MS1 Chapter 40

• Fluids and electrolytes are essential for cellular metabolism, blood volume, body temperature regulation, and solute transport
• Signs and symptoms of common fluid imbalances: Dehydration: thirst, rapid weak pulse, low blood pressure, rapid shallow respirations, dry skin, decreased urine output, dark concentrated urine, constipation, increased temperature, weight loss
• Patients at highest risk for dehydration and fluid excess: elderly, infants
• Dehydration: deficient fluid volume, hypovolemia, severe vomiting/diarrhea, profuse diaphoresis, third spacing

  Fluid excess: overhydration, hyper volemia, poorly controlled IV therapy, excessive water ingestion, excessive sodium intake, adrenal gland dysfunction
• Monitor daily weight, intake and output, urine specific gravity, blood urea nitrogen (BUN) and Hematocrit (Hct)
• For deficient fluid volume: increase fluid intake, treat underlying cause, monitor weight

  For excess fluid volume: place in semi-Fowler or high Fowler position, administer oxygen, administer diuretics, restrict sodium and fluid
• Educate on the importance of fluid balance, signs and symptoms of imbalances, and the role of sodium, potassium, calcium, and magnesium
• Common causes, signs and symptoms, and treatments for sodium, potassium, calcium, and magnesium imbalances:
• Sodium: hyponatremia (sodium deficit) and hypernatremia (sodium excess)

  Potassium: hypokalemia (potassium deficit) and hyperkalemia (potassium excess)
• Sodium: pizza, canned vegetables, salty snacks

  Potassium: sweet potatoes, bananas, yogurt

  Calcium: cheese, salmon, dairy products
• Acidosis: renal failure, diabetes, alcoholism

  Alkalosis: vomiting, excessive antacid use, hypokalemia
• Arterial blood gases changes for each type of acid-base imbalance:
• Acidosis: decreased pH, decreased bicarbonate

  Alkalosis: increased pH, increased bicarbonate
• Hyperkalemia signs and symptoms:

  • Muscle twitching and cramps
  • Later profound muscle weakness
  • Diarrhea
  • Slow, irregular heartrate with weak pulse
  • Low blood pressure
  • Cardiac arrhythmia, respiratory failure
• Interventions for Hyperkalemia:

  • Limit dietary potassium
  • Hold potassium supplements
  • Administer medications as ordered
  • Potassium-wasting diuretic
  • Kayexalate (sodium polystyrene sulfonate)
  • Insulin with glucose
  • Cardiac monitoring
  • Monitor for potentially lethal arrhythmias
• Calcium Imbalances:

  • Normal serum calcium is 8.2-10.2 mg/dL
  • Hypocalcemia: Low calcium level
  • Hypercalcemia: High calcium level
• Food Sources of Calcium:

  • Fortified cereals
  • Cheese
  • Yogurt
  • Milk
  • Almond milk
• Hypocalcemia Signs and Symptoms:

  • Calcium less than 8.2 mg/dL
  • Low Vitamin D prevents calcium absorption
  • Brittle bones
  • Mental status changes
  • Hyperactive deep tendon reflexes (DTR)
  • Positive Trousseau sign
  • Positive Chvostek sign
  • Diarrhea, abdominal cramping
  • Heart rate changes and low blood pressure
  • Tetany
  • Continuous muscle spasms (airway compromise)
• Hypocalcemia Signs and Symptoms (continued):

  • Trousseau Sign: Hand and fingers become spastic with palmar flexion in hypocalcemia
  • Chvostek Sign: Facial twitching near the ear in hypocalcemia
• Interventions for Hypocalcemia:

  • Treat cause
  • Administer medications as ordered
  • IV calcium gluconate
  • Oral calcium supplements
  • Aluminum hydroxide to bind phosphate
  • Increase dietary calcium
  • Teach about high-calcium foods
• Hypercalcemia Signs and Symptoms:

  • Calcium greater than 10.2 mg/dL
  • Mild or slowly progressing calcium increase may have no obvious signs and symptoms
  • Increased heart rate and blood pressure
  • Skeletal muscle weakness
  • Decreased GI motility
  • Urinary calculi (kidney stones)
  • Respiratory and/or heart failure if severe
• Interventions for Hypercalcemia:

  • Cardiac monitoring
  • Administer IV fluids; promote diuresis
  • Administer medications as ordered
  • Diuretics to promote calcium excretion
  • Drugs that slow calcium movement from bones to the blood
  • Pamidronate disodium (Aredia), zoledronic acid (Zometa), or calcitonin
  • Hemodialysis to cleanse the blood of excess calcium
• Magnesium Imbalances:

  • Normal serum magnesium is 1.6-2.2 mEq/L
  • Hypomagnesemia: Low magnesium level
  • Hypermagnesemia: High magnesium level
• Hypomagnesemia Signs and Symptoms:

  • Serum magnesium less than 1.6 mEq/L
  • Alcoholism common cause
  • Positive Trousseau sign
  • Positive Chvostek sign
  • Cardiac arrhythmia and/or cardiac arrest
  • Cardiac arrhythmias such as Torsades may occur
• Interventions for Hypomagnesemia:

  • Treat underlying cause
  • Administer magnesium replacement
  • Cardiac monitoring
• Hypermagnesemia Signs and Symptoms:

  • Serum magnesium greater than 2.2 mEq/L
  • Usually not apparent until the serum level is greater than 4 mEq/L
  • Hypotension
  • Lethargy
  • Skeletal muscle weakness
  • Respiratory failure &/or cardiac failure
• Interventions for Hypermagnesemia:

  • Administer IV fluids
  • Administer medications as ordered
  • Furosemide (Lasix) to increase magnesium secretion
  • Dialysis for kidney failure
• Acid–Base Balance:

  • Acid: Substance that releases a hydrogen ion
  • Base (Alkali): Substance that binds hydrogen
  • Normal serum pH is 7.35 to 7.45
  • pH of a solution can vary from 0-14, with 7 being neutral; 0 to 6.99 being acidic; and 7.01 to 14 being basic (alkaline)
  • It must remain in this extremely narrow range to sustain life
• Acid–Base Control:

  • Cellular buffers, lungs, kidneys help in maintaining serum pH
  • Cellular buffers act as a sponge to regulate hydrogen ions
  • Lungs regulate carbon dioxide levels in blood
  • Kidneys regulate bicarbonate levels in the body
• Acid–Base Imbalances:

  • Two broad types of acid–base imbalance are acidosis and alkalosis
  • Acidosis: Blood is more acidic than normal
  • Alkalosis: Blood is more alkaline than normal
• ABG Interpretation:

  • pH high = basic, pH low = acidic
  • pCO2 high = acidic, pCO2 low = basic
  • HCO3 high = basic, HCO3 low = acidic
  • ROME: Respiratory Opposite, Metabolic Equal
• ABG Examples:

  • Respiratory Acidosis: pH 7.29, pCO2 64, HCO3 21
  • Respiratory Alkalosis: pH 7.49, pCO2 24, HCO3 22
  • Metabolic Acidosis: pH 7.29, pCO2 34, HCO3 12
  • Metabolic Alkalosis: pH 7.49, pCO2 35, HCO3 32
• Review Questions:

  1. A patient with skin tenting and decreased urine output is most likely experiencing which fluid or electrolyte disorder? Dehydration

  2. Which electrolyte is most critical to healthy cardiac rhythm? Potassium

  3. Which interventions are appropriate to a patient with fluid excess? Monitor weight, Place in Fowler position, Restrict fluid and sodium

  4. What are good food sources of calcium? Milk, Fortified cereals, Yogurt, Cheese