Potassium

Question 1

Frequently encountered etiologies of hyperkalemia in the ED

Answer 1

1 Alkalosis 2 GI loss 3 Diuretic therapy

Question 2

Extracellular to intracellular potassium shifts etiologies of hypokalemia (4)

Answer 2

1 Alkalosis* 2 Increased plasma insulin (treatment of diabetic ketoacidosis) 3 Adrenergics 4 Hypokalemic periodic paralysis

Question 3

Cardiovascular signs and symptoms of hypokalemia

Answer 3

1 Hypertension 2 Orthostatic hypotension 3 Potentiation of digitalis toxicity 4 Dysrhythmias (usually tachydysrhythmias) 5 T-wave flattening, U waves, ST depression

Question 4

No more than mEq should be added to each liter of IV fluid, and infusion rates should be no greater than mEq/h.

Answer 4

40 40

Question 5

The most common cause of hyperkalemia is

Answer 5

factitious hyperkalemia due to release of intracellular potassium caused by hemolysis during phlebotomy.

Question 6

Frequent or important ED diagnostic considerations for hyperkalemia (6)

Answer 6

1 Hemolysis (in vitro) 2 Acidosis 3 Rhabdomyolysis/crush injury* 4 Renal failure 5 Drugs 6 Aldosterone deficiency

Question 7

Most common drugs causing hyperkalemia

Answer 7

1 potassium-sparing diuretics, 2 beta blockade, 3 NSAIDs, 4 angiotensin-converting enzyme inhibitors

Question 8

ECG changes in high K (6.5 to 7.5 ) [3]

Answer 8

1 Prolonged PR interval, 2 tall peaked T waves, 3 short QT interval

Question 9

ECG changes in high K (7.5 to 8)

Answer 9

1 Flattening of the P wave, 2 QRS widening

Question 10

ECG changes in high K (10 to 12)

Answer 10

QRS complex degradation into a sinusoidal pattern

Question 11

Emergency Therapy of Hyperkalemia

Answer 11

Albuterol (nebulized) 2.5 milligrams in 4 mL normal saline, 15–30 min 2–4 h Upregulates cyclic adenosine monophosphate, nebulized over 20 min shifts [K+] into cell

Calcium chloride (10%)* 5–10 mL IV 1–3 min 30–50 min Membrane stabilization

Calcium gluconate (10%)* 10–20 mL IV 1–3 min 30–50 min Membrane stabilization

NaHCO3 50–100 mEq IV 5–10 min 1–2 h Shifts [K+] into cell

Insulin and glucose 5–10 units regular insulin IV 30 min 4–6 h Shifts [K+] into cell

1–2 amps D50W IV

Furosemide 40 milligrams IV Varies Varies Renal [K+] excretion

Sodium polystyrene sulfonate 25–50 grams PO or PR 1–2 h 4–6 h GI [K+] excretion

Hemodialysis — Minutes Varies Removes [K+]

*Calcium chloride is three times as potent as calcium gluconate. 10% calcium chloride = 27.2 milligrams [Ca2+]/mL; 10% calcium gluconate = 9 milligrams [Ca2+]/mL.