Fluid therapy according to dehydration status

1. Fluid Therapy in Canines
Dr. Punit Jhandai
Department of Veterinary Public Health
and Epidemiology, LUVAS, HISAR

2. Why Give Fluids…
• Correct dehydration(best route IV)
• Correct acid-base abnormalities d/t disease
• Correct electrolyte abnormalities
• Deliver drugs in a constant-rate infusion
• Prevent dehydration (GI disease)
• Diuresis (renal disease, toxicities)

3. Why Give Fluids During Surgery?
• Number one reason:
• Prevent hypotension:
– Blood loss
– Evaporative fluid losses
• Maintenance during surgery 10 ml/kg/hr

4. Assessment of dehydration
Mild Moderate Severe
Skin Good Elasticity Decreased No Elasticity
Eyes Slightly sunken
Bright
Slightly sunken
Duller
Sunken Deeply
Dry Cornea
Mouth Moist, Warm Sticky and Dry Dry, Cold and
Cyanotic
Body Wt
Decreases
4-6% 8% 10%
12-15% obvious shock, imminent death.

5. Diagnosing Dehydration
• Physical exam
• Weight loss
• PCV
– INCREASED
• albumin or total protein
– INCREASED
• BUN, creatinine
– INCREASED

6. Fluids: How Much to Give?
• Correct dehydration
• Weight in kg times percent dehydration
equals the amount in liters that the animal
is dehydrated
• Example: 10 kg animal who is 8% dehydrated
• 10kg X 0.08 = 0.8 liters
• Patient is lacking 0.8 liters, or 800 ml fluids

7. Principles of Rehydration
Do not attempt to replace chronic fluid losses all at
once
– Severe dilution of plasma proteins, blood cells and
electrolytes may result
• Aim for 80% rehydration within 24 hours
• Monitor pulmonary, renal and cardiac function
closely

8. Types of Fluids
1. Crystalloid 2. Colloids
* Isotonic- 0.9% sodium chloride (0.9% NaCl)
Lactated Ringer's solution
5% dextrose in water (D5W)
Ringer's solution
* Hypotonic- 0.45% sodium chloride (0.45% NaCl), 0.33% sodium
chloride, 0.2% sodium chloride, and 2.5% dextrose in water
* Hypertonic- 3% sodium chloride (3% NaCl)

9. Saline
• 0.9% Sodium chloride = ISOTONIC
• Lacking in K+, Ca2+
• Used for metabolic acidosis, hyperkalemia,
hypercalcemia
• Used as a carrier for some drugs
• As it replace extracellular fluid,
it s/b used cautiously in patient
those with cardiac or renal disease
for fear of fluid volume overload.

10. Lactated Ringer’s Solution
• Used to replace GI tract fluid losses, loss due to burns and
trauma and when acute blood loss or hypovolemia due to
third space fluid shifts.
• LR s/n/b given to patient with liver disease as they cant
metabolize lactate, used cautiously in patient with severe
renal impairment because it contain some potassium.
• Also contains lactate, which is metabolized by the liver
alkaline-forming
– Because small animals that are sick or under
anesthesia tend towards acidosis

11. Ringer’s Solution
• Same as LRS except no lactate added
• Commonly used in Large animals
• Why?
– Large animals who are sick tend towards
alkalosis instead of acidosis

12. Dextrose Solutions
• 5% dextrose is isotonic
• Used for hypoglycemia, provide 170
calories per lt but doesn’t replace
electrolyte.
• It is not good for patient with renal failure
or cardiac problems since it cause fluid
overload.

13. Hypotonic Fluids
• Hypotonic solutions have a lower concentration of solutes
(electrolytes). And osmolality less than 250 mOsm/L .
• 0.45% sodium chloride (0.45% NaCl), 0.33% sodium chloride, 0.2%
sodium chloride, and 2.5% dextrose in water
• Hypotonic fluids are used to treat patients with conditions causing
intracellular dehydration, when fluid needs to be shifted into the
cell , such as:
1. Hypernatremia
2. Diabetic ketoacidosis
3. Hyperosmolar hyperglycemic state.

14. Hypotonic Fluids
Precautions with hypotonic solutions
 Never give hypotonic solutions to patients who
are at risk for increased ICP because it may
exacerbate cerebral edema
 Don't use hypotonic solutions in patients with
liver disease, trauma, or burns due to the
potential for depletion of intravascular fluid
volume

15. Hypertonic Fluids
• Solution that have a higher tonicity or solute
concentration. Hypertonic fluids have an osmolarity of
375 mOsm/L or higher
• The osmotic pressure gradient draws water out of the
intracellular space, increasing extracellular volume so
they are used as volume expanders.

16. Hypertonic Fluids
Some examples and Indications:
1- 3% sodium chloride (3% NaCl):
• May be prescribed for patients in critical situations of severe
hyponatremia.
• Patients with cerebral edema may benefit from an infusion of
hypertonic sodium chloride
2- 5% Dextrose with normal saline (D5NS): which replaces sodium,
chloride and some calories.
Maintain vigilance when administering hypertonic saline solutions
because of their potential for causing intravascular fluid volume
overload and pulmonary edema.

17. Natural Colloids
• Blood products:
– Whole blood
– Plasma
– Platelet-rich plasma
– Packed RBC’s
– “Parvo serum”

18. Synthetic Colloids
• Dextrans, Hetastarch
• Used when quantity of a crystalloid is too
great to be able to infuse quickly
• Stays within the vasculature maintain
blood pressure
• They mainly administered in shock
• More effective in maintaining intravascular
volume.

19. Fluid therapy in Hypovolemic shock
• Fluid to be Avoided- 5% dextrose(risk of hyponatremia,
ineffective in raising BP, hyperglycemia, osmotic diuresis)
• Most preferred fluids- Isotonic saline(correct hypotension
effectively)
Ringer’s Lactate(Composition
similar to extracellular fluid so large volume can be infused without fear of
electrolyte imbalance)
• Colloid, albumin, blood products most effective
agents.(these agents are distributed in intravascular compartment, so they
correct hypotension most effectively with least volume)

20. Fluid therapy in Diarrhea
• As diarrheal fluid is rich in sodium, bicarbonate
and potassium, diarrhea leads to hypokalemic
hyperchloremic acidosis with dehydration.
• Ringer lactate is most preferred IV fluid to correct
dehydration, lactate content of RL converted into
bicarbonate by liver.

21. Fluid therapy in Vomiting
• Vomiting leads to hypokalemic
hypochloremic alkalosis with dehydration.
• Most preferred IV fluid to correct
dehydration due to vomiting is isotonic
saline(prevent further loss of potassium).

22. Parameters to be monitored during fluid
therapy
• Cause and pathogenesis of dehydration.
• Mechanism of fluid and electrolyte balance.
• Blood parameter like PCV and total protein.
• Urinary output.
• Normal bronchovesicular lung sound on auscultation.

23. Ringer Lactate preferred to correct deficit due to diarrhea, is
detrimental in vomiting, as it aggravates metabolic alkalosis
so we give NS in this case.