Study objectives: Noninvasive intermittent positive-pressure ventilation (NIPPV) may improve exercise performance in COPD patients. It is not known whether this also applies to other patient groups such as those with restrictive respiratory diseases.
Design: Randomized controlled trial.
Setting: Regional center for assisted ventilation.
Subjects: Eight patients with severe congenital scoliosis.
Interventions: A submaximal treadmill test was performed with NIPPV applied via a mouthpiece. Each subject performed three walks breathing with three different ventilators and one walk breathing through the mouthpiece alone in random order. In addition, four unencumbered walks breathing normally and without monitoring were performed.
Measurements and results: The four unencumbered walks did not show a significant learning effect. The mean (SD) distance walked was 204 m (134.9 m). Using the mouthpiece alone, the walking distance fell to 140 m (75.8 m), and with the addition of the ventilators it fell further to 109 m (59.3 m). Grouped-effects analysis of variance showed this to be a significant difference in walking distance according to the type of walk (p = 0.048). There was no difference shown among the three brands of ventilator. At the breakpoint of exercise, significant increases were seen in tidal volume and minute volume (Mv) in the ventilator-assisted walks (p < 0.05) compared to walks performed breathing with the mouthpiece alone.
Conclusions: Breathing via a mouthpiece impaired exercise performance, and there was no improvement when breathing with a ventilator, despite the observed increase in Mv. NIPPV has no beneficial effect on exercise endurance in patients with severe scoliosis.