Fluid Replacement Flashcards
What do we replenish with IV fluids?
intravascular space (plasma)
TBW % for females
50%
TBW % for males
60%
TBW % for newborns
80%
Why are infants and young children more vulnerable to dehydration?
high metabolic H20 turnover daily/hour
larger SA relative to their weight
greater % of TBW located in ECF (fluid in EC is more available for transfer to environment and is more readily available for evaporation –> dehydration)
Sensible losses of fluid
urine
sweat
feces
vomitus
Insensible losses of fluid
metabolic water (high metabolic = lose more)
evaporation from skin
evaporation from respiratory tract
insensible is relatively larger component in infants and young children
Fluid loss rises during increased:
metabolic rate
fever
ambient temperature
What is the first choice for resuscitation
isotonic fluid - normal saline = 0.9% saline
bc fluid needs to stay in the intravascular space
what is the fluid choice for burn patient or surgical?
lactated ringers
hypotonic solution
full of water –> swelling of cells
hypertonic solution
full of solutes –> shrinking of cell
Quick calculation for calculating hourly rate in adult (for weight > or equal to 20 kg)
Weight in kg + 40
Na+ needs over 24H
30 mEq/L
K+ needs over 24H
20 mEq/L
Cl- needs over 24H
20 mEq/L
1 L H2O =
1 kg
1 kg =
2.2 lbs
how are deficits given?
first 1/2 given over 8 hours
second 1/2 given over 16 hours
Where is most sodium lost from?
the ECF
amount of sodium last during first 3 days of illness
80% of H20 volume and Na+ are lost from the ECF
20% of H20 volume and Na+ are lost from ICF
amount of sodium and water lost after day 3 of illness
60% of H20 volume and Na+ are lost from ECF
40% of H20 volume are Na+ are lost from ICF
Total hourly rate is determined by calculating…
maintenance fluids + deficits - any initial bolus
what tells us the RATE of fluid replacement
H2O
What tells us the TYPE of fluid replacement
Na+
Fluids given for volume expansion
crystalloid
colloid
Crystalloid fluid
water soluble electrolytes in solution
exert a significant hydrostatic effect (pushes against walls to increase volume)
colloid fluid
larger molecules suspended in aqueous solution; exert oncotic effect (pulls fluid in and retains it in intravascular space and doesn’t let it go out to interstitial space)
Natural: albumin, fresh frozen plasma (FFP), blood
Synthetic: hetastarch
What fluid should you use for acidosis
lactated ringers –> convert HCO3- in the liver
What fluid for burns
saline solution from maintenance
plus LR for deficit replacement
What fluid for pyloric stenosis (babies –> projectile vomit –> hypochloremic, hypokalemic, metabolic alkalosis)
D5 0.45% NS or D10 0.45% NS
Dextrose adds some calories (bc vomiting)
Avoid LR due to alkalosis
Effects of adding dextrose to maintenance fluids
water will be drawn into the intracellular compartment more effectively
some calories – but minimal – may decrease ketone generation (prevents ketone generation so can be used for someone with DKA)
For fever
add 10-12% to maintenance fluid per degree C above 37.8 degree C (99F)
bc higher metabolic demands
For burns: do not give KCl
cell lysis –> intracellular K+ release
Rhabdomyolysis secondary to burn –> increased K+
patient will be hyperkalemic
Daily need of Na+ if we are well
30 mEq/L or 3 mEq/100 mL
signs of fluid overload
edema
hepatic congestions
crackles on lungs
What tells us HOW MUCH solution
water
Why is 0.22% NS banned from some hospitals
too hypotonic and often causes hemolysis
