Differences between elevations of plasma and serum potassium in pentobarbital-narcotized cats during asphyxia.

During acute asphyxia in pentobarbital-narcotized cats, the elevation in plasma potassium level was parallel to that of PCO2. From the time when PO2 reached its minimum, the elevation in serum potassium was higher than that of plasma potassium. The increase of the difference between serum and plasma potassium values seems therefore to be more related to hypoxia than hypercapnia; it could be due to membrane alteration of blood cells.