Crystalliods (Lanaux) Flashcards
1
Q
How much of body is made of water?
What proportion is inside cells?
A
- Intracellular fluid (40% of BW)
- Extracellular fluid (20% of BW)
- intravascular and extravascular
- Intravascular fluid (5% of BW)
- Interstitial fluid (15% of BW)
- fluid around cells and outside blood vessels
2
Q
Na is actively pumped….
A
out of our cells
3
Q
Electrolyte fluid characteristics
Intracellular
Extracellular
A
- Intracellular
- Low sodium
- High potassium
- Extracellular
- High sodium
- Low potassium
*Water follows Na
*Na concentration determines IV volume
*Total body sodium determines hydration
4
Q
Methods to calculate daily water requirements
A
- based on daily resting energy requirement equations
- 70 x BW0.75 = mL/kg/24 hours
5
Q
Difference between dehydration and hypovolemia?
A
- Dehydration: interstitial/intracellular fluid loss
- usually occurs slowly (days to weeks)
- can be replaced slowly
- Hypovolemia: intravascular fluid loss
- usually occures more rapidly
- requires rapid restoration of blood volume
6
Q
fluid loss
sensible
insensible
A
- Sensible
- Urine output
- feces
- vomitus
- wound exudates
- Insensible (20-30 mL/kg/day)
- Sweat
- Saliva
- Excessive panting
7
Q
Fluid Gain
Fluid Loss
A
- Gain
- drink
- food
- foodstuff oxidation
- metabolism
- Loss
- Hemorrhage
- Vomit/Diarrhea
- Urine
- Wound exudates
- Respiratory evaporation
- Salivation
8
Q
Calculating fluid deficit
A
BW (kg) x % dehydration = volume of fluid deficit (L)
9
Q
5% dehydration
A
- Mild dehydration
- no CS
10
Q
5-7% dehydrated
A
- moderate
- CS
- mildly prolonged skin tent
- mucous membranes normal to tacky
- CRT normal ( < 2s)
11
Q
8-10% dehydrated
A
- Severe dehydration
- CS
- prolonged skin tent
- dry mucous membranes
- eyes may be sunken
- tachycardia and poor pulse quality possible
- urine prod may be decreased
12
Q
> 10% dehydration
A
- critical dehydration causing hypovolemia
- CS
- markedly prolonged skin tent
- dry mucous membranes
- sunken eyes
- signs of shock
- tachycardia
- hypotension
- prolonged CRT
- cool extremeties
- hypothermia
- Decreased urine production
13
Q
Signs of hypovolemia
A
- Tachycardia
- Prolonged CRT
- Hypotension
- Hypothermia, cool extremities
- Weak pulses
- Weakness, lethargy
14
Q
Tx hypovolemia
A
- Goal directed therapy
- 10-20 ml/kg bolus crystalloids
15
Q
Crystalloid
A
- solution containing electrolyte and nonelectrolyte solutes
- capable of entering all fluid compartments
16
Q
Two major fluid determinants of fluid balance w/in the body
A
- Na
- albumin
17
Q
Three characteristics used to describe a crystalloid soln.
A
- Tonicity
- buffer
- balance
18
Q
Tonicity
A
- effective osmolality of a solution
- Osmole generates osmotic pressure by causing shift of water across a semipermeable membrane
- Mannitol
- Sodium
- Crystalloids classified based on tonicity relative to extracellular fluid
- hypotonic
- Isotonic (between 270-350 mOsm/kg)
- Hypertonic
19
Q
Buffers
A
- Excess chloride in some fluids have a mild acidifying effect
- Anions added as source of base
- acetate
- gluconate
- lactate
- metabolism of these make bicarb
- Acetate bolus to cats can cause hypotension
- Normosol-R
- Avoid lactate buffered solns in end stage liver dz
20
Q
Balanced solutions
A
- Major electrolytes similar proportion to extracellular fluid
- LRS
- Normosol R
- Plasmalyte 148
- Unbalanced solns
- normal saline (0.9% NaCl)
- 5% dextrose in water (D5W)
21
Q
If you bolused water IV….
A
Red blood cells would swell and rupture
Has a tonicity of zero
22
Q
Maintenance fluids
A
- Used to replace daily obligate losses of water and solutes in patients not eating/drinking
- This fluid loss occurs via kidneys
- low in Na
- higher in K (compared to extracellular fluid)
- This fluid loss occurs via kidneys
- tend to be hypotonic
- some have dextrose
- Na about 50-70 meq/L
- K about 10-20 meq/L
23
Q
Dextrose
A
- False osmol
- increases tonicity
- diffuses across plasma membrane quickly
24
Q
Maintenance fluid therapy
A
- Never bolus maintenance fluids
- intended for use at maintenance rates
- Rarely used in vet med
- Examples
- half stregnth saline (0.45%NaCl)
- normosol M
- Home-made concoctions: replacement with 5% dextrose)
- Plasmalyte 56
25
Examples of replacement fluids
* LRS
* 0.9% saline
* Plasmalyte 148
* Normosol R
26
About replacement fluids
* Most common type of fluid used in vet med
* Used to replace fluid deficit from IV or interstitial spaces
* hypovolemia
* dehydration
* Looks like plasma
* Na about 140-150
* K 0-5
* Isotonic
27
Using replacement fluids
* May be bolused or admined at high rates
* Often used as a maintenance fluid
* kidney will excrete extra sodium
28
Hypertonic fluids and potential use
* Mannitol - dec IC pressure
* Hypertonic saline - vascular expansion, dec IC pressure
29
About hypertonic fluids
* Hypertonic fluids pupll fluid from interstitial space into intravascular space
* cause rapid intravascular volume expansion
* Effects usually short lived (15-20 min)
* usually need to be followed by isotonic/maintenance fluids
30
danger of hypertonic fluids
* May cause electrolyte abnormalities
31
**Hypertonic fluids**
**Possible contraindications**
* Severe dehydration
* Hypernatremia (some exceptions)
* Examples
* 3% saline
* 7.5% saline
* 20% Mannitol
32
Hypertonic saline
* shock or head trauma
* expand blood volume 3 to 3.5 times amount admined
* dose is 2-4 mL/kg bolus over 5 minutes
33
Hypertonc saline
proposed benefits
* Rapid intravascular volume expansion
* Dec cerebral edema
* Increased cardiac contractility
* Immunomodulatory effects
* Improved microcirculatory perfusion
* due to arteriolar vasodilation
34
Hypertonic saline
Proposed adverse effects
* Hypernatremia
* Rapid administration ( \> 1 mL/kg/min)
* bradycardia
* Hypotension
* Bronchoconstriction
35
Mannitol
Proposed benefits
Proposed adverse effects
* benefits
* dec cerebral edema
* improves rheology
* decreases blood viscosity
* free radical scavenger
* adverse effects
* may exacerbate edema/hemorrhage
* dehydration
36
Fluid discontinuation
* eating and drinking on own
* no vx/d
37
Most important aspect of fluid admin
reassess
