Fluids 2

Question 1

How do we use a replacement solution as a maintenance solution and what do we have to do? why does it work?

Answer 1

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

Question 2

anesthetized animals will generally be given what type of fluid at what rate?

Answer 2

replacement solution at 5-10mL/kg/h
>need to account for excess evaporation etc. during surgery

Question 3

advantages/uses of hypertonic saline

Answer 3

-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

Question 4

what are colloids? what do they do and how long do they remain in the vascular space?

Answer 4

-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

Question 5

how do we administer colloids?

Answer 5

– Rule of 1:1 replacement
– 5-10 mL/kg/h
* Do not exceed 30 mL/kg/day
* Clotting is affected

Question 6

examples of synthetic colloids

Answer 6

– Dextran, Starches (Hetastarch, Pentastarch, Tetrastarch)

Question 7

problems with synthetic colloids

Answer 7

can cause more harm than good
>clotting can be affected
>can do the same thing with crystalloids with less risk

Question 8

what are natural colloids?

Answer 8

-plasma, blood

Question 9

when should we give blood as a natural colloid? how much?

Answer 9

– 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

Question 10

when should we give plasma as a natural colloid?

Answer 10

– 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

Question 11

if we have a 20kg dog with 10% blood loss, how do we correct for this with colloids? how long will it take?

Answer 11

• 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

Question 12

when can we give a colloid?

Answer 12

– Recommended for losses of > 10% BV

Question 13

major disadvantage of giving blood vs crystalloids

Answer 13

cost

Question 14

what are dehydration measures based on?

Answer 14

total body weight

Question 15

<5% dehydration physical exam findings

Answer 15

History of fluid loss but no findings on physical examination

Question 16

5% dehydration physical exam findings

Answer 16

Dry oral mucous membranes but no panting or pathological tachycardia

Question 17

7% dehydration physical exam findings

Answer 17

Mild to moderate decreased skin turgor, dry oral mucous membranes, slight tachycardia, and normal pulse pressure.

Question 18

10% dehydration physical exam findings

Answer 18

Moderate to marked degree of decreased skin turgor, dry oral mucous membranes, tachycardia, and decreased pulse pressure.

Question 19

12% dehydration physical exam findings

Answer 19

Marked loss of skin turgor, dry oral mucous membranes, and significant signs of shock.

Question 20

calculate the missing fluid volume for a 20kg dog that is 10% dehydrated. How long would it take to replace?

Answer 20

• 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

Question 21

what values are commonly effected by fluid changes?

Answer 21

PCV, TP

Question 22

how will PCV and TP change in a dehydrated patient

Answer 22

– High PCV and TP

Question 23

how will PCV and TP change due to blood loss

Answer 23

– May not change PCV and TP until the body retains fluids through kidney actions
– Then, low PCV and TP

Question 24

what will happen to PCV and TP if we administer crystalloids in the presence of blood loss

Answer 24

– Acute lowering of PCV and TP

Question 25

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?

Answer 25

– 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