Self-Selected Walking Velocity for Functional Ambulation in Patients With End-Stage Emphysema

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Abstract
Considerable attention has been given to ambulation and dyspnea in the population with chronic obstructive pulmonary disease; however, previous studies leave the question of what constitutes functional ambulation in this population unanswered. This article examines ambulation for functional independence in the community for patients with-end-stage emphysema based on their self-selected walking velocity (SSWV) during a 6-minute walk (6 MW) and a timed get up and go (GUG) test. Fifty-nine patients (28 women, 31 men; mean age of 65.1 +/- 7.2 years) referred for lung transplantation or lung volume reduction surgery (mean forced expiratory volume in 1 second [FEV1] of 0.60 +/- 0.20 L; mean FEV1 as percent of predicted [FEV1%] of 22.7 +/- 8.7%) each had a 6 MW and GUG test performed on the same day. Calculations for SSWV and estimated energy expenditure were determined using the horizontal walking formula by the American College of Sports Medicine. No statistically significant gender differences were identified for distance walked (235.1 +/- 92.0 m), rest time taken (33.2 +/- 58.5 seconds), actual walk time (5.5 +/- 1.0 minutes), or SSWV (42.2 +/- 13.9 m/min or 1.6 +/- 0.5 miles per hour) during the 6 MW. Men tended to walk farther and faster but rested more. The SSWV during the GUG test was similar (mean 41.8 +/- 10.9 m/min or 1.6 +/- 0.4 miles per hour) to the SSWV during the 6 MW. Estimated energy expenditure was approximately 1.6 to 3.4 metabolic equivalents (METS; mean 2.3 +/- 0.5 METS). The literature defines independent community ambulation as the ability to walk at least 332 m at a near-normal velocity of approximately 80 m/min. This study population was significantly impaired for both distance and the velocity required to ambulate independently in the community. Documentation of both rest time and walk time taken during a 6 MW test will enable SSWV to be calculated and interpreted as it relates to independent community ambulation.