Fluid, Electrolyte & Acid-Base Balance

Fluid, Electrolyte & Acid-Base Balance

Body Fluids
* Your body is 66% water
* Not evenly distributed – separated into compartments
* Able to move back and forth thru the cell membranes to maintain an equilibrium

Fluid Compartments
* Intracellular fluid – fluid inside cells [ICF]
* Extracellular fluid – fluid outside cells and all other body fluids --- ž is plasma [intravascular fluid], remaining ū is interstitial fluid. Small amount is localized as CSF, serous fluid, synovial fluid, humors of eye & endo/perilymph of ears

Edema
* Condition in which fluid accumulates in the interstitial compartment. Sometimes due to blockage of lymphatic vessels or by a lack of plasma proteins or sodium retention

Fluid Balance
* Amount in = amount out
* Average daily intake is 2500 ml [ fluids, food and metabolic water]
* Average daily output is 2500 ml [ urine, feces, perspiration, insensible perspiration]
* What can throw off these numbers?

Electrolyte Balance
* Def: - concentration of individual electrolytes in the body fluid compartments is normal and remains relatively constant.
* Electrolytes are dissolved in body fluids
* Sodium predominant extracellular cation, and chloride is predominant extracellular anion. Bicarbonate also in extracellular spaces
* Potassium is the predominant intracellular cation and phosphates are the predominant intracellular anion
* Cations are actively reabsorbed, anions passively follow by electrochemical attraction
* Aldosterone works at kidney tubules to regulate sodium & potassium levels
* Because of sodium and potassium influence, water will move between compartments
* Example: if high [sodium], then water will move from intracellular space to extracellular space due to osmotic pressure

Balance of other Electrolytes
* Calcium – hypercalcemia / hypocalcemia
* Magnesium – hypermagnesemia/ hypomagnesemia
* Phosphate – hyperphosphatemia/ hypophosphatemia
* Chloride – hyperchloremia/ hypochloremia
Acid - Base Balance
* Blood - normal pH of 7.2 – 7.45
* < 7.2 = acidosis > 7.45 = alkalosis
* 3 buffer systems to maintain normal blood pH
* Buffers
* Removal of CO2 by lungs
* Removal of H+ ions by kidneys
Buffers
* Protein Buffer Systems
* Amino Acid buffers
* Hemoglobin buffers
* Plasma Protein buffers
* Phosphate Buffer Systems
* Carbonic Acid – Bicarbonate Buffer System
Maintenance of Acid-Base Balance
* Respiratory System: removal of CO2 by lungs – stabilizes the ECF, has direct effect on Carbonic Acid – Bicarbonate Buffer System

* Urinary System: removal of H+ ions by kidneys

Disturbances to Acid-Base Balance
* Respiratory Acidosis
* Respiratory Alkalosis
* Metabolic Acidosis [ lactic acidosis, ketoacidosis]
* Metabolic Alkalosis

Fluid, Electrolyte & Acid-Base Balance.ppt