Body Compartments and Fluid Shifts

Body Compartments

• The body is divided into two main compartments: intracellular and extracellular.
• The intracellular compartment makes up 2/3 of the body's fluid, while the extracellular compartment makes up 1/3.

Fluid Shifts

• Fluid shifts occur between the two compartments due to osmotic pressure.
• Fluid shifts occur through the cell wall, from an area of high concentration to an area of low concentration.

Maintaining Homeostasis

• The goal is to maintain homeostasis, which requires monitoring input and output (I&O's).

Types of Fluids

• There are three main types of fluids: crystalloids, colloids, and blood products.

Types of IV Fluids

• Isotonic fluids have the same osmotic pressure as blood plasma and are used to replace lost fluids, electrolytes, and blood volume, with examples including 0.9% Sodium Chloride (normal saline) and Lactated Ringer's solution.
• Hypotonic fluids have lower osmotic pressure than blood plasma and are used to provide free water and treat dehydration, with an example being 0.45% Sodium Chloride.
• Hypertonic fluids have higher osmotic pressure than blood plasma and are used to treat severe hyponatremia, cerebral edema, and increased intracranial pressure, with examples including 3% Sodium Chloride and 7.5% Sodium Chloride.

Components of IV Fluids

• Electrolytes in IV fluids include Sodium (Na+), Potassium (K+), Calcium (Ca2+), and Magnesium (Mg2+).
• Buffering agents in IV fluids include Bicarbonate (HCO3-) and Phosphate (PO42-).
• IV fluids can contain energy sources like Dextrose (glucose).

Indications for IV Fluid Administration

• IV fluids are used for fluid resuscitation in cases of hypovolemic shock, burns, and trauma.
• IV fluids are used for electrolyte replacement in cases of diarrhea, vomiting, and diuretic therapy.
• IV fluids are used for medication administration, such as pain management, antibiotics, and chemotherapy.

Complications of IV Fluid Administration

• Fluid overload can lead to pulmonary edema and heart failure.
• Electrolyte imbalance can occur due to IV fluid administration, resulting in hypernatremia, hyponatremia, hypokalemia, and hyperkalemia.

Crystalloids

• Definition: Fluids and electrolytes normally found in the body without proteins

Indications

• Maintenance of fluid volume
• Treatment of dehydration, as they can move easily between compartments
• Volume replacement
• Management of acute liver failure
• Burns
• Dialysis

Side Effects (SE)

• Edema
  • Peripheral edema
  • Pulmonary edema

Isotonic Fluids

• Have the same concentration of solutes as blood
• Examples of isotonic fluids:
  • Normal saline (0.9% NaCl)
  • Lactated Ringers
• Lactated Ringers composition:
  • Sodium (Na)
  • Potassium (K)
  • Calcium (Ca) in water
• Function of Lactated Ringers:
  • Replaces fluids and electrolytes
  • Used in cases of:
    • Low blood pressure (BP)
    • Low blood volume
  • Indications:
    • Burn patients
    • Trauma patients
    • Malnourished patients

Hypotonic Fluids

• Have a lower concentration of solutes compared to blood
• Cause fluid to shift out of the vascular system and into the tissues
• Examples of hypotonic fluids include:
  • 0.45% sodium chloride
  • 0.25% sodium chloride
• Indications for use:
  • Diabetic ketoacidosis (DKA)
  • Hypernatremia

Hypertonic Fluids

• Characterized by fluid shift from cells into the vascular compartment
• Examples include 3% or 5% sodium chloride solutions
• Indicated for severe symptomatic hyponatremia

D5W Solution

• Initially an isotonic solution due to dextrose content
• Becomes hypotonic once glucose is metabolized, leaving behind hypotonic solution
• Characterized by fluid shift from vascular into tissues
• Indicated for:
  • Hypernatremia treatment
  • Providing free water for kidney hydration

Colloids as Plasma Expanders

• Colloids move fluid from cells to the vascular space by containing large molecules that cannot pass through, including albumin, globulin, and fibrinogen (three blood proteins in the body).
• Compared to crystalloids, colloids require less fluid to cause a fluid shift.

Indications for Colloid Use

• Shock
• Burns
• Plasma volume expansion is needed

Characteristics of Colloids

• Usually well-tolerated without problems
• Do not contain clotting factors or carry oxygen

Side Effects of Colloids

• Bleeding possibility due to dilution of clotting factors with added fluid

Types of Colloids

• Albumin (5% or 25%): naturally produced, requiring human donors
• Dextran 40: a glucose solution

Blood Products

• Increase plasma volume through colloids and hypertonic crystalloids, causing fluid shifts from cells into vascular.
• Donated blood products require type and cross-matching to prevent anaphylaxis.

Administration

• Administer blood products intravenously (IV) using a pump.
• Can only be administered with normal saline.

Types of Blood Products

Fresh Frozen Plasma (FFP)

• Contains clotting factors.
• Indicated for increasing clotting factors, particularly for prevention of bleeding.

