End-Tidal O2


End-Tidal O2, End-Tidal Oxygen, End Tidal O2, EtO2

  • See Also
  • Definitions
  1. End-Tidal O2
    1. Measured concentration of oxygen in expired breath
    2. Measured by Face Mask or nasal detector that attaches to a monitor module (measures EtCO2 and EtO2)
  • History
  1. Has historically been limited to operating room measurement, but is becoming available in Emergency Department in 2019
  • Indications
  1. Endotracheal Intubation Preoxygenation
    1. Adjunct to Oxygen Saturation in identifying adequate preoxygenation (prevents desaturation during apnea)
    2. Ideal Oxygen Saturation prior to intubation: Approaching 100%
    3. Ideal End-Tidal Oxygen: >=85%
      1. Suggests adequate nitrogen wash-out in Functional Residual Capacity
      2. Ideal EtO2 is difficult to achieve without high oxgen flow rates or Positive Pressure Ventilation
        1. Caputo (2019) Ann Emerg Med 74(3):410-5 +PMID:30879700 [PubMed]
  • References
  1. Swaminathan and Caputo in Herbert (2019) EM:Rap 19(12): 14-5