Early changes in plasma potassium after acute alterations in PaCO2 in anesthetized dogs, monitored continuously with intravascular potassium-selective electrodes.

Changes in plasma potassium in the first 10 min after alterations in PaCO2 in anesthetized greyhounds were monitored continuously in vivo with potassium-selective electrode catheters. Elevation of PaCO2 resulted in a small transient fall in plasma potassium whereas reduction in PaCO2 resulted in a small transient rise in plasma potassium. Maximum changes occurred at approximately 5 min after alterations in PaCO2 with levels tending to return to control thereafter. Changes of similar magnitude in normal man would not be expected to have an adverse effect on cardiac function, but they may have greater significance in subjects with pre-existing abnormal potassium levels, during concurrent treatment with digoxin, and after sudden alterations in PaCO2 in chronic hypo- or hypercapnic conditions.