Answer
The infusion of K+ enhanced iv solution would cause Mrs Miller's blood to become hyperkalemic.This would reverse the [K+} gradient across the cell membranes of her neurons( and muscle cells). One consequence would be that K+ ions would movement of K+ ions down their concentration gradient into the cytosol of the affected cells ; this would decrease the negativity of the inside of the plasma membranes with respect to their exterior surfaces. This make each the cell more sensitive/irritable because it would be less depolarized.
Work Step by Step
In a neuron the resting membrane potential is about 65-70 mV( 90-75 mV for myocytes). If the hyperkalemia is prolonged and severe, the consequent increase of [K+] in the cytosol could decrease membrane potential from, for example, -65 mV/-70 mV to -52 mV/-55 mV. At this new (lower) resting membrane potential (RPM) the membrane would be more excitable (closer to threshold) and an action potential would be more easily triggered
Normal cell [K+] : 3.5-5.2 mEq/L
Severe hyperkalemia : 7 mEq/L
Symptoms: nausea, malaise, palpitation, numbness, tingling , bradycardia, dyspnea arrhythmia. Cardiac arrest may occur in severe cases.
