Glossary of Nursing - fluid balance

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intracellular fluid
40% of total body weight
extracellular fluid
20% of total body weight
formula for plasma osmolarity
2(Na) + BUN/5 + glucose/20

normal range is 275-295 milliosmoles/L
antidiuretic hormone - ADH
Secreted by posterior pituitary in response to increased serum osmolarity
Parathyroid hormone
Secreted by parathyroid gland in response to low serum calcium
Atrial natriuretic factor
Released from cardiac muscle cells in response to atrial distention from fluid overload
Secreted by the adrenal cortex in response to decreased blood volume, decreased renal perfusion, angiotensin
secreted by kidneys in response to aldosterone
produced in liver, normally found in blood, acted upon by renin to form angiotensin
stimulates adrenal gland to produce aldosterone
causes of hypovolemia
excess urine output, diabetes insipidus, burns, fever, wound drainage, NG suction, diarrhea, vomiting, diuretics
s/s of hypovolemia
orthostatic changes, neg. I&O, fever, increased heart rate, weak thready pulses, weight loss
isotonic fluid volume deficit
fluid and electrolyte losses are equal
In isotonic hypovolemia, what happens to EC and IC fluids?
Volume & solute are lost from EC space; IC fluid unchanged
Causes of isotonic hypovolemia
Hemorrhage, diarrhea, decreased po intake, third spacing (trauma, burns, sepsis, cirrhosis)
compensatory mechanisms for isotonic hypovolemia
renin-angiotensin-aldosterone mechanism, SNS shunts blood to vital organs
assessment of isotonic hypovolemia
Increased Hgb and Hct
Na+ normal
Urine SG >1.010 slightly conc.
BUN increased
treatment for isotonic hypovolemia
NS or LR, blood, albumin, antidiarrheals, increased PO intake and nutrition, ABX
hypotonic hypovolemia
solute loss is greater than fluid loss
In hypotonic hypovolemia, what happens to EC and IC fluids?
EC fluid hypotonic; EC fluid shifts to IC space, cells swell & lyse
causes of hypotonic hypovolemia
CRF, malnutrition, rehydration with hypotonic fluids
compensatory mechanisms for hypotonic hypovolemia
Renin-angiotensin-aldosterone mechasism, stim. by decr. arterial pressure
assessment of hypotonic hypovolemia
Increased Hgb & Hct
Na+ decreased
Urine SG<1.010, slightly dilute
treatment for hypotonic hypovolemia
NS or 3% saline w/ Lasix
K+, nutrition
Hypertonic fluid volume deficit
Fluid loss greater than solute loss
In hypertonic hypovolemia, what happens to EC and IC fluids?
EC fluid hypertonic, IC fluid shifts to EC space, cell dehydrate
Causes of hypertonic hypovolemia
excess sweat, hyperventilation, fever, ketoacidosis, high osmolarity tube feeds
compensatory mechanisms for hypertonic hypovolemia
increased ADH (posterior pituitary stim by hyperosmolar ECF), increased thirst (hypothalamus)
assessment of hypertonic hypovolemia
Hgb & Hct normal or increased
Na+ increased
Urine SG>1.030 more conc.
treatment for hypertonic hypovolemia
1/2 NS, treat the cause (w/ insulin, antibiotics, tylenol...)
causes of hypervolemia
kidney probs, heart probs, corticosteroids, excess Na+ or fluid intake, hypotonic fluids, SIADH, low protein, venous return probs, immobility
s/s of hypervolemia
incr. HR, bounding pulses, incr. BP & CVP, JVD, dysrhthmias, incr. RR, dyspnea, moist crackles, skin cool & pale, edema, muscle weakness, diarrhea, ascites
isotonic hypervolemia
serum osmolarity is normal
what happens to EC and IC fluids in isotonic hypervolemia?
EC space is expanded
causes of isotonic hypervolemia
excess isotonic fluids infused, ingested, retained
compensatory mechanisms for isotonic hypervolemia
decr. ADH & aldosterone, incr. urine output
incr. natriuretic factor r/t atrial distension, incr. urine output
hypotonic hypervolemia
AKA water intoxication, serum electrolytes decreased
what happens to EC and IC fluids in hypotonic hypervolemia?
hypotonic EC fluid moves into IC space, all compartments expand
causes of hypotonic hypervolemia
SIADH, excess water consumption
hypertonic hypervolemia
rare occurence, incr. serum osmolarity
what happens to EC and IC fluids in hypertonic hypervolemia?
IC fluid shifts to EC space; EC space expands, IC space contracts, cell shrivel
causes of hypertonic hypervolemia
excessive sodium intake
treatments for hypervolemia
caution with IV fluids, electrolyte solutions only, no free water, Lasix (furosemide)/Bumex (bumetanide), fluid restrictions
What condition can result from too rapid IV infusions or blood transfusions?
result - isotonic hypervolemia
what is anasarca?
generalized body edema from isotonic hypervolemia
what are symptoms of anasarca?
respiratory distress, weight gain, venous distension, incr. blood pressure
what condition can results from intake of hypertonic fluids or extreme Na+ ingestion or retention (as from steroids or liver/rental failure)?
result - hypertonic hypervolemia
You see pitting edema and circulatory overload - what is the condition?
dx - hypertonic hypovolemia

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