title: Benefits of an oxygen reservoir cannula versus a conventional nasal cannula during exercise in hypoxemic COPD patients: a crossover trial.
abstract: BACKGROUND
  The Oxymizer® is a special nasal cannula that provides a higher luminal diameter in combination with an incorporated oxygen (O2) reservoir. It is assumed that a higher O2 concentration can be delivered breath by breath in order to increase oxygenation.
  
  
  OBJECTIVE
  We aimed to investigate the effects of the Oxymizer on endurance time in comparison to a conventional nasal cannula (CNC).
  
  
  METHODS
  Forty-three patients with severe chronic obstructive pulmonary disease (COPD, age 60 ± 9 years, FEV1 37 ± 16% pred.) and indications for LTOT were recruited during pulmonary rehabilitation for this cross-over study. After an initial maximal incremental cycle test, all patients performed 4 cycling endurance time tests at 70% of their peak work rate (twice with the Oxymizer and twice with a CNC, in reverse order).
  
  
  RESULTS
  The endurance time was significantly higher when patients cycled while using the Oxymizer in comparison to while using the CNC [858 ± 754 vs. 766 ± 652 s; between-group difference 92 s (95% confidence interval 32-152), p < 0.001]. In addition to a longer cycling duration, O2 saturation at isotime was significantly higher with the Oxymizer (93.5 ± 5.4 vs. 90.4 ± 5.3%; p = 0.027). Furthermore, there was a positive correlation (r = 0.427, p = 0.002) between the O2 flow rate and improvements in the constant work rate test, showing greater improvements in favor of the Oxymizer in patients with a higher demand for O2 (≥ 4 liters/min).
  
  
  CONCLUSIONS
  We show that O2 delivery via the Oxymizer is superior to a CNC with regard to endurance capacity and oxygenation during exercise in patients with severe COPD. It seems that patients with a higher demand for O2 (≥ 4 liters/min), in particular, may benefit more from the use of the Oxymizer.
authors.affiliation: Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Gloeckl
authors.forename: Inga
authors.initials: I
authors.lastname: Heinzelmann
authors.forename: Maximilian
authors.initials: M
authors.lastname: Matthaei
authors.forename: Stella
authors.initials: S
authors.lastname: Seeberg
authors.forename: Thomas
authors.initials: T
authors.lastname: Damisch
authors.forename: Andreas
authors.initials: A
authors.lastname: Jerrentrup
authors.forename: Klaus
authors.initials: K
authors.lastname: Kenn
mesh_terms: D000368:Aged; D057785:Catheters; D018592:Cross-Over Studies; D004867:Equipment Design; D015444:Exercise; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation*; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000503:physiopathology / Q000628:therapy*