Table 1

Factors associated with success or failure in NIV

High Paco2 with low A–a oxygen gradientHigh 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 NIVCopious respiratory secretions
Good level of consciousnessEdentulous
Poor nutritional status
Confusion or impaired consciousness