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NURSING LECTURE NOTES: Fluid, Electrolyte, and Acid-Base Medications

I. Fluid Replacement Therapy

Types of IV Fluids

• Three main categories:
      1. Crystalloids
      2. Colloids
      3. Blood & Blood Products

A. Crystalloids

• Definition:
      - IV fluids containing electrolytes or small molecules.
      - Mimic extracellular fluid (ECF).
      - Do NOT contain proteins.
      - Can easily move across membranes (into interstitial + intracellular spaces).

• Uses:
      - Replace fluid loss (e.g., vomiting, diarrhea).
      - Promote urine output.
      - Serve as short-term maintenance fluids.

• Types of Crystalloids:
      - 1. Isotonic Solutions
        - Key Concept: “Same = stays”
        - Osmolarity: 280–300 mOsm/L
        - Effects: No fluid shift between compartments; expands intravascular volume only.
        - Uses:
            - Hypovolemia (e.g., due to vomiting, diarrhea).
            - Surgical patients.
            - Low blood pressure.
            - Hydration.
        - Examples:
            - Normal saline (0.9% NS).
            - Lactated Ringer’s (LR).
            - D5W.
        - Nursing Considerations:
            - Risk of fluid volume overload.
            - Use caution in patients with:
                - Cardiac issues.
                - Renal issues.

    - 2. Hypertonic Solutions
      - Key Concept: “Pulls fluid OUT of cells”
      - Osmolarity: > 300 mOsm/L
      - Effects: High solute concentration pulls water into the bloodstream; causes cell shrinkage.
      - Uses:
          - Cerebral edema.
          - Severe hyponatremia.
      - Example: D5 ½ NS.
      - Risks:
          - Cellular dehydration.
          - Fluid overload.

    - 3. Hypotonic Solutions
      - Key Concept: “Pushes fluid INTO cells”
      - Osmolarity: < 280 mOsm/L
      - Effects: Water moves into cells, leading to cell swelling.
      - Uses:
          - Hypernatremia.
          - Cellular dehydration.
      - Example: 0.45% NS (Half NS).
      - Risks:
          - Cell rupture.
          - Hypotension (as fluid leaves vessels).
      - Memory Trick:
          - Hypo = cells get BIG (like an "O").

B. Colloids (Plasma Expanders)

• Definition:
      - Contain large molecules (proteins/starches).
      - Stay in bloodstream (cannot cross capillaries).

• Mechanism:
      - Increase oncotic pressure.
      - Pull fluid into plasma.

• Uses:
      - Hypovolemic shock from:
          - Burns.
          - Hemorrhage.
          - Surgery.

• Example: Dextrin.

• Side Effects:
      - Fluid overload.
      - Hypertension.
      - Hypersensitivity reactions.

C. Blood & Blood Products

• Types:
      - PRBCs (Packed Red Blood Cells).
      - Plasma.
      - Platelets.
      - Albumin.
      - Clotting factors.

• Nursing Considerations:
      - Use ≥ 19 gauge IV.
      - Special tubing required.
      - Max infusion time: 4 hours.
      - NEVER add medications to blood.

General Nursing Responsibilities (Fluids)

• Complete health history (fluid loss/excess).

• Conduct medication review.

• Monitor daily weight.

• Monitor:
      - Vital signs.
      - Intake & output.
      - Neuro status.
      - Urine output.

• Watch for:
      - Fluid overload.
      - Allergic reactions.

II. Electrolyte Replacement Therapy

A. Potassium Chloride (KCl)

• Uses:
      - Treat and prevent hypokalemia.
      - Manage mild alkalosis.

• Forms:
      - PO: tablets, liquid, powder.
      - IV.

• CRITICAL SAFETY:
      - NEVER push IV KCl.
      - Infuse slowly (maximum rate of 5–10 mEq/hr).
      - High levels can lead to cardiac arrest.

• Nursing Considerations:
      - Dilute with water to reduce GI irritation risk.
      - Do NOT crush tablets.
      - Monitor IV site to avoid burns.
      - Use a large vein or central line.

• Side Effects:
      - Nausea, vomiting.
      - Risk of hyperkalemia.

B. Sodium Chloride (NaCl)

• Uses:
      - Treat hyponatremia.

• Forms:
      - IV fluids.
      - Tablets.
      - Eye drops/nasal spray.

• Side Effects of Hypernatremia:
      - Confusion.
      - Restlessness.
      - Muscle tremors.
      - Hypertension.
      - Risk of pulmonary edema.

C. Calcium Gluconate

• Uses:
      - Treat hypocalcemia.

• Forms:
      - IV, oral (e.g., antacids like Tums).

• Administration:
      - Administer with meals for better absorption.

• Side Effects:
      - Risk of hypercalcemia.
      - IV risks include:
          - Bradycardia.
          - Dysrhythmias.
          - Hypotension.
          - Cardiac arrest.

D. Magnesium

• Uses:
      - Treat hypomagnesemia.

• Forms:
      - IV, oral.

• Nursing Considerations:
      - Administer IV slowly (over approximately 4 hours).
      - Monitor cardiac rhythm (telemetry).

• Side Effects of Hypermagnesemia:
      - Flushing.
      - Sedation.
      - Muscle weakness.
      - Increased thirst.

III. Acid-Base Correction

A. Sodium Bicarbonate (NaHCO₃)

• Uses:
      - Treat metabolic acidosis.

• Forms:
      - IV, oral.

• Nursing Considerations:
      - Do NOT give with calcium (it binds).
      - Separate from other medications (2–3 hours).

• Side Effects:
      - Risk of metabolic alkalosis (if administered too much).

B. Ammonium Chloride

• Uses:
      - Treat metabolic alkalosis.

• Nursing Considerations:
      - Administer slowly.

• Risk:
      - Potential for metabolic acidosis (if too much is given).

IV. Potassium Removal (Hyperkalemia)

Ion Exchange Resin (Kayexalate)

• Uses:
      - Treat hyperkalemia.

• Mechanism:
      - Exchanges sodium for potassium.
      - Eliminates potassium via the GI tract.

• Route:
      - Usually administered as an enema.

• Side Effects:
      - Constipation.
      - Nausea/vomiting.
      - Risk of hypokalemia (if overcorrected).

HIGH-YIELD NCLEX TIPS

• Potassium = heart killer if administered too quickly.

• Hypertonic solutions shrink cells.

• Hypotonic solutions swell cells.

• Isotonic solutions stay in vessels.

• Blood products = NEVER mix medications with blood.

• Always monitor:
      - Cardiac rhythm.
      - Fluid status.
      - Neuro changes.