Symptoms appear when serum K drops below 3. Cardiac arrythmias may also develop.
Potassium is necessary for proper nerve conduction.
Cardiac arrythmia is the most serious effect. If the K is less than 3, or the patient is symptomatic, the patient should be placed on a cardiac monitor during treatment. Urine output should be measured to make sure that urine is produced, and that K will not accumulate to toxic levels. Unlike treatment of hyponatremia, K replacement is not a matter of calculating a correction based on serum K levels, since these are a poor reflection of the overwhelming proportion of K that is intracellular. Except for emergency management, K replacement should proceed slowly to allow equilibration.