title: A randomized multi-arm repeated-measures prospective study of several modalities of portable oxygen delivery during assessment of functional exercise capacity.
abstract: BACKGROUND
  Ambulatory oxygen is an important component of long-term oxygen therapy. Pulse-dose technology conserves oxygen and thus increases the operation time of a portable oxygen system.
  
  
  METHODS
  We tested 4 ambulatory oxygen systems (Helios, HomeFill, FreeStyle, and the compressed-oxygen cylinder system we regularly provide for long-term oxygen therapy at our Veterans Affairs hospital) with 39 subjects with stage-IV chronic obstructive pulmonary disease. Each subject performed one 6-min walk test with each oxygen system, and we measured blood oxygen saturation (via pulse oximetry [S(pO(2))]), heart rate, and modified Borg dyspnea score, and surveyed the subjects' preferences about the oxygen systems. We also studied whether the 2 systems that provide gas with a lower oxygen concentration (from a home concentrator or portable concentrator) showed any evidence of not providing adequate oxygenation.
  
  
  RESULTS
  With all 4 systems the mean pre-walk S(pO(2)) at the prescribed pulse-dose setting was 95-96%. The mean post-walk S(pO(2)) was 88-90% after each of the 4 walk tests. Between the 4 systems there were no statistically significant differences between the pre-walk-versus-post-walk S(pO(2)) ( = .42). With each system, the pre-walk-versus-post-walk S(pO(2)) difference was between -8% and -6%.
  
  
  CONCLUSIONS
  Between these 4 ambulatory oxygen systems there were no significant differences in S(pO(2)), walk time, or walk distance, and there was no evidence of inadequate oxygenation with the 2 systems that provide a lower oxygen concentration.
authors.affiliation: Cardiopulmonary and Diagnostic Sciences, University of Missouri School of Health Professions, Columbia, MO 65211, USA. stricklandsl@health.missouri.edu
authors.forename: Shawna L
authors.initials: SL
authors.lastname: Strickland
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Hogan
authors.forename: Rosemary G
authors.initials: RG
authors.lastname: Hogan
authors.forename: Harjyot S
authors.initials: HS
authors.lastname: Sohal
authors.forename: Wayland N
authors.initials: WN
authors.lastname: McKenzie
authors.forename: Gregory F
authors.initials: GF
authors.lastname: Petroski
mesh_terms: D000368:Aged; D004417:Dyspnea / Q000503:physiopathology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006699:Home Care Services; D006801:Humans; D008297:Male; D010092:Oximetry; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation*; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology*