- Failure to maintain the airway. e.g. snoring, stridor, is requiring manual airway opening maneuvers or the placement of simple airway adjuncts.
- Failure to protect the airway. If patient is assessed as not protecting their airway, based on a low level of consciousness, I.e. a Glasgow Coma Scale of 8 or less
- Failure to oxygenate. Falling or low SaO2 despite treatment of pneumothoraces and giving high flow oxygen,
- Expected or anticipated clinical course. e.g. The patient with failing respirations or a reducing GCS,