Final Exam: Intro to Fluid Therapy

Question 1

What is osmolarity?

Answer 1

Another way of expressing a concentration of dissolved particles

Question 2

What is tonicity?

Answer 2

Refers to the effect of a fluid on a cell it surrounds

It is discussed in terms of osmolarity relative to the inside of the cell

Question 3

What does an isotonic solution cause?

Answer 3

No volume change to cells placed in that solution

Question 4

What does a hypertonic solution cause?

Answer 4

Causes cells to shrink

Question 5

What does a hypotonic solution cause?

Answer 5

Causes cells to swell

Question 6

What is fluid diuresis?

Answer 6

Fluid infusion rates in excess of maintenance needs to promote removal of drugs/toxins, increase GFR, and increase urine production
A value of 2-2.5x normal maintenance rates is common

Question 7

What is a crystalloid solution?

Answer 7

A solution that diffuses readily through semipermeable membranes and generally is capable of being crystallized
Includes solutions with major electrolytes (Na, K, Ca, Cl, etc) or dextrose as solutes

Question 8

What are colloid fluids?

Answer 8

A mixture with properties between those of a solution and fine suspension
Proteins form the major colloids in the body
Includes blood products and synthetic hetastarch

Question 9

In what form of shock is fluid therapy contraindicated?

Answer 9

Cardiogenic: patients in heart failure are already fluid volume overloaded

Question 10

What are the main causes of hypovolemic shock?

Answer 10

Rapid blood loss

Severe dehydration from fluid loss (vomiting, diarrhea, polyuria)

Question 11

What is distributive shock?

Answer 11

A relative hypovolemioa due to vasodilation

Question 12

What are the subtypes of shock that fall under the general categorization of distributive shock?

Answer 12

Septic or endotoxic shock
Anapylactic shock
Addisonian crisis
Neurogenic shock

Question 13

What are the ions commonly found in a Balanced Electrolyte Solution (AKA MultiElectrolyte Solution)?

Answer 13

Na, Cl, K, Ca

Question 14

Contrast replacement versus maintenance crystalloid solutions as to relative sodium content and when they are indicated

Answer 14

Maintenance fluids contain much less sodium (such as half-strength saline or 5% dextrose in water) and are intended for animals that have free water loss or require prolonged fluid admin
Replacement fluids given to an animal with free water deficits or for prolonged periods of time (without access to water) will result in hypernatremia and hyperosmolarity

Question 15

Why do oral electrolyte solutions provide better rehydration that oral water? Indicate the role of sodium and glucose in the solution

Answer 15

Oral electrolytes are high in Na and glucose. Na and glucose will enter intestinal epithelial cells via a co-symport. Once inside, a Na+/K+ pump will snag that Na and pull it out into the blood or lymphatics. Wherever sodium goes, water will follow which is when we start rehydrating. Proteins use energy from sodium gradient to transport glucose into the cells against the glucose gradient. Glucose exits the cells via a uniport and enters blood

Question 16

Explain how D5W is considered isotonic in vitro but mildly hypotonic in vivo

Answer 16

In vitro, it has no volume change meaning it stays put.
In vivo, very little stays in the vascular system or ECF- it mostly moves into the tissue
Therefore, D5W is not for volume expansion

Question 17

Why is D5W not considered appropriate for use in hypovolemia?

Answer 17

If you have an animal in hypovolemic shock, you must use a solution with sodium in it. D5W does not, so it will not work

Question 18

When are hypertonic dextrose solutions indicated?

Answer 18

To stop hypoglycemic seizures

Given as an energy source; part of the total parenteral nutrition or partial parenteral nutrition

Question 19

What risks or side effects can hypertonic dextrose solutions cause?

Answer 19

If it gets outside of the vein, it is very hypertonic and will damage the tissue
Should not be administered if there is any active brain or spinal cord hemorrhage because mannitol will go into the clot and it will osmotically draw fluid into the brain or spinal cord and make it worse
Concentrations >20% dextrose should not be given in a peripheral vein due to risk of phlebitis
Rapid infusion can cause osmotic diuresis
Can cause volume overload in heart or kidney failure

Question 20

What are the pros for hypertonic saline use in managing hypovolemic or distributive shock?

Answer 20

We want to use hypertonic saline in shock scenarios where isotonic fluids are either not working or not available
It osmotically draws rapidly into vascular space from interstitial fluids in the tissues

Question 21

What are the cons for hypertonic saline use in managing hypovolemic or distributive shock?

