Fluid & Electrolytes balance Mat & Peds

• On average a child's body weight in water is 75 - 80%
• Diffusion: solutes move from high concentration to area of low concentration
• Osmosis: Fluid moves passively from areas of high concentration to areas of low concentration
• Fluid shifts happen through a semipermeable membrane
• Reabsorption: prevents too much fluid from leaving the capillaries, no matter the hydrostatic pressure
• Albumin: A large molecule that acts like a magnet to attract and hold water molecules inside the blood vessel
• Electrolytes account for approximately 95% of the solute molecules in body water
• Sodium helps transmit impulses in nerve and muscle fibers
• Potassium plays a role in muscle contraction and myocardial membrane responsiveness
• Magnesium contributes to protein synthesis; acts as a catalyst for enzyme reactions
• Chloride plays a vital role in maintaining acid-base balance
• Phosphate has a crucial role in cell membrane integrity; promotes energy storage and carbohydrate, protein, and fat metabolism
• normal range for sodium is 135 - 145 mmol/L
• Hyponatremia can cause plasma hypo-osmolality and cellular swelling
• Hypernatremia: Water moves from the ICF to the ECF
• A patient is experiencing hypotension, tachycardia, decreased urine output, and neurological changes (seizures, decreased reflexes). What kind of electrolyte imbalance are they experiencing?

  Hyponatremia
• A patient is experiencing weight gain, excessive thirst, an increase in blood pressure, and neurological changes (muscle twitches). What kind of electrolyte imbalance are they experiencing?

  Hypernatremia
• Mild hyponatremia is treated with oral sodium chloride
• Mild hyponatremia is treated using a fluid restriction and oral sodium chloride
• Adverse effects of oral sodium administration includes nausea, vomiting, and cramps
• Adverse effects of sodium IV administration includes venous phlebitis and edema
• Normal range for potassium is 3.5 - 5.5 mmol/L
• Hypokalemia causes membrane hyperpolarization
• Hyperkalemia is caused by renal excretion issues, insulin deficiency, or cellular trauma, K+ moves from ICF into ECF
• S/S of hypokalemia

  • Decrease in neuromuscular excitability (weakness, low tone)
  • Skeletal muscle weakness and smooth muscle atony
  • Cardiac dysrhythmias (weak/irregular pulse, postural hypotension, cardiac arrest)
  • Nausea and vomiting, decreased GI motility
• S/S Hyperkalemia

  • Increased neuromuscular irritability
  • Restlessness, intestinal cramping, and diarrhea
  • Cardiac changes (dysrhythmias, bradycardia, cardiac arrest)
  • Diarrhea
  • Abdominal pain
• When administering oral potassium, it must be diluted (water or orange juice) and taken with food (or immediately after) to minimize GI upset.
• When administering oral potassium must monitor for nausea, vomiting, GI pain, and GI bleeding
• When administering IV potassium *must be monitored closely*, do not infuse it faster than 10 mmol/hr for patients who are NOT on cardiac monitors. For critical cardiac monitor p.t's, rates of 20 mmol/L may be used
• When administering an IV potassium, NEVER give it as an IV bolus or undiluted
• Treatments of hyperkalemia include IV sodium bicarbonate, calcium gluconate, calcium chloride, or dextrose with insulin.

  • Can also administer sodium polystyrene sulfonate (Kayexalate) or hemodialysis to remove excess potassium
• Adverse effects of oral potassium are

  • Diarrhea, nausea, vomiting
  • GI bleeding
  • ulceration
• Adverse effects of potassium IV administration are

  • Pain/irritation at injection site
  • Phlebitis
• Excessive administration of potassium can cause

  • Hyperkalemia
  • Toxic effects
  • Cardiac arrest
• Acid-base balance depends on the regulation of free hydrogen ions
• Acid-base balance is maintained by chemical buffers, respiratory reactions and kidney reactions
• Children are at higher risk for acid-base imbalance because they have a low residual lung volume, higher metabolic rate and immature organs
• A blood gas analysis is the main evaluating tool for acid-base balance and focuses on

  • pH (acidity or alkalinity)
  • PaCO2 (adequacy of ventilation by lungs)
  • Bicarbonate level (activity of kidneys in retaining or excreting bicarbonate)
• The normal pH range is 7.35 to 7.45
• Normal PaCO2 levels are between 35 and 40 mm Hg