Serum potassium imbalance
It is a major intracellular cation.
The normal plasma potassium concentration is 3.5-5.0 mEq/L whereas that inside the cells is about 150 mmol/L.
Disorders of Potassium includes
Hypokalemia is defined as a plasma potassium concentration level of less than 3.5mEq/L. It is a common disorder especially in older adult population.
· GI losses – Vomiting and Diarrhea, fistulas, NG suction
· Renal losses – potassium wasting Diuretics (thiazide, loop and osmotic diuretics) hyperaldosteronism (mineralocorticoid excess), magnesium depletion.
· Skin losses – Diaphoresis
2.Shift of potassium into cells:
· Increased insulin
· Alkalosis – potassium exchange with hydrogen ion across the cell wall, thus increasing the level of hydrogen but decreasing the level of potassium in the plasma
· Tissue repair
· Beta adrenergic agonists (basically K goes inside the cells)
3.Lack of potassium intake:
· Potassium restricted diet.
· Failure to include potassium in parenteral fluids if NPO
· Slowed skeletal muscle contraction
· Slowed smooth muscle contraction
· Deterioration of respiratory muscle contraction
· Decrease in myocardial contraction
· Increased conduction of nerve impulses
· Slowed smooth muscle contraction leads to GI manifestations – anorexia, abdominal distension and constipation.
· Slowed Skeletal muscle contractions – weakness muscle cramps, may progress to paralysis.
· Decreased nerve conduction – Fatigue, paresthesia, hyporeflexia and irritability
· Decreased myocardial contractility – hypotension weak and slow pulse. If K less than
· 2.5 mEq/L
· ventricular fibrillation and cardiac arrest.
· Pulmonary – Shallow respiration, shortness of breath, apnea and respiratory arrest.
· ST segment depression
· Flattened T wave
· Presence of U wave
· Ventricular dysrhythmias
· Enhanced digitalis effects
In Progressive stage
· Confusion, depression, convulsions, areflexia, and coma
· Vomiting, urinary retention
· Inability of kidney to concentrate urine leads to Polyuria, nocturia, and decreased plasma osmolality.
History and physical examination:-A detailed history and physical examination
Serum potassium levels
· It is focused on identifying and correcting the cause of the imbalance.
· The aggressiveness of the therapy depends on the potassium level and the clinical manifestations.
Minor potassium deficit
· Administering foods high in potassium helps correct the deficit and offsets losses.
Mild to moderate potassium deficits:
· Oral potassium replacement
· Oral potassium is extremely irritating to the gastric mucosa and can produce small bowel lesion and must be taken with a glass of water or juice or with meals.
· KCl supplement added to IV solution.
· Should not add more than 60 mEq/L.
· The preferred level is 40 mEq/L.
· The rate of administration should not exceed 10 to 20 mEq per hour to prevent hyperkalemia and cardiac arrest.
· Potassium given intravenously must always be diluted in IV fluids
· Hypokalemia related to nausea, vomiting or prolonged use of diuretics
· Risk for injury related to muscle weakness and hypotension or seizures secondary to hypokalemia.