Fluids and Electrolytes

1
Fluids and Electrolytes

• Water is the largest single component of the
  body.
• Water comprises 95 of the bodys fluids.

2
Water content varies

• Infant 70 water
• Males 60 water
• Females 50 water
• Elderly 45 water
• Muscle 65 water
• Fat 20 water

3
Intake equals Output

• Intake (2500ml)
• preformed ingested water (60,30)
• metabolic water (10)
• Output (2500ml)
• urine, feces
• sweat, evaporation
• Regulated by aldosterone and ADH

4
Water Compartments

• Intracellular compartments
• 2/3 of total water volume
• Extracellular compartments
• 1/3 of water volume
• Movement between regions by filtration and
  osmosis

5
Electrolytes

• Acids, Bases and Salts
• Substances that dissolve in water, conduct
  electricity and dissociate into ions

6
Acid-Bases Balance

• pH - log H
• pH 7.0 is neutral
• Normal range is 7.35-7.45
• Control mechanisms
• Kidneys
• Respiratory System
• Buffers

7
Buffers

• Carbonic Acid/Bicarbonate system major regulator
  of extracellular pH
• HCO3- functions as weak base
• H2CO3 functions as weak acid
• Work by converting a strong acid/base to a weaker
  one

8
Phosphate Buffer System

• Similar to that of the bicarbonate system
• Important urine and intracellular buffer
• Component parts
• NaH2PO4 acts as a weak acid
• Na2HPO4 acts as a weak base

9
Protein Buffer System

• Most abundant buffering system in the body
  including intracellular and extracellular
  compartments
• Carboxyl groups (COOH) and amine groups (NH3) act
  as either an acid or a base

10
Acid - Base Imbalance

• Acidosis (pHlt7.35)
• Alkalosis (pHgt7.45)

11
Respiratory Acidosis or Alkalosis

• Results from an imbalance of CO2
• Respiratory Acidosis - due to increase of CO2
• decreased respiration results in
• ? CO2 ? ?H ? ?pH
• Respiratory Alkalosis - decrease of CO2
• increased respiration or hyperventilation
• ?CO2 ? ?H ??pH
• CO2 H2O ? H2CO3 ? H HCO3-

12
Metabolic Acidosis or Alkalosis

• Results from imbalance of HCO3-
• Metabolic acidosis - due to decrease of HCO3, ,
  which lowers pH
• excessive alcohol, prolonged diarrhea, renal
  dysfunction
• Metabolic alkalosis - due to increase of HCO3,
  which increases pH
• excessive vomiting