Fluids and electrolytes

  1. TBW
    (total body water) sum of all fluids within body, 45-80% of body weight. Fat cells=less water. muscle cells=more water
  2. ICF
    intracellular fluid 2/3 of bodily fluids
  3. ECF
    extracellular fluid. 1/3. interstitial fluid (between cells 2/3). Intravascular fluid (blood vessels) 1/3. Miscellaneous body fluids (lymph joints csf intestinal)
  4. Importance of fluids
    homeostasis, maintaining volume balance, maintaining solute/electrolyte concentrations (osmolarity) balance, Maintaining pH acidity basicity
  5. Solute
    a substance dissolved in a solution (lemon water)
  6. solvent
    a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute resulting in a solution. (the water, in sugar water)
  7. Solution
    a homogeneous mixture composed of 2+ substances dissolved in a solvent (the lemonade)
  8. three solute states
    • Hypertonic=concentrated
    • Hypotonic=diluted
    • Isotonic=balanced
  9. osmoreceptors
    neurons in the hypothalmus (regulate concentrations to 2% changes, releases antidiuretic hormone)
  10. ADH
    antidiuretic hormone: increases the permeability of renal tubular cells to water so water can be reabsorbed where needed
  11. volume states (vascular volume)
    • Dehydration: to little
    • Overhydration: to much
    • Balanced: normovolemic
    • regulated within 10% by RAAS and natriuretic factors
  12. RAAS
    Renin-angiotensin-aldosterone system: kidney signals that volume is low by secreting renin. Angiotensinogen from liver meets renin and forms angiotensin 1. Ace (angiotensin converting enzyme) from surface of lungs and kidneys converts angiotensin1 to angiotensin 11. this signals everything to reabsorb water.
  13. capillaries
    usually hold proteins and cells in and are permeable to O2 CO2 H2O and glucose. (liver more, Brain less, more during inflammatory response)
  14. hydrostatic pressure
    pushes water
  15. osmotic pressure
    pulls water
  16. osmotic force
    principal force determining movement of water. (attraction of particles in solution for water) water moves toward the compartment where the number of particles is the greatest
  17. filtration & reabsorption
    • filtration: movement of fluid out of the capillary into interstitial space
    • reabsorption: movement of fluid back into the capillary from the interstitial space
  18. starlings hypothesis
    forces favoring filtration:capillary hydrostatic pressure and interstital oncotic pressure - forces opposing filtration= capillary oncotic pressure and interstitial hydrostatic pressure
  19. Edema
    • excessive accumulation of fluid within interstitial spaces
    • lymphatic obstruction (post-mastectomy scarring)
    • inflammation (anaphylaxis)
    • increased hydrostatic pressure in vessels (excessive iv, chronic renin activation)
    • decreased osmotic concentration of the blood(starvation)
  20. isotonic alterations
    • isotonic dehydration: vomiting diarrhea bleeding, orthostatic hypotension, flat neck veins, dizziness, weight loss
    • isotonic overhydration: CHF(congestive heart failure), renal failure, excessive iv fluid, edema, weight gain, destended neck veins
  21. Hypertonic alterations
    • Hypernatremia: gain in sodium or loss of water (almost always accompanied with dehydration)results in intracellular dehydration
    • Causes:salt water, hypertonic saline, oversecretion of aldosterone (keep salt in)
    • Symptoms: thirst fever dry membranes, confusion lethargy seizures
  22. hypotonic alterations
    • Hyponatremia: sodium loss, inadequate sodium intake, or water excess
    • Causes: vomiting diarrhea (pure sodium deficit, intake of large omounts of water, iv fluids to much water not enough sodium
    • Symptoms: lethargy confusion decreased reflexes
  23. potassium (K+)
    • ECF: concentration 3.5-5.5 mEq/L
    • ICF 150-160 mEq/L
    • Maintained my sodium potassium adenosin, triphophatase pump, can be secreted by distal tubul of kidneys and by colon
  24. Hypokalemia
    • K+ <3.5 mEq/L
    • Causes:low intake, laxative abuse, diarrhea, ecf leaking, alkalosis (metabolic or respiratory)
    • Symptoms: with severe losses, muscle weakness/loss <3
  25. Hyperkalemia
    • K+>5.5 mEq/L
    • Causes: increased intake, leak into ecf (crushing injury), decreased renal excretion
    • Symptoms: neuromuscular irritability (restlessness, cramping, weakness, paralysis)
  26. fluid therapies
    • Isotonic
    • 0.9% NaCl (normal saline)
    • 5% Dextrose (D5W)
    • 5% Dextrose in 0.225% NaCl
    • Lactated Ringers

    • Hypertonic
    • 5% Dextrose in 0.9% NaCl- Hypertonic
    • 5% Dextrose in 0.45% NaCl- Hypertonic
    • 10% Dextrose (D10W)-Hypertonic

    • Hypotonic
    • 0.45% NaCl (1/2 normal saline)-Hypotonic
Card Set
Fluids and electrolytes
structure function and alterations of renal and urologic systems