Factors associated with success or failure in NIV
| Success | Failure |
|---|---|
| High Paco2 with low A–a oxygen gradient | High APACHE score |
| pH 7.25–7.35 (H+ 56–45 nmol/l) | Pneumonia on chest radiography |
| Improvement in pH, Paco2, and respiratory rate after 1 hour of NIV | Copious respiratory secretions |
| Good level of consciousness | Edentulous |
| Poor nutritional status | |
| Confusion or impaired consciousness |