Fluid therapy, types, and calculations

1. FLUID THERAPY
THE BASIC AND APPLIED
KNOWLEDGE
Dr. Muhammad Rizwan
PhD (Clinical Medicine)

2. What is fluid?
Any liquid, gas, or material that
cannot sustain a tangential, or
shearing, force at rest and
undergoes a continuous change in
shape when subjected to such
stress.
What is Fluid Therapy?
Fluid therapy is the administration
of fluids to a patient as a treatment
or preventative measure.
It can be administered via
intravenous, intraperitoneal,
intraosseous, subcutaneous, and
oral routes.
What is Fluid Therapy?

3. Fluid Distribution in Body
Total Body Water
60% of Body
Weight
Extracellular Fluid
20% of
Body Weight
Interstitial Fluid
15% of Body
Weight
Intravascular Fluid
5% of Body Weight
Intracellular
Fluid=40% of
Body Weight

4. Types of fluid disturbances
Dehydration
Electrolyte Imbalance
Acid-base Imbalance
Disturbance in Oncotic
Pressure

5. Intravenous fluids
 Intravenous fluids are chemically prepared
solutions that are administered to the patient.
 They are tailored to the body’s needs and
used to replace lost fluids and/or aid in the
delivery of IV medications.

6. INDICATIONS OF FLUID THERAPY
 For rapid restoration of fluid and electrolytes
in dehydration due to vomiting, diarrhea,
shock due to hemorrhage or sepsis or burns.
 Total parenteral nutrition.
 Anaphylaxis, cardiac arrest, hypoxia.
 Post gastrointestinal surgeries.
 For maintenance, replacement of loss or as a
special fluid.

7. Advantages of fluid therapy
 Provides the patient with life-sustaining fluids,
electrolytes, and drugs.
 Immediate and predictable therapeutic effects.
 Preferred for administering fluids, electrolytes,
and drugs in emergencies.
 Allow fluid intake when the patient has GI
malabsorption.

8. Disadvantages
 Needs hospitalization, costly.
 Infection
 Pyrogenic reaction.
 Discomfort, and poor patient
compliance.
 Fluid overload- chance.

9. IV Fluids
 The majority of an IV solution is sterile water.
 Solvent and solute
 Solvent is water
 Solutes can be molecules called electrolytes
or other large compounds such as proteins or
molecules.

10. Intravenous Fluids
 IV fluids come in three different forms
 Colloids
 Crystalloids
 Blood and blood products

11. Colloidal Solutions
 Colloid solutions are IV fluids containing large
proteins and molecules that tend to stay
within the vascular space (blood vessels).
 They shift the fluids from the interstitial to the
intravascular compartment
 Colloids are useful in maintaining blood
volume.
 Colloids are expensive, have specific storage
requirements, and have a short shelf life.
 Commonly used colloids include plasma
proteins, salt-poor albumin, and dextran.

12. Crystalloid Solution
 Crystalloid solutions are primarily fluids used
for IV therapy.
 Contains electrolytes but lacks the large
proteins and molecules found in colloids.
 Crystalloids come in different preparations
and are classified according to their “tonicity”.
 A crystalloid’s tonicity describes the
concentration of electrolytes dissolved in
water, as compared with that of body plasma.

13. Blood and Blood Products
 When PCV decreases then there is a need of
blood transfusion. In severe anemia: where
there is extreme depletion of oxygen carrying
capacity of the blood occurs & life is
threatened.
 PCV between 10 & 15% will benefit from a
transfusion.
 Normal PCV of Ruminants is 24-46% and of
equines 32-48%.

