Outcome of Non-Invasive Ventilation in Patients of Acute Respiratory Failure.

Abstract

Introduction: Non-invasive ventilation (NIV) is a method of ventilator support or delivery of positive pressure into the lungs usually through a face mask, mostly initiated before severe acidosis occurs. NIV failure requiring invasive mechanical ventilation in decompensated chronic obstructive pulmonary disease (COPD) patients is low, but, in critical patients, it is as high as 60%. Acute respiratory failure (ARF) is the common reason for admission to the intensive care unit. This study assesses the outcome of NIV among patients with acute respiratory failure, the duration of use, stay in ICU, and failure rate of NIV. Such type of study result is scarce in our country.

Methods:  Arterial blood gases were assessed prior, after, and at discontinuation of NIV. NIV was delivered by ventilator via face mask. All patients above age 15 years who presented to the hospital, diagnosed to have ARF by ABG were included and admitted to Medical Intensive Care Unit (MICU). . Appropriate statistical tests (Chi-square) were performed and the statistical significance of the results was assessed.

Results: 35 patients with the median age of 73 years (range: 39- 89 years), of 60.0 % females among which 74.3 % were current smokers. Arterial blood pH prior to admission ranged from 7.11-7.39 and 7.06-7.41 among NIV success and failure, respectively. Similarly, PCo2 ranged from 54.0-127.5 and 29.5-105.9 among them, respectively. Two hours after ventilation pH ranged from 7.12-7.43 and 7.05-7.30 respectively in the success and failure group. The most common disease condition requiring NIV was 77.1% COPD.  Out of NIV failure group (n=19) ,57.8 % were intubated and 42.1% patients left the intervention. 

Conclusions: Usage of NIV among ARF patients was associated with lower intubation and ICU mortality rate. COPD patients showed the most benefit with NIV, whereas patients suffering from interstitial lung disease, lung cancer had less benefit.