Ch 8 Fluids and Electrolytes (1)

Introduction

• Fluid and Electrolyte Management presents critical concepts in nursing related to the management of fluids and electrolytes in patients.

• Chapters cover fundamental definitions, physiological processes, regulatory systems, disorders, clinical manifestations, medical and nursing management.

Electrolytes

• Electrolytes: Electrically charged particles in solutions. Examples include Potassium Chloride, Calcium Chloride, Sodium Chloride.

• Cations: Positive ions (e.g., Na+, K+, H+, Mg+).

• Anions: Negative ions (e.g., Cl-, CO3-, PO4-).

Cellular Fluids

• Water: The primary constituent of cells; 55% of women and 65% of men body mass.

• Body Water Compartments:

  • Intracellular Fluid: Fluid within cells.

  • Extracellular Fluid: All fluid outside cells, further categorized into:

    • Plasma: Blood fluid.

    • Interstitial/Intercellular Fluid: Between cells.

    • Transcellular Fluid: Fluids in specific compartments like the GI tract and cerebrospinal fluid.

Fluid Movement

• Osmosis: Diffusion of water through a semi-permeable membrane (passive). Important for maintaining fluid balance.

• Filtration: Active pushing of water through membranes.

• Diffusion: Movement of other particles through cellular membranes.

Fluid Intake and Output

• Fluid Intake: 2,500 mL/day through:

  • Drinking: 1,600 mL

  • Food: 500 mL

  • Metabolism: 400 mL.

• Fluid Output: 2,500 mL/day including urine, feces, skin, and breath.

Fluid and Electrolyte Regulation

• Osmolality: Concentration of solutes in a solution.

• Osmotic Pressure: Ability of water to move between compartments based on solute concentration.

• Types of Solutions:

  • Isotonic: Equal concentrations (e.g., Normal saline).

  • Hypertonic: Higher solute concentration leading to cell shrinkage.

  • Hypotonic: Lower solute concentration leading to cell swelling.

Movement Across Membranes

• Diffusion and Active Transport: Movement of substances across membranes, often assisted by pumps (e.g., sodium-potassium pump).

• Filtration: Water and solutes move across membranes due to hydrostatic pressure from blood vessel walls.

Homeostasis

• Renal System: Regulates blood fluid and pressure through sodium absorption or urine excretion (regulatory hormones: renin, angiotensin, aldosterone).

• Endocrine System: Controls fluid balance via hormones like ADH and natriuretic peptides.

Fluid Volume Status Indicators

• Key indicators include serum osmality ratio, Blood Urea Nitrogen (BUN), creatinine levels, and specific gravity of urine.

Age-Related Changes

• Older adults may experience decreased taste, smell, and thirst which can affect fluid intake.

Hypovolemia**

• Causes: Excessive fluid loss, insufficient intake, and fluid shifts.

• Laboratory Values: Electrolyte levels, BUN, creatinine, urine specific gravity.

• Clinical Manifestations: Weight loss, decreased skin turgor, concentrated urine.

• Management: Oral and IV isotonic solutions, close monitoring to treat the underlying cause.

Hypervolemia**

• Causes: Retention of water and sodium, heart failure, cirrhosis.

• Clinical Manifestations: Weight gain, edema, pulmonary congestion.

• Management: Fluid restrictions, diuretics, adjusting underlying causes.

Case Studies**

• Example of a patient with heart failure and fluid management issues showing how to interpret symptoms in relation to electrolytes and fluid.

• Includes management steps and monitoring throughout the patient's treatment journey.