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26 Cards in this Set
- Front
- Back
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What is the normal value of Potassium?
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3.5 - 5.0 mEq/L
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What are the "panic" values?
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<2.5 MEq/L and >6.5 mEq/L
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80%-90% of the body's potassium is excreted through where?
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The Kidneys
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What happens to the potassium levels when there is tissue breakdown?
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Potassium leaves the cells and enters the extracellular fluid (interstitial and intravascular fluids).
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Explain how potassium is excreted through the kidneys.
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With adequate kidney functions, the potassium in the intravascular fluid (plasma/blood vessels) will be excreted, and with excessive potassium excretion, a serum potassium deficit (hypokalemia) occurs.
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How does Hyperkalemia occur?
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If the kidneys are excreting less than 600 cc of urine daily, potassium will accumulate in the intravascular fluid and serum potassium excess will occur.
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Does the body conserve potassium?
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No.
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On average, how much potassium does the kidneys secrete?
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40 mEq/L daily (range is 25 - 120)
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What is the daily potassium requirement?
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40 - 60 mEq/L or 3 - 4 grams.
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What can cause Hypokalemia?
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Vomiting/diarrhea, dehydration, malnutrition, stress, gastric suction, intestinal fistulas, diabetic acidosis, burns, renal tubular disorders, hyperaldosteronism, excessive ingestion of licorice, excessive ingestion of glucose, metabolic alkalosis.
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What are some medications that can cause Hypokalemia?
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Potassium-wasting diuretics (furosemide LASIX, thiazides HYDRODIURIL, ethacrynic acid EXCEDRINE), steroids (cortisone, estrogen), antibiotics (gentamicin, amphotericin, polymyxin B), bicarbonate, insulin, laxatives, lithium carbonate, sodium polystyrene sulfonate (KAYEXALATE), salicylates (aspirin).
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What are some causes of Hyperkalemia?
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oliguria and anuria, ARF, IV potaassium in fluids, Addison's disease (adrenocortical hormone), cruched injury and burns (with kidney shutdown), acidosis (metabolic or lactic).
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What are some medications that can cause Hyperkalemia?
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Potassium-sparing diuretics, spironolactone (Aldactone), triamterene (Dyrenium), antibiotics (penicillin G potassium), cephaloridine (Loridin), heparin, epinepherine, histamine, isoniazid.
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What are signs and symptoms of Hypokalemia?
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Vertigo, hypotension, cardiac dysrhythmias, N/V/D, abd distention, decreased peristalsis, muscle weakness, LEG CRAMPS.
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If the serum potassium is <3.5 mEq/l, how much potassium will it take to correct?
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It will take 100 - 200 mEq of KCl to raise the potassium level 1 mEq.
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If the potassium level is 2.9 mEq or less, how do you dose the potassium?
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It well take 200 - 400 mEq of potassium to raise the level 1 mEq.
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What EKG changes will you see with Hypokalemia?
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A prolonged and depressed ST segment and a flat or inverted T-wave.
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Why do you need to monitor Digitalis levels when a patient is receiving potassium -wasting diuretic or steroid?
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Because a lower serum-potassium level enhances the action of digitalis.
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What are s/sx of digitalis toxicity?
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N/V, anorexia, bradycardia, cardiac dysrhythmia, and visual disturbances.
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What is the relationship between potassium and insulin?
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Insulin causes potassium to shift into the cells thereby decreasing the extracellular K level. That's why insulin is used in the treatment of hyperkalemia.
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How does the level of Potassium in the serum affect insulin secretion from the pancreas?
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Because the beta cells have an ATP dependent K channel which is when closed leads to retained K inside the beta cell which favors depolarization thereby enhancing Calcium mediated release of secretory granules. Therefore, in hyperkalemia more K will enter the beta cell and insulin secretion will increase and conversely in hypokalemia the K ions are more likely to leave the beta cell and so insulin secretion will decrease.
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What other serum levels are needed to measure when hypokalemia is present?
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Serum chloride, serum magnesium, and serum protein. Correcting a potassium deficit with potassium only is not effective if chloride, mag and protein levels are also low.
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What are s/sx of hyperkalemia?
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Bradycardia, abd cramps, oliguria or anuria, tingling and twitching, or numbness of the extremities.
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What does the EKG look like with someone who is hyperkalemic?
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QRS spread and peaked T waves.
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How can you treat Hyperkalemia?
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(1) IV sodium bicarbonate increases the pH, causing potassium to shift back into cells. (2) IV glucose and insulin can also cause potassium to shift back into the cells and are usually effective for 6 hours. (3) Calcium gluconate decreases the myocardial irritability resulting from hyperkalemia but does not decrease the serum potassium level (4) Sodium polystyrene sulfonate (Kayexelate) is a drug used as ion (resin) exchange, sodium for potassium MOST EFFECTIVE!
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What is the normal lab value for Sodium?
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135 - 145 mEq/l
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