Potassium Imbalances

what is potassium necessary for?

• resting membrane potential of nerve and muscle cells

• regulates intracellular osmolality

• promotes cellular growth

• maintenance of cardiac rhythm

• acid-base balance

what are common sources of potassium?

fruits and vegatables, salt substitutes, potassium medications, stored blood

What causes a shift of potassium out of cells?

• Acidosis

• Tissue catabolism (fever, crush injury, sepsis, burns)

• Tumor lysis syndrome

• Intense exercise

What causes failure to eliminate potassium?

• Renal disease

• Adrenal insufficiency

• Medications: ACE inhibitors, ARBs, NSAIDs, heparin, potassium-sparing diuretics

what causes potassium loss?

vomiting, diarrhea, BG suctioning

diuretics, hyperaldosteronism, magnesium depletion

diaphoresis

what causes a shift of potassium into cells?

• alkalosis

• increase epinephrine

• increase insulin

what causes lack of potassium intake?

• Low potassium diet

• Starvation

• NPO without potassium replacement

What are symptoms of hyperkalemia?

• Abdominal cramping, diarrhea, vomiting

• Muscle weakness, loss of tone

• Fatigue, irritability, confusion

• Paresthesias, decreased reflexes

• Irregular pulse

• Tetany

What are symptoms of hypokalemia?

• Muscle weakness, cramps

• Leg cramps, flabby muscles

• Fatigue, constipation, paralytic ileus

• Shallow respirations

• Hyperglycemia

• Irregular, weak pulse

What ECG changes occur with hyperkalemia?

• Tall, peaked T waves

• Widened QRS

• Loss of P wave

• Prolonged PR interval

• Ventricular fibrillation or standstill

What ECG changes occur with hypokalemia?

• Flattened T wave, presence of U wave

• ST depression

• Prolonged QRS

• Peaked P wave

• Ventricular dysrhythmias

• Heart block (1st and 2nd degree)

How does hyperkalemia affect the ECF/ICF ratio and cell excitability?

It increases potassium in the ECF, altering the ECF/ICF ratio, leading to increased cell excitability and disrupted nerve and muscle impulse transmission

what is the most clinically significant effect of hyperkalemia?

changes in cardiac conduction

what is the initial ECG finding in hyperkalemia

tall, peaked T wave

what happens to cardiac conduction as potassium levels increase?

• decreased cardiac depolarization (heart contracts easily)

What neuromuscular symptoms may occur with hyperkalemia?

• Fatigue, confusion, tetany

• Muscle cramps and paresthesias

• Loss of muscle tone, weakness, paralysis

What can result from paralysis of respiratory muscles in hyperkalemia?

respiratory arrest

what GI symptoms are associated with hyperkalemia?

• Abdominal cramping

• Vomiting

• Diarrhea

What are the four main treatment strategies for hyperkalemia?

• Stop potassium intake

• Increase potassium excretion

• Force potassium into cells

• Stabilize cardiac membranes

What is the first step in managing hyperkalemia?

stop all oral and IV potassium intake

What medications and methods are used to increase potassium excretion?

• Loop or thiazide diuretics

• Dialysis

• Sodium polystyrene sulfonate (Kayexalate)

• Patiromer (Veltassa)

• Sodium zirconium cyclosilicate (ZS-9, Lokelma)

How does Kayexalate work?

binds to potassium in the bowel and removes about 1 mEq of potassium per gram and releases 1-2 mEq of Na

When is patiromer (Veltassa) preferred?

For chronic hyperkalemia due to chronic renal failure; takes up to 7 hours to begin working, 2 days for max effect

What is the mechanism of ZS-9 (Lokelma)?

Traps potassium in the GI tract to promote fecal excretion; max effect in 2–3 hours.

What treatments shift potassium from ECF into cells?

• IV regular insulin and dextrose

• Beta-adrenergic agonist (albuterol)

• IV sodium bicarbonate

why is dextrose given with insulin in hyperkalemia?

To prevent hypoglycemia while insulin shifts potassium into cells.

What IV drugs are used to stabilize the heart in hyperkalemia?

• IV calcium chloride

• IV calcium gluconate

Do calcium preparations lower potassium levels?

