Fluid therapy

Question 1

need for fluid therapy

Answer 1

Replacement of fluids “lost”

Maintenance of fluid “needs”

Question 2

ways to loose fluid

Answer 2

Blood loss 
Dehydration 
excessive urination 
Vomiting, diarrhoea 
Sequestered fluid (“third space”– in bowel, in cavities)

Question 3

“flushing things out”

Answer 3

azotaemia (pre-renal, renal, post-renal) may require fluid therapy as a means of increasing Glomerular Filtration Rate (GFR)
Animals intoxicated with water soluble substances may also benefit from fluid therapy

Question 4

whats in a fluid bag

Answer 4

Water
Electrolytes - Sodium, Chloride, Potassium, Magnessium, Calcium
± Buffers - Lactate, Citrate
± Dextrose

Question 5

Fluid Therapy to Deliver Nutrients

Answer 5

When animals cannot receive nutrition through the gastrointestinal tract (enteral nutrition) animals may be fed parenterally

Question 6

fluid types

Answer 6

Crystalloids

Colloids - Natural, Synthetic

Question 7

fluid tonicities

Answer 7

Isotonic
Hypertonic
Hypotonic

Question 8

Crystalloids - Components

Answer 8

Water + small molecules
Electrolytes - Sodium, Chloride, Potassium, Magnessium, Calcium
± Buffers - Lactate, Citrate
± Dextrose

Question 9

crystalloids

Answer 9

Most common used fluid in practice
Cheapest
Can be administered PO, IV, SQ, IO, IP
After administered, distributes equally amongst all fluid compartments - Only a third of volume remains intravascularly after equilibration
Complications only related to amounts of fluid used (too little/too much)

Question 10

Synthetic Colloids - Components

Answer 10

water + large molecules
electrolytes - sodium, chloride
+/- buffers - lactate, citrate

Question 11

Synthetic Colloids

Answer 11

Some form of colloid available in most practices
Can be rather expensive
Generates colloid osmotic pressure - This delays equilibration of fluid with other compartments, Useful for resuscitation of intravascular volume
Complications include fluid overload and coagulopathy
unavailable in UK
possible harm to patients – kidney injury mainly

Question 12

natural colloids

Answer 12

Blood products - Fresh whole blood, Packed red blood cells, Fresh frozen plasma
Concentrated albumin solutions

Question 13

parenteral nutrition

Answer 13

Mixture of amino acids solutions, dextrose, lipids (all crystalloids)
Provides energy and building blocks for protein synthesis

Question 14

Effects of Tonicity

Answer 14

Isotonic = same tonicity as blood
Hypertonic = much higher than blood
Hypotonic = less than blood
Tonicity determines distribution of fluid between compartments, i.e., tonicity is what can move fluids from one compartment to another

Question 15

Isotonic fluid administered IV - effect

Answer 15

fluid distributed equally amongst all compartments

Question 16

Hypertonic fluid administered IV - effect

Answer 16

Draws fluid from intracellular and interstitial compartments into intravascular compartmen

Question 17

Hypotonic fluid administered IV - effect

Answer 17

Fluid shifts to the intracellular compartment – cellular oedema

Question 18

isotonic crystalloid use

Answer 18

Rehydration 
Resuscitation – treatment of hypovolaemia 
Correction of acid/base electrolytes 
Deliver drugs 
Induce diuresis

Question 19

Considerations for colloid use

Answer 19

Require rapid resuscitation 
Want to increase COP 
Need resuscitative effect to last more than 1 hr 
Most colloids are isotonic 
Typically used when animal is oedematous

Question 20

hypertonic saline use

Answer 20

Not used very much
extremely rapid resuscitation 
Very effective! 
Patient has to be well hydrated for hypertonic saline to work 
Can be used to treat brain oedema 
Very small doses required

Question 21

mannitol

Answer 21

Most commonly used for brain oedema
Treatment for acute glaucoma
Sometimes used for oliguric renal failure
Osmotic diuretic – main effect is to shift fluid into the intravascular space to be excreted by the kidneys

Question 22

hypotonic fluid use

Answer 22

Not used very much at all
Supposed to be a true “maintenance fluid”
For short term use – only a few hours
Only really useful if you are treating extremely hypernatraemic patients
Nicknamed “Devil’s Fluid” - Causes too many complication with electrolytes and cellular oedema

Question 23

Parenteral Nutrition - Indications

Answer 23

Dysfunctional GI tract - vomiting, diarrhoea
Existing malnutrition or risk of becoming malnourished
contraindicated enteral feeding
Pancreatitis (?)
Unable to protect airway

Question 24

Total Parenteral Nutrition

Answer 24

Meets 100% of energy requirements 
Very hypertonic (hyperosmolar) 
Needs to be delivered via jugular catheters

Question 25

Partial or Peripheral Parenteral Nutrition

Answer 25

Only meets 40-70% of energy
Lower osmolarity
can be given peripherally

Question 26

parenteral nutrition in use

Answer 26

used in referral practices - Requires special expertise, equipment
Needs to be handled completely aseptically
Amino acids and dextrose ready to use
Meets 40-70% energy depending on case