Fluid tx Flashcards
How is water divided up within the body?
1/3 intra vascular
- within this 1/4 intravascular, 3/4 interstitial
2/3 intracellular
- need change in Na to affect water movement here
What is Starlings law?
Balance of oncotic and hydrostatic pressure within and outside capillaries
Potential complications from too much fluid?
- pulmonary oedema
- interstitial oedema (subcut oedema, organs, v function)
- 3rd spacing
> clinics, signs - pulm crackles
- peripheral oedema
- chemosis of the eyes
- bilateral serous nasal discharge
- jugular distension, pulsation
- increase body weight (weigh 3x a day)
- large left atrium on us
Which patients are at risk of fluid overload?
- cardiac or pulmonary disease
- oliguric/anuric renal failure
- geriatric cats
- hypoalbumenaemia
- Sepsis/SIRS
How does Tx of shock and dehydration differ?
Shock intravascular Dehydration interstitial (NOT INTRACELLUALR)
Goals for Tx of shock?
- fluid bolts to fill intravascular space
- Tx until 6 perfusion parameters Normal
- care to not give too much (at risk patients)
- defo no more than one blood volume (80ml/kg dog, 50ml/kg cat)
- Tx underlying causes
5 questions to think about wrt IVFT?
- Type
- Dose/rate (dose shock, rate dehydration)
- Additive
- Delivery
- When to stop
Outline board fluid types LOOK UP
> crystalloid - isotonic (Hartmanns, CSL, LRS, 0.9% nacl) - hypertonic (7.5% NACl) - hypotonic (0.45% NaCl, 5% Dextrose) > colloid (high oncotic pressure) - synthetic (Volulyte) - Natural (blood products, albumin)
Which fluids do you not use for shock treatment?
HypOOO tonic
Which fluids are balanced and which are not?
- Hartmanns
- LRS
- CSL
> Na, K, Cl, Ca, Lactate
Which fluids are not balanced?
- 0.9% NaCl
- Na and Cl only
What are the 3 main substances in balanced crystalloid a (Hartmanns etc) ? Why are they there?
> lactate
- metabolised to bicarbonate
- tx metabolic acidosis (which occour in shock)
potassium
- Some worry about ^ K but doesn’t usually cause hyperkalaemia as diuresis causes ^ renal excretion
calcium
- BEWARE chelates with sodium citrate preservative in blood products so don’t give together
Indications for isotonic crystalloids
- all causes hypovolaemic shock
- obstructive shock (GDV)
- vasodilatory shock
- dehydration maintInance
- diuresis (azotaemia, toxicity)
- Tx metabolic acidosis (Hartmanns, CSL, LRS)
- Tx metabolic alkalosis (0.9% Nacl)
Dose isotonic crystalloids?
- dogs 10-20ml/kg IV
- cats 5-10ml/kg IV
> over 15 minutes
> repeat up to 4 times (monitor, if no improvement after 2 doses, STOP)
Indications for hypertonic saline
- traumatic brain injury (can occour with hypoxia in cardiac arrest)
- cerebral oedema
- large breed dog (^ intravascular space quicker)
- CPR
- used commonly in equine
Contraindications for hypertonic saline?
- hyper/hyponatraemia
- dehydration
Doses of hypertonic saline
2-4ml/kg over 10 minutes
- once ONLY
- follow with isotonic crystalloids
How do colloids work?
Prevent fluid leaving intravascular space (DO NOT DRAW WATER IN FROM INTERSTITIAL SPACE !!)
Indications for artificial colloids
- severe hypoproteinaemia
- large dog
Potential adverse effects/contraindications for artificial colloids?
- kidney injury or renal failure
- coagulopathy
- ^ risk fluid overload
- sepsis (^risk kidney injury)
Dose of artificial colloids
- dogs 5-10ml/kg over 15 mins
- cats 2.5-5 ml/kg over 15 mins
- repeat up to 4 times
How does delivery of fluids differ between species ?
- small dog (fluid pump)
- medium large dog (pressure bag)
- cats (careful!!! 50ml syringe, by hand, or syringe driver, or pump with paediatric burette)
What is the maintainance fluid rate?
- normal daily fluid requirement
- isotonic crystalloids
> 2ml/kg/hr
What are the 3 components of fluid therapy (ongoing)?
Maintainance + replacement (dehydration) + ongoing losses
What levels of dehydration are noticeable on clinical exam? LOOK UP
How can replacement fluid amounts be calculated?
Total amount in mls = (% dehydration / 100) X body weight (kg) X 1000
~ administer over 8-24 hours
Causes of ongoing losses?
- VD+
- 3rd spacing
- wounds
- PU
How can ongoing losses be measured?
- measure/weigh (VD+ urine)
Estimate (0.5-1.5x maintainance)
Indications for using hypotonic saline?
Tx hypernatraemia
NOT DEHYDRATION OR SHOCK
When may potassium chloride be added to fluids?
- hypokalaemia (VD+, PU)
- don’t exceed >0.5mmol/l/kg/hr
When would potassium phosphate be spiked?
Hypophosphataemia (diabetic ketocidosis)
When is dextrose added to fluids?
Hypoglycaemia
What should be remembered when using potassium spiked fluids?
Don’t bolus!! If animal goes into shock get new bag of CSL
Indications for IVFT
- shock
- dehydration (Tx and prevention)
- acidaemia/alkalaemia
- electrolyte imbalance (K, P, Na)
- hypoglycaemia
- azotaemia
- toxicity
- anaesthesia
- parenteral nutrition
