Fluids & IV Therapy

Normal Physiology

Maintenance of Homeostasis:
- Importance of maintaining a stable internal environment.
- Composition and volume of fluids and electrolytes must be kept within narrow limits.
Water Content:
  - Varies with age, gender, and fat content:
    - Infants have a high percentage of body water.
    - Elderly individuals have reduced body water.

Fluid Compartments

Intracellular Fluid (ICF):
- Fluid located inside cells.
Extracellular Fluid (ECF):
  - Fluid located outside cells, which is further divided into:
    - Interstitial Fluid: Fluid between cells.
    - Intravascular Fluid (Plasma): Fluid within blood vessels.
    - Transcellular Fluid: Specialized fluids (e.g., cerebrospinal fluid, synovial fluid).

Fluid Shifts

Edema:
  - Definition: Abnormal accumulation of fluid in tissue.
  - Causes:
    - Shift of plasma to interstitial fluid.
    - Elevation of venous hydrostatic pressure.
    - Decrease in plasma oncotic pressure.
    - Elevation of interstitial oncotic pressure.

Calculation of Fluid Gain or Loss

Weight Correlation: 1 L of water weighs 2.2 pounds (1 kg).
  - Body weight change is an accurate indicator of overall fluid volume loss or gain.
  - Example: Drinking 240 ml of fluid adds approximately 0.5 lbs.
  - Clinical Significance: A patient on a diuretic who loses 4.4 lbs (2 kg) indicates a fluid loss of 2 L.

Hypovolemia

Causes:
- Abnormal loss of body fluids, inadequate fluid intake, or shift of plasma to interstitial fluid.
- Conditions may include: hemorrhage, vomiting, diarrhea, burns, pancreatitis, diuretics.
Clinical Manifestations:
  - Restlessness, lethargy, confusion.
  - Thirst, dry mucous membranes.
  - Cold, clammy skin.
  - Decreased skin turgor and capillary refill.
  - Postural hypotension, tachycardia, tachypnea.
  - Decreased urine output or concentrated urine.
  - Symptoms may include weakness, dizziness, weight loss, seizures.

Hypovolemia – Interprofessional Care

Goals:
- Correct the underlying cause.
- Replace lost water and electrolytes.
Methods:
  - Oral rehydration or blood products.
  - Use of balanced IV solutions (e.g., Normal Saline (NSS), Lactated Ringer's (LR)).
  - Essential to check daily weight, strict intake/output (I/O) monitoring, and lab tests.

Fluid Volume Excess (Hypervolemia)

Causes:
- Excess intake of fluids, abnormal retention, or interstitial-to-plasma fluid shift.
- Associated with: heart failure, renal failure, excessive intravenous fluids, long-term corticosteroid use, polydipsia.
Clinical Manifestations:
  - Weight gain (most common).
  - Distended neck veins, jugular venous distention (JVD).
  - Edema, crackles in lungs.
  - Liver enlargement.
  - Symptoms of confusion, lethargy, murmur, hypertension.
  - Polyuria, dyspnea, crackles, pulmonary edema, seizures, coma.

Hypervolemia – Interprofessional Care

Goals:
- Remove excess fluid without altering electrolyte composition or osmolality of extracellular fluid.
Methods:
  - Use of diuretics, fluid restrictions, sodium intake restriction.
  - Removal of fluid to treat ascites or pleural effusion.
  - Regular lab tests and assessment of cardiac and pulmonary systems.

Electrolyte Basics and Imbalances

Sodium (Na⁺)

Normal Range: 136–145 mEq/L.
Functions:
- Regulates fluid balance, assists in nerve signals, and muscle contractions.
- Maintained by kidneys.
Hypernatremia: (Na⁺ > 145 mEq/L)
  - Causes:
    - Inadequate water: dehydration, fever, sweating, diarrhea.
    - Excess sodium intake (e.g., hypertonic IV solutions).
  - Symptoms:
    - Thirst, dry mouth, confusion, restlessness, seizures, coma.
    - If fluid volume is high: swelling, hypertension; if low: hypotension, weakness.
  - Treatment:
    - Administer water orally or IV fluids (especially sodium-free fluids).
    - Gradually lower sodium levels to prevent brain swelling.

Hyponatremia (Na⁺ < 136 mEq/L)

Causes:
- Loss of sodium (vomiting, diarrhea, diuretics).
- Excess water intake (heart failure, excessive IV fluids).
Symptoms:
- Swelling of brain cells leading to confusion, nausea, seizures, coma.
- Signs depending on volume status: indicates hypovolemia (dizziness, cold skin) or hypervolemia (edema, weight gain).
Treatment:
  - If excess water: fluid restriction, diuretics.
  - If sodium lost: replace sodium via IV or oral, discontinue diuretics.
  - Slow correction to avoid brain damage.

Potassium (K⁺)

Normal Range: 3.5–5.0 mEq/L.
Functions:
- Major intracellular electrolyte essential for nerve and muscle signaling, regulating heart rhythm, and acid-base balance.
Hyperkalemia: (K⁺ > 5.0 mEq/L)
  - Causes:
    - Excess intake, renal failure, shifting out of cells (e.g., acidosis).
  - Symptoms:
    - Dysrhythmias, muscle cramps, fatigue, GI symptoms.
  - Treatment:
    - Stop intake, increase excretion (diuretics or dialysis), shift K⁺ into cells (IV insulin + dextrose).
    - Continuous ECG monitoring.

