w2_ch13_fluid &electro balance Flashcards
isotonic fluid
osmolarity & cell shift
270-300 mOsm/L
equal cellular shift
hypotonic fluid
osmolarity &cell shift
<270 mOsm/L
cell swells
hypertonic fluid
osmolarity & cell shift
> 300 mOsm/L
cell shrinks
normal serum osmolarity (adults)
270-300 mOsm/L
isotonic fluid used for? what happens when there is too much?
- hypotensive/hypovolemic
- risk for fluid overload (LV dys, hx CHF/htn, older adults)
- no shift until hydrostatic pressure is too high
*avoid vol hyper-expansion w/intracranial pathology or space occupying lesions
hypotonic fluids
- dilutes serum decreasing osmolarity
- cellular dehydration & normal b/p
- used for medication
- cautions: cardiovascular collapse, increase ICP
hypertonic fluids
- higher osmolarity than serum
- increases serum osmolarity
- cell shrinks
- stabilize b/p, increase urine output, decrease edema
- most D5 solutions
what is corrected by using hypertonic fluids?
fluid, electrolyte, and acid-base imbalance
what type of fluids for a patient with decrease skin turgor, dry mucous membranes, and normal b/p
hypotonic fluid
colloids
- blood
- blood products, plasma
- plasma fraction
- synthetic plasma expanders (albumin and synthetic albumin)
what type of fluids for a patient with decrease skin turgor, dry mucous membranes, and hypotension
isotonic
- will fill vascular and increase b/p then when vessels are filled then hydrostatic pressure fills the cells
crystalloids, advantages & disadvantages
- water + electrolyte, small molecules
- advant: inexpensive, long shelf life, low adverse reactions, variety of formulations for fluid replacement/balance
- dis: 2-3x volume to correct vascular expansion but wont stay d/t hydrostatic pressure
colloids
- large molecules that stay in vascular
- high osmolarity (brings fluid to vascular)
- stays in the vascular longer than crystalloids
patient that will benefit from colloids
- reduces edema
- helps maintain b/p
- protein malnourished pt
- liver failure pt
5% dextrose (D5W), uses?
- sugar & water
- in the bag = isotonic, bloodstream = hypotonic
(glucose metabolizes)
Uses: maintain water balance when NPO
- provides calories
- electrolyte free
- rapid resdistribute into ICS, less than 10% stays in IVS
dextrose-saline
- a bit of sugar and salt
- primarily to replace water loss post-op
- neither really saline or dextrose
- advantages: doesn’t commonly cause water/salt overload
how to assess volume status (determine IVF)
- what is the volume status of my pt?
- do we want to shift fluid to another compartment?
- can my patient take PO safely?
- is my pt NPO for a reason?
- is the patient diabetic?
- what fluids was the pt on before?
how does hydrostatic pressure effect fluid shift?
it pushes the fluid out of the vessels d/t increased pressure in the vessels
how does oncotic pressure effect fluid shift?
the protein in the vessels stay in the vessels and when the hydrostatic pressure in the vessel decreases the protein pulls water back into the vessels
osmolality vs omolarity
osmolality - measures solvent (fluid) concentration for kidneys
osmolarity - measures concentration (particles) in the blood
regulation mechanisms
- thirst
- kidneys (vol & osmolality)
- RAA mech, responds to HTN, vasoconstriction, Na+ regulation
- ADH,
sodium function
- maintains ECF volume
- regulates acid base balance w/other ions
- conducts nerve impulses
potassium function
- major cation of ICF
- cellular depolarization & repolarization
- neuromuscular impulses
- acidbase balance
- cardiac contractions
calcium function, regulation of it
- neuromuscular transmission
- muscle contraction
- bones & teeth
- requires vitamin d
regulated by
- vit D
- calcitonin
- parathyroid hormone (PTH)
magnesium function
- skeletal muscle contraction
- neurotransmission
- generation of energy stores
- carbohydrate metabolism
- blood coagulation
- cell growth
