Evaluation of an Assistive Device for Ambulation in Oxygen Dependent Patients With COPD

Purpose The purpose of this study was to determine the ability of an assistive device to increase exercise tolerance in patients with severe chronic obstructive pulmonary disease (COPD), and to identify characteristics associated with benefit from use of the device. Methods The sample consisted of 12 subjects (all male) who were diagnosed with severe COPD, (FEV1/FVC <60% of predicted) and who required continuous oxygen therapy. Mean age was 62.8 years, mean FEV1 was 33 ± 12% of predicted and mean oxygen flow rate was 2.3 L/min (range 1–4 L/min). All patients performed two 12-minute walks: one while pushing an assistive device (NextStep, NobleMotion, Pittsburgh, PA), the assistive walk, and one without the device, the independent walk. The order of the walks was randomized and practice walks were performed before data collection. Oxygen saturation and pulse were measured during the walks using pulse oximetry. Results Mean distance for the independent walk was 1,274 ± 846.4 feet, and for the assisted walk 1,426 ± 761 feet. This represented a mean increase of 151 feet or 10.2% However, distance for the patients who could not walk 1,000 feet (n = 6) was 491 ± 183 feet without the device, and 717 ± 157 feet with the device increased significantly (P <.0001). This represented a mean increase of 46%. Conclusions Patients with severe COPD who were unable to walk 1,000 feet during a 12-minute walk increased walk distance significantly when allowed to push an assistive device. Further research is needed to determine if severely obstructed patients will obtain additional benefit from use of an assistive device in conjunction with a pulmonary rehabilitative/exercise program.