Cryoprecipitate

• High in clotting factors and fibrinogen.
• Indicated for acute bleeding, especially with 25% blood loss rapidly or 50% slowly.
• Check hemoglobin and hematocrit (H&H) levels before administration, and consider its use when blood clotting is necessary.

Packed Red Blood Cells (PRBC's)

• Does not contain plasma.
• Indicated for increasing oxygen-carrying capacity, particularly for:
  • Anemia
  • Low H&H
  • Low blood volume
  • Blood loss up to 25%

Whole Blood

• Contains plasma, protein, and red blood cells.
• Indicated when more than 25% of whole blood is lost.

Blood Product Administration

• Blood products can only be administered using an IV pump.
• Normal saline is the only compatible solution for blood product administration.

Types of Blood Products

• Fresh Frozen Plasma (FFP)
  • Contains clotting factors
  • Indicated for increasing clotting factors
  • Used for bleeding prevention
• Cryoprecipitate
  • High in clotting factors and fibrinogen
  • Indicated for acute bleeding
  • Used when there is 25% blood loss rapidly or 50% slowly
  • Check if H&H is low or if blood clotting is necessary
• Packed Red Blood Cells (PRBC's)
  • Does not contain plasma
  • Indicated for increasing oxygen carrying capacity
  • Used for anemia, low H&H, low blood volume, or blood loss up to 25%
• Whole Blood
  • Containing plasma, protein, and red blood cells
  • Indicated when over 25% of whole blood is lost

Blood Products and Indications

• Cryoprecipitate is indicated in acute bleeding cases where: • 25% blood loss occurs rapidly • 50% blood loss occurs slowly

Packed Red Blood Cells (PRBC's) Indications

• PRBC's are given to increase oxygen carrying capacity in: • Anemia cases • Low Hemoglobin and Hematocrit (H&H) levels • Low blood volume situations

Electrolytes: Potassium

• Responsible for muscle contraction, cardiac function, acid-base balance, and nerve impulse transmission
• Given when levels are low due to inadequate diet or loss caused by medications
• 95% of potassium is found inside cells, with only 5% in the blood
• Food sources: fruit, fish, veggies, meats, and dairy products
• Normal potassium levels: 3.5-5 mmol/L

Hyperkalemia

• Causes:
  • K+ sparing diuretics
  • ACE inhibitors
  • K+ supplements
• Signs and symptoms:
  • Muscle weakness
  • Paresthesia
  • Ventricular fibrillation (V-fib)
  • Cardiac arrest
• Treatment of Mild Hyperkalemia:
  • Restrict dietary intake of potassium
• Treatment of Severe Hyperkalemia:
  • IV sodium bicarbonate: increases pH level while removing potassium
  • IV calcium: reduces risk of ventricular fibrillation
  • IV insulin with dextrose: moves glucose into cells, taking potassium with it
  • IV diuretic: if blood pressure is high enough
  • Sodium polystyrene sulfonate (Kayexalate): slow, oral, or rectal administration
  • Hemodialysis: fast and effective

Electrolytes: Potassium

• Potassium is responsible for maintaining:
  • Cardiac function
  • Acid-base balance
  • Nerve impulse transmission

Sources of Potassium

• Food sources of potassium include:
  • Fruit
  • Fish
  • Vegetables
  • Meats
  • Dairy products

Hyperkalemia (High Potassium Levels)

• Hyperkalemia can be caused by:
  • ACE inhibitors
  • Potassium supplements

Signs and Symptoms of Hyperkalemia

• Symptoms of high potassium levels include:
  • Muscle weakness
  • Paraesthesia (abnormal sensations)
  • Ventricular fibrillation (V-fib)
  • Cardiac arrest

Treatment of Mild Hyperkalemia

• Treatment for mild hyperkalemia involves:
  • Restricting dietary intake of potassium

Causes of Hypokalemia

• Loop diuretics can cause hypokalemia
• Thiazide diuretics can also lead to hypokalemia
• Corticosteroids are another potential cause of hypokalemia
• Vomiting and diarrhea can cause hypokalemia due to potassium loss
• Crash diets with little to no nutrition can lead to hypokalemia
• Consuming large amounts of licorice can cause hypokalemia

Symptoms and Signs of Hypokalemia

• Hypotension is a symptom of hypokalemia
• Lethargy is a common sign of hypokalemia
• Confusion can occur in individuals with hypokalemia
• Cardiac dysrhythmias are a potential symptom of hypokalemia
• Neuropathy can be a sign of hypokalemia

Treatment of Hypokalemia

• Potassium chloride is used to treat hypokalemia
• Potassium chloride can be administered orally (PO) or intravenously (IV)
• IV potassium chloride should be given via IVPB (intravenous piggyback)
• IV potassium chloride should never be given as an IV bolus or undiluted
• When administering IV potassium chloride, it should be done slowly using a pump
• The maximum rate of IV potassium chloride administration is 10mEq per hour

