Background: The objective of the present analysis is to describe the outcomes of high-intensity non-invasive positive pressure ventilation (NPPV) aimed at maximally decreasing PaCO(2) as an alternative to conventional NPPV with lower ventilator settings in stable hypercapnic COPD patients.
Methods: Physiological parameters, exacerbation rates and long-term survival were assessed in 73 COPD patients (mean FEV(1) 30+/-12 %predicted) who were established on high-intensity NPPV due to chronic hypercapnic respiratory failure between March 1997 and May 2006.
Results: Controlled NPPV with breathing frequencies of 21+/-3 breath/min and mean inspiratory/expiratory positive airway pressures of 28+/-5/5+/-1 cmH(2)O led to significant improvements in blood gases, lung function and hematocrit after two months. Only sixteen patients (22%) required hospitalisation due to exacerbation during the first year, with anaemia increasing the risk for exacerbation. Two- and five-year survival rates of all patients were 82% and 58%, respectively. The five year survival rate was 32% and 83% in patients with low (< or =39%) and high (> or =55%) hematocrit, respectively.
Conclusion: High-intensity NPPV improves blood gases, lung function and hematocrit, and is also associated with low exacerbation rates and a favourable long-term outcome. The current report strongly emphasises the need for randomised controlled trials evaluating the role of high-intensity NPPV in stable hypercapnic COPD patients.
Keywords: COPD; exacerbation; hematocrit; non-invasive ventilation; survival.