Fluid and Electrolyte balance

Willy Handoko

Body is mostly water

• New planet does it have water?

Body is in osmotic equilibrium

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?

Water balance

Electrolytes in body fluids

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

Graphical representation of volume vs solute in ICF and ECF

Check point 3 - IV fluid

• Crystalloid vs colloid • NS 0,9%• NS 0,45%, 3%• RL• D5%• D40%• D5% - NS0,9%• D5% - NS0,45%

Thanks