Fluid Therapy

Question 1

What are the bodies fluid compartments?

Answer 1

Question 2

Discuss whole blood loss?

Answer 2

Possible causes: severed superficial arteries or large veins.

Compartment lost from: intravascular
compartment.

Components of fluid lost: water,
colloidal particles, red cells and electrolytes, platelets, clotting
factors etc.

Question 3

Discuss extracellular fluid losses?

Answer 3

Possible causes: Diarrhoea, diuresis,
sweating, “3rd space losses”

Compartment lost from: Interstitial
compartment and intravascular
compartment

Components in fluid lost: Na+, Cl- and water

Question 4

Discuss protein rich extracellular fluid losses?

Answer 4

Possible causes: Some pleural/peritoneal
effusions, G.I. sequestration, protein losing enteropathies, burns.

Compartment fluid lost from: interstitial
compartment and intravascular
compartment

Components in fluid loss: Na+, Cl-, water and
proteins!

Question 5

Discuss Pure water fluid losses?

Answer 5

Possible causes for loss e.g. high respiratory
rate or primary water deprivation

Compartments losses from: as pure water
loss as water moves freely across all
compartments, water is lost from all
compartments
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Question 6

What is the maintenance rate for cats and dogs?

Answer 6

*50ml/kg/day or 2ml/kg/hr (3-3.5 in cats)

Should provide water and electrolytes
*Na+
*Cl-
*K+

Question 7

Discuss colloid fluids and what they’re for?

Answer 7

*Colloids are fluids in which large molecular
weight particles are suspended but not visible.
*Colloids contain large molecules that cannot
pass through the vascular endothelium
*They increase the colloid osmotic pressure of
the plasma, they also ‘pull’ water from the
interstitial space into the intra vascular space
*Make sure you pay back the fluid

Question 8

What are natural colloids?

Answer 8

Natural colloids
*Plasma
*Albumin preparations
*Whole blood

Question 9

What are some artificial colloids?

Answer 9

*Starches
*Gelofusin
*Dextrans

Question 10

What should be considered when calculation IVFT?

Answer 10

If replacing loss….
– Think what type of fluid has been lost
– Think how much fluid has been lost
– Think how quickly that fluid has been lost
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Question 11

What are maintenance fluids?

Answer 11

Amount of fluid an animal needs to match its normal losses

Question 12

What are the objective and subjective ways to measure dehydration?

Answer 12

Subjective tests:
skin turgor, mucous
membranes, sunkeness of eyes.

Objective tests; urea, pcv, total protein, USG,
sodium.

Put the clinical information together to get a picture of % dehydration.

Question 13

How can you correlate clinical signs to percentage dehydration?

Answer 13

Question 14

How do you calculate a fluid deficit?

Answer 14

*The % figure means the % of body weight
*So 10% dehydrated 20kg dog
=10/100 x 20 = 2kg =2,000g = 2,000ml
*This deficit should be addressed in the first 12-24 hours
*In more acute cases, can be addressed in 1-4
hours
*Remember to add on top the animals
‘maintenance’ rate

Question 15

Look at this example of calculating a fluid deficit?

Answer 15

*3kg cat off food and limited oral intake for 2
weeks
*Quiet but ambulatory
*Approx 10% dehydrated
*10/100 x 3 = 300g = 300ml fluid
*Maintenance 3.5ml/kg/hr over 24 hours = 252ml
*= 552ml over first 24 hours
*= 23 ml/hr

Question 16

How can you use fluids to manage hypotension under
anaesthesia?

Answer 16

Question 17

How much total blood volume do cats and dogs have?

Answer 17

*Dog = 90ml/kg total blood volume

*Cat = 56ml/kg total blood volume

Question 18

A fluid is termed hypertonic, isotonic, or hypotonic based on?

Answer 18

Higher, equal, or lower
concentrations of electrolytes (usually sodium) compared to normal plasma.

Hypotonic: Na+ concentration is lower than plasma

Isotonic: Na+ concentration is similar to plasma

Hypertonic: Na+ concentration is higher than plasma

Question 19

An animal’s maintenance requirement is defined as?

Answer 19

The amount of water and electrolytes
required to replace those lost through normal physiological processes, i.e. through respiration,
perspiration and excretion via the alimentary and urinary tracts.

Question 20

Discuss replacing blood loss with fluids?

Answer 20

Only one third of crystalloid fluid remains in the intravascular space after a time, the rest
will pass into the other fluid compartments. So remember that if you are using crystalloids
to replace small volumes of blood loss that you will therefore need to administer three
times to blood loss to be able to replace the intra-vascular volume. If you are using blood
or colloids however, they will remain in the intravascular space and so you only need to
give the equivalent fluid volume to the blood lost.