Flush Rate Oxygen for Emergency Airway Preoxygenation

Ann Emerg Med. 2017 Jan;69(1):1-6. doi: 10.1016/j.annemergmed.2016.06.018. Epub 2016 Aug 10.


Study objective: Recent data suggest that emergency airway preoxygenation with a bag-valve-mask (BVM) device (held with a tight mask seal but without squeezing the bag) is superior to a nonrebreather (NRB) mask at standard oxygen flow rates. We seek to determine whether preoxygenation with an NRB mask with flush rate oxygen (>40 L/min by fully opening a standard oxygen flowmeter) is noninferior to BVM device with standard-flow oxygen (15 L/min). We also seek to compare the efficacy of preoxygenation with NRB mask at flush rate oxygen with both NRB mask with oxygen at 15 L/min and simple mask at flush rate oxygen.

Methods: We performed a crossover trial using healthy volunteers. In random sequence, subjects underwent 3-minute trials of preoxygenation with nonrebreather mask with oxygen at 15 L/min (NRB-15), nonrebreather mask with flush rate oxygen (NRB-Flush), BVM device with oxygen at 15 L/min (BVM-15), and simple mask with flush rate oxygen. The primary outcome measure was the FeO2 in a single exhaled breath. We compared the FeO2 of NRB-Flush to other study groups, using a prespecified noninferiority margin of 10%.

Results: We enrolled 26 subjects. Mean FeO2 values for NRB-15, NRB-Flush, BVM-15, and simple mask with flush rate oxygen were 54% (95% confidence interval [CI] 50% to 57%), 86% (95% CI 84% to 88%), 77% (95% CI 74% to 81%), and 72% (95% CI 69% to 76%), respectively. FeO2 for NRB-Flush was noninferior to BVM-15 (difference 8%; 95% CI 5% to 11%). FeO2 for NRB-Flush was higher than both NRB-15 (FeO2 difference 32%; 95% CI 29% to 35%) and simple mask with flush rate oxygen (FeO2 difference 13%; 95% CI 10% to 17%).

Conclusion: Preoxygenation with NRB-Flush was noninferior to BVM-15. NRB with flush rate oxygen may be a reasonable preoxygenation method for spontaneously breathing patients undergoing emergency airway management.

Trial registration: ClinicalTrials.gov NCT02708862.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Airway Management / methods*
  • Emergency Medical Services / methods*
  • Female
  • Humans
  • Laryngeal Masks*
  • Male
  • Oxygen / metabolism


  • Oxygen

Associated data

  • ClinicalTrials.gov/NCT02708862