Understanding Fluids and Electrolytes

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Understanding Fluids and Electrolytes

• Prepared By
• Gerald Glotfelty EMT-P I/C
• Wayne County Community College
• Detroit MI

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Fluids ElectrolytesIons Charged particles

• Cation Positively Charged particles.
• Sodium ( Na )
• Potassium ( K)
• Calcium (Ca)
• Magnesium (Mg)

• Anion Negatively charged particles.
• Chloride (Cl-)
• Bicarbonate (HCO3-)
• Phosphate (HPO4 -)

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Sodium

• Most abundant extracellular cation.
• Regulates body water distribution.
• Aids nerve impulse transmission.
• Aids transfer of calcium into cells.
• Sodium levels are controlled by the kidneys

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Potassium

• Most abundant intracellular cation.
• Necessary for transmission and conduction of
  nerve impulses.
• Maintenance of normal cardiac rhythm.
• Necessary for smooth and skeletal muscle
  contraction.

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Calcium

• Extracellular cation
• Plays role in nerve impulse transmission.
• Increases force of muscle contractions.
• Functions as an enzyme co-factor in blood
  clotting.
• Necessary for structure of bone and teeth.

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Magnesium

• Intracellular cation.
• Activates (ATP-ase) the primary energy source for
  the sodium potassium pump.
• Plays important role in the relaxation of smooth
  muscle.
• Stabilizes cardiac muscle cells - decreases
  fibrillation threshold.

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Chloride

• Balances cations
• Plays role in fluid balance and renal function.

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Bicarbonate

• Principle buffer of body pH. (extracellular)
• Neutralizes acids.
• Plays important role in acid / base balance.
• Acts as chemical sponge to soak up Hydrogen ions.
  (Acidic metabolic waste) For every one Hydrogen
  ion twenty bicarbonate ions are released to
  maintain balance.

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Phosphate

• Plays an important role in ATP storage.
• Chief intracellular buffer acts to maintain
  intracellular pH.

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Body fluid compartments60 of adult total body
weight is fluid

• Intra-cellular
• 75 of all body fluid.
• ________________
• Special note
• 80 TBW infants.
• 50 TBW geriatrics.

• Extra-cellular
• 25 of all body fluid Three extra-cellular
  compartments.
• 1. Intra-vascular 7.5
• 2. Interstitial 17.5
• 3. Third space (eyes, joints,plural
  space,etc.)

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Fluid movement
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Movement of body fluids (a.)Natural movement no
energy required.

• Osmosis
• Movement of solvent, H2O across a semi-permeable
  membrane, from an area of lesser solute
  (particle) concentration to an area of higher
  solute concentration.

• Diffusion
• Movement of solute (particles) from an area of
  higher concentration to an area of lower
  concentration.

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Movement of body fluids (b.)Movement requiring
energy (Biochemical Processes)

• Active transport
• Movement of a substance across a cell membrane,
  through special portals in the cell wall, from an
  area of less concentration to an area of high
  concentration.
• Calcium channels

• Facilitated diffusion
• a Biochemical process in which a substance is
  selectively transported across a cell membrane
  using a carrier molecule and energy.
• Insulin/glucose

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TonicityThe concentration and size of particles
in solution.
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Intravenous Fluids

• Colloids
• Contain large protein molecules. Stay in vascular
  space.
• Not used pre-hospital.
• Plasmanate
• Dextran
• Hetastarch

• Crystalloids
• Contain non-protein particles.
• Commonly used Pre-hospital.
• Normal saline
• Lactated Ringers
• D5W

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Pre-hospital Intravenous Fluids
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Acid / Base Balance
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Acid /Base Balance

• Acid base balance is the regulation of free
  hydrogen ions in extra-cellular fluid.
• Acids dissociate in solution to release H.
• Bases combine with free H and remove it from
  solution.