14. Isotonic Solutions
 Tonicity equal to plasma
 Even distribution between intravascular space
and plasma.
 5% dextrose
 Lactated ringer
 Normal saline

15. Hypotonic Solutions
 Tonicity lower than body plasma
 Shift from intravascular space to
extravascular space and then to cell.
 0.45% NaCl
 Used for dehydration

16. Hypertonic Solutions
 Tonicity higher than body plasma
 Cause the water to shift from extravascular
space into the bloodstream, increasing
intravascular volume.
 5% dextrose in 0.45% NaCl

17. Dehydration

18. Types of dehydration
Isotonic
Dehydration
Hypotonic
Dehydration
Hypertonic
Dehydration

19. Commonly Used Fluids
 Normal Saline
 Dextrose Saline
 Balanced Electrolyte Solutions
 Sodium Bicarbonate Solution
 Mixture of KCl and Dextrose Saline
 Dextrose Solution
 Plasma Expanders
 Mannitol 20%

20. Normal Saline
Composition
Indications:
Expand Blood
Circulating Volume
Severe Sweating
Pyloric obstruction
Abomasal disorder
Vomiting

21. How N/S helps in the Expansion of
Blood Volume
Fluid
therapy
with N/S
Increase stroke volume
due to increased
diastolic and decreased
systolic volume
Decreased
Blood
viscosity
Decreased vascular
resistance/expansion of
volume
N/S is isotonic with blood composition. Insert a
308mosmol/liter pressure.
Na is the main electrolyte of extracellular
fluids, integral in the distribution of fluids and
other electrolytes.
Chloride ion is 2nd
most important ion, and
serves as a buffering agent in lungs and
tissues. Helps to bind CO2and O2 to
hemoglobin

22. • NaCl is mild acidifying as effective.
• Has little merit in routine treatment of
ruminants, as ruminants develop
hypokalemia and hypocalcemia when
inappetent.
• Can act as a vehicle for adding other
electrolytes and dextrose.

23. Contraindications to the Use of N/S
 Impaired Kidney Functions
 Congestive heart failure, can lead to
pulmonary edema
 If infused in too large quantities can lead to
net acidosis

24. Dextrose Saline
Composition
Indications
Indications
Sodium Chloride
0.9%
Dextrose 5%
Dehydration
Vomiting
Heat Stroke
Mild Diarrhoea

25. • Dextrose injected parenterally oxidized to
carbon dioxide and water. Sodium chloride
provides sodium and chlorine.
• Used in mild diarrhea as in this case loss of
sodium ions occurs. Na is the principal cation
of extracellular fluid

26. Balanced Electrolyte Solutions
Ringer’s Solution
Mildly acidifying isotonic
solution.
Composition:
NaCl 0.9g, KCl 0.03g, CaCl2
0.03g, Distilled water 100mL
Indications:
• Dehydration
• Alkalosis
• Electrolyte loses
Lactated Ringer’s Solution
Alkalinizing hypotonic solution.
Composition:
NaCl 0.6g, KCl 0.03g, CaCl2
0.02g, sodium Lactate 0.31g
(D- and L- lactate), DW 100mL
Indications:
Mild to moderate acidosis with
dehydration

27. Mechanism of Action of Ringer
Solution
 SID ( Effective strong ion difference): it is the strong
difference between the cation and strong anion
concentration after metabolized anions have been
completely metabolized to produce bicarbonate. Solutions
having SID greater than 27mEq/L are alkalinizing. Solutions
having SID=0 are acidifying.
 Ringer solution SID= 0mEq/L. so acidifying in nature.
 Adult ruminants tend to get alkalemic when inappetent so
this solution will be preferred.
 As containing major electrolytes required by the body so
helps in electrolyte balance.
 Helps in rehydration as containing sodium helps in the
expansion of blood volume.

28. Mechanism of action of Lactated Ringer
Solution
 Osmolality 275 mOsmol/L.
 It is alkalinizing as lactate metabolizes into
bicarbonate ion.
 Standard intravenous solution for neonates
and horses, as these become acidemic when
inappetent.

