fluid therapy-water distribution, crystalloids and colloids Flashcards
What influences water content in the body?
age: older-less, peds-more
pregnancy/lactation
gender
% body fat-fat is lower in H20 content, estimate lean body mass
how much water is in your body
50-70%
where is the water?
intracellular, extracellular, transcellular
how much of the ECF is intravascular?
25%
how many ml/kg of blood in various species
dogs, horses, most spp=9% body weight in kg (90 ml/kg)
cats-6% of body weight in kg (60 ml/kg)
what is the shock dose of fluids for dog? cat?
dog-9% of body weight (90 ml/kg)
cat-6% of body weight (60 ml/kg)
effect on K levels when patient is acidiotic or alkaliotic?
acidosis-increase serum K
alkalosis decrease serum K
if you want fluids intravascular, what composition of electrolytes would you want?
sodium-140
chloride-100
K-4
maintenance fluids
volume of fluids/eletrolytes needed to maintain normal function
normal fluid losses: 40-60 ml/kg/day, approximately 2 ml/kg/hr
increase or decrease depending on hydration status
anesthesia rate for fluids
10-20 ml/kg/hr
species variation
why higher fluid rates for anesthesized patients?
vasodilation (ace, propofol)
dry air
blood loss
increased surface area exposed to dry cool air
10 yr MC standardbred, 500 kg
presenting for colic
sweating, skin remains tented, prolonged CRT, dry MM, weak pulses, pulse rate 90 bpm
what volume of fluids are needed for replacement of dehydration
10% dehydrated
500 kg * 0.1 = 50 L of fluids
can’t get fully hydrated before sx for colic
try to get 15-20 L in before sx
deficit replacement
percent dehydration X BW (kg) = volume deficit in L
shock rates
dogs horses, most species: 90 ml/kghr
cats: 60 ml/kg/hr
replacement fluids
higher in Na, lower in K
more like extracellular space
not for indefinite use
maintenance fluids
lower in Na, higher in K
more like the intracellular space
what are colloids?
any fluid with large particles suspended equally throughout.
large molecular weight stuff (sugars, starches, proteins)
size and number of particles determine power-larger particles last longer, higher numbers of particles have more oomph!
allow faster restoration of intravascular voume with lower doses of IV fluids
remain withini intravascular space longer
classification of colloids
natural vs artifical
- albumin, plasma proteins, PRBCs, blood
- hetastarch, dextrans, gelatins, HBOC
oxygen transport
- oxyen carriers, non oxygen-carriers
What do colloids do?
active-osmotic and oncotic pull
lower volumes-faster and reduced side effects
why? more stays in vascular space, active oncotic pull
replace blood, plasma protein losses
How are colloids used?
rely on adequate interstitial and intracellular reserves
avoid risks associated wtih aggressive crystalloid therapy
often use crystalloids and colloids in combination
