Non invasive ventilation in acute respiratory failure due to COPD vs non COPD conditions: Effectiveness and failure predictors

Abstract

Background: Acute respiratory failure is a common indication for ICU admission & mechanical ventilation. NIV is coming out to be a safer alternative free from complications of mechanical ventilation. While it has got a proven role in COPD patients, little is known about non COPD ARFs. Aim: To compare effectiveness of NIV in COPD vs non COPD ARFs & find out predictors of the failure in two groups. Methods: We performed a comparative prospective study over the patients of ARF (pO2 45 mm Hg) due to COPD & non COPD respiratory conditions. The patients (n=182) were divided into COPD(n=98) & non COPD(n=84) groups based on history, examination, previous records like PFT. Baseline investigations ( ABG, routine hematology, chest xray etc) including APACHEII score calculation is done. NIV is applied and ABG was recorded at 1st, 4th, and 24th hour. Primary endpoint was NIV failure i.e need for endotracheal intubation and mechanical ventilation. Secondary end point was in-hospital mortality and length of hospital stay. Measurements and Main Results: NIV succeeded more in COPD group then non COPD conditions (77.4% vs 53.1%). High heart rate, and pCO2 at 1st hour predicted the failure in COPD group while high APACHEII, high pCO2 after one hour, and high respiratory and heart rates at baseline and after one hour were important predictors of failure in non COPD group. Maximum mortality was in pneumonia patients. Conclusion: NIV is a one of the promising mode of treatment in ARF due to acute exacerbation of COPD. It can also prevent endotracheal intubation and mechanical ventilation in more than half of non COPD patients also.