Fluid and Electrolyte Balance

Causes of Edema

  • Four possible causes of edema:
    • Oncotic pressure decreases.
    • Hydrostatic pressure increases.
    • Capillary permeability increases.
    • Lymphatic vessels become obstructed.

Electrolytes

  • Most abundant electrolyte in extracellular fluid: Sodium.

Sodium

  • Sodium has the highest influence on osmotic pressure.
    • Osmotic pressure: The force that keeps fluids inside blood vessels, determined by sodium.
    • Oncotic pressure: The force that keeps fluids inside blood vessels, determined by albumin.
  • Think of sodium as volume.
  • Changes in sodium levels often accompany changes in fluid levels.
  • Where sodium goes, water follows.
  • High sodium intake leads to increased circulating blood volume.
  • Increased osmotic pressure pulls fluids into the intravascular space, increasing circulating blood volume and blood pressure.
  • Patients with hypertension restrict sodium intake because sodium is responsible for osmotic pressure and intravascular volume.

Hyponatremia

  • Hyponatremia: Not enough sodium.
    • Can be hypovolemic or hypervolemic.
      • Hypovolemic hyponatremia: Decreased circulating blood volume and decreased sodium levels (e.g., bleeding out).
      • Hypervolemic hyponatremia: Increased fluid levels but decreased sodium levels (e.g., overhydration).
        • Example: Drinking 10 liters of water in two hours increases circulating blood volume (hypervolemia) but decreases sodium concentration (hyponatremia).
  • Sodium is responsible for the volume of fluids in the body.

Potassium

  • Potassium is the most lethal electrolyte.
  • 95% of potassium is eliminated via urine.
  • Decreased urine output leads to potassium retention (hyperkalemia), which can cause cardiac arrest.
  • Excessive potassium loss (hypokalemia) can occur with diuretics like furosemide (Lasix), a loop diuretic that increases potassium excretion.
  • Both hyperkalemia and hypokalemia can cause cardiac arrest.
  • Potassium supplements should be regulated properly, preferably via an infusion pump rather than a roller clamp, to prevent hyperkalemia.

Calcium

  • 99% of calcium is in bones and teeth, 1% in the blood.
  • 1% of calcium is responsible for the threshold of neuromuscular excitability.
  • Calcium increases the threshold for neuromuscular excitability.
    • Higher calcium levels mean a higher threshold, requiring more stimulation to create an effect.
  • Hypercalcemia: Increased calcium levels increase the threshold, requiring more stimulation to create an effect, resulting in hypoactive reflexes.
  • Calcium affects contraction of skeletal, smooth, and cardiac muscles.
  • Hypercalcemia can cause constipation due to decreased peristalsis.
  • Immobility can lead to hypercalcemia due to osteoclast activity, causing constipation.
  • Hypocalcemia: Decreased calcium levels lower the threshold, requiring less stimulation to create a reaction.
  • Vostek's sign: Tap the cheek, facial twitching indicates hypocalcemia (chvostek).
  • Trousseau’s sign (carpopedal spasm): Inflate a BP cuff, and a carpopedal spasm indicates hypocalcemia (trousseau).
  • Laryngeal spasms are the most dangerous sign of hypocalcemia; prepare a tracheostomy tube at the bedside.
  • Hormones regulating calcium levels:
    • Parathyroid hormone (from the parathyroid gland) increases calcium levels in the blood by moving calcium from bone to blood.
    • Calcitonin (from the thyroid gland) decreases calcium levels in the blood by moving calcium from blood to bone.
    • Vitamin D (synthesized in the skin) increases the absorption of calcium in the intestines.
  • Hypocalcemia refers to calcium levels in the blood.
  • Hypercalcemia can cause constipation and kidney stones (calcium-based).

Magnesium

  • Magnesium is important for enzyme activity.
  • ATP (adenosine triphosphate) is the currency of energy; energy is released by breaking the bond between the second and third phosphate using ATPase.
  • Magnesium is necessary for the creation of ATPase.
  • The sodium-potassium pump uses energy to keep sodium outside and potassium inside the cell.
  • Magnesium is needed for the sodium-potassium pump to function.
  • Correct magnesium levels before potassium levels in patients with both hyperkalemia and hypomagnesemia, as the sodium-potassium pump needs to work first.

Chloride

  • Chloride will always accompany sodium.
  • Signs of hyperchloremia are the same as hypernatremia, and signs of hypochloremia are the same as hyponatremia.
  • Exception: In hyperchloremia, the acidity of the body, specifically the stomach (hydrochloric acid), decreases, making it more acidic.

Phosphate

  • Phosphate is essential for ATP (adenosine triphosphate) and energy utilization.
  • Refeeding syndrome can occur in individuals starving for a long period, leading to hypophosphatemia.
  • For cells to utilize energy from glucose and oxygen, they need ATP.
  • To form ATP, phosphate is required; glucose utilization decreases phosphate levels as it is used for ATP.
  • If all phosphate goes into the cell to work as ATP, it causes hypophosphatemia in the blood, resulting in refeeding syndrome.

