Introduction to fluid therapy Flashcards
Underdose vs overdose of fluid therapy
Underdose: ineffective
Overdose: SE, hypervolaemia, even fatal complications
Goal of fluid therapy
- treat hypovolaemia
- treat dehydration
- maintain tissue perfusion
- correct electrolyte imbalance
- correct acid-base disorders
Intravascular volume of cat and dos
Cat: 60-65 ml/kg
Dog: 80-90 ml/kg
Average fluid intake
40-60 ml/kg/day
Fluid loss through…
Physiological: urine, feces, panting, evaporation
Pathological: vomitus, salivation, diarrhoea, polyuria
What questions to answer when applying fluid therapy?
- What kind of infusion?
- How much?
- How fast?
4 most common situations of fluid state
Examination of the fluid homeostasis
Physical exam: dehydration and perfusion parameters
Simple lab tests: PCV, TP, USG
Body weight measurement
Hypovolaemia
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
Dehydration
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
Classification of their infusion
- 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% - Colloid - large molecular weight compounds
- synthetic: starch (HAES), gelatine
- natural: human albumin, blood products (plasma, blood)
Infusion choice
Hypovolaemia, dehydration -> isotonic crystalloids
Bleeding -> packed RBC + plasma; whole blood
Hypoproteinaemia -> natural or synthetic colloid
The ROSE model
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
First choice in shock
ISOTONIC CRYSTALLOIDS (RiLac)
to normalise the vital signs
Other forms of shock (signs)
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
In what type of shock fluid therapy is contraindicated?
Cardiogenic shock
Rehydration
- 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
Maintenance therapy
- 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
Side effects of fluid therapy
- 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)
