Drugs for Fluid Balance and Acid-Base Disorders

Focus on intravenous (IV) solutions used for fluid replacement.
Classification of IV solutions into three major categories: - Crystalloids - Colloids - Blood and Blood Products

Definition: IV solutions containing electrolytes or other substances that mimic body's extracellular fluid; do not contain proteins.
Uses: Replace depleted fluids, promote urine output, and used short-term as maintenance fluids.
Properties: - Quickly diffusing across membranes, entering interstitial and intracellular fluid.
Classifications:
- Isotonic - Hypertonic - Hypotonic

Function: Expand circulating intravascular volume without major fluid shifts between compartments.
Characteristics: Same osmolarity as extracellular fluid (280-300 osmoles/L).
Applications: Used to treat fluid loss due to vomiting, diarrhea, or surgical procedures, particularly for hydration and expanding extracellular fluid volume.
Co-morbid Caution: Use cautiously in patients with cardiac or renal disease to prevent fluid volume excess.
Examples: - Lactated Ringer's Solution - Normal Saline (0.9% sodium chloride) - D5W (5% dextrose in water)

Function: Expand plasma volume by drawing water away from cells and tissues.
Characteristics: Higher osmolarity than extracellular fluid (greater than 300 osmoles/L).
Mechanism: Water moves from lower to higher solute concentration, potentially causing cellular dehydration and shrinkage.
Applications: Used to relieve cellular edema, especially with cerebral edema.
Example: D5 ½ NS (5% dextrose in half normal saline).

Function: Move water from extracellular fluid into intracellular fluid compartments.
Characteristics: Lower osmolarity than extracellular fluid (less than 280 osmoles/L).
Mechanism: Water moves into cells, potentially causing hemolysis (bursting of cells).
Applications: Used for clients with hypernatremia and dehydration.
Example: 0.45% Normal Saline (half normal saline).

Definition: Solutions containing proteins, starches, or large molecules that remain in blood due to size.
Function: Draw water from cells into plasma, increasing plasma osmolality and oncotic pressure.
Uses: Treat hypovolemic shock from burns, hemorrhage, and surgery.
Examples: Dextrin.
Adverse Effects: Hypersensitivity reactions, fluid overload, hypertension due to increased blood volume.

Components: Packed red blood cells, plasma, platelets, albumin, clotting factors.
Administration Requirements: - Large gauge IV catheter and special filter tubing needed. - Maximum transfusion time for one unit: 4 hours. - Never add medications to blood units.

Assess health history for factors contributing to fluid volume excess or deficit.
Examine medication history, perform physical exams (including weight), and conduct lab tests (CBC, serum electrolytes, BUN, creatinine).
Monitor hydration status via plasma and serum osmolality.
Track vital signs, hypersensitivity reactions, fluid volume status, urinary output, and neuro status.

Uses: Prevent or treat hypokalemia; treat mild alkalosis.
Forms: Tablets, powders, liquids, IV. Examples include K-Dur, K-Lyte, Micro K.
Administration Guidelines: - Dilute with water to prevent gastric irritation and ulcers; flush NG tube adequately. - IV given slowly, not exceeding 5-10 mEq/hr; solution concentration max: 1 mEq/10 mL. - Oral tablets should not be crushed or chewed.
Adverse Effects: Nausea, vomiting; monitor for hyperkalemia when replacing potassium.

Uses: Treat hyponatremia.
Forms: IV solutions, tablets, inhalations (saline sprays).
Adverse Effects: Monitor for hypernatremia symptoms (CNS issues, muscle tremors, hypotension, restlessness).

Uses: Treat hypocalcemia.
Forms: IV, oral supplements (e.g., Caltrate, Citracal).
Administration: Oral supplements taken with meals for better absorption.
Adverse Effects: Monitor for hypercalcemia (drowsiness, nausea, increased thirst).

Uses: Treat severe hypomagnesemia.
Forms: IV, IM.
Administer: Over 4 hours.
Adverse Effects: Monitor for hypermagnesemia (flushing, confusion, decreased reflexes).

Uses: Treat metabolic acidosis.
Forms: IV and oral.
Administration: Do not mix oral preparations with calcium solutions; administer 2-3 hours apart from other medications.
Adverse Effects: Hyperkalemia; monitor for symptoms of metabolic alkalosis.

Profile: 72-year-old male experiencing vomiting and diarrhea, taking Digoxin and Hydrochlorothiazide.
Symptoms: Serum potassium level of 3.2, dizziness, low blood pressure, weak muscles, bloated abdomen, decreased peristalsis.
Assessment: - Recognize potassium imbalance due to hypokalemia; normal potassium ranges from 3.5-5.5 mEq/L. - Immediate factors leading to imbalance: vomiting, diarrhea, diuretic and medication use.
Intervention: - Administer IV potassium and oral replacements. - Recommend potassium-rich foods (e.g., bananas, apricots, potatoes).
Instructions for Nursing Interventions: - IV potassium must be diluted and administered cautiously; typically given slowly. - Monitor for urine output to avoid hyperkalemia from potassium excess.

How to monitor effectiveness of sodium bicarbonate: - Correct answer: Monitor serum pH.
Statements about D5W: - Correct answer: May be used to dilute mixed IV drugs.
Nursing interventions for hypernatremia: - Correct answers: Assess for dehydration, notify physician, and hydrate appropriately (but not excessively).
Weight gain observation during lactated ringers infusion: - Correct answer: Assess for edema and blood pressure for hypertension; ensure nursing assessment prioritization.