Blood Gases in Children: Venous or Capillary?

Capillary blood gases (CBGs) provide an alternative to arterial blood gases (ABGs), but they correlate well only for pH. O₂ and CO₂ correlations are unreliable. Venous blood gases (VBGs) can be measured from routine venous blood sampling. These authors from Montreal sought to compare VBG and CBG values in 78 ill but well perfused pediatric ED patients aged 1 month to 18 years. Two intensivists interpreted the blood gas values and used the results to make decisions regarding clinical management of acid-base disorders.

The correlation between VBG and CBG values was high for pH but highly variable for pCO₂ and pO₂. The two physicians were poorly concordant in therapeutic decisions based on the two gas values: 0.59 for gas interpretation, 0.91 f…