Outcome of non-invasive ventilation in acute hypercapnic respiratory failure in a recently established respiratory ward

Non-invasive ventilation (NIV) is a well established therapeutic tool in acute exacerbation of COPD (AECOPD) and obesity hypoventilation syndrome (OHS) and to a lesser extent in other causes of acute hypercapnic respiratory failure. Aim: To present the results of NIV applied in an acute setting in a newly established respiratory service in an emergency hospital. Methods: Consecutive patients presenting at the emergency room of a general hospital in 2012 with acute hypercapnic respiratory failure have been treated in a respiratory ward with NIV through an oronasal or full facial mask. Results: 33 patients were included, 16 men, mean age 66 years-old, 22 with AECOPD and 4 with OHS. NIV failed in 6 patients (4 with AECOPD) and in-hospital death supervened in the same 6 patients. Initial blood gases values (PaO2, PaCO2, pH and HCO3-) did not differ between dead and surviving patients. PaCO2 and pH had a significant improvement in the first hours and at discharge in surviving patients (see table). PaO2 had a significant decrease at 4-6 hours. Mean length of stay in hospital was 8.5±7.5 days. Out of 27 surviving patients 5 were discharged on home NIV and 18 on home oxygen therapy. Baseline 1-2h NIV 4-6h NIV Discharge n=33 n=22 p vs baseline n=28 p vs baseline n=27 p vs baseline PaO2 (mmHg) 68±27 59±17 0.19 55±20 0.03 68±20 0.49 PaCO2 (mmHg) 82±16 76±15 < 0.01 68±14 < 0.001 60±12 < 0.001 pH 7.23±0.06 7.28±0.08 < 0.001 7.34±0.09 < 0.001 7.41±0.05 < 0.001 Conclusion: NIV was efficient in improving hypercapnia and acidosis in acute hypercapnic respiratory failure, with a reasonable failure rate. Initial blood gases values did not predict NIV failure or death in this population.