Fluid electrolyte

• Electrolytes


  Positive: Sodium, Potassium, Calcium, Magnesium

  Negative: Chloride, Bicarbonate, Phosphate, Sulfate
• Sodium (Na+)


  • Major cation in extracellular fluids

  Responsible for muscle contraction, heart contraction, transmission of nerve impulse, maintaining urine concentration

  Low sodium (hyponatremia) - draws water into the cell

  High sodium (hypernatremia) - draws water out from the cell
• Potassium (K+)


  • Major cation in intracellular fluid

  Important for protein synthesis, storage glucose, maintenance of excitability of cellular membrane in the heart and nervous system

  Low potassium (hypokalaemia)

  High potassium (hyperkalaemia)
• Osmolality


  Concentration of body fluids - affects movement of fluid by osmosis

  Reflects hydration status
• Osmolarity


  Describes the concentrations of solution, measured in milliosmoles per litre (mOsm/L)
• Fluid balance


  Amount in = amount out

  Average daily intake is 2500 ml, average daily output is 2000 ml
• Body fluid compartments


  Separated into two compartments by semi-permeable membranes that control movement of water and solutes

  
• Osmosis


  Movement of water through a selectively permeable membrane from an area of low solute concentration to a higher concentration until equilibrium occurs
• Diffusion


  Movement of solutes from an area of higher concentration to an area of lower concentration in a solution and/or across a permeable membrane
• Active transport


  Allows molecules to move against concentration and osmotic pressure to areas of higher concentration

  Requires energy expenditure
• Na/K pump


  Exchange of Na ions for K ions, more Na ions move out of cell, more water pulled out from cell, ECF/ICF balance is maintained
• Insulin and glucose regulation

  CHO consumed, blood glucose peaks, pancreas secretes insulin, blood glucose returns to normal
• Serum osmolality normal value - 280-300 mOsm/kg

  Serum <240 or >320 is critically abnormal

  Normal urine osmolality - 250 - 900 mOsm /L
• Factors affecting serum osmolality

  • Increasing: Free water loss, Diabetes Insipidus, Na overload, Hyperglycemia, Uremia

  Decreasing: SIADH, Renal failure, Diuretic use, Adrenal insufficiency
• Factors affecting urine osmolality

  • Increasing: Fluid volume deficit, SIADH, Heart Failure, Acidosis

  Decreasing: Diabetes Insipidus, Fluid volume excess
• Hypernatremia


  Serum Sodium level > 145 mEq/L

  Caused by a gain of Na+ in excess of water or a loss of water in excess of Na+

  Can happen in normal fluid volume or fluid volume deficit & excess
• Treatment for hypernatremia


  Free water to replace ECF volume, Gradual lowering with hypotonic saline, Decrease by no more than 2 mEq/L/hr, Offer fluids at regular intervals, Supplement tube feedings with free water, Teach about foods/meds high in Na, Treat underlying problem
• Hyponatremia lab findings: Decreased serum Na, Cl, Bicarbonate, UOP with low Na and Cl concentration, Urine specific gravity ↓ 1.010
• Treatment for hyponatremia


  Mild: Water restriction, Increase Na in foods

  Moderate: IV 0.9% NS, 0.45% NS, Lingers Lactated (LR)

  Severe: 3% NS - short-term therapy in ICU setting
• Hypokalaemia


  Low potassium
• Hyperkalaemia


  High potassium
• Treatment for hyperkalaemia


  10% Calcium gluconate, Sodium bicarbonate, 50% glucose solution+, IV Insulin, Kayexalate PO or PR, Stop K supplements, Avoid K in foods/fluids/salt substitutes
• Acute pain related to intravenous potassium

  1. Choose a larger vein for IV cannulation to reduce irritation to the veins

  2. Give potassium through the infusion pump to control the flow speed & to prevent cardiac arrest

  3. Advice patient do not bend the hands with IV drip so the drip can flow smoothly

  4. Divide intravenous doses of potassium evenly within 24 hours to dilute and reduce pain

  5. Advise the patient to report to the nurse when IV site is painful, red, hot at the intravenous site so the nurse can exchange intravenous site
• Potential constipation related to weak peristalsis

  1. Encourage patient to take high fibre foods such as vegetables and fruits so that the faeces become soft

  2. Teach patient about ways to avoid constipation such as exercise regularly to promote peristalsis movement

  3. Encourage the patient to take 2-3 liters of liquid so that the stools are soft

  4. Encourage the patient to develop daily bowel habits to train the movement of peristalsis

  5. Give potassium intravenously in the drip according to doctor's order to improve peristalsis movement
• Calcium


  Normal 4.5-5.5 mEq/L<|>99% of Ca in bones, other 1% in ECF and soft tissues<|>Total Calcium – bound to protein – levels influenced by nutritional state<|>Ionized Calcium – use in physiologic activities – crucial for neuromuscular activity
• Calcium