Answer 21

It only lasts for 30-60 minutes, but this gets you through the immediate crisis while you transport the animals to where it needs to go or get proper supplies
Avoid its use in uncontrolled hemorrhagic shock, patients that are hypernatremic and markedly dehydrated patients
This is so hypertonic that if you give it in a peripheral vein you cause phlebitis, so it is given in the jugular

Question 22

What is the follow-up therapy with hypertonic saline?

Answer 22

Always follow-up with isotonic crystalloids to replenish interstitial fluid loss
By using the hypertonic saline, you sacrifice the hydration of the tissues to improve the vascular volume. So, once you are out of the woods you need to rehydrate the tissues which is where isotonic crystalloids come in

Question 23

Name a use of hypertonic saline other than for management of shock?

Answer 23

Cerebral edema

Question 24

Name the 2 common concentrations of hypertonic saline and which can be given in a peripheral vein

Answer 24

7.5% hypertonic colution for IV infusion in central catheter
3% hypertonic solution for IV infusion in central or peripheral catheter
If we gave the full 7.5% in peripheral vein, we cause phlebitis. To minimize that risk, we cut concentration to 3%.

Question 25

What are the indications for use of hetastarch?

Answer 25

Rapid IV volume expansion and/or when crystalloid volume expansion is ineffective
Maintenance of plasma oncotic pressure to prevent edema in hypoproteinemic patients

Question 26

What are the potential toxicities or side effects of hetastarch?

Answer 26

Volume overload is possible especially in heart or renal failure patients
Coagulopathies from platelet inhibition at a very high dose
FDA black box warning: do not use in critically ill adult human patients with preexisting renal dysfunction or sepsis

Question 27

What is fresh whole blood?

Answer 27

Contains RBCs, platelets, leukocytes, and plasma proteins including clotting factors
Transfuse it within 4-6 hours after collection

Question 28

What is stored whole blood?

Answer 28

Contains RBCs and plasma proteins
No longer viable platelets or labile clotting factors
Transfuse it after 6-8 hours
Shelf life of 21-28 days

Question 29

What is packed RBCs?

Answer 29

Plasma has been removed and packed RBCs remain

Question 30

What is fresh frozen plasma?

Answer 30

It comes from fresh whole blood centrifuged immediately

Clotting factors are good for at least 1 year

Question 31

What is cryoprecipitate?

Answer 31

It comes from thawed fresh frozen plasma
Rich in factor VIII and VWF
Used for treatment of hemophilia A and von Willebrand’s disease

Question 32

What is frozen plasma?

Answer 32

It comes from stored whole blood centrifuged immediately
We lose some labile clotting factors (fibrinogen, factor VIII, VWF) but it is still worthwhile if fresh frozen plasma is not available
Good for up to an additional 4 years

Question 33

What are the clinical signs and percent dehydration with mild dehydration?

Answer 33

5% dehydrate

Mild loss of skin elasticity

Question 34

What are the clinical signs and percent dehydration with moderate dehydration?

Answer 34

8%

Slight sinking of eyes, prolonged skin tenting, CRT 2-3 seconds

Question 35

What are the clinical signs and percent dehydration with severe dehydration?

Answer 35

10% dehydrated

Animal semi-comatose, >3 sec CRT, severe skin tenting and sinking of eyes into sockets, cool extremities, and tachcardic

Question 36

What is/are the indications for oral fluid therapy?

Answer 36

If only 5-6% dehydrated and the GI tract is okay, we are good to use oral isotonic solutions

Question 37

What is/are the indications for SC fluid therapy?

Answer 37

If 5-6% dehydrated, we can do SQ in small animals and calves

Question 38

What fluids are appropriate for SC fluid therapy?

Answer 38

Isotonic fluids (LRS, balanced electrolyte solutions)

Question 39

What is the rate of isotonic fluid therapy use in the initial management of shock for digs versus cats?

Answer 39

With shock, we want to go fast enough to restore vascular volume and blood pressure, but slow enough to avoid volume overload and resultant heart failure and edema formation
80 mls/kg/hr in dogs; 50 mls/kg/hr in cats

Question 40

Over what time frame should the first 1/4 of that dose be given and the patient reassessed?

Answer 40

We give 1/4 of the shock dose and then reassess every 15 minutes and decrease as needed

Question 41

What is the recommended rate of fluid therapy during anesthesia in dogs and cats?

Answer 41

3 ml/kg/hr in cats

5 ml/kg/hr in dogs

Question 42

In mild dehrydation, the fluid deficit is replaced over how many hours?

Answer 42

In mild dehrydation, the fluid deicit is replaced over several hours (8-24 hours)

Question 43

Describe how to monitor for overhydration during fluid therapy

Answer 43

Monitor HR, RR, BP
Peripheral and/or pulmonