Fluid Replacement Therapy and its applications

1. FLUID REPLACEMENT
THERAPY

2. 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 an:
• intravenous,
• intraperitoneal,
• oral and other routes.

3. Distribution of fluids in the body:

4. Types of fluid therapy:
• Replacement therapy: Fluid replacement or fluid
resuscitation is the medical practice of replenishing
bodily fluid lost through sweating, bleeding, fluid shifts
or other pathologic processes.
Fluids can be replaced with oral rehydration, intravenous
injection or the direct injection of fluid into the
subcutaneous tissue.
1. Supportive therapy: In this type of therapy, fluids
or injections are administered for supportive care of
animal e.g. B.complex inj., B12 inj, Vit. ADE inj.

5. 3. Adjunctive therapy:
This type of therapy is done to remove
unwanted fluid present in body at any site.
e.g. Mannitol solution(hypertonic) is
administered to remove edema fluid from the
body.

6. Fluid therapy serves to correct
• Dehydration
• Acidosis and alkalosis
• Electrolyte deficiencies
• Nutrition and calorie

7. Indications:
Hypovolemia
Hypotension
Electrolyte,
metabolic and
acid-base
disorders
Geriatric
patients at risk
of organ
failure
Decreased
oxygen
delivery

8. Special considerations:
Shock
Cardiac
diseases
Hepatic
diseases
Central
nervous
system
diseases
Anesthesia

9. Dehydration:
Clinical dehydration
Isotonic
dehydration
Hypotonic
dehydration
Hypertonic
dehydration

10. Conditions causing fluid loss:
• Many conditions may cause rapid and continued fluid losses
and lead to dehydration:
• Fever, heat exposure, and too much exercise.
• Vomiting, diarrhea, and increased urination due to infection
• Diseases such as diabetes
• The inability to seek appropriate water and food (as in the
case of a disabled person)
• An impaired ability to drink (for instance, someone in
a coma or on a respirator)
• No access to safe drinking water
• Significant injuries to skin, such as burns or mouth sores, or
severe skin diseases or infections (water is lost through the
damaged skin)

11. Signs and Symptoms of dehydration:
• The signs and symptoms of dehydration range from
• Increased thirst
• Dry mouth and swollen tongue
• Weakness
• Dizziness
• Palpitations (feeling that the heart is jumping or pounding)
• Confusion
• Sluggishness fainting
• Fainting
• Inability to sweat
• Decreased urine output
• Urine color may indicate dehydration. If urine is concentrated
and deeply yellow or amber, you may be dehydrated.

12. The General Symptoms of
Dehydration:
• Sunken eyes
• Lethargy
• Loss of appetite
• Dry mouth
• Depression

13. Signs of Dehydration
• <5%
• No clinical signs

14. Signs of Dehydration
• 5-6% = “mild dehydration”:
• Tacky mucous membranes
• Slight skin tint

15. Signs of Dehydration
• 7-8% = “moderate dehydration”
• Dry mucous membranes
• Skin tint
• CRT 2-3 sec
• Slight depression of eyes into
sockets

16. Signs of Dehydration
• 10-12% = “severe dehydration”
• Severe skin tint
• CRT >3 sec
• Markedly sunken eyeballs
• Cold extremities
• +/- shock

17. Signs of Dehydration
• 12-15% obvious shock, imminent death.

18. Types of dehydration with clinical
manifestations
Parameters Isotonic Hypertonic Hypotonic
Mucous
membranes
Dry Perched Clammy (stickily
moist)
Eye ball Sunken Sunken Sunken
Temporal fossa Sunken Sunken Sunken
Demeanour Lethargic Hyper irritable Comatosed
Skin Dry Dry Dry
Turgor Poor Fair Very poor
Muzzle Dry Dry Dry

20. General indications:
• Loss of fluid from compartment
• Severity(Dehydration status)
• Laboratory results
• Symptoms

21. Types of fluids:
Crystalloids are able to
enter all body
compartments.
Colloids are restricted
to the plasma
compartment.

22. Crystalloids:
 Ringer lactate
 Normal saline 0.45%,0.9%,7%
 Dextrose 2.5%,5%,10%,20%
 Hartmann’s solution
 Plasmalayte

23. Colloids:
 Dextrans
 Hydroxy ethyl starch (HES)
 Canine albumin
 Stroma free hemoglobin

24. Selection of fluids:
• Fluids must be administered that will concentrate
within the body fluid compartment where the volume
deficit lies.
• Crystalloids are water-based solutions with small-
molecular-weight particles, freely permeable to the
capillary “membrane.”
• Colloids are water-based solutions with a molecular
weight too large to freely pass across the capillary
“membrane.”