Side Effects of Potassium Chloride

• Nausea, vomiting, and diarrhea are potential side effects of potassium chloride
• Gastrointestinal bleeding is a possible side effect of potassium chloride
• Hyperkalemia is a potential side effect of potassium chloride administration

Causes of Hypokalemia

• Loop diuretics and thiazide diuretics can cause hypokalemia due to potassium loss
• Corticosteroids can lead to potassium depletion
• Vomiting and diarrhea can cause hypokalemia due to potassium loss through gastrointestinal fluids
• Crash diets with little to no nutrition can lead to potassium deficiency
• Consuming large amounts of licorice can cause hypokalemia due to its potassium-lowering effects

Signs and Symptoms of Hypokalemia

• Hypotension is a common symptom of hypokalemia
• Neuropathy can occur as a result of potassium deficiency

Treatment of Hypokalemia

• Potassium chloride is used to treat hypokalemia
• It is administered via IVPB (intravenous piggyback) to prevent rapid increases in potassium levels
• It should never be given as an IV bolus, IVP, or undiluted to avoid adverse effects

Side Effects of Potassium Chloride

• Nausea, vomiting, and diarrhea are common side effects of potassium chloride administration
• Gastrointestinal bleeding is a potential side effect of potassium chloride
• Hyperkalemia can occur as a result of excessive potassium administration

Sodium Functions

• Responsible for water distribution and fluid/electrolyte balance
• Plays a crucial role in maintaining acid-base balance

Normal Sodium Level

• Normal sodium level is between 135-145 mmol/L
• Sodium is the most abundant electrolyte in extracellular fluid

Sodium Sources

• Common sources of sodium include:
  • Salt
  • Fish
  • Meat
  • Seasonings

Hyponatremia

• Hyponatremia is a condition characterized by low sodium levels
• Symptoms of hyponatremia include:
  • Lethargy
  • Hypotension
  • Stomach cramps
  • Seizures
  • Vomiting and diarrhea
• Treatment of hyponatremia depends on severity:
  • Mild hyponatremia (130-135 mmol/L):
    • Oral sodium chloride tablets
    • Restrict fluid intake
  • Moderate hyponatremia (125-129 mmol/L):
    • IV normal saline or lactated ringers
  • Severe hyponatremia (less than 125 mmol/L):
    • Requires urgent medical attention

Treatment of Hyponatremia

• Mild hyponatremia (130-135 mmol/L) is treated with: • Oral sodium chloride tablets • Restricting fluid intake

Moderate Hyponatremia

• Moderate hyponatremia (125-129 mmol/L) is treated with: • IV administration of normal saline • IV administration of lactated Ringer's solution

Fluids and Electrolytes

Hypotonic Fluids

• Lower concentration of solutes than blood
• Fluid shifts out of the vascular and into the tissues
• Examples: 0.45% or 0.25% sodium chloride
• Indications: DKA, hypernaturemia

Hypertonic Fluids

• Higher concentration of solutes than blood
• Fluid shifts from cells into the vascular
• Examples: 3% or 5% sodium chloride
• Indications: severe symptomatic hyponaturemia

Isotonic Fluids

• Same concentration of solutes as blood
• Examples: 0.9% sodium chloride (normal saline), lactated Ringer's solution
• Indications: maintenance of fluid volume, dehydration, volume replacement, acute liver failure, burns, dialysis

Colloids (Plasma Expanders)

• Moves fluid from cells to the vascular
• Contains large molecules that cannot pass through cell membranes
• Examples: albumin, globulin, fibrinogen (3 blood proteins in the body)
• Indications: shock, burns, plasma volume expansion needed
• Advantages: does not have to give as much fluid to cause fluid shift (compared to crystalloids)

Blood Products

• Increases plasma volume
• Fluid shifts from cells into vascular
• Examples: fresh frozen plasma (FFP), cryoprecipitate, packed red blood cells (PRBC's), whole blood

Electrolytes

Potassium (K+)

• Responsible for: muscle contraction, cardiac function, acid-base balance, nerve impulse transmission
• Normal level: 3.5-5
• Sources: fruit, fish, veggies, meats, dairy
• Hyperkalemia: ACE inhibitors, K+ supplements, symptoms include muscle weakness, parasthesia, v-fib, cardiac arrest
• Treatment of hyperkalemia: restrict dietary intake of K+, IV sodium bicarbonate, IV calcium, IV insulin with dextrose, IV diuretic, sodium polystyrene sulfonate (Kayexalate), hemodialysis

Sodium (Na+)

• Responsible for: water distribution, fluid/electrolyte balance, acid-base balance
• Normal level: 135-145
• Sources: salt, fish, meat, seasonings
• Hyponaturemia: symptoms include lethargy, hypotension, stomach cramps, seizures, V/D; treatment includes oral sodium chloride tablets, IV normal saline or lactated ringers, restricting fluid intake

Magnesium (Mg2+)

• Normal level: 1.5-2.5

Phosphate (PO42-)

• Normal level: 2.5-4.5

Calcium (Ca2+)

• Normal level: 8.5-10