Fluid & Electrolyte Nursing Notes

Composition of Body Fluids

  • The two largest constituents of the body are water and electrolytes.
  • Water and electrolytes are especially impactful because infants and the elderly are more easily affected by changes in fluid balance.

Water Functions

  • Functions include:
    • Transport
    • Heat regulation
    • Hydrogen balance (acid-base balance)
    • Digestion
  • The amount of body water varies with age, sex, and health.

Sources of Water and Avenues of Loss

  • Intake totals: 1500\ \text{mL} (Oral) + 800\ \text{mL} (Food) + 200\ \text{mL} (Metabolism) = 2500\ \text{mL}
  • Output totals: 1500\ \text{mL} (Urine) + 400\ \text{mL} (Perspiration) + 200\ \text{mL} (Feces) + 400\ \text{mL} (Expired air) = 2500\ \text{mL}
  • Net balance assumes intake equals output at rest.

Electrolytes

  • Diet is a major source of electrolytes contributing to water regulation and balance.
  • Roles of specific electrolytes:
    • Sodium: heart rhythm, nerve impulse transmission, muscle contraction
    • Potassium: muscle activity, blood coagulation
    • Calcium: nerve impulse transmission, muscle contraction, blood coagulation
    • Magnesium: helps maintain acid-base balance
    • Chloride: ATP production
    • Phosphate: (listed; no specific function detailed in the transcript)

Major Electrolytes: Normal Range

  • Sodium: 135-145\ \mathrm{mEq/L}
  • Potassium: 3.5-5\ \mathrm{mEq/L}
  • Calcium: 9-10.5\ \mathrm{mg/dL}
  • Magnesium: 1.5-2.5\ \mathrm{mg/dL}
  • Phosphate: 2-4.5\ \mathrm{mg/dL}
  • Chloride: 98-106\ \mathrm{mEq/L}

Non-Electrolytes

  • Amino acids (proteins), glucose, and fatty acids
  • Remain bound together when dissolved in body fluid

Blood

  • Normal circulating blood volume: 4\text{ to }6\ \text{L}
  • Components: Erythrocytes (red cells), Leukocytes (white cells), Platelets (thrombocytes)
  • Carried in plasma; Plasma proteins and colloids contribute to plasma osmotic pressure, which keeps fluid in the vascular compartment

Body Fluids: Intracellular vs Extracellular

  • Intracellular: within the cell
    • About \tfrac{2}{3}\$ of total body water
    • Most cell walls are permeable to water
  • Extracellular: outside the cell
    • Intravascular
    • Interstitial
    • Transcellular

Extracellular Fluid

  • About \tfrac{1}{3} of the total body water
  • Transports nutrients, oxygen, and waste products to and from cells
  • Regulated by renal, metabolic, and neurologic factors
  • High in sodium content

Intravascular Fluid

  • Fluid within the blood vessels
  • Consists of plasma and fluid within the blood cells
  • Contains large amounts of protein and electrolytes, which help maintain intravascular volume

Transcellular Fluids

  • Aqueous humor (eyes)
  • Saliva
  • Cerebrospinal fluid
  • Pleural, peritoneal, synovial, and pericardial fluids
  • Gastrointestinal secretions
  • Fluid in the urinary tract
  • Lymphatic system fluids

Movement of Fluid & Electrolyte

  • Water moves by water in / water out across compartments
  • Hypothalamus: thirst mechanism
  • Main organ for fluid excretion: kidneys
  • Hormones involved: ADH\ (antidiuretic\ hormone)$$, Aldosterone, ANP (atrial natriuretic peptide)

Fluid & Electrolyte Imbalance: Impactors

  • Impacts include: kidney function, illness, circulatory conditions

Deficient Fluid Volume

  • Occurs when patients are unable to take in enough fluid or lose excessive amounts of fluid
  • At risk: dehydration
  • Result: dehydration

Dehydration

  • Mechanism: when too little water in the plasma, water is drawn out of cells by osmosis to equalize concentration; cells shrink
  • Treatment: fluid administration, either orally or intravenously
  • Signs/symptoms: depend on severity (not exhaustively listed in the transcript)

Testing for Tissue Turgor

  • Method used to assess hydration status (as noted in Mosby’s Guide to Physical Examination)

Fluid Volume Excess (Hypervolemia)

  • At risk scenarios:
    • Receive intravenous fluid too quickly
    • Given tap-water enemas
    • Drink more fluids than can be eliminated
    • Overproduction of ADH or aldosterone
  • Result: hypervolemia

Fluid Overload: Signs

  • Weight gain
  • Crackles in the lungs (wet lungs)
  • Slow bounding pulse
  • Elevated blood pressure
  • Possibly edema
  • Signs indicate overhydration

Edema (Example)

  • Pitting edema cited as an example of fluid overload/edema assessment

Assessment of Fluid/Electrolyte Status

  • Key components of assessment:
    • Urine
    • Electrolytes
    • Vital signs (VS)
    • Physical assessment

Nursing Process – Diagnosis

  • Possible diagnoses include:
    • Fluid volume excess
    • Fluid volume deficit

Interventions

  • Interventions include:
    • Assess I&O (input and output)
    • Daily weight
    • Limit fluid intake
    • Administer diuretics as ordered
    • Administer IV fluids as ordered
    • Encourage fluid intake
    • Monitor electrolyte values

Additional Notes

  • Course branding mentioned in slides: GALEN COLLEGE OF NURSING
  • Some slide text appears as decorative or branding elements rather than content; focus on the clinical concepts above for study purposes.