Nocturnal mechanical ventilation improves exercise capacity in kyphoscoliotic patients with respiratory impairment.

BACKGROUND: Patients with severe kyphoscoliosis, with or without stable respiratory failure, frequently experience oxyhaemoglobin desaturation during sleep, exercise, or both. Nasal Intermittent Positive Pressure Ventilation (NIPPV) applied during sleep has been demonstrated to be able to control nocturnal desaturations and also improve diurnal respiratory failure, if this is present, in this group of patients. The aim of this study was to evaluate the effect of a seven-day treatment with nocturnal NIPPV on exercise tolerance in a group of 6 patients with severe kyphoscoliosis and significant nocturnal and exercise-induced oxyhaemoglobin desaturation. METHODS: NIPPV was applied each night for a week by means of a volume cycled pressure ventilator set in assisted/controlled mode. In each patient lung function, daytime arterial blood gas analysis, overnight non invasive recording of arterial saturation, and 6-minutes walking test were carried out initially and at the end of the NIPPV course. RESULTS: During nocturnal NIPPV, as compared to baseline, the percent of night time spent below 90% of oxyhaemoglobin saturation significantly fell from 20 +/- 12.8 to 2.3 +/- 1.9 (Student t-test: p = 0.017). The 6-minute walking distance significantly increased from 244.7 +/- 132.2 to 340 +/- 122.3 m (p = 0.0097). Spirometry, daytime arterial blood gas analysis, and exercise-induced oxyhaemoglobin desaturation were unaffected by treatment. CONCLUSION: A one-week course of treatment with nocturnal NIPPV improves exercise capacity in patients with severe kyphoscoliosis.