29. Sodium Bicarbonate Solution
Sodium bicarbonate
Composition:
1.3% isotonic solution of
sodium bicarbonate
Indications:
Acidosis
Sodium bicarbonate
Composition:
5% Hypertonic Solution of
sodium bicarbonate
Indications:
Severe Acidosis

30. Sodium bicarbonate solution mechanism of
action
• Alkalinizing serum indirectly
causes a moment of
potassium into cells via an
H+/K+ exchange mechanism.
Administration of
sodium
bicarbonate
Increase plasma
bicarbonate level
Buffer excess H+
concentration
Raise in solution
pH

31. Mixture of Isotonic KCl (1.1%)
and Dextrose saline
Indications:
Alkalosis
Indications:
• Parenteral nutrition
• Liver disorder
• Hypoproteinemia
• Extensive burns
Amino acid solution

32.  Amino acids help in the synthesis of protein.
 In the liver amino acids help in detoxification.
 Amino acids are building blocks of proteins.
 In the case of burn inflammatory mediators
such as cytokines release results in
vasodilation due to which edema develops. So
amino acids as building blocks of protein help
to keep fluid in vessel and prevent edema
formation.

33. Dextrose Solutions
Dextrose 5%
• Isotonic solution
Indications:
• High fever
• starvation
• decreased water intake
Dextrose 20%, 25%
• Hypertonic solution
Indications:
• Parenteral nutrition
• Ketosis
• Hypoglycemia

34.  Dextrose 5% only purpose is to supply free
water.
 Dextrose 25% or 50% provides glucose (a
carbohydrate), which acts as a source of
energy.

35. Plasma Expander
Dextran
70mL, 500mL
How to use?
Dextran 6% in normal saline/ 5%
dextrose
Dose: 10-20mL/kg/day IV
Indications:
• Shock
• Haemorrhage
• Burns
• Endotoxic shock
Haemacel
500mL
Composition:
Polymer form degraded gelatin
3.5% + Electrolytes Na+ K+Ca+Cl
Indications:
• Hypovolemic Shock
• Haemorrhage
• Burn
• Endotoxic Shock

36. Dextran
 High molecular weight glucose
polymers formed by fermentation
of sucrose.
 As mol. Wt. is similar to albumin
therefore limiting diffusion into
interstitial spaces. Results in
increased oncotic pressure in
blood vessels, due to which fluid
stays in vessels.
 Act as a plasma volume expander
in contrast to crystalloids, which
expand extracellular fluid volume.
Haemacel
• Shorter plasma half
life than dextran

37. Mannitol 20%
Indications:
Cerebral Edema
Dose:
0.5g/kg IV

38. Mechanism of action of mannitol
• It elevates blood plasma osmolality, resulting
in enhanced flow of water from tissues,
including the brain and cerebrospinal fluids,
into interstitial fluids and plasma.

39. Fluid Calculations
• Replacement = % Dehydration x Bodyweight (kg) x 10
• Ongoing losses = Amount per loss (ml/kg) x Bodyweight
(kg) x No. of losses
• Example of overall fluid requirements for 50kg calf:
• 10 percent dehydration will result in a deficit of 50 × 0.10
= 5 liters
• Maintenance fluids for a calf = 50ml/kg/day = 2.5 liters
• Ongoing losses approximately = 80mls/kg/day = 4 liters
• Total fluid volume required over 24 hours = 5 + 2.5 + 4 =
11.5 liters

40. Serum calculations by taking FMD
as an example
 1500g IgG’s required to produce enough immunity
against FMD.
 If IgG’s checked in serum of a donor cow, found to be
25g then how much blood will be transfused to
produce immunity.
 25g IgG’s in serum= 1mL serum
 1g IgG’s in how much serum= 1/25
 1500 IgG’s in how much serum=1/25*1500=60mL
 Serum is almost 50% of whole blood so 120mL blood
will be infused.

41. Blood transfusion calculations
 Total Volume Infused= ([Patient PCV-Minimum
PCV]/Patient PCV)*Blood Volume
 Blood Volume is 7-9% of body weight.