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
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2
Q

Na is actively pumped….

A

out of our cells

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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

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4
Q

Methods to calculate daily water requirements

A
  • based on daily resting energy requirement equations
    • 70 x BW0.75 = mL/kg/24 hours
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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
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6
Q

fluid loss

sensible

insensible

A
  • Sensible
    • Urine output
    • feces
    • vomitus
    • wound exudates
  • Insensible (20-30 mL/kg/day)
    • Sweat
    • Saliva
    • Excessive panting
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7
Q

Fluid Gain

Fluid Loss

A
  • Gain
    • drink
    • food
    • foodstuff oxidation
    • metabolism
  • Loss
    • Hemorrhage
    • Vomit/Diarrhea
    • Urine
    • Wound exudates
    • Respiratory evaporation
    • Salivation
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8
Q

Calculating fluid deficit

A

BW (kg) x % dehydration = volume of fluid deficit (L)

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9
Q

5% dehydration

A
  • Mild dehydration
  • no CS
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10
Q

5-7% dehydrated

A
  • moderate
  • CS
    • mildly prolonged skin tent
    • mucous membranes normal to tacky
    • CRT normal ( < 2s)
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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
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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
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13
Q

Signs of hypovolemia

A
  • Tachycardia
  • Prolonged CRT
  • Hypotension
  • Hypothermia, cool extremities
  • Weak pulses
  • Weakness, lethargy
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14
Q

Tx hypovolemia

A
  • Goal directed therapy
    • 10-20 ml/kg bolus crystalloids
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15
Q

Crystalloid

A
  • solution containing electrolyte and nonelectrolyte solutes
  • capable of entering all fluid compartments
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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)
  • 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