An open randomized controlled trial of noninvasive positive pressure ventilation in patients of acute on chronic hypercapnic respiratory failure in a general respiratory ward setting

Abstract

Objective : To compare the standard medical therapy (SMT) and noninvasive posi­tive pressure ventilation (NPPV) in acute on chronic hypercapnic respiratory fail­ure due to exacerbation of chronic obstructive pulmonary disease (COPD). Method : Between June 2002 and May 2003, 19 patients with acute on chronic hypercapnic respiratory failure were prospectively and randomly recruited to re­ceive either SMT (n=10) or NPPV plus SMT (n=9) in a general respiratory ward and followed up after 4 to 6 weeks after discharge. NPPV was given with a silicone cushioned nasal mask via a bilevel ventilator with initial pressure support of 5 cm of H 2 O. Results : At the time of randomization there was no significant difference in respiratory rate, PaO 2 , PaCO 2 , pH and HCO3 - , between the two groups. At 2 hours with SMT, there was significant improvement only in respiratory rate (p = 0.0000) and PaO 2 (p=0.0014). However with NPPV, respiratory rate (p=0.0000), PaO2 (p=0.0011), pH (0.0002), pulse rate (p=0.0329) and mean arterial pressure (p=0.0096) improved significantly at 2 hours while PaCO2 (p=0.0008 significantly improved at24 hours. Hospital stay was significantly shorter for NPPV group as compared to SMT group (9.63 + 1.4 days vs. 13.33 + 4.69 days, p Conclusion : The study suggests that early application of NPPV in acute on chronic hypercapnic respiratory failure due to COPD facilitates improvement, favors early mobiliation and discharge from hospital.