title: AccuO2 oximetry-driven oxygen-conserving device versus fixed-dose oxygen devices in stable COPD patients.
abstract: BACKGROUND
  Because standard home oxygen (O2) systems deliver O2 at fixed rates, these systems are not designed to ensure optimal oxygen delivery based on physiologic need. We tested the ability of the AccuO2 (OptiSat Medical, Minneapolis, Minnesota), a portable, closed-loop, oximetry-driven, O2-conserving device to maintain SpO2 at ≥ 90%, compared to continuous-flow oxygen and a standard O2-conserving device (CR-50, Puritan-Bennett, Pleasanton, California).
  
  
  METHODS
  We randomly assigned 28 patients who were on continuous home O2 for COPD to use each of 3 O2 delivery systems (continuous-flow O2, CR-50, and AccuO2) for 8 hours a day, for 2 consecutive days, at home, at their current O2 prescription. We recorded SpO2 and calculated the conservation ratio (duration of a given O2 supply with an O2-conserving device compared to continuous-flow O2).
  
  
  RESULTS
  Twenty-two patients completed all 3 study arms; 2 additional patients completed the AccuO2 arm and the continuous-flow O2 arm. The mean ± SD SpO2 was 92 ± 4% with continuous-flow O2, 92 ± 4% with the CR-50, and 91 ± 2% with AccuO2 (P = .006 for the AccuO2 vs continuous-flow O2, P = .03 for the AccuO2 vs the CR-50). SpO2 variability was less with the AccuO2 (P < .001 vs continuous-flow O2 and vs the CR-50). The conservation ratios were 9.9 ± 7.3 for the AccuO2 and 2.6 ± 1.0 for the CR-50 (P < .001).
  
  
  CONCLUSIONS
  Compared to continuous-flow O2 or the CR-50, the AccuO2 maintained SpO2 closer to the target, and AccuO2 had a higher conservation ratio than CR-50.
authors.affiliation: Minneapolis Veterans Affairs Medical Center, Minneapolis, MN, USA.
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Rice
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Schmidt
authors.forename: John S
authors.initials: JS
authors.lastname: Buan
authors.forename: Francene
authors.initials: F
authors.lastname: Lebahn
authors.forename: Ted K
authors.initials: TK
authors.lastname: Schwarzock
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004867:Equipment Design; D006801:Humans; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000295:instrumentation* / Q000379:methods; D010092:Oximetry / Q000295:instrumentation*; D010101:Oxygen Consumption / Q000502:physiology; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation* / Q000379:methods; D029424:Pulmonary Disease, Chronic Obstructive / Q000628:therapy*