Fluid Management & Blood Products Vocabulary

Vocabulary

• Osmolality: Measurement of solute versus solvent.
• Osmosis: Movement of liquids across a semi-permeable membrane.
• Semi-permeable Membrane: Allows solvent (e.g., water) to pass but not solute.
• Solute: Particles (such as salts) dissolved in a solution.
• Solution: Mixture of solute and solvent.
• Solvent: Liquid that dissolves a solute (e.g., water).
• Tonicity: Measure of osmotic pressure between solutions.

Review of Pathophysiology of Fluid Balance

• Total Body Water: Approximately 60% of body weight;
  • Intracellular Fluid: 2/3 of total body water, inside cells (40% body weight).
  • Extracellular Fluid: 1/3 of total body water, outside cells (20% body weight):
  • Interstitium: space between cells.
  • Intravascular: blood volume.

Distribution of Body Fluids

• Intracellular Fluid: 2/3 of total.
• Extracellular Fluid: 1/3, made up of:
  • Interstitial Fluid: ¾ of ECF.
  • Intravascular Fluid: 14% of ECF.
• Body fluids comprise 50% to 60% of body weight.

Role of Water in Regulating Hydration

• Joints: Synovial fluid for lubrication.
• Digestion: Saliva moistens food, intestinal juices break down food.
• Blood: Transports oxygen and glucose; eliminates toxins through urination.
• Temperature Regulation: Adjusts blood vessel diameter (dilate/constrict) to maintain homeostasis.

Normal Loss of Fluids

• Daily Fluid Loss:
  • Urine: 800-2000 mL/day.
  • Sweat: ~500-700 mL/day (more during exercise).
  • Insensible losses: 600-900 mL/day (through breathing).

Excessive Fluid Loss - Dehydration

• Causes: Vigorous exercise, insufficient intake, vomiting, diarrhea, excessive sweating, inability to swallow, use of diuretics.
• Symptoms:
  • Thirst, dry mouth/lips, nausea, fatigue, lightheadedness, darkened urine.
  • Loss of 2% body weight may lead to irritability, difficulty concentrating, headaches.

Fluid Management: Intravenous Fluids

• Categories:
  • Crystalloids: Liquid solutions of salts/water that easily transfer through membranes.
  • Colloids: Larger molecules that expand plasma volume, always hypertonic.

Crystalloids vs. Colloids

• Crystalloids:
  • Advantages: Cheap, non-allergic, limited infection risk.
  • Disadvantages: Requires larger volumes; shorter half-life.
• Colloids:
  • Advantages: Superior volume expansion.
  • Disadvantages: Expensive, risk of allergy, potential for fluid overload.

Types of Intravenous Solutions

• Hypertonic: High solute concentration (draws fluid out of cells).
• Isotonic: Equal solute/solvent (no net fluid shift).
• Hypotonic: Low solute concentration (draws fluid into cells).

Hypertonic Solutions

• Indications: Cerebral edema, severe hyponatremia.
• Cautions: High potential for fluid overload, pulmonary edema.
• Common examples: 3% NaCl, D5NS, D5LR.

Isotonic Solutions

• Common types: 0.9% NaCl (Normal Saline), Lactated Ringer's, 5% Dextrose in Water (D5W).
• Normal Saline is used for fluid replacement and blood product administration.

Hypotonic Solutions

• Indications: Treatment for intracellular dehydration (e.g., DKA).
• Concerns: May deplete circulatory volume.
• Common types: 0.45% NaCl, D5W (after metabolism).

Blood Products: Colloids

• Colloids: Hypertonic, used to draw fluid into the intravascular space.
• Types Include:
  • Blood, Albumin, Plasma.
• Functions: Increase BP rapidly, expand intravascular volume without excessive fluid.

Blood Administration Considerations

• ABO and Rh Systems: Compatibility is critical. Type O is universal donor; AB+ is universal recipient.
• Procedure:
  • Obtain type and cross matching.
  • Monitor for transfusion reactions and document findings.

Common Transfusion Reactions

• Symptoms: Rash, fever, chills, difficulty breathing, changes in vital signs.
• Immediate action: Stop the transfusion, assess the patient, and notify the doctor.

Nursing Interventions for IVs

• Monitor for complications:
  • Infiltration, extravasation, thrombosis, phlebitis.
• Maintain proper flow and secure connections.