Kyphoscoliotic ventilatory insufficiency: effects of long-term intermittent positive-pressure ventilation.

OBJECTIVES To determine the effects of long-term nocturnal intermittent positive-pressure ventilation (NIPPV) on symptoms, pulmonary function test results, sleep, and respiratory muscle performance in patients with ventilatory insufficiency due to severe kyphoscoliosis. DESIGN A prospective study in which 16 severe kyphoscoliotic patients were treated with NIPPV delivered by volume-cycled and pressure-cycled ventilators, over a period of 36 months. INTERVENTIONS AND MEASUREMENTS At baseline, pulmonary function tests, blood gas measurements, polysomnography, and respiratory muscle strength (measured by noninvasive indexes) were obtained. Symptoms and the number of hospitalizations in the previous 6 months also were recorded. Patients then began using a ventilator for > 1 to 2 days, in order to select the type of ventilator and the appropriate interface. Patients returned for evaluation (in outpatient setting) every 6 months for a follow-up period of 3 years. At 6 months, polysomnography was repeated, and by the third year clinical and functional parameters had been reassessed. RESULTS All symptoms improved significantly with NIPPV therapy, when compared with the baseline values. The mean (+/- SD) PaO(2) and FVC values increased at 36 months compared with baseline values (62.6 +/- 7.1 vs 67.8 +/- 8.8 mm Hg, respectively; and 37.9 +/- 7.2% vs 47.5 +/- 11.9%, respectively; p < 0.05 for both). There were significant improvements in mean maximal inspiratory pressure (55.8 +/- 17.4 to 78.5 +/- 17.5 cm H(2)O), maximal expiratory pressure (53.8 +/- 17.7 to 72.3 +/- 11.0 cm H(2)O), mouth pressure (0.28 +/- 0.08 to 0.22 +/- 0.02 cmH(2)O), and pressure-time index (0.18 +/- 0.05 to 0.11 +/- 0.02; p < 0.05 for all comparisons). There were no significant differences in breathing pattern and ventilatory drive. After 6 months, nocturnal oxyhemoglobin saturation improved, however, there was no significant change in sleep architecture. All patients subjectively perceived a better quality of life after beginning ventilation, which persisted over the course of the study. CONCLUSIONS Long-term NIPPV therapy improves daytime blood gas levels, respiratory muscle performance, and hypoventilation-based symptoms in patients with severe kyphoscoliosis.