Check point 1
• Osmosis vs osmotic pressure• Molarity vs osmolarity• Osmolarity vs osmolality– Iso, hyper and hypo osmolar
• Osmolarity vs tonicity– Iso, hyper and hypo tonic
• Posm = 2[Na] + [glucose]/18 + BUN/2.8• Posm in human?
Two carefully regulated parametersEffective circulating volume (ECV)
Tonicity
Plasma volume Serum osmolarity
Extracellular fluid volume
Serum Na+ concentration
Check point 2
• How kidney conserve water– Vasopressin and aquaporins
• Plasma volume and osmolarity– osmoreceptors, baroreceptors and atrial stretch
receptor– AngII, Ald, ANP, thirst, ADH
Check point 3 - IV fluid
• Crystalloid vs colloid • NS 0,9%• NS 0,45%, 3%• RL• D5%• D40%• D5% - NS0,9%• D5% - NS0,45%