Capillary and venous blood compared with arterial blood in the measurement of acid-base and blood gas status of dogs.

Acid-base and blood gas status of capillary blood from the ear was compared with acid-base and blood gas status of arterial and venous blood in dogs with induced hypoxemia, hypercapnea, and hypovolemia. It was concluded that capillary blood samples can replace arterial blood samples for the measurement of acid-base and blood gas status of dogs with severe impairment of lung function. When circulation is impaired capillary blood samples cannot replace arterial blood samples for the measurement of acid-base and blood gas status of dogs. With impaired capillary circulation, the capillary-arterial differences become unacceptably large. It is, therefore, advisable to submit samples of capillary blood for analysis only if circulation is not impaired and microtubes can be filled quickly and easily.