Lecture 4 Fluid Volume Balance Flashcards
how much of adult body weight is fluid?
60%
how much of the body’s fluid is intracellular?
2/3
how much of the body’s fluid is extracellular?
1/3
what are the components of extracellular fluid?
intravascular
interstitial
transcellular
what is osmosis?
- water goes towards higher solute concentration
- passive transport
normal urine output
about 1mL/kg/hr
1-2 L per day
what triggers RAAS and what does it do?
- triggered by low kidney perfusion
- retains sodium and salt in the body by reabsorption
what do natriuretic peptide hormones do?
decrease water and sodium retention
what is ADH?
- antidiuretic hormone, causes water reabsorption in the kidneys
- released in response to change in blood osmolality detected by the hypothalamus
what indicates fluid status?
- body weight
- creatinine and BUN
- Urine specific gravity
- hemoglobin and hematocrit
what does high creatinine and BUN mean?
waste products are not being filtered from the blood effectively, impaired kidney function
what does urine specific gravity indicate?
low means more diluted urine
high means more concentrated urine
isotonic
fluid that has same solute load as intracellular fluid
hypotoic
lower solute load than intracellular fluid
causes cell swelling as water moves towards solutes
hypertonic
higher solute load than intracellular fluid
causes cell shrinking as water moves towards solutes
crystalloid IV fluid
- has electrolytes
- used to restore fluid volume
what is isotonic IV fluid used for?
dehydration
maintaining fluid balance
what is hypotonic IV fluid used for?
DKA
promotes fluid into cells
what is hypertonic IV fluid used for?
treats cerebral edema
promotes fluid out of cells
colloid IV fluid
large insoluble molecules
remains in vascular space for longer
used to treat hypovolemia
what are common isotonic IV fluids?
0.9% NaCl (Normal Saline)
Lactated Ringer
D5W
what are common hypotonic IV fluids?
0.45% NaCl (½ Normal Saline)
0.33% NaCl
what are common hypertonic IV fluids?
3% or 5% NaCl
D5 with 0.45% or 0.9% NaCl
what are common colloid IV fluids?
Albumin
Dextran
Plasma
what can cause hpovolemia?
vomiting, diarrhea, NG suction
perspiration
hemorrhage
diabetes insipidus
diuretics
third spacing
manifestations of hypovolemia
anxiety and confusion
tachycardia
tachypnea
hypotension
pallor
decreased urine output
diagnostic findings for hypovolemia
increased urine specific gravity (more concentrated)
increased BUN and creatinine
increased hematocrit = decreased circulating volume
decreased hemoglobin and hematocrit = hemorrhage
managing hypovolemia
promote oral fluid intake
Isotonic IV fluids initially
hypotonic IV fluids later - promote fluid into cells
blood products for hemorrhage
monitoring response to hypovolemia treatment
strict I/Os
urine output
pulmonary status (pulmonary edema = fluid overload)
neuro status (cerebral edema from isotonic fluids)
vital signs
what can cause hypervolemia?
retention of sodium and water
SIADH
heart failure
high salt diet
diagnostic findings of hypervolemia
decreased HGB and HCT (blood more diluted by fluid)
decreased serum and urine osmolality
chest x-ray for pulmonary edema
clinical manifestations of hypervolemia
headache and confusion
hypertension
tachycardia
JVD
pulmonary edema, dyspnea, crackles, tachypnea
general edema
decreased specific gravity of urine and increased UOP
acute weight gain
managing hypervolemia
sodium restriction
fluid restriction
monitor daily weight
diuretics and dialysis
elevate HOB for pulmonary edema
lung sounds
