure^a (any one or more of the following):

 a. Bilateral/diffuse infiltrates on thoracic radiographs (more than 1 quadrant/lobe)

 b. Bilateral dependent density gradient on CT

 c. Proteinaceous fluid within the conducting airways

 d. Increased extravascular lung water

4. Evidence of inefficient gas exchange (any one or more of the following):

 a. f. Hypoxemia without PEEP or CPAP and known FiO2

  i. PaO₂/FiO₂ ratio (≤300 mmHg for VetALI; ≤200 mmHg for VetARDS)

  ii. Increased alveolar-arterial oxygen gradient

  iii. Venous admixture (non-cardiac shunt)

 b. Increased ‘dead-space’ ventilation

5. Evidence of diffuse pulmonary inflammation

 a. Transtracheal wash/bronchoalveolar lavage sample neutrophilia

 b. Transtracheal wash/bronchoalveolar lavage biomarkers of inflammation

 c. Molecular imaging (PET)