03 session 1

• types of electrolytes

  • Cations (+)
  • Anions (-)
• Electrolytes


  • Integral part of metabolic and cellular processes, charged particles in solution
• Cations (+)


  • Sodium
  • Potassium
  • Calcium
  • Magnesium
• Anions (-)


  • Chloride
  • Bicarbonate
  • Phosphate
  • Sulfate
• Major Cations


  • EXTRACELLULAR SODIUM (Na+)
  • INTRACELLULAR POTASSIUM (K+)
• Sodium


  • Major extracellular cation
  • Attracts fluid and helps preserve fluid volume
  • Combines with chloride and bicarbonate to help regulate acid-base balance
  • Normal range of serum sodium 135 - 145 mEq/L
• Sodium and Water


  1. If sodium intake suddenly increases, extracellular fluid concentration also rises

  2. Increased serum Na+ increases thirst and the release of ADH, which triggers kidneys to retain water

  3. Aldosterone also has a function in water and sodium conservation when serum Na+ levels are low
• Types of Hyponatremia


  • Dilutional
  • Depletional
  • Hypovolemic
  • Hypervolemic
  • Isovolumic
• Hyponatremia


  • Serum Na+ level < 135 mEq/L
  • Deficiency in Na+ related to amount of body fluid
• Assessment of Hyponatremia


  1. Primarily neurologic symptoms

  2. Hypovolemia - poor skin turgor, tachycardia, decreased BP, orthostatic hypotension

  3. Hypervolemia - edema, hypertension, weight gain, bounding tachycardia
• Interventions for Hyponatremia


  1. MILD CASE - Restrict fluid intake for hyper/isovolumic hyponatremia, IV fluids and/or increased po Na+ intake for hypovolemic hyponatremia

  2. SEVERE CASE - Infuse hypertonic NaCl solution (3% or 5% NaCl), Furosemide to remove excess fluid, Monitor client in ICU
• Hypernatremia


  • Excess Na+ relative to body water
  • Occurs less often than hyponatremia
  • Thirst is the body's main defense
  • When hypernatremia occurs, fluid shifts outside the cells
  • May be caused by water deficit or over-ingestion of Na+, also may result from diabetes insipidus
• Assessment of Hypernatremia


  Think S-A-L-T - Skin flushed, Agitation, Low grade fever, Thirst, Neurological symptoms, Signs of hypovolemia
• Interventions for Hypernatremia


  Correct underlying disorder, Gradual fluid replacement, Monitor for s/s of cerebral edema, Monitor serum Na+ level, Seizure precautions
• Potassium


  • Major intracellular cation
  • Untreated changes in K+ levels can lead to serious neuromuscular and cardiac problems
  • Normal K+ levels = 3.5 - 5 mEq/L
• Balancing Potassium


  1. Most K+ ingested is excreted by the kidneys

  2. Three other influential factors - Na+/K+ pump, Renal regulation, pH level
• Renal Regulation


  1. Increased K+ levels ⇒ increased K+ loss in urine

  2. Aldosterone secretion causes Na+ reabsorption and K+ excretion
• pH


  1. Potassium ions and hydrogen ions exchange freely across cell membranes

  2. Acidosis ⇒ hyperkalemia (K+ moves out of cells)

  3. Alkalosis ⇒ hypokalemia (K+ moves into cells)
• Hypokalemia


  • Serum K+ < 3.5 mEq/L
  • Can be caused by GI losses, diarrhea, insufficient intake, non-K+ sparing diuretics (thiazide, furosemide)
• Assessment of Hypokalemia


  Think S-U-C-T-I-O-N - Skeletal muscle weakness, U wave (EKG changes), Constipation, ileus, Toxicity of digitalis glycosides, Irregular, weak pulse, Orthostatic hypotension, Numbness (paresthesias)
• Interventions for Hypokalemia


  Increase dietary K+, Oral KCl supplements, IV K+ replacement, Change to K+-sparing diuretic, Monitor EKG changes
• Hyperkalemia


  • Serum K+ > 5 mEq/L
  • Less common than hypokalemia
  • Caused by altered kidney function, increased intake (salt substitutes), blood transfusions, meds (K+-sparing diuretics), cell death (trauma)
• Assessment of Hyperkalemia


