5- Fluid replacement and renal response Flashcards
What is osmolality
Number of particles of solute per Kg of solvent mOsm/g
What is osmolarity
Solute per litre of solution mOsm/L
What is tonicity
Effective osmotic pressure gradient of two solutions separated by semipermeable membrane
Where does water move when hypotonic
Into cells = swells
Distribution of water in Male
60% 2/3 ICF 1/3 ECF 25% plasma 75% interstitial
Why do women have less fluid
More fluid in muscle then in fat
55% in women 60% men
Total body water of baby
75%
Total body water of elderly
45%
Main intracellular cation and anion
K and PO4
Main extracellular cation and anion
Na and Cl-
What happens to water in hypernatremia
Water drawn out of cell
Shrinks
Confusion/ seizures
What happens to water in hyponatremia
Water moves into cells
Swells
Cerebral oedema
Headache/ seizures
Where does 5% dextrose distribute
Glucose taken up by cell H2O reduces osmolarity of all compartments 2/3 rd to intracellular 1/3 to interstitial 1/12 to intravascular
Where does NaCl 0.9% go
Remains in ECF
3/4 interstitial
1/4 intravascular
Where does Hartmanns go
Majority retained in ECF
3/4 and 1/4