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.
Footnotes
- Correspondence: Kathryn L Rice MD, Pulmonary Section, Minneapolis Veterans Affairs Medical Center, 1 Veterans Drive, Minneapolis MN 55417. E-mail: kathryn.rice{at}va.gov.
This research was partly supported by the University of Minnesota Technology Partnership Fund and the Minneapolis Veterans Affairs Research Service. Dr Rice has disclosed a relationship with Wyeth Pharmaceuticals. Dr Schmidt, Dr Buan, and Mr Schwarzock have disclosed relationships with OptiSat Medical. Ms Lebahn has disclosed no conflicts of interest.
Dr Rice presented a version of this paper at the 103rd International Conference of the American Thoracic Society, held May 18–23, 2007, in San Francisco, California.
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