No. They protect the heart by stabilizing cell membranes but do not lower potassium

Why is continuous ECG monitoring used in hyperkalemia?

To detect dysrhythmias and monitor the effectiveness of therapy.

What should be monitored when giving IV calcium?

Blood pressure—rapid administration may cause hypotension

What should be monitored when giving insulin for hyperkalemia?

Blood glucose—monitor for hypoglycemia and give glucose as needed.

What are the three general causes of hypokalemia?

• Increased potassium loss

• Shift of potassium from ECF to ICF

• Decreased dietary intake (rare)

What are common GI causes of potassium loss in hypokalemia?

• diarrhea

• Laxative misuse

• Vomiting

• Ileostomy drainage

What are common renal causes of potassium loss?

• Increased urinary output

• Use of loop or potassium-depleting diuretics

• Low magnesium levels

How does low magnesium contribute to hypokalemia?

It stimulates renin and aldosterone release, which leads to potassium excretion by the kidneys

How does alkalosis contribute to hypokalemia?

Hydrogen ions move out of cells into ECF, and potassium moves into cells to maintain electrical neutrality, lowering ECF potassium.

What ECG changes are seen with hypokalemia?

• Flattened T wave

• Depressed ST segment

• U wave present

• Peaked P waves

• Prolonged QRS complex

What cardiac rhythm complications may occur due to hypokalemia?

• Heart block

• Ventricular dysrhythmias (potentially lethal)

How does hypokalemia affect skeletal muscles?

• Muscle weakness

• Paresthesias

• Severe hypokalemia may cause paralysis, especially in the extremities.

What is a dangerous complication of muscle paralysis in hypokalemia?

Respiratory muscle involvement, which may lead to shallow respirations and respiratory arrest.

How does hypokalemia affect smooth muscle and the GI tract?

It can cause decreased GI motility, resulting in constipation and potentially paralytic ileus.

How does hypokalemia affect insulin and glucose metabolism?

It impairs insulin secretion, which can lead to glucose intolerance and hyperglycemia.

What are the two main treatment strategies for managing hypokalemia?

• Potassium chloride (KCl) supplements (oral or IV)

• Increased dietary intake of potassium-rich foods

What is typically sufficient to correct mild hypokalemia?

Increasing potassium-rich food intake

Why must IV KCl always be diluted?

To prevent vein irritation, cardiac complications, and tissue damage.

How should IV KCl bags be handled before infusion?

Invert IV bags several times to ensure even potassium distribution.

What should you never do when administering IV KCl?

• Never give IV KCl as a push or bolus.

• Never add KCl to a hanging IV bag

What is the maximum recommended IV KCl infusion rate for non-critical care patients?

10 mEq/hour

What conditions must be met to exceed 10 mEq/hr when administering IV KCl?

• Critical care setting

• Continuous ECG monitoring

• Central line access

What device must always be used when infusing IV KCl?

Infusion pump

How often should IV sites be assessed during IV KCl infusion?

At least hourly

Why is it important to monitor IV sites during KCl infusion?

To detect phlebitis and infiltration, which can lead to necrosis and tissue sloughing

Name 5 fruits that are high in potassium.

• Apricot (raw, medium)

• Avocado (¼ whole)

• Banana (¼ whole)

• Cantaloupe

• Dried fruits

Name 5 more potassium-rich fruits.

• Grapefruit juice

• Honeydew

• Orange (medium)

• Orange juice

• Prunes, Raisins

Name 5 vegetables that are high in potassium

• Baked beans

• Butternut squash

• Refried beans

• Black beans

• Broccoli (cooked)

Name 5 more potassium-rich vegetables.

• Carrots (raw)

• Greens (except kale)

• Mushrooms (canned)

• Potatoes (white and sweet)

• Spinach (cooked)

Name 2 more potassium-rich vegetable products.

• Tomatoes or tomato products

• Vegetable juices

Name at least 5 other foods high in potassium.

• Bran or bran products

• Chocolate (1.5–2 oz)

• Granola

• Milk (all types, 1 cup)

• Nutrition supplements (under medical guidance)

Name 5 more high-potassium items.

• Nuts and seeds (1 oz)

• Peanut butter (2 Tbsp)

• Salt substitutes / Lite Salt

• Salt-free broth

• Yogurt