Role of Hyperkalemia in Production of Ventricular Fibrillation Following Hypercapnia.

Abstract

Dogs regularly show an increase in plasma K concentration during breathing of 30% and 40% CO2 mixtures. Immediately following return to air breathing, there is a further sharp rise in this concentration. This secondary rise reaches a peak after 5 minutes of air breathing. Concentration of plasma K following 4 hours of high CO2 breathing is not as high as that which is necessary to produce fibrillation or arrest when KCi solution is given as an intravenous drip to normal or acidotic dogs. Rapid return to air breathing following 30 minutes of high CO2 breathing does not produce cardiac arrhythmias, ventricular fibrillation, or cardiac arrest in dogs. However, when this rapid elevation in blood pH and/or fall in pCO2 takes place in the presence of sub-lethal but elevated plasma K concentrations, cardiac arrest or ventricular fibrillation may occur. The combination of elevated but sub-lethal plasma K concentration and a rapid fall in CO2 tension and/or pH, work together to produce the damage to the heart.