When is ABG useful to investigate oxygenation?

pulse-ox

Almost never. For patients with an adequate oximetry waveform, pulse oximetry is usually superior to ABG for measuring oxygenation. ABG is only useful to investigate oxygenation when:

  • Pulse oximetry waveform is unreliable.
  • Diagnosis of methemoglobinemia.
  • Calculation of the PaO2/FiO2 ratio to guide a specific therapeutic decision.

 

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Keep Calm AND Get a Venous Blood Gas

Unless you want to know a patient’s oxygenation (because your pulse oximeter has failed), stop turning your patient into a pin cushion looking for the radial artery and get a venous blood gas