26. Crystalloids:
 The small-molecular-weight particles in crystalloids are
primarily electrolytes and buffers .Intravascular administration
of isotonic crystalloids (e.g. lactated Ringer's, 0.9% saline)
will result in interstitial volume replacement and minimal
intracellular fluid accumulation.
 Hypotonic fluids (e.g.5% dextrose in water, saline) will result
in intracellular water accumulation and should not be used as
resuscitation fluids.
 Hypertonic solutions (e.g. 7% NaCl) contain higher
concentrations of sodium and are best used when hydration is
normal and concurrently with other fluids.

27. Colloids:
When colloids are to be administered, it must
be decided whether a natural colloid (e.g.,
plasma, albumin, or whole blood) or a
synthetic colloid(HES, dextran) is to be used.
 When the animal requires RBCs, clotting
factors, anti-thrombin III, or albumin, blood
products are the colloids of choice.

28. Administration Routes
• Oral
– If the stomach works,
use it!
– Safest route if tolerated

29. Administration Routes
• Subcutaneous
– Works well in most animal
– Sometimes need to use
multiple sites
– Can’t add glucose, large
quantity KCl, or some drugs
– No MICRO drip for SQ

30. Administration Routes
• Intravenous
– Best route in dehydrated animals
– Possible problems:
• Volume overload
• Catheter reactions (swelling, fever)
–24-hour maintenance

31. INTRAOSSEOUS
• If situation is dire and no vein accessible
• Into the medullary (bone marrow) cavity of
long bones
– Femur or Humerus are commonly used
• Used frequently in birds

32. IV Catheters
• Size: In GAUGES like needles
– Smaller = BIGGER
• Types:
– Cephalic
• How long in?
– Jugular
• How long in?
• Other Advantages?

33. So How Is It Delivered?
• Infusion pump (easy)
• IV drip set: drops per ml written on
package
• Regular Drip sets have 10, 15, or 20
drops per ml
– Med – large dogs
• Micro drip sets have 60 drops per
ml
– Small dogs - cats

34. When to use which solution?
 Hypotonic saline fluids such as 0.45% sodium
chloride solution
expand the intracellular compartment
hypertonic dehydration, gastric fluid loss, and cellular
dehydration from excessive diuresis.

35. Cont……
 Isotonic saline fluids 0.9% sodium chloride solution
 expand the extracellular compartment
 circulatory insufficiency, replenish sodium and
chloride losses, treat diabetic ketoacidosis, replenish
fluids in the early treatment of burns and adrenal
insufficiency.
 Because their osmolality is similar to that of blood,
they're also the standard flush solutions used with
blood transfusions.

36. Cont….
 Hypertonic saline fluids 5% dextrose in 0.9% sodium
chloride solution
 are used cautiously to treat severe hyponatremia.

37. Precautions:
 Closely monitor the patient for complications, such
as electrolyte imbalances, calorie depletion, and
increased intracranial pressure (ICP).
 Because hypertonic fluids pull water from the
intracellular space into the extracellular space, fluid
volume and ICP can increase. Watch for fluid
overload in patients with a history of heart failure or
hypertension.

38. Electrolyte replacement fluids
• Ringer's solution: isotonic fluids containing electrolytes in the
same concentrations found in plasma.
• However, these solutions don't contain magnesium and
phosphorus, which shouldn't be routinely given.
• The exact electrolyte content depends on the fluid
manufacturer. Ringer's injection and lactated Ringer's solution,
the two most common electrolyte fluids, contain potassium,
sodium, chloride, and calcium. Lactate, added as a buffer to
produce bicarbonate, is contraindicated in patients with liver
disease because they can't metabolize it.

39. • Electrolyte fluids provide hydration and electrolytes for
patients who can't take in food or fluid orally and for those
who've experienced abnormally high fluid losses from severe
vomiting, diarrhoea or diuresis.
• Lactated Ringer's solution is also used for volume
replacement in patients with third-spacing.
• 5% dextrose may be mixed with the electrolyte fluid to
provide energy, keep in mind that the resulting solution is
hypertonic.

40. Precautions:
• Precautions: These fluids generally aren't
given for more than 48 hours (unless the
patient's condition is unchanged) because of
the risk of over-hydration, hypernatremia,
hyperkalemia, metabolic alkalosis, and calorie
depletion if the fluid isn't mixed with dextrose.

