fluid and electrolytes Flashcards
describe intracellular
-in the cell
-ICF is critical for maintaining cell size
-70% of total body fluid
-about 40% of adult body weight is from ICF
describe extracellular
-outside cell
-30% of total body fluid and ~20% of body weight
describe intravascular fluid
plasma of the blood -> blood volume, impacts HR and BP
describe interstitial fluid
surrounds cells (like tissue)
describe trans cellular fluid
cerebrospinal, pleural, peritoneal, synovial, digestive secretions, sweat
what is osmolarity
concentration of particles in a solution (or its pullin power)
describe isotonic
-when osmolarity is equivalent to plasma
-isotonic fluid remains in the intravascular space
-no shift in cell size
describe hypertonic
-when osmolarity is greater than plasma
-hypertonic fluids pull water from the cells and into the intravascular spaces
-cells shrink
describe hypotonic
-when the osmolarity is less than plasma
-hypotonic fluids move from the intravascular spce to the ICF
-cells swell
give two examples of isotonic IV solutions
normal saline, lactated ringers
what does normal saline do
expand extracellular compartment, treat hypovolemia, hyponatremia, hyercalcemia, metabolic alkalosis
what does LR do
contains multiple electroltes in the same concentration as in plasma, treats hypovolemia, burns, and GI losses
give and example of hypertonic IV solution
5% dextrose in lactated ringers (D5LR)
what does D5LR do?
replaces electrolytes, provides calories, shifts fluid from cells to vascular space expanding vascular volume
give an example of hypotonic IV solution
half strength normal saline (0.45%)
what does hald strength normal saline do
often used as maintenance fluid, provides Na, Cl, and free water
describe fluid balance
-generally balance is achieved with oral intake of fluid matching the output of the kidney
-perfect balance is not always met every day, but over 2-3 days
-output can be sensible or insensible
what is sensible output
-things you can measure
-UOP, emesis, wound drainage, suction
what is insensible output
-harder to account for and not measurable
-sweat, respiratory vapors
describe volume overload
positive I&O balance
findings:
-crackles
-JVD
-edema
-dyspnea/SOB
describe volume deficit
negative I&O balance
findings:
-hypotension
-increased HR
-fatigue
-pale and cool
-dry mucus membranes
-dizziness
what are seom causes of abnormal fluid status
-CHF
-small bowel obstruction
-kidney disease
-liver dysfunction
kidneys, liver, heart, and GI
what are some tests to evaluate fluid balance
-CMP
-urinalysis
-daily weight
-telemetry
what organs and systems manage sluid and electrolyte balance
-kidneys
-heart and vascular
-lungs
-nervous system
-GI
organs and systems manage sluid and electrolyte balance
kidneys
-filter 180L of plasma/day while excreting ~1.5L/day
-manage ECF volume and osmolarity
-regulates electrolyte levels by retaining or eliminating
organs and systems manage sluid and electrolyte balance
heart and vascular
-circulate fluid, adequate perfusion pressure in kidneys for filtration
-stretch receptors respond to changes in olume and stimulate fluid retention when hypovolemia is present
organs and systems manage sluid and electrolyte balance
lungs
water vapor excreted/lost per day ~300ml/day
organs and systems manage sluid and electrolyte balance
nervous system
-osmoreceptors sense changes in ECF concentration and stimulate the pituitary gland to release or inhibit release of ADH
-thirst center in the hypothalamus is activated by cellular dehydration
organs and systems manage sluid and electrolyte balance
GI track
absorbs water and nutrients
hormonal control of fluid and electrolyte balance
adrenal glands
-aldosterone secretion causes sodium (and water) retention and potassium loss
-excess cortisol secretion can cause the same effect of aldosterone
hormonal control of fluid and electrolyte balance
pituitary gland
manages ADH
hormonal control of fluid and electrolyte balance
what does ADH do
-allows the body to retain water
-released when osmotic pressure of ECF is greater than that of cells, when blood volume is decreased
-suppressed when osmotic pressure of the ECF is less than that of the cells, or when blood volume is increased
hormonal control of fluid and electrolyte balance
thyroid gland
thyroxine secretion released to increased blood flow including to the kidneys, whey increases flitration rate and UOP
hormonal control of fluid and electrolyte balance
parathyroid gland
regulates calciuma dn phosphate balance through parathyroid hormone (PTH)
hormonal control of fluid and electrolyte balance
what does PTH do
-influences bone reabsorption, calcium absorption from the intestines and calcium reabsorption from the kidneys
-increased PTH causes increased blood calcium and decreased phosphate
-decreased PTH causes decreased calcium and increased phosphate
name some different fluid volume problems
-fluid volume deficit/hypovolemia
-dehydration
-fluid volume excess
describe fluid volume deficit/hypovolemia
-low circulating volume
-loss of fluid and solutes from ECF