Fluid Therapy Flashcards
What are the roles of water in the body?
- Solvent for reactions
- Transportation of substances
- Heat regulation
- Essential for organ function
What percentage of body weight is made up of water in adults?
60%
What percentage of body weight is made up of water in neonates?
~80%
Is % water higher or lower for obese animals?
Lower
What percentage of water is in ICF?
40%
What percentage of water is in ECF?
20%
What percentage of water is in IVF?
5%
What percentage of water is in ISF?
15%
What is the blood volume per kg for dogs, cats, equine, bovine, ovine, and porcine?
Dogs 90mL/kg Cats 65mL/kg Equine 70mL/kg Bovine 60mL/kg Ovine 60mL/kg Porcine 50mL/kg
T/F: Cell membranes are permeable for water.
True- impermeable to ions
T/F: Vascular walls are permeable for water and ions.
True- impermeable for large molecules
What ion is in the highest concentration in ICF?
Potassium
What ion is in the highest concentration in ECF?
Sodium
What molecule is the highest concentration in IVF?
Albumin
The movement of water across semipermeable membranes is called?
Osmosis
What is osmolality?
Number of molecules per kg of water
What is the pressure required to prevent water movement called?
Osmotic pressure
What is the normal osmolality of ECF/ICF?
~300 mOsm/kg
What effect will an isotonic solution have on RBCs?
None
What effect will an hypotonic solution have on RBCs?
Increased volume (swelling and hemolysis)
What effect will an hypertonic solution have on RBCs?
Decreased volume (shrinking and crenation)
What is the name of the osmostic pressure exerted by proteins?
Oncotic or colloid osmotic presure
T/F: Oncotic pressure pushes water out of the vascular space.
False- oncotic pressure pulls water into the vascular space
What molecule contributes the most to oncotic pressure?
Albumin
What is normal physiological plasma oncotic pressure?
~23 mmHg
When is edema formed in hypoalbuminemia?
When albumin is
Is the degree of hypoalbuminemia a good prognostic factor in severely ill patients?
Yes
What direction does hydrostatic pressure move fluid?
Out of the vascular space
What direction does oncotic pressure move fluid?
Into the vascular space
What are crystalloid solutions?
Crystalline solids dissolved in water
eg- NaCL, glucose, etc
Can crystalloids be any tonicity?
Yes!
T/F: Balanced electrolyte solutions have a composition similar to ECF.
True
eg- Normosol and LRS
What are balanced electrolyte solutions used for?
Replacement therapy
T/F: Balanced electrolyte solutions can be given quickly in large volumes and do not cause changes in electrolyte balance
True!
T/F: Balanced electrolyte solutions can be given in large amounts to hypoalbuminemic patients.
False- dilutes what little is left
What fraction of a balanced electrolyte solution will stay intravascularly after 30 min?
only 1/3
What is an indication for a balanced electrolyte solution?
- Replacement after blood loss
2. Initial phase of shock treatment
Should maintenance solutions be used peri-operatively?
Typically not appropriate
What are the Na and K levels in a maintenance fluid compared to plasma levels
Na- 50%
K- 4-6x
What is the daily volume demand when considering maintenance fluids?
40-60mL/kg
What percent NaCl is hypertonic saline?
7.5%
What are the indications for hypertonic saline?
- Quick IV volume expansion
- Severe shock
- Head injury with elevated ICP
What does hypertonic saline due to increase ICF volume?
Rapidly draw water out of the ECF
What are contraindications for hypertonic saline?
- Uncontrolled haemorrhage
- Dehydration
- Cardiac dysrhythmias
What percentage dextrose is considered isotonic?
5%
T/F: 5% dextrose becomes hypotonic once metabolized
True
T/F: Colloids contain large molecules that stay inside blood vessels.
True- increase plasma oncotic pressure and vascular volume
When should colloids be considered?
When albumin is
What are some issues with colloids?
- Volume overload
- Allergic reaction
Possible effect on hemostasis (bleeding tendency)
What are the types of colloids?
- Hydroxy-ethyl starch
- Dextran
- Gelatine
- Albumin
- Plasma
- Whole blood
What are the most common Hydroxy-ethyl starches?
Hetastarch and vetstarch
T/F: HES can alter hemostasis at high doses or in already sick animals
True
What type of fluid is associated with renal failure in septic patients in humans?
HES
Should crystalloids be given over colloids in shock patients?
Yes
What is the max dose for HES?
20mL/day/kg (half for cats)
What route can crystalloids be administered?
IV, IO, SC, IP
What are the three ways water is lost?
Physiological- renal, GIT, etc
Pathological- vomiting/diarrhea etc
Anesthesia- open cavities
What are the reasons to give IV fluids during anesthesia?
- Maintain patent IV catheter
- Compensate for vasodilation
- Increase preload/CO
- Compensate for dehydration
- Replace ongoing fluid losses
What is the standard fluid rate for anesthesia?
10 mL/kg/hr for crystalloids
5mL for young animals
1-2 for cardiac failure, anuria, or lung edema
2mL/kg/hr for colloids
Should fluids be bolused in cases of hypotension?
Yes- 10mL/kg
