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Electrolyte Administration and
Acid-Base Balance in Nursing
Practice
Electrolyte Administration and Acid-Base
Balance
Sodium
Indications for Use: - Sodium is important in generating and transmitting nerve impulses, muscle contractility, and regulating acid-base balance. - Sodium level reflects the ratio of sodium to water. - Imbalance is associated with extracellular fluid (ECF) volume (osmolality).
Regulation: - Sodium leaves the body through urine, sweat, and feces. - The kidneys primarily regulate sodium balance by excreting or retaining water under the influence of antidiuretic hormone (ADH). - Aldosterone plays a smaller role in sodium regulation by promoting sodium reabsorption from the renal tubules.
Potassium
Mineral or Electrolyte: - The sodium-potassium pump in cell membranes maintains the concentration difference between extracellular fluid (ECF) and intracellular fluid (ICF) by pumping potassium into the cell and sodium out. - The ratio of ECF potassium to ICF potassium is the major factor in the resting membrane potential of nerve and muscle cells, so potassium imbalances often affect neuromuscular and cardiac function. - Potassium is involved with regulating intracellular osmolality and promoting cellular growth. It is required for glycogen to be deposited in muscle and liver cells, and it also plays a role in acid-base balance.
Regulation: - The kidneys are the primary route for potassium loss, eliminating about 90% of the daily potassium intake. - Potassium excretion depends on the serum potassium level, urine output, and renal function. - When serum potassium is high, urine potassium excretion increases, and when serum levels are low, excretion decreases.
Hypocalcemia
Parathyroid hormone (PTH) and calcitonin regulate calcium levels. The bones serve as a readily available store of calcium, and the body can usually keep calcium levels normal by regulating the movement of calcium into or out of the bone. Low serum calcium levels stimulate the parathyroid glands to make and release PTH, which increases bone resorption, increases
gastrointestinal (GI) absorption of calcium, and increases renal tubule reabsorption of calcium. High serum calcium levels stimulate the release of calcitonin from the thyroid gland, which has the opposite effect of PTH, lowering the serum calcium level.
Magnesium
Mineral or Electrolyte: - Magnesium, the second most abundant intracellular cation, plays a key role in essential cellular processes. - It is a cofactor in many enzyme systems, including those responsible for carbohydrate metabolism, DNA and protein synthesis, blood glucose control, and blood pressure regulation. - Magnesium is needed for the production and use of ATP, the energy source for the sodium-potassium pump. - Muscle contraction and relaxation, normal neurologic function, and neurotransmitter release depend on magnesium.
Role in Bone Formation: - About 50-60% of magnesium is stored in the muscle and bone.
Hypermagnesia: - Symptoms include muscle weakness, flaccid paralysis, respiratory depression, and hypotension.
Hypomagnesia: - Symptoms include neuromuscular excitability, tetany, and cardiac arrhythmias.
Bicarbonate
Regulation: - Bicarbonate is regulated by the kidneys, which can produce more bicarbonate when needed (high hydrogen) or excrete more bicarbonate when needed (low hydrogen).
Administration: - Bicarbonate can be administered intravenously or orally.
Adverse Effects: - Metabolic alkalosis, edema, hypernatremia, hypokalemia, and fluid overload.
Chloride
Regulation: - Chloride is regulated in the kidneys, where loop diuretics inhibit the absorption of sodium and chloride in the loop of Henle and proximal and distal tubules, causing fluid loss.
Electrolyte Imbalances: - Loop diuretics, such as furosemide, can induce various electrolyte imbalances, including hypokalemia, hypomagnesemia, hypocalcemia, hyponatremia, and hyperuricemia.
Magnesium Sulfate
Action: - Magnesium supplement
Insulin and Potassium
Mechanism of Action: - Insulin increases the activity of the sodium- potassium pump, facilitating the uptake of potassium into the cells.
Administration: - Insulin should be given with dextrose (D50) to prevent adverse effects.
Acid-Base Balance
Role of Bicarbonate: - Bicarbonate is used to manage acid-base imbalances by regulating its excretion or production through the kidneys.
