potassium imbalances

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POTASSIUM IMBALANCESHYPOCALEMIA & HYPERCALEMIA

2 JULY 2004

POTASSIUM BALANCE1. Potassium (K) is the major intracellular electrolyte; 98% of the bodys potassium is inside the cell.

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The remaining 2% is in the ECF.

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Normal serum K level ranges from 3.5 - 5.0 mEq/L

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The daily dietary requirement of K is about 40 mEq; the average daily intake is 60 100 mEq

5. Functions:a) K maintains cell electroneutrality and cell osmolality. b) K directly affects cardiac muscle contraction and electrical conductivity. c) K aids neuromuscular transmission of nerve impulses.

6. Regulationa) K must be ingested daily because the body does not conserve it. b) The kidneys eliminate about 80% of ingested K; about 20 40 m Eq are lost in each liter of urine. c) The remaining K is secreted in feces; 5 10 mEq are lost in each liter of GI fluid. d) Aldosterone secretion leads to renal Na reabsorption and K excretion.

HYPOKALEMIA1. Hypokalemia potassium level < 3.5 mEq/L. Hypokalemia is usually results from excessive excretion or inadequate intake of K Hypokalemia is a dangerous condition because it increase the risk of dysrhythmia.

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Causes1. Renal lossesa) Potassium-losing diuretics such as thiazides. Potassiumb) Excess aldosterone production. c) Excessive steroid administration arthritis, asthma. d) Medication Gentamicin.

2. Gastrointestinal lossesa) Vomiting and gastric suction. b) Diarrhea and prolonged intestinal suction. c) Laxative abuse

3. Poor intakea) Anorexia nervosa b) Alcoholism c) Debilitation.

Clinical Manifestations1. Clinical signs are usually not present until the potassium level falls below 3.0 mEq/L. 2. The diagnosis is usually made by measurement of the serum potassium level.

3. Cardiovascular effects.a) Abnormalities of electrophysiology and contractility.

b) Increase the risk of dysrhythmia.

4. Muscular changesa) Muscle weakness (begin with extremities and move up to trunk) Symptoms such as anorexia, nausea, vomiting, gaseous distention are due to weakness of the smooth muscle of the GI tract.

b) Impaired respiratory muscle functions. c)

5. Renal changesa) b) c) d) Dilute urine Polyuria Nocturia Polydipsia.

Treatment1. The best treatment for hypokalemia is prevention.

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For patients at risk, a diet with potassium content should be provided.

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However, once hypokalemia has developed, dietary potassium intake maybe ineffective replacement because most potassium in food is complexed to anions that metabolize into bicarbonate.

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Therefore, patients with significant hypokalemia associated with metabolic alkalosis should be given potassium chloride (KCl). Because KCl is efficiently absorbed through the GI tract, no solution should be given orally. When potassium cannot be consumed in adequate amounts in the diet, and when oral potassium supplements are not feasible, the IV route is indicated for replacement.

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The IV is mandatory for patients with severe hypokalemia (5.0 mEq/L b) Decreased arterial pH. c) ECG abnormalities

Treatment1. Restriction of potassium intake and drugs potentiating hyperkalemia. 2. Promote potassium excretion.a) b) c) d) e) f) Sodium polystyrene sulfanate Dialysis Diuretics Calcium gluconate Sodium bicarbonate Insulin and glucose.

Nursing interventions1. 2. Be aware of patients at risk for hyperkalemia. Take measures to prevent hyperkalemia when possible by following guidelines for administering potassium safely both orally and IV. Avoid administration of potassium-conserving potassiumdiuretics, potassium supplements or salt substitutes to patient with poor renal function.

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4. Cardiac monitoring and a 12-lead ECG are indicated 12with elevated serum K. 5. Assess cardiovascular status by monitoring pulse rate and rhythm and blood pressure. 6. Assess for hyperactive bowel sounds and diarrhea. 7. Monitor serum K levels to determine treatment effectiveness.

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Caution hypercalemic patients to avoid foods high in potassium content. To avoid false report of hyperkalemia (pseudohyperkalemia), take the following precautions: a) Avoid prolonged use of a tourniquet while drawing blood sample. b) Do not allow patient to exercise extremity immediately before drawing blood sample. c) Take blood sample to laboratory as soon as possible. d) Avoid drawing blood specimen from a site above an infusion of potassium solution.

