Long-term effects of nasal intermittent positive-pressure ventilation on pulmonary function and sleep architecture in patients with neuromuscular diseases

Study objective: This article evaluates the long-term clinical and physiologic effects of nocturnal nasal intermittent positive-pressure ventilation (NIPPV) in patients with neuromuscular disease. Methods: Before and after 18+/-2 months of NIPPV, we measured during the daytime arterial blood gases, lung mechanics, and respiratory muscle strength in 8 patients (51+/-5 years; mean+/-SEM). Sleep parameters were also evaluated at 10+/-2 months. Results; All patients tolerated NIPPV and none required hospitalization during follow-up. After NIPPV, daytime arterial PO2 increases (71+/-4 to 81+/-2 mm Hg; p<0.05) and arterial PCO2 decreased (46+/-3 to 41+/-1 mm Hg; p<0.05). The change of PaO2 after NIPPV was related to its baseline value (r(2)=0.78, p<0.05). Vital capacity (50+/-6% predicted), total lung capacity (63+/-4% predicted), alveolar-arterial oxygen gradient (20+/-3 mm Hg), and maximal inspiratory (39+/-9% predicted) or expiratory (32+/-5% predicted) pressures did not change after NIPPV. The apnea-hypopnea index fell from 22+/-6 to 1+/-1 (p<0.05), and both sleep architecture and sleep efficiency (from 59+/-8% to 83+/-5%; p<0.05) were enhanced. The time spent with an arterial oxygen saturation (SaO(2)) value below 90% decreased from 160+/-53 min to 8+/-4 min (p<0.05). Mean (88+/-3 to 95+/-1%; p<0.05) and minimal nocturnal SaO(2) (67+/-5 to 89+/-1%; p<0.001) improved after NIPPV. Conclusions: In patients with neuromuscular disease, long-term NIPPV is well tolerated and easy to implement clinically. In these patients, long-term NIPPV improves daytime arterial blood gas values and sleep-disordered breathing. However, it does not modify lung mechanics or respiratory muscle strength.