41. Standard shock rate:
• For crystalloid solution is 80 to 90 ml/kg for a dog and 40 to
60 ml/kg for a cat, and it is normally given in increments
(e.g. one-third, one-half) of the calculated amount over a
period of 10 to 30 minutes.
• For colloid solution is 10 to 20 ml/kg for dogs and 5 to 10
ml/kg for cats.
• The amount of crystalloids administered with colloids must be
reduced by 40%–60% of what would be administered if
crystalloids were used alone.

42. Fluid rate calculation:

43. Replacement:
 Replacements are calculated based on the level of
dehydration. To calculate the amount required for
replacement within a 24 hour period, the percentage
dehydration is used in the following calculation.
Replacement = % Dehydration x Bodyweight
(kg)

44. Maintenance:
 Maintenance is the basic rate which a patient
requires during a 24 hour period.
50ml/kg/24hr, or 2ml/kg/hr.

45. Ongoing losses:
 Ongoing losses are calculated based on a
predicted fluid amount lost by a patient within a 24
hour period.
 To calculate the fluid requirement, the following
calculation is used.
Ongoing losses = Amount per loss (ml/kg) xbody weight

46. Example:
 Fluid replacement in a dog weighing 25kg.
 Replacement= %dehydration*body weight
=5% * 25kg
=1.25 liter or kg
 Maintenance= 2ml/kg/hr
For 25kg: 50ml/hr or 1250ml/24hrs
 total required volume= 1250ml+1250ml= 2500ml/24hrs

47. Requirements
 Requirement per hour (ml/hr) = Requirement per
day (ml/24hr) ÷ 24
 Requirement per minute (ml/min) = Requirement
per hour (ml/hr) ÷ 60
 Requirement per second (ml/s)= Requirement per
minute(ml/min) ÷ 60
 Drops per second = Requirement per second
(ml/s)x Giving Set Factor

48. Calculation of drops per minute:
Drops per minute= total volume to be given(ml) drop factor
time(min) 1
• Commonly used drop factor are 10 drops/ml (blood set), 15
drops / ml (regular set), 60 drops / ml (microdrop).
1500 (ml) X 15 (gttss / ml)
----------------------------------
12 x 60 (gives us total
minutes)
= 31 gtts / minute
Example:
1500 ml IV Saline is ordered over 12 hours. Using a drop factor
of 15 drops / ml, how many drops per minute need to be
delivered?

49. Clinical conditions:
I. Hyponatraemia: ( serum conc of Na+ < 140mEq/L in dogs)
II. Hypernatraemia: ( dogs Na+ > 155mEq/L & cats > 160mEq/L
)
III. Hypochloremia: ( excessive loss/sequestration of fluids)
IV. Hyperchloremia: (hypernatremic animals due to loss of free
H2O)
V. Hypokalemia: ( serum K+ conc < 3.5mEq/L )
VI. Hyperkalemia: ( serum K+ conc > 6 mEq/L )
VII. Hypocalcemia: ( total serum Ca+ < 10-11mg/dL dogs )
VIII. Hypophosphatemia: ( post-parturient Haemoglobinuria )
IX. Hypomagnesaemia: (plasma level of Mg++ < 1.5-2.5 mEq/L )

50. Clinical observation during fluid
therapy
• Until urine flow restored rate will be parallel to
severity of dehydration, first rapidly then slowly.
• First hour ; 15 ml – 20 ml / kg body weight / hour.
• Second hour ; 10ml/kg body weight /hour
continuously.
• If no urine is voided within 1 hour reduce to rate of
fluid approximately half the quantity.
• Clinical observation is very important during the
administration of fluids.

51. Monitoring fluid therapy:
Urine output
Total protein
Skin turgor
PCV
Blood pressure
Mucous membrane color
Edema

52. Drug contraindications:
 Do not mix sulpha drugs with calcium and dextrose solutions.
 Do not mix oxytetracycline with calcium solutions.
 Try to avoid mixing of too many drugs in fluids.
 Do not mix chloramphenicol with vitamin B complex to the
solutions.

53. References:
 http://www.merckmanuals.com/vet/emergency_medi
cine_and_critical_care/fluid_therapy/the_fluid_resus
citation_plan.html
 http://en.wikivet.net/Principles_of_Fluid_Therapy
 http://veterinaryteam.dvm360.com/fluid-therapy-
calculating-rate-and-choosing-correct-solution
 Textbook of veterinary clinical medicine