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HYPOCALCEMIANursing Interventions1. Carefully assess patients at increased risk for hypocalcemia especially after parathyroidectomy or massive transfusions. Remember that seizure precautions may indicated based on the extent of musculoskeletal complications. Institute safety precautions, such as padded bed rails to prevent injury, especially if the patient is confused.

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Remember that Ca may be given initially as a slow IV bolus, followed by a slow IV drip infusion if Ca deficit is acute. Administer IV Ca replacement carefully, ensuring that the vein is patent; infiltration can cause tissue necrosis. Place the patient on a cardiac monitor, and observe for changes in heart rate and rhythm.

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Monitor a patient receiving IV Ca for arrhythmias, especially if the patient is also taking digitalis glycosides. Expect to administer oral Ca supplements or Vit.D for mild to moderate hypocalcemia. Keep the calcium gluconate at the bedside of a patient recovering from parathyroid or thyroid surgery to andminister if a rapid drop in serum Ca level occurs.

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10. Teach the patients and familya) Foods and fluids high in Ca such as dairy products and green leafy vegetable. b) Exercise enhances Ca mobilization from bone to replenish ECF level. c) Female hormones, such as estrogen may be administered to maintain adequate Ca level in patients with osteoporosis.

HYERCALCEMIANursing Interventions1. Monitor patients at risk for hypercalcemia, especially those with hyperparathyroidism or cancer and those on long-term bed rest. longAmbulate the patient as soon as possible to prevent Ca mobilization from the bone. Have the patient drink 3-4L of fluids daily (if not 3contraindicated) to stimulate renal Ca excretion.

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Offer the patient foods or fluids high in Na (if not contraindicated) because the kidney excrete Ca in favor of Na.

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In a patient with acute moderate to severe hypercalcemia (levels greater than 13 mg/dl), administer isotonic normal saline solution, usually at a rate of 200 to 500 ml/hr, to reserve dehydration and promote urinary Ca excretion.

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Place client in cardiac monitor to detect arrhythmias. Institute safety precautions such as elevated side rails for a confused and disoriented patient. Teach the patient to avoid Ca-containing foods and Cafluids, particularly dairy products, to prevent increased serum Ca level. Monitor serum Ca levels to determine treatment effectiveness and to detect new imbalance resulting from therapy

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HYPOPHOSPHATEMIANursing Interventions1. Monitor patients at risk for hypophosphatemia, especially those receiving TPN without P replacement. Assess for paresthesia, particularly in the circumoral area an early sign of hypophosphatemia. Initiate safety precautions for a patient with confusion or decreased level of conciousness.

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Assess for signs and symptoms of infection; in hypophosphatemia, granulocytes have less ability to fight foreign bodies.

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Expect to administer oral P supplements to a patient with mild to moderate hypophosphatemia Use caution when administering

parenteral P to a patient with severe hypophosphatemia; hypocalcemia may occur as P levels rise.

HYPERPHOSPHATEMIANursing Interventions1. Monitor patients at risk, particularly those with hypocalcemia. Initiated seizure precautions in patients with elevated P levels. Monitor for neuromuscular irritability, which accompanies high P levels. Administer Ca supplements to promote elevation of serum Ca, which lowers serum P levels.

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Teach the patient and family to avoid foods and fluids high in P, such as cheeses, nuts, wholewholegrain cereals, dried fruits and vegetables.

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Teach the patient and family to avoid excessive use of enema and laxatives containing P.

HYPOMAGNESEMIANursing Interventions1. Monitor patients at risk for hypomagnesemia, particularly those with hypokalemia and those receiving TPN without Mg replacement. Institute cardiac monitoring in a patient with severe hypomagnesemia. Remember that hypomagnesemia may be treated with oral, IM or IV Mg salt. Administer IV Mg slowly because too rapid infusion can cause cardiac or respiratory arrest.

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During IV Mg therapy, monitor urine output; it should be at least 120 ml every 4 hours. Monitor serum Mg and K levels to evaluate treatment effectiveness. Initiate safety precautions, such as elevated bed rails, for a confused patient. Teach the patient and family about foods high in Mg, such as green vegetables, nut, beans and fruits.

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HYPERMAGNESEMIANursing Interventions1. Monitor patients at risk, especially those with conditions predisposing to hypermagnesemia, such as renal failure. Monitor vital signs, particularly BP which can drop precipitously and respirations which may be depressed and can progress to apnea. Assess neuromuscular status for deficits; evaluate reflexes, grip strength and respiratory muscle function.

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