Noninvasive Positive Pressure Ventilation in Patients with Acute Respiratory Failure.

Noninvasive positive pressure ventilation (NIPPV) delivered by nasal route or facemask is increasingly being used in the management of patients with acute respiratory failure. 45 patients (29 males,16 females) with a mean age of 68.32 years (range 29 to 82 years) having acute onset hypoxemic and/or hypercapnic respiratory failure who were managed with NIPPV in a tertiary care centre of Armed Forces were analyzed retrospectively. Patients with hemodynamic instability, coma and uncooperative patients were excluded from study. Etiology of acute respiratory failure was acute exacerbation of chronic obstructive pulmonary disease (COPD) in 29 patients, adult respiratory distress syndrome (ARDS) in 4 patients, severe kyphoscoliosis in 2 patients, interstitial lung disease (ILD) in 4 patients, lung contusion with pneumonia in 1 patient, thoracoplasty in 1 patient and difficult weaning in 4 patients. Initial resting arterial blood gases showed mean arterial oxygen tension (PaO2) 61 mmHg (range 45 to 78 mmHg), mean arterial carbon dioxide tension (PaCO2) 75.2 mmHg (range 32 to 127 mmHg) and mean arterial pH-7.26 (range 7.03 to 7.45). Mean inspiratory positive airway pressure (IPAP) was 14 cm H2O (range 10 to 20 cm H2O). Mean expiratory positive airway pressure (EPAP) was 5.8 cm H2O (range 4 to 8 cm H2O). On an average, NIPPV was required for 5.4 days (range 2 to 15 days) prior to discharge. 11 patients required long term intermittent NIPPV along with domiciliary oxygen therapy. 9 patients died out of which 4 patients had advanced interstitial lung disease. NIPPV has been found useful in acute respiratory failure due to acute exacerbations of COPD, thoracic wall abnormalities and ARDS. It has not been found useful in hypoxemic respiratory failure due to interstitial lung disease and diffuse interstitial pneumonia.