ABG vs VBG vs CBG
Posted by dkwinter

Arterial Blood Gas (ABG)

  • standard nomenclature: pH / PaCO2 / PaO2 / HCO2 / O2Sat / BE
  • normal values
    • pH: 7.35-7.45
    • PaCO2: 33 - 45 mmHg
    • PaO2: 80 - 100 mmHg
    • HCO2: 21 - 27 mEq/L
    • O2Sat: 95-100%
    • BE +/- 2 mEq/L

 

Correlation of VBG and CBG with ABG are as follows:

 

Venous Blood Gas (VBG)

  • pH correlates well with ABG
  • PvCO2 is usually within 4-6 mmHg of PaCO2 on ABG (but a bigger gradient is seen in a patient with poor perfusion)

 

Capillary Blood Gas (CBG)

  • pH is comparable to the ABG reading
  • PaCO2 is comparable to the ABG reading

 

 

Reference: PALS Provider Manual 2015. American Heart Association.