The document discusses the importance of intravenous fluid therapy during anesthesia, covering definitions, fluid compartments, and assessment of dehydrated patients. It details options for fluid replacement, including crystalloid and colloid solutions, along with methods for calculating fluid needs. Key factors in assessing fluid status and treatment options are also highlighted.

1. Intravenous fluid
therapy during
anesthesia
By Dr. Ahamd Y. Alansi
January 2018 1

2. Headlines:
• Why it is important to know about fluids
therapy?
• Definitions
• Fluids compartments
• Assessment of dehydrated patient
• Options of fluids replacement
• Calculations
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3. Why it is important to know about fluids
therapy?
•To compensate fluid deficits
•To maintain electrolyte balance
•To correct Acid–base disorders
•To treat some disease e.g. renal
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4. Definitions :
• (SI):The system of international units
• Mole :One mole of a substance represents 6.02 ×
10 23 molecules
• Molarity: the number of moles of solute per liter of
solution.
• Molality : moles of solute per kilogram of solvent.
• Equivalency is used for ionize: is the number of
moles multiplied by its charge (valence).
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5. Definitions :
• Osmosis is the net movement of water across a
semipermeable membrane as a result of a difference
in non-diffusible solute concentrations between the
two sides.
• Osmotic pressure is the pressure that must be
applied to the side with more solute to prevent a net
movement of water across the membrane to dilute
the solute.
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6. Definitions :
• Osmolarity of a solution is equal to the number of
osmoles per liter of solution,
• Osmolality equals the number of osmoles per kilogram
of solvent.
• Tonicity, a term that is often used interchangeably with
osmolarity and osmolality, refers to the effect a
solution has on cell volume.
• An isotonic solution has no effect on cell volume,
• hypotonic increase cell volume.
• hypertonic decrease cell volume.
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7. Fluids compartments:
• potassium is the most important
determinant of intracellular
osmotic pressure, sodium is the
most important determinant of
extracellular osmotic pressure
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8. Fluids compartments:
• When interstitial fluid and pressure increase
rapidly, it appears clinically as edema.
• Most electrolytes (small ions) freely pass
between plasma and the interstitium, resulting in
nearly identical electrolyte composition
• Plasma proteins (mainly albumin) are the only
osmotically active solutes in fluid not normally
exchanged between plasma and interstitial fluid.
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9. Fluids compartments:
• The rate of diffusion of a substance across a
membrane depends upon:
• (1) permeability of that substance through that
membrane.
• (2) concentration difference for that substance
between the two sides.
• (3) pressure difference between either side
because pressure imparts greater kinetic energy.
• (4) electrical potential across the membrane for
charged substances. 9

10. Fluids compartments:
• Diffusion between interstitial fluid and ICF may
take place by one of several mechanisms:
• (1) directly through the lipid bilayer of the cell
membrane, eg. Oxygen, CO2, water, and lipid-soluble molecules
• (2) through protein channels within the
membrane eg.Cations such as Na+, K+, and Ca2+
• (3) by reversible binding to a carrier protein that
can traverse the membrane (facilitated diffusion)
eg. Glucose and amino acids 10

11. Fluids compartments:
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12. Assessment of dehydrated patient:
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History:
• Recent oral intake
• vomiting
• Diarrhea
• gastrointestinal preparation before bowel surgery
• recent significant blood loss
• wound drainage
• intravenous fluid intake
• recent hemodialysis

13. Assessment of dehydrated patient:
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Physical examination:
Indications of hypovolemia
• skin turgor
• poor hydration of the mucous membranes
• increased resting heart rate
• decreased blood pressure (including orthostatic changes), decreased
urine output.
Indications of hypervolemia may include
• edema
• elevated jugular pulse pressure
• pulmonary crackles; wheezing
• cyanosis; and pink, frothy pulmonary secretions.

14. Assessment of dehydrated patient:
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15. Assessment of dehydrated patient:
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Laboratory evaluation:
• rising hematocrit (acute blood loss will not result in an
acute change of hematocrit)
• metabolic acidosis
• urinary specific gravity greater that 1.010
• urinary sodium less than 10 mEq/L,
• hypernatremia
• ratio of blood urea nitrogen to creatinine > 10:1.
Hemodynamic measurements:
• Central venous pressure (CVP)
• Pulmonary artery (PA) catheter

16. Options of fluids replacement:
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Crystalloid solutions: (The intravascular half-life is between 20-30 min.)
• initial resuscitation fluid in hemorrhagic and septic shock, burns, and
traumatic brain injuries
• NPO >>>hypotonic solutions e.g. DW5% specially pediatric
• If losses involve water, electrolytes (i.e., blood loss), replacement is with
isotonic electrolyte solutions.
Colloid solutions: (The intravascular half-life is between 3 and 6 hours).
• derived either from plasma proteins or synthetic glucose polymers.
• Crystalloid versus colloid an ongoing debate
• albumin (5% and 25%) is justified in the hypoalbuminemia or large burns
(large protein loss).
• risk of antiplatelet effects & should not be administered > 20 mL/kg/day.
• The dextrans have also been found to be antigenic and can produce
anaphylactoid reactions.

17. Options of fluids replacement:
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18. Calculations:
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19. ‫الستماعكم‬ ‫شكرا‬ 19