NIV during exercise training in patients with CRF on long-term ventilatory support

Abstract

Role of non-invasive ventilation (NIV) during exercise training in patients with chronic respiratory failure (CRF) is unclear. The aim of this study in CRF patients on long-term home nocturnal NIV was to test whether use of NIV during exercise training can lead to a greater increase in exercise tolerance than that from exercise training alone. Patients (n=50) were randomly assigned to two groups and all underwent 3 weeks (20 sessions) of exercise (cycle and muscle) training either with (group 1) or without (group 2, controls) NIV. Outcome measures were the 6-min walking test (6MWT) (primary outcome), incremental and endurance cycle ergometer exercise tests, respiratory muscle function, quality of life assessed by the Maugeri Respiratory Failure questionnaire (MRF-28), and perceived dyspnoea and leg fatigue at rest (modified Borg scale). After training, no significant difference between groups was found in 6MWT changes (fig 1), but endurance time was significantly longer in group 1 (754±973 vs. 51±406 s, p=0.0271). 68% patients of group 1 vs 31% of controls increasing endurance time more than the reported MID of 200 seconds (p = 0.063). Dyspnoea improved in both groups whereas respiratory muscle function and leg fatigue improved only in group 1. MRF-28 improved only in controls. In CRF patients on long-term NIV, use of NIV as an adjunct to exercise training significantly improved endurance time, but not 6MWT, with respect to exercise training alone.