Hypokalemia (K⁺ < 3.5 mEq/L)

Causes:
- Loss of potassium (vomiting, diuretics).
- Shift into cells, insufficient intake.
Symptoms:
- Dysrhythmias, weakness, leg cramps, hypoventilation.
Treatment:
- Administer potassium (oral or IV), dilute IV KCl, monitor cardiac rhythm.
- Ensure adequate urine output.

Calcium (Ca²⁺)

Normal Range: 9.0–10.5 mEq/L.
Functions:
- Important for bone health, muscle and heart contractions, blood clotting, and nerve signaling.
Hypercalcemia: (Ca²⁺ > 10.5 mEq/L)
  - Causes:
    - Hyperparathyroidism, cancer, vitamin D overload, acidosis.
  - Symptoms:
    - Dysrhythmias, weakness, kidney stones.
  - Treatment:
    - Low calcium diet, hydration, IV fluids, treatment for underlying causes.

Hypocalcemia

Causes:
- Hypoparathyroidism, kidney failure, vitamin D deficiency.
Symptoms:
- Dysrhythmias, tingling, muscle cramps, seizures.
Treatment:
- Treat the underlying issue, supplement calcium with vitamin D, IV calcium for severe cases.

Phosphate (Phos⁻)

Normal Range: 3.0–4.5 mEq/L.
Functions:
- Critical for muscle function, energy metabolism, and cell function.
Hyperphosphatemia: (Phos⁻ > 4.5 mEq/L)
  - Causes:
    - Renal failure, rhabdomyolysis.
  - Symptoms:
    - Can cause hypocalcemia symptoms due to binding with calcium.
Hypophosphatemia: (Phos⁻ < 3.0)
  - Causes:
    - Malabsorption, chronic diarrhea.
  - Symptoms:
    - Confusion, muscle weakness, seizures.
Treatment for both:
- Relative to underlying cause, supplementation as needed.

Magnesium (Mg²⁺)

Normal Range: 1.3–2.1 mEq/L.
Functions:
- Important for metabolism, heart rhythm, and neuromuscular function.
Hypermagnesemia: (Mg²⁺ > 2.1 mEq/L)
- Causes:
- Renal failure, high intake from IV or laxatives.
Symptoms:
- Lethargy, hypotension, bradycardia.
Hypomagnesemia: (Mg²⁺ < 1.3 mEq/L)
- Causes:
- Loss via GI, malnutrition.
Symptoms:
- Similar to hypocalcemia, including muscle cramps and tachycardia.
Treatment:
- Magnesium supplementation, IV administration with monitoring.

Chloride (Cl⁻)

Normal Range: 96–106 mEq/L.
Functions:
- Major extracellular anion regulating fluid balance, osmotic pressure, acid-base balance.
Hyperchloremia: (Cl⁻ > 106 mEq/L)
  - Causes:
    - Dehydration, excessive IV chloride.
  - Symptoms:
    - Rapid breathing, fatigue.
Hypochloremia: (Cl⁻ < 96 mEq/L)
  - Causes:
    - Loss of stomach acid through vomiting.
  - Symptoms:
    - Muscle twitching, confusion.
Treatment:
- Replace chloride, monitor status.

IV Therapy Basics

IV Insertion Selection

Proper selection of vein based on:
- Cephalic vein, basilic vein, metacarpal plexus.
Consideration of patient condition and site accessibility.

Common Problems

Occlusion:
- Blockage preventing fluid flow.
Leakage:
- Fluid leaking out of the vein.

Intermittent Saline Lock

Definition: Method to maintain venous access.
Allows intermittent medication administration while minimizing continuous IV fluid delivery.

Alaris IV Pump System

Components:
- Roller clamp, universal spike, safety clamp, injection port.
- Important for controlled delivery of IV fluids and medications.

Venipuncture

Definition: Medical procedure used to access a vein for withdrawing blood or administering therapies.
Complications:
  - Infiltration: Stopping infusion and allowing fluid leakage; treated with cold/warm compresses.
  - Extravasation: Leakage of damaging substances; treat with antidotes and consult specialists.
  - Phlebitis: Inflammation; managed with warm compresses and analgesics.
  - Infection: Requires catheter removal and antibiotics.
  - Hypersensitivity Reactions: Varying severity; treated with cessation of infusion and necessary medications or epinephrine for severe cases.

IVF Solutions

Classification of IV Solutions

Isotonic Solutions:
   - Maintain fluid balance without affecting cell volume.
   - Examples: NSS, Lactated Ringer's.
   - Used to increase fluid volume after fluid loss.
Hypotonic Solutions:
- Cause fluid to enter cells, which can lead to swelling.
- Example: Half-normal saline. Used when cells need hydration.
Hypertonic Solutions:
- Draw fluid out of cells, causing them to shrink.
- Example: 3% saline. Used to reduce swelling.

Blood Transfusion

Pre-Transfusion:
- Verify order exists, conduct physical assessment, confirm informed consent.
- Ensure proper venous access (at least an 18-gauge IV line).
During Transfusion:
- Teach patient about potential reactions (fever, chills, breathlessness).
- Monitor patient closely especially in the first 15 minutes.
If Reactions Occur:
- Immediately stop transfusion and manage symptoms appropriately.