Introduction to fluid therapy

Question 1

Underdose vs overdose of fluid therapy

Answer 1

Underdose: ineffective
Overdose: SE, hypervolaemia, even fatal complications

Question 2

Goal of fluid therapy

Answer 2

• treat hypovolaemia
• treat dehydration
• maintain tissue perfusion
• correct electrolyte imbalance
• correct acid-base disorders

Question 3

Intravascular volume of cat and dos

Answer 3

Cat: 60-65 ml/kg
Dog: 80-90 ml/kg

Question 4

Average fluid intake

Answer 4

40-60 ml/kg/day

Question 5

Fluid loss through…

Answer 5

Physiological: urine, feces, panting, evaporation
Pathological: vomitus, salivation, diarrhoea, polyuria

Question 6

What questions to answer when applying fluid therapy?

Answer 6

1. What kind of infusion?
2. How much?
3. How fast?

Question 7

4 most common situations of fluid state

Answer 7

Question 8

Examination of the fluid homeostasis

Answer 8

Physical exam: dehydration and perfusion parameters
Simple lab tests: PCV, TP, USG
Body weight measurement

Question 9

Hypovolaemia

Answer 9

Colour of mm: pale
CRT: > 2 sec
Heart rate: >140/min, cat: bradycardia
Pulse quality: weak
Venous return: decreased (>2sec)
Temperature of extremities: cold
Mental status: decreased
BP: low

Question 10

Dehydration

Answer 10

Grade of the dehydration in the % of BW
- <5% - can’t be detected
- 5-6% - tacky mm
- 6-8% - decreased skin turgor, dry mm
- 8-10% - +enophtalmus
- 10-12% - persistent skin tenting, cloudy cornea, hypovolemia
- >12% - hypovolaemic shock and death

Question 11

Classification of their infusion

Answer 11

1. Crystalloid - small molecular weight compounds
   - isotonic: 0,9% NaCl (saline), Ringer, Lactated Ringer, Sterofundin
   - hypotonic: sterofundin B, 5%glucose, 0,45% NaCl, Rindex
   - hypertonic: NaCl 10%
2. Colloid - large molecular weight compounds
   - synthetic: starch (HAES), gelatine
   - natural: human albumin, blood products (plasma, blood)

Question 12

Infusion choice

Answer 12

Hypovolaemia, dehydration -> isotonic crystalloids
Bleeding -> packed RBC + plasma; whole blood
Hypoproteinaemia -> natural or synthetic colloid

Question 13

The ROSE model

Answer 13

Resuscitation: quickly, IV or IO, boluses
1. Mini bonus 3-5 ml/kg in 1 min
2. Bonus 20 ml/kg in 15-20 min
The goal is: to normalise the vital signs nit to administer certain amount of fluid

Optimisation: reserculation of water to important organs

Stabilisation: enough of fluid but loss still can happen (e.g. diarrhea) - so called maintenance dose

Question 14

First choice in shock

Answer 14

ISOTONIC CRYSTALLOIDS (RiLac)

to normalise the vital signs

Question 15

Other forms of shock (signs)

Answer 15

1. distributive shock
septic shock:
- vasoplegia: red mm, CRT < 1sec
- warm extremities/skin
- severe hypotension
- peripheral edema (vascular leakage)

Anaphylactic shock: vaccination reaction

2. Obstructive shock - decompression
Gastric dilatation and volvulus -> v.cava compression; cardiac tamponade

3. Cardiogenic shock
FLUID THERAPY IS CONTRAINDICATED

Question 16

In what type of shock fluid therapy is contraindicated?

Answer 16

Cardiogenic shock

Question 17

Rehydration

Answer 17

• over 6-24 (-48) hours
• isotonic crystalloids (lactated ringer solution - 1st choice)

Deficit (ml) = kg x dehydratoin% x 10
Take into consideration lean body mass:
Fat: 0,7xkg
Normal: 0,8xkg
Thin: 1xkg

Question 18

Maintenance therapy

Answer 18

• daily fluid needed if no drinking/eating
• replacement of daily compulsory fluid loss
• does not cover caloric needs
• sterofundin B, LRS+KCl
• RER (resting energy requirement) 1kcal =1 ml
• 30-50 ml/kg/day
• 2-3 ml/kg/hour

Question 19

Side effects of fluid therapy

Answer 19

• cerebral oedema (impaired cognition, delirium)
• pulmonary oedema (impaired gas exchange, reduced compliance, laboured breathing)
• myocardial oedema (conduction disturbance, impaired contractility, diastolic dysfunction)
• increased renal venous pressure (renal interstitial oedema) - (reduced RBF, increases interstitial pressure, reduced GFR, uremia, salt and water retention)
• hepatic congestion (impaired synthetic function, choleastasis)
• gut oedema (malabsorption, ileus)
• tissue oedema (impaired lymphatic drainage, microcirculatory derangements) - (poor wound healing, wound infection, pressure ulceration)