Reported contraindications for noninvasive ventilation
| Cardiac or respiratory arrest |
| Severe encephalopathy |
| Severe gastrointestinal bleeding |
| Severe haemodynamic instability with or without unstable cardiac angina |
| Facial surgery or trauma |
| Upper airway obstruction |
| Inability to protect the airway and/or high risk of aspiration |
| Inability to clear secretions |