The use of noninvasive mechanical ventilation in COPD with severe hypercapnic acidosis

SummaryStudy Objectives: To compare the effect of noninvasive mechanical ventilation (NIV) in severely acidotic with mildly acidotic patients with acute hypercapnic chronic obstructive lung disease (COPD).Design: Comparison of NIV in consecutively enrolled patients with acute hypercapnic COPD with mild (pH 7.25–7.35) or severe (pH<7.25) acidosis on time to normalise pH and improve PaCO2, duration of NIV treatment, length of stay in hospital and survival.Results (meadian (IQR)): Twenty-nine patients had 36 episodes of acute hypercapnic respiratory failure: Seventeen with pH<7.25 and 19 with pH 7.25–7.34. Compared with the mildly acidotic group, the severely acidotic group took a similar length of time for pH to normalise and PaCO2 improve (12 (6–34) vs 12 (4–28) h, respectively, P=0.42P=0.42), with similar duration of NIV treatment (60 (35–96) vs 68 (36–48) h, respectively, P=0.25P=0.25) and hospital length of stay (8 (7–18) vs 9 (5–17) days, respectively, P=0.61P=0.61). Overall survival was 89%, with 95% in the mild and 82% in the severely acidotic groups.Conclusions: Noninvasive ventilation is effective in the treatment of patients with severe acidosis due to acute hypercapnic COPD.