Randomized controlled trial of ambulatory oxygen and an ambulatory ventilator on endurance exercise in COPD

In a prospective, randomized study we examined the effect of (i) ambulatory oxygen and (ii) a portable, inspiratory pressure support (IPS) device on t he endurance shuttle walk test (ESWT) in patients with severe chronic obstr uctive pulmonary disease (COPD). Ten outpatients [median (range) FEV1 0.601 (0.35, 1.45)] performed the ESWT under five test conditions: baseline walk (no assistance), IFS at 14 cmH(2)O from a portable ventilator (the HIPPY, Friday Medical, U.K.), sham IFS (< 8 cmH(2)O), ambulatory oxygen at 21min(- 1), and sham oxygen (carrying the portable oxygen cylinder and breathing ai r). There were significant improvements in the ESWT with ambulatory oxygen, but a negative effect with the HIPPY device [mean (SD) time: baseline 172 (48) sec; oxygen 242 (62) sec; HIPPY 84 (35) sec]. The ESWT appeared sensit ive to the effect of cylinder weight although differences in endurance capa city were not significant [sham oxygen 151 (45) sec]. The ESWT was sensitiv e to the acute application of oxygen, demonstrating a beneficial effect on endurance performance in patients with severe COPD. The ESWT could form the basis of a standardized assessment for ambulatory oxygen.