IV fluid therapy Chap 59

Question 1

most important active pump is the Na+/K+-ATPase pump, which extrudes three sodium ions from the cell in exchange for two potassium ions into the cell. This pump is responsible for generation of:
____RMP

Answer 1

electrochemical gradient across cell membranes

negative resting membrane potential

Question 2

Larger molecules _____ do not easily vasc. endothelial and may attract small, charged particles, thus creating the:

There are three main natural colloid particles:

Answer 2

> 20,000 Daltons
colloid osmotic pressure (COP) a.k.a oncotic pressure

albumin, globulins, and fibrinogen

Question 3

Isotonic Fluid Loss ddx:

ICF volume will ____:

if the animal has been drinking water to replace the isotonic fluid losses, _____may result.

Answer 3

polyuric renal failure
vomiting, diarrhea
bleeding

isotonic losses will not alter ECF osmolality, there will be no movement of water across the cell membrane and ICF
= unchanged

hyponatremia

Question 4

Hypotonic Fluid Loss ddx:

Answer 4

DI
panting

=hyper Na, >mOsm

Question 5

Hypertonic Fluid Loss ddx:
Loss of hypertonic fluid occurs infrequently

You would expect Na to be low because it is being lost without Aldosterone, but its mainly low bc:

Answer 5

Hypertonic Fluid Loss
hypoadrenocorticism

but more commonly hyponatremia results from excessive free water intake or retention.

Question 6

what is osmotic demyelination syndrome:

Answer 6

rapid > Na = shrink - central pontine myelinolysis

Question 7

Maintenance fluid needs take into account:

Answer 7

sensible (feces, urine)

insensible ongoing fluid losses (panting, sweating).

Question 8

5 formulas for maintenance:

obese predisposed to over or under calc.?

Answer 8

70(BWkg)0.75
Formula 1: 30(BWkg) + 70/day
Formula 2: 60(BWkg) + 140/day
Formula 3: 40-60 ml/kg/day
Formula 4: 2-4 ml/kg

less water in fat than in muscle, most calculations overestimate maintenance needs of overweight patients

Question 9

IV periph. osmolality cut off:

Answer 9

600 mOsm/L

greater than 700 mOsm/L central catheter to decrease the risk of phlebitis or thrombosis

Question 10

Replacement fluids, also known as isotonic crystalloids

Answer 10

fluids with a composition similar to that of the ECF. They have a similar osmolality as plasma (290 to 310 mOsm

Question 11

Isotonic crystalloids can cause harm, via interstitial fluid gain:
Patients with a low COP, pulmonary contusions, cerebral trauma, fluid-unresponsive renal disease, or cardiac disease/failure are at highest risk for complications. In addition

Answer 11

interstitial edema, pulmonary edema, and cerebral edema

hemodilution of blood constituents
hypoproteinemia, electrolyte derangements, and hypocoagulability can occur after large-volume

Question 12

Explain how D5W are hypotonic in nature:

mOsm:

Answer 12

dextrose may make the fluid iso-osmotic to plasma, but the dextrose is metabolized rapidly to CO2 and H2O

252

Question 13

D5W indicated for animals with a free water deficit i.e.:

Good starting point rate:

or calc free water deficit:

Answer 13

hyperNa or DI or CHF maybe

rate of 3.7 ml/kg/hr of free water
to safely lower the sodium concentration by 1 mEq/hr

FWD = 0.6 x Kg x (curr Na - norm Na/norm Na) x 1000

Question 14

Colloids:
most commonly used synthetic colloid solutions are

polydisperse
hyperoncotic

Answer 14

hydroxyethyl starch - hetastarch (7?) and tetrastarch (5)

contain molecules with a variety of molecular weights
hyperoncotic .:. cause fluid from the extravascular to the intravascular space

Question 15

Hetastarch:
\_\_\_hydroxyethyl starch
average molecular weight of \_\_\_\_ Daltons
mean average molecular weight of \_\_\_\_ Daltons
COP of \_\_\_\_\_

Answer 15

6% hydroxyethyl starch
10,000 to 1,000,000
450 000 mean average weight
34 mm Hg

Question 16

volumes greater than ______ increase in incisional bleeding has been reported with hetastarch solutions, which may be due to:

Answer 16

40ml/kg/DAY

increase hydrostatic pressure and dilutional

Question 17

-ve:
what clotting factors does it affect:
Clinical evidence of bleeding has not been reported in:

Answer 17

dilution
affects vWF, VIII, platelet function
increase in the activated partial thromboplastin time (aPTT) may develop in animals that receive large amounts of synthetic colloid therapy, although the quantitative aPTT change is not predictive of clinical bleeding

20ml/kg/DAY

Question 18

Vetstarch:
\_\_\_hydroxyethyl starch
\_\_\_particles daltons MW
mean average molecular weight of \_\_\_\_ Daltons
COP of \_\_\_\_\_

Answer 18

6% tetrastarch solution
110,000 to 150,000 Daltons
130,000 Daltons
COP of 40 mm Hg

Because of its lower average molecular weight (130 000 vs 450 000 and low molar substitution, VetStarch may be less likely to cause adverse renal and coagulation side effects but may also require higher doses to achieve similar effects to that of hetastarch.