The changes in oxygen and carbon dioxide are not that much. The object of the question is for you to recognize that the heparin solution is acidic.

Correct answer

Too much heparin will result in a false low pH due to the acidic nature of the heparin solution.

REF: Bageant RA. Variations in arterial blood gas measurements due to sampling techniques. Respir Care 1975;20:565-570.