An increase in external K+  concentration:
Decrease RMP
Increase RMP by  –10 mv for each 10 mEq/L increase in K+
No change
Increase RMP by –20 mv for each 10 meq/L increase in K+
With hyperkalemia, membrane voltage is depolarized gradually. Depolarization of membrane voltage means decrease in RMP. Remember, a decrease in the membrane potential (RMP) means that the voltage has moved closer to ground (0 mv) or become more positive.