Noninvasive ventilation with helium-oxygen in acute exacerbations of chronic obstructive pulmonary disease

The use of helium-oxygen (HeO2) was tested in combination with noninvasive ventilation (NIV) in 10 patients with acute exacerbation of chronic obstruc tive pulmonary disease (COPD). Effort to breathe as assessed by the respira tory muscle pressure-time index (PTI), work of breathing (WOB), and gas exc hange were the main endpoints. Results of NIV-HeO2 were compared with those obtained with standard NIV (AirO(2)), at two levels of pressure-support ve ntilation (PSV), 9 +/- 2 cm H2O and 18 +/- 3 cm H2O. Significant reductions in PTI were observed between HeO2 and AirO(2) at both the low PSV level (n = 9; 160 +/- 58 versus 198 +/- 78 cm H2O/s/ min; p < 0.05) and the high PS V level (n = 10; 100 +/- 45 versus 150 +/- 82 cm H2O/s/min; p < 0.01). WOB also differed significantly between HeO2 and AirO(2) (7.8 +/- 4.1 versus 10 .9 +/- 6.1 J/min at the low PSV level, p < 0.05; and 5.7 +/- 3.3 versus 9.2 +/- 5. J/min, p < 0.01 at the high PSV level). HeO2 reduced Paco(2) at bot h the low PSV level (61 +/- 13 versus 64 +/- 15 mm Hg; p < 0.05) and the hi gh PSV level (56 +/- 13 versus 58 +/- 14 mm Hg; p < 0.05), without signific antly changing breathing pattern or oxygenation. We conclude that use of He O2 during NIV markedly enhances the ability of NIV to reduce patient effort and to improve gas exchange.