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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