  Irritability, Paresthesia, Muscle weakness (especially legs), EKG changes (tented T wave), Irregular pulse, Hypotension, Nausea, abdominal cramps, diarrhea
• Interventions for Hyperkalemia


  1. MILD - Loop diuretics (Lasix), Dietary restriction

  2. MODERATE - Kayexalate

  3. EMERGENCY - 10% calcium gluconate for cardiac effects, Sodium bicarbonate for acidosis
• Magnesium


  • Helps produce ATP
  • Role in protein synthesis & carbohydrate metabolism
  • Helps cardiovascular system function (vasodilation)
  • Regulates muscle contractions
• Hypomagnesemia


  • Serum Mg++ level < 1.5 mEq/L
  • Caused by poor dietary intake, poor GI absorption, excessive GI/urinary losses
  • High risk clients - Chronic alcoholism, Malabsorption, GI/urinary system disorders, Sepsis, Burns, Wounds needing debridement
• Assessment of Hypomagnesemia


  1. CNS - Altered LOC, Confusion, Hallucinations

  2. Neuromuscular - Muscle weakness, Leg/foot cramps, Hyper DTRs, Tetany, Chvostek's & Trousseau's signs

  3. Cardiovascular - Tachycardia, Hypertension, EKG changes

  4. Gastrointestinal - Dysphagia, Anorexia, Nausea/vomiting
• Interventions for Hypomagnesemia


  1. MILD - Dietary replacement

  2. SEVERE - IV or IM magnesium sulfate, Monitor neuro status, cardiac status, safety
• Magnesium Sulfate Infusion


  1. Use infusion pump - no faster than 150 mg/min

  2. Monitor vital signs for hypotension and respiratory distress

  3. Monitor serum Mg++ level q6h

  4. Cardiac monitoring

  5. Calcium gluconate as an antidote for treating Mg++ toxicity
• Hypermagnesemia


  • Serum Mg++ level > 2.5 mEq/L
  • Not common
  • Renal dysfunction is most common cause - Renal failure, Addison's disease, Adrenocortical insufficiency, Untreated DKA
• Assessment of Hypermagnesemia


  Decreased neuromuscular activity, Hypoactive DTRs, Generalized weakness, Occasionally nausea/vomiting
• Interventions for Hypermagnesemia


  Increased fluids if renal function normal, Loop diuretic if no response to fluids, Calcium gluconate for toxicity, Mechanical ventilation for respiratory depression, Hemodialysis (Mg++ free dialysate)
• Calcium


  • 99% in bones, 1% in serum and soft tissue (measured by serum Ca++)
  • Works with phosphorus to form bones and teeth
  • Role in cell membrane permeability
  • Affects cardiac muscle contraction
  • Participates in blood clotting
• Calcium Regulation


  1. Affected by body stores of Ca++ and by dietary intake & Vitamin D intake

  2. Parathyroid hormone draws Ca++ from bones increasing low serum levels

  3. With high Ca++ levels, calcitonin is released by the thyroid to inhibit calcium loss from bone
• Hypocalcemia


  • Serum calcium < 8.9 mg/dl
  • Ionized calcium level < 4.5 mg/Dl
  • Caused by inadequate intake, malabsorption, pancreatitis, thyroid or parathyroid surgery, loop diuretics, low magnesium levels
• Assessment of Hypocalcemia


  1. Neuromuscular - Anxiety, confusion, irritability, muscle twitching, paresthesias (mouth, fingers, toes), tetany, Fractures

  2. Diarrhea

  3. Diminished response to digoxin

  4. EKG changes
• Interventions for Hypocalcemia


  Calcium gluconate for postop thyroid or parathyroid client, Cardiac monitoring, Oral or IV calcium replacement
• Hypercalcemia


  • Serum calcium > 10.1 mg/dl
  • Ionized calcium > 5.1 mg/dl
  • Two major causes - Cancer, Hyperparathyroidism
• Assessment of Hypercalcemia


  1. Fatigue, confusion, lethargy, coma

  2. Muscle weakness, hyporeflexia

  3. Bradycardia ⇒ cardiac arrest

  4. Anorexia, nausea/vomiting, decreased bowel sounds, constipation

  5. Polyuria, renal calculi, renal failure
• Interventions for Hypercalcemia


  1. If asymptomatic, treat underlying cause

  2. Hydrate the patient to encourage diuresis

  3. Loop diuretics

  4. Corticosteroids