Acid-Base Imbalances

  • ABG interpretation

Assessment

  • Health history:
    • Gather information via interviews about past and present history and recent changes.
  • Vital signs:
    • Changes in fluids and electrolytes accompany changes in vital signs.
    • Initially through compensation.
  • Intake and output:
    • Intake: Everything the patient consumes.
    • Output: Everything measurable.
  • Include IV fluids in the intake.
  • Do not measure sweat from diaphoresis in output but measure urine and drainage.
  • For defecation, count the number of times per day and describe the consistency of the stool.
  • Weight:
    • Every kilogram of body weight gained is equivalent to one liter of fluid.
    • Sudden weight gain indicates fluid retention.
  • Edema:
    • Assess via palpation.
    • Grading:
      • One plus: 2 mm indentation
      • Two plus: 4 mm indentation
      • Three plus: 6 mm indentation
      • Four plus: 8 mm indentation
    • Non-pitting edema (brawny edema): Obvious swelling without indentation.
  • Skin turgor:
    • Assess fluid status
    • Skin folds can be bad assessment areas.
    • Best place to assess, especially in pediatric patients, is the abdomen.
  • Mucous membranes:
    • Assess the oral membrane.
    • Dehydration causes dry lips and fissures (slit-like lesions) in the mouth.

Diagnostic Tests

  • Arterial blood gases.

Factors Affecting Fluid, Electrolyte, and Acid-Base Balance

  • Age:
    • Older adults have a decreased thirst reflex, making them more prone to dehydration.
  • Sex:
    • Males have a higher percentage of total body water (70%) compared to females (50-55%).
    • Males are more prone to dehydration because they require higher levels of fluid to function properly.

Planning

  • Plans should be SMART (Specific, Measurable, Attainable, Relevant, Time-bounded).
  • Plans should be in accordance with the nursing diagnosis.

Interventions

  • Monitoring fluid volume:

    • Assess assessments to monitor the fluid balance of your patient can include checking the urine output, weight, vital signs, mucous membranes and skin turgor. If overhydrated, urine output will increase. If dehydrated, urine output will decrease.

  • Maintain electrolyte balance, especially in patients with kidney problems.

    • In end-stage renal disease (ESRD), decrease fluid intake because the kidneys cannot get rid of the extra fluids.
    • In patients with heart problems, decreased fluid intake because signs of heart failure is fluid retention. Excessive fluid increases exacerbates fluid retention.
    • Regulate IV fluids to prevent fluid overload, first sign being you will notice the rattlles in your patient’s lungs via lung sounds.

  • Regulate sodium levels due to its association with hypertension, which can increase their blood pressure.

    • Decreased sodium intake.
    • Dietary approach to stop hypertension (DASH) diet.

  • Oral replacement of fluids:

    • Applicable if the patient can tolerate oral feeding.

  • IV fluids:

    • Administer if the patient cannot take oral fluids.
    • Common sites:
    • Peripheral vein
      • Peripheral axis
    • Central vein Jugular or subclavian vein.
      • We place a band visual. It's just like a tourniquet, then we insert the vein.
    • Scalp (in dehydrated babies)
    • IV insertion is difficult in babies and dehydrated patients due to decreased circulating blood volume, causing veins to be more easily collapsible, as well as elderly patients.
    • Bones: interosseous

  • IV therapy:

    • Equipments peripheral catheters an central venous catheters.

  • Flow rate:

    • Amount of drops per minute or ml per hour

  • Roller clamp (less accurate) versus infusion pump (more accurate) to regulate the flow rate.

  • Use the more accurate infusion with potassium!

Complications of IV Therapy

  • Local complications:
    • Extravasation It's an irritant to the blood vessel. Vesicant= v e s I c a n t.
    • Infiltration
    • Phlebitis
  • Phlebitis: Inflammation of the vein
  • Infiltration: Unintended introduction of fluids into the subcutaneous space, that causes the hand to swell.
  • Extravasation: Introuduces vesicular subcutaneous tissue or solution that is irritating the blood vessels,
  • Potassium is very vescial and patient’s antineoplastic drugs. If exposed, look for picturessolutions of extravasation patient or patient.
  • Systemic:
    • Fluid overload
    • Septicemia Systemic-septicemia or a systemic infection. mobility can cause fluid overload

Total Parenteral Nutrition (TPN)

  • TPN is used when the gastrointestinal tract (GIT) cannot be used for feeding.
  • It Bypass by using NGP tube.
  • Total parenteral nutrition contains nutrients such as carbohydrates, propels, lipids, vitamins minerals etc.
  • Hyperglycemia, which causes an increase in blood glucose.
    • Now Microorganisms love glucose which causes you to get a source of infection. Especially central line.