Noninvasive ventilation: Are we overdoing it?

BACKGROUND: Use of noninvasive ventilation (NIV) outside guideline recommendations is common. We audited use of NIV in our tertiary care critical care unit (CCU) to evaluate appropriateness of use and patient outcomes when used outside level I recommendations.

MATERIALS AND METHODS: Prospective observational study of all patients requiring NIV. Clinical parameters and arterial blood gases were recorded at initiation of NIV and 2 h later (or earlier if clinically warranted). NIV titration and decision to intubate were left to the discretion of treating intensivist. Patients were categorized into two groups: Group 1: Those with level I indications for use of NIV and group 2: All other levels of indications. Patients were followed until hospital discharge.

RESULTS: From January 2010 to June 2010, 1120 patients were admitted to the CCU. Of these 106 patients required NIV support with 40.6% (n = 43/106) being in group 1 and 59.4% (n = 63/106) in group 2. Of these 35.8% patients (38/106) failed NIV and required endotracheal intubation. NIV failure rates (41.27% vs. 27.91%; P = 0.02) and mortality (30.6% vs. 18.6%; P = 0.03) were significantly higher in group 2 patients. In a logistic regression analysis Acute Physiology and Chronic Health Evaluation (APACHE) II score (P = 0.02), time on NIV before intubation (P = 0.001) and baseline PaCO2 levels (P = 0.01) were strongly associated with mortality.

CONCLUSION: Noninvasive ventilation failure and mortality rates were significantly higher when used outside level I recommendations. APACHE II score, baseline PaCO2 and duration on NIV prior to intubation were predictors of increased mortality.