Water Balance Flashcards
what is an effective osmole
“osmotically active”
- Molecule/ ion that can cause water to move toward it
what is the MVP of effective osmoles
Na
effective osmoles in serum
Na+, Cl-, HCO3-, proteins, glucose, ethylene glycol
osmotically active solutes in serum:
can be measured
osmolarity can be estimated from a calculation
what can we do with the measured osmolality and the calculated osmolarity
osmole gap
Osmole Gap = measured osmolality - calculated osmolality
what doe an increase in osmole gap indicate
An increase in an osmotically active molecule in blood; that is not measured on the serum biochemical profile
what can alter osmole gap
TOXINS! and some therapeutics
o Ethylene glycol, methanol, paraldehyde
o Mannitol or radiographic contrast medium
what osmole gap value = sad pusheen
greater than 30
means there is an unaccounted osmole
Normal osmole gap with increased measured osmolality
There is increased Na+ (usually), or markedly increased urea or glucose (diabetes, renal failure)
Normal osmole gap with a decreased measured osmolality
There is a decrease in [Na+]
Even a marked decrease in BUN or glucose can only cause a minor decrease in osmolality
Increased osmole gap
There is an increase in the osmole gap and signifies the presence of an unmeasured osmole. (Ethylene glycol etc.)
usually a toxin
what is plasma hyperosmolality usually associated with
‒ Hypernatremia
‒ Hyperglycemia = Hyperglycemic Hyperosmolar State (diabetics)
‒ Ketoacidosis
‒ Uremia
‒ Presence of exogenous toxins (ie, ethylene glycol)
T/F clinical signs depend on whether or not fluid shifts occur
true
Hyperosmolality with NO Fluid Shifts
Increased plasma concentration of ineffective solutes: intracellular osmolality = extracellular osmolality
ex: uremia
Hyperosmolality with Fluid Shifts
Increased plasma concentration of effective solutes: intracellular osmolality
