Hypokalemia

Immediate QuestionsA. Is the patient symptomatic? Symptoms of hypokalemia include weakness, nausea, vomiting and abdominal tenderness. Severe hypokalemia can depress reflexes and cause weakness.

B. What medications is the patient taking? Loop diuretics and amphotericin causes potassium wasting by direct renal effects.

Immediate QuestionsC. Is there a history of vomiting, nasogastric suction, diarrhea or renal problems (such as renal tubular acidosis)?

Database

Because potassium is the principle intracellular action, measured serum hypokalemia usually represents a significant loss of body potassium. Thus, serum levels of 3.0 meg/L (mmol/L) often reflects total deficits of 100-200 mEq or more. Look for coexisting hypocalcemia and hypomagnesemia. Check ABG's, as acid-base disorders may coexist and obtain an ECG. Severe hypokalemia can cause blunting of reflexes, paresthesia and paralysis.

PlanA. Aggressive potassium replacement should be performed only after adequate renal function has been documented.B. Parenteral replacement should be considered for digoxin toxicity, significant arrhythmia, and severe hypokalemia (<3.0 mmol/L). Maximum concentrations of KCl used in peripheral veins generally should not exceed 10 meq/100 cc, due to the damaging effects of high concentrations on the veins.

PlanC. For lesser degrees of hypokalemia that require parenteral replacement, 10 to 15 meq/h may be infused peripherally. The maximum infusion rate is 10 meq/hour. Check serum levels frequently (every 2-4 hours depending on clinical response) to avoid hyperkalemia. ICU monitoring is required if arrhythmias are present or for rapid infusions of KCl.

PlanD. Oral replacement include liquids and tablets. Slow-release pills typically contain 8, 10 or 20 mEq tablet. Thus, it will take several days to replete the potassium depletion. Replacement doses should be 40-120 meq qd in divided doses, depending on the patient's weight and level of hypokalemia. More than 20 meq in one dose can cause GI upset.