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Acid 1----------7-----------14 base

• 7 on the pH scale is neutral, (H2O) the universal
  solvent.
• The human body has a pH of 7.35-7.45
• A rise or drop of pH of greater than 0.4 is
  lethal.
• 6.9 pH lethal acidosis.
• 7.8 pH lethal alkalosis.

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Balance in the body is maintained by three buffer
mechanisms
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Acid / Base Derangements.

• Acidosis
• Respiratory
• Metabolic

• Alkalosis
• Respiratory
• Metabolic

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Practical Application

• Acidosis causes loss of muscle tone patient
  becomes weak and flaccid.
• Alkalosis causes muscles to spasm and cramps.

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Etiology of Respiratory Acidosis

• Decreased rate, Airway Decreased
  and depth of obstruction gas exchange
  breathing
• Accumulation of CO2
• Respiratory Acidosis

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Etiology of Metabolic Acidosis

• Kidney Failure / Diabetes Mellitus
• Accumulation of non-Respiratory acids.
• Metabolic Acidosis
• Excessive loss of Base
• Prolonged diarrhea or vomiting

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Etiology of Respiratory Alkalosis

• Anxiety Fever Poison High Altitude
• Hyperventilation
• Loss of CO2
• Concentration of H2CO3
• Concentration of H
• Respiratory Alkalosis

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Etiology of Metabolic Alkalosis

• Diarrhea (gastric drainage) Vomiting
• Loss of acid H2O CO2
• in alkaline substance HCO3
• Metabolic Alkalosis

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Analyzing ABGs

• 1. Look at the pH. (lt7.4) acid (gt 7.4) base
• 2. Look at the CO2 (gt45) acid (lt35) base
• 3. Look at the HCO3 (lt22)Acid (gt26) base
• If pH and CO2 indicators are the same origin is
  Respiratory.
• If pH and HCO3 are indicators are the same origin
  is metabolic.

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Compensated ? / Uncompensated?

• Uncompensated The value that does not match the
  A-B status of the pH, is normal. (Third value
  is normal)
• Partially Compensated Both the value that
  doesnt match the A-B status of the pH, and the
  pH itself are above or below normal. ( All
  values are abnormal)
• Completely Compensated The value that doesnt
  match the A-B status of the pH is above or below
  normal but the pH is normal. (pH is the only
  normal value)

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Acid base Problems

• pH 7.5, PaCO2 50 mm Hg, HCO3 30 mEq/L
• Metabolic Alkalosis Partially Compensated.
• pH 7.31, Pa CO2 50 mm Hg, HCO3 22 mEq/L
• Respiratory Acidosis Uncompensated.
• pH 7.31, PaCO2 44 mm Hg , HCO3 20 mEq/l
• Metabolic Acidosis Uncompensated.

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More, Acid / Base problems.

• pH 7.47, PaCO2 48 mm Hg , HCO3 30 mEq/L
• Metabolic Alkalosis Partially Compensated.
• pH 7.33, Pa CO2 40 mm Hg, HCO3 21
  mEq/L
• Metabolic Acidosis Uncompensated.
• pH 7.48, Pa CO2 44 mm Hg, HCO3 30 mEq/L
• Metabolic Alkalosis Uncompensated

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Even more, Acid /Base Problems

• pH 7.33, PaCO2 49 mm Hg, HCO3 26 mEq/L
• Respiratory Acidosis Uncompensated.
• pH 7.48, PaCO2 33 mm Hg, HCO3 24 mEq/L
• Respiratory Alkalosis Uncompensated.
• pH 7.31, PaCO2 33 mm Hg, HCO3 20
  mEq/L
• Metabolic Alkalosis Partially Compensated.
• pH 7.45, Pa CO2 34 mm Hg, HCO3 20
  mEq/L
• Respiratory Alkalosis Compensated.

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Summary

• A general understanding of fluids, electrolytes,
  acid base balance and the compensatory mechanisms
  involved play an important role in the paramedic
  patient assessment and field interventions.
• Paramedics need to understand the physiology of
  patients conditions and the physiological effects
  of treatment choices.

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The End