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Blood Gas Interpretation

This is the blood gas result for Melanie Slater from scenario SIG001US

Clinical Picture

  • 28-year-old woman presenting with shortness of breath
  • Patient identifies presentation in keeping with previous acute asthma episodes, with a clear precipitant. 
  • Effective inhaler use with shortness of breath now resolved. 
  • Looks well, normal physical examination, no wheeze.



  • Sample type: arterial
  • Supplemental oxygen: no
  • paO2: 91.7 mmHg
  • paCO2: 36.1 mmHg
  • pH: 7.43
  • Bicarbonate (HCO3-): 23.9mEg/L
  • Base excess: +1.4
  • Acid-base balance: normal
  • Other parameters: normal



  • All parameters were within normal limits on this blood gas.
  • The low-normal paCO2, high-normal pH and normal base excess would be consistent with a mild or resolving acute respiratory alkalosis, such as that commonly found in acute asthma.


Further reading