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 increased (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 (r2 = 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 (SaO2) 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 SaO2 (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.