Life and homeostasis depend largely on fluid and electrolyte balance and its dynamic processes.
Fluid
Our body consists of almost 70% of water. It helps the body to balance biochemical reactions that produce life.
Two Categories of Fluid in the Body:
1. Intracellular fluid: also known as the cytoplasm of the cell. It is almost 40 percent of the body weight. This fluid is stable in the body. It doesn’t adapt to the rapid changes in the body during activities such as exercise. This is the compartment that maintains homeostasis and where the chemical reaction takes place.
Intracellular fluid has higher concentrations of:
- Phosphate
- Magnesium
- Potassium
- Proteins
Intracellular fluid has lower concentrations of:
- Sodium
- Chloride
- Bicarbonate
2. Extracellular fluid: extracellular cells are almost 20 percent of the body weight. It has 2 subcategories:
- Plasma which is approximately 5 percent of the bodyweight
- Interstitial space which is almost 12 percent of the bodyweight
Extracellular fluid has higher concentrations of:
- Sodium
- Chloride
- Bicarbonate
- Proteins
Extracellular fluid has lower concentrations of:
- Potassium
- Magnesium
- Phosphate
Quick Facts
- Fluid moves in the body through a semipermeable membrane.
- The normal level of blood osmolarity is 200 mOsmoles/L. When levels go low, it is hypoosmotic. High levels mean it’s hyperosmotic.
- Approximately 1 kilogram is equal to 1 liter of free water.
- Parkland formula is used when treating burn patients with fluid replacements. The example formula is 4 mL/kg/% of body surface burned. This is for the first 24 hours starting from the time of the burn.
- The brain consists of at least 90 percent fluid.
- Fluid transports nutrients and oxygen into the cell.
- It moisturizes the air in our lungs to help in metabolism.
- Muscle consists of almost 70 percent of water.
- Bones consist of almost 22 percent of water.
- The fluid protects and moisturizes our joints.
- Blood consists of at least 80 percent of water.
Fluid Imbalances
- Edema: occurs when there is fluid overload. It is observed in the extremities like the hands and feet. Yet, in other situations, it will show in other areas of the body. A patient can identify edema when the face or limbs get bigger or there’s a feeling of tightness.
Types of Edema
- Peripheral edema is fluid pooled in the legs. Compression stockings help in the prevention of the development of this type of edema. It pushes back fluids to the capillaries thus lessening the effects of the edema.
- Pulmonary edema is a condition when fluid accumulates in the lungs. This occurs during cardiac and renal failure. This compresses the airways making it a life-threatening condition.
- Liver disease may also cause edema. Patients with liver disease couldn’t produce albumin. The albumin maintains the osmosis in the liver.
- Intravenous administration can cause increased fluid overload if not monitored. Too much intravenous fluid is dangerous.
Treatment
Diuretics are medications that remove fluid from the body through the renal system. Yet, the best treatment for edema is treating the underlying condition.
- Dehydration is the low or inadequate water intake for metabolic needs. The adult on average has to drink at least 1L a day. This may increase depending on the needs of the adult, especially when pursuing activities like exercise.
Reasons for fluid loss can either be normal or pathologic. Pathologic means it’s caused by bacteria or underlying conditions, like burns.
Normal fluid loss includes:
- Urine
- Sweat
- Respiration
- Stool
Pathologic fluid loss includes:
- Diarrhea
- Vomiting
- Infection
- Increase urination from SIADH
- Diabetes mellitus
- Diabetes insipidus
Signs and Symptoms of Dehydration
- Decreased urine output
- Dizziness
- Tachycardia
- Fatigue
- Decreased skin turgor
- Confusion: occurs in severe cases
Treatment
- IV fluid replacement: 0.9 percent NaCl (normal saline solution)
- 30 mL/kg bolus administered for children: initial treatment for emergency situations
- Bolus fluid administration has a different proportion when used in obese patients
Electrolytes
Functions of Electrolytes
- Contraction of muscles
- Sending nerve impulses
- Osteogenesis or ossification
- Balancing fluids in our body via osmosis
- Maintaining the blood’s acid-base balance
Electrolytes Found in the Body
1. Sodium: one of the most important electrolytes in the extracellular fluid. It regulates the membrane potential of the cells and extracellular fluid volume. Normal values are 135 to 145 mmol/L.
Imbalances:
Hyponatremia: when values are lower than normal or 135 mmol per liter. Seen in patients with low-sodium diets; also seen in hyperglycemia and congestive heart failure.
Hypernatremia: when values are higher than 145 mmol per liter. These values are seen in patients with conditions of unreplaced fluid loss, that is through the gastrointestinal tract and skin.
2. Potassium: this is an intracellular ion. It plays a role in maintaining the homeostasis between sodium and potassium in the cells. The normal levels are 3.6 – 5.5 mmol/L.
Imbalances:
Hypokalemia: the serum potassium level is below 3.6 mmol per liter. The signs and symptoms are fatigue, weakness, and muscle twitching. Cardiac arrhythmias are also present.
Hyperkalemia: potassium serum level is more than 5.5 mmol per liter. The patients may experience muscle weakness, muscle cramps, and myoglobinuria. Patients may also experience cardiac arrhythmias.
3. Calcium: helps in the skeletal system. It helps in the contraction of muscles, skeletal mineralization, and blood clotting. This is present in extracellular fluid. Normal values are 8.8 to 10.7 mg/dl.
Imbalances:
Hypocalcemia: occurs when serum calcium level is below 8.8 mg/dl. This is present in patients with conditions like hypoparathyroidism and vitamin D deficiency.
Hypercalcemia: is present when serum calcium values are higher than 10.7 mg/dL. This condition is seen along with parathyroidism.
4. Bicarbonate: its main job is to regulate the acid-base balance of the body. The kidneys are the organs that regulate bicarbonate. Diarrhea causes acid-base imbalance because the patient loses bicarbonates. Normal levels are 23 to 30 mmol/L.
Imbalances:
Metabolic acidosis: low serum bicarbonate levels
Metabolic alkalosis: high serum bicarbonate levels
5. Magnesium: found in the intracellular cell. The main work of magnesium is helping the skeletal system. It works in metabolism of the ATP, relaxation and contraction of muscles, and neurotransmitter release. Normal levels are 1.46 to 2.68 mg/dl.
Imbalances:
Hypomagnesemia: happens when the serum levels of magnesium goes under 1.46 mg/dl. The patient may experience ventricular arrhythmia. Loss of magnesium is due to alcohol disorder and gastrointestinal and renal conditions.
Hypermagnesemia: occurs when the serum magnesium goes above 2.68 mg/dl. This usually accompanies renal failure.
6. Chloride: this is an ion found in the extracellular fluid. The kidneys regulate chloride serum levels.
Imbalances:
Hyperchloremia usually occurs when there is bicarbonate loss.
Hypochloremia is seen when the patient has vomiting or excess water in congestive heart failure.
7. Phosphorus is found in the extracellular fluid. It helps in the metabolic pathways. It’s mostly seen in bones and teeth. This is regulated by calcium through vitamin D3 and calcitonin. The kidneys excrete phosphorus. The three conditions that cause phosphorus imbalances are: gastrointestinal disorders, dietary intake, and excretion through kidneys.
Imbalances:
Hypophosphatemia : levels are below 2.5 mg/dl
Hyperphosphatemia: when levels go more than 4.5 mg/dl
Nursing Intervention
- Check the patient’s vital signs. When there is a central venous line, track the central venous pressure.
- Weigh patient every day. Take note when there is a sudden change in the weight. Sudden weight gain is dangerous when patients are having electrolyte imbalances.
- Take note when there is dyspnea, pitting edema, or distention in the neck and peripheral veins.
- Track the patient’s input and output of fluid.
- Encourage patient to get enough bed rest.
- When dyspnea is present, encourage the patient to sit in a semi-fowler’s position.
- Educate the patient about the importance of safety measures such as low positioning of the bed, use of side rails, and frequent observation.
- Check sudden increase in blood pressure.
- Palpate pulses in the peripheries. Look for changes in the skin color. Monitor temperature and capillary refill.