  • Required for blood coagulation, neuromuscular contraction, enzymatic activity, and strength and durability of bones and teeth
  • Nerve cell membranes less excitable with enough calcium
  • Ca absorption and concentration influenced by Vit D, calcitriol (active form of Vitamin D), PTH, calcitonin, serum concentration of Ca and Phosphate
• Causes of Hypocalcemia


  • Depressed function or surgical removal of the parathyroid gland
  • Hypomagnesemia
  • Hyperphosphatemia
  • Administration of large quantities of stored blood (preserved with citrate)
  • Renal insufficiency- elevated PO4 level inverse relationship between the two electrolytes
  • Less vitamin D -↓ absorption of calcium from intestines
• Signs/Symptoms of Hypocalcemia


  • Abdominal and/or extremity cramping
  • Tingling and numbness
  • Positive Chvostek or Trousseau signs
  • Tetany; hyperactive reflexes
  • Irritability, reduced cognitive ability, seizures
  • Prolonged QT on ECG, hypotension, decreased myocardial contractility
  • Abnormal clotting
• Labs for Hypocalcemia


  Serum calcium <4.5mEq/L<|>Serum magnesium <1.6mg/l<|>Serum phosphate> 4.5mg/l
• Treatment for Hypocalcemia


  1. High calcium food - dairy product, broccoli

  2. Oral calcium salts (mild) – example Calcium carbonate, calcium gluconate, calcium lactate

  3. IV calcium as 10% calcium chloride or 10% calcium gluconate – give with caution

  4. Close monitoring of serum Ca and digitalis levels

  5. ↓ Phosphorus levels ↑ Magnesium levels

  6. Vitamin D therapy
• Risk of injury related to tetany


  1. Assess early signs of tetany, spasm around the mouth, hands and feet

  2. Provide a safe environment: Lower the beds, raised cot side all the time & ensure floor not slippery to avoid fall

  3. Ensure the room is quiet - allow patient rest to reduce irritation

  4. Give high calcium food such as dairy product, cheese, tofu, yogurt etc.

  5. Serve Calcium chloride medication according to doctor's order using infusion pump to avoid venous irritation
• Hypercalcemia


  Serum calcium more than 5.5 mEq/L
• Causes of Hypercalcemia


  • Mobilization of Ca from bone
  • Malignancy
  • Hyperparathyroidism
  • Immobilization – causes bone loss
  • Thiazide diuretics
  • Thyrotoxicosis
  • Excessive ingestion of Ca or Vit D
• Signs/Symptoms of Hypercalcemia


  • Decreased tone in smooth muscle and ↓neuromuscular excitability causes

  GIT-Anorexia, constipation

  Muscle- Generalized muscle weakness, lethargy, loss of muscle tone, ataxia

  CNS-Depression, fatigue, confusion, coma

  CVS-Dysrhythmias and heart block

  Muscular-Deep bone pain and demineralization, Pathologic bone fractures

  GU-Polyuria & predisposes to renal calculi
• Labs for Hypercalcemia


  Serum calcium > 5.5mEq/L @10mg/dl<|>Serum PTH to identify hyperparathyroidism<|>ECG shortened QR interval, shortened and depressed ST segment, widened T wave
• Complications of Hypercalcemia


  • Peptic ulcer
  • Pancreatitis
  • Renal calculus
  • Cardiac arrest
• Hypercalcemic Crisis


  Emergency – level of 8-9 mEq/L<|>Intractable nausea, dehydration, stupor, coma, azotemia, hypokalemia, hypermagnesemia, hypernatremia<|>High mortality rate from cardiac arrest
• Treatment for Hypercalcemia


  1. NS IV

  2. I&O hourly

  3. Loop diuretics

  4. Corticosteroids and Mithramycin in cancer clients help decrease bone turnover

  5. Phosphorus and/or calcitonin to decrease calcium levels

  6. Encourage fluids 3-4 liters per day

  7. Keep urine acid
• Magnesium


  Normal 1.5 to 2.5 mEq/L<|>Ensures K and Na transport across cell membrane<|>Important in CHO and protein metabolism<|>Plays significant role in nerve cell conduction<|>Important in transmitting CNS messages and maintaining neuromuscular activity
• Magnesium


  • Causes vasodilatation - Hot, flushed skin

  Decrease peripheral vascular resistance

  Balance - closely related to K and Ca balance

  Intracellular compartment electrolyte

  Hypomagnesemia - < 1.5 mEq/L

  Hypermagnesemia - > 2.5 mEq/L