CO₂ dissociation curve of dog brain

¹ Cardio-Pulmonary Laboratory, The Mary Imogene Bassett Hospital, Cooperstown, New York

The CO₂ dissociation curve of canine brain has been determined in vitro immediately after death, as well as the CO₂ solubility coefficient, water content, and density of brain. The slope of the CO₂ dissociation curve of brain is .36 ml CO₂/100 g brain per mm Hg at 37 C over the range of pCO₂ from 5 to 60 mm, .23 from 60 to 150 mm, and .15 at pCO₂ values above 150 mm Hg. Problems of measurement of CO₂ dissociation curve of brain are discussed and evidence presented which justifies the acceptance of the CO₂ dissociation curve presented here as nearly representing that which exists in the dog in vivo. It is shown that postmortem acid formation by the brain is dependent upon hypoxia and can be prevented by high O₂ tensions. The previous observation that it can also be prevented by rapid cooling is confirmed.