Fluids 2 Flashcards
How do we use a replacement solution as a maintenance solution and what do we have to do? why does it work?
we should add K+ to the replacement solution, then we can use it as a maintenance solution
-the body will get rid of the excess sodium and chloride
anesthetized animals will generally be given what type of fluid at what rate?
replacement solution at 5-10mL/kg/h
>need to account for excess evaporation etc. during surgery
advantages/uses of hypertonic saline
-volume expansion
>can be given with replacement solution: if you are resuscitating a patient and volume is a concern due to the time it will take, you can give hypertonic saline along with isotonic crystalloids
>in such situations, can restore some cardiovascualr functions so that drugs will have less dramatic effect
>also can increase contraction of the heart/+inotropic
what are colloids? what do they do and how long do they remain in the vascular space?
-fluids with molecules that attract fluids into the circulation
– Isotonic, volume expanders
– Large molecules
– 1.5-2 times oncotic pressure of blood for synthetic colloids
– Remain in the vascular compartment for 6-16 h
how do we administer colloids?
– Rule of 1:1 replacement
– 5-10 mL/kg/h
* Do not exceed 30 mL/kg/day
* Clotting is affected
examples of synthetic colloids
– Dextran, Starches (Hetastarch, Pentastarch, Tetrastarch)
problems with synthetic colloids
can cause more harm than good
>clotting can be affected
>can do the same thing with crystalloids with less risk
what are natural colloids?
-plasma, blood
when should we give blood as a natural colloid? how much?
– Blood- if PCV < 20-25%
* mL of blood = (Desired PCV - Recipient PCV)/(Donor PCV)80BW
> note that 80 in the formula represents blood volume, which for a dog is 8%. Adjust based on species
-1:1 replacement
– 5-10 mL/kg/h or as fast as needed
when should we give plasma as a natural colloid?
– Plasma- if TP (Total Protein) < 3.5 – 4.0 g/dL
* mL of plasma = (Desired TP - Recipient TP)/(Donor TP)60BW
> note that 60 in the formula represents plasma volume, which for a dog is 6%. Adjust based on species.
– Rule of 1:1 replacement
– 5-10 mL/kg/h or as fast as needed
if we have a 20kg dog with 10% blood loss, how do we correct for this with colloids? how long will it take?
- 20 kg dog
– 10% blood loss - 8% of body weight corresponds to blood volume- 1.6 L
- 10% blood loss= 160 mL
- Effective replacement- 160 mL of colloids – 1:1 rule
– 10 mL/kg/h- will require 50 min
– Recommended for losses of > 10% BV
when can we give a colloid?
– Recommended for losses of > 10% BV
major disadvantage of giving blood vs crystalloids
cost
what are dehydration measures based on?
total body weight
<5% dehydration physical exam findings
History of fluid loss but no findings on physical examination
5% dehydration physical exam findings
Dry oral mucous membranes but no panting or pathological tachycardia
7% dehydration physical exam findings
Mild to moderate decreased skin turgor, dry oral mucous membranes, slight tachycardia, and normal pulse pressure.
10% dehydration physical exam findings
Moderate to marked degree of decreased skin turgor, dry oral mucous membranes, tachycardia, and decreased pulse pressure.
12% dehydration physical exam findings
Marked loss of skin turgor, dry oral mucous membranes, and significant signs of shock.
calculate the missing fluid volume for a 20kg dog that is 10% dehydrated. How long would it take to replace?
- 20 kg dog, 10% dehydrated
– 10/100 x 20 x 1000 = 2000 mL, or
– 100 mL/kg x 20 = 2000 mL
– To move fluid to ISF and ICF, several hours are required. Therefore, hydration may require 12-24 hours to be completed
what values are commonly effected by fluid changes?
PCV, TP
how will PCV and TP change in a dehydrated patient
– High PCV and TP
how will PCV and TP change due to blood loss
– May not change PCV and TP until the body retains fluids through kidney actions
– Then, low PCV and TP
what will happen to PCV and TP if we administer crystalloids in the presence of blood loss
– Acute lowering of PCV and TP
if we have a 500kg horse that is 8% dehydrated, what is the fluid deficit? how fast should we administer the fluid? What should we add if the horse is not drinking or eating?
– Fluid deficit (dehydration):
* 8/100 x 500 x 1000 = 40 L, or
* 80 x 500 = 40 L
* Plan is to administer volume over 12 hours (3.3 L/h)
– Add maintenance requirements if not drinking/eating:
* 2 mL/kg/h
– 500 x 2 = 1 L/h
– Total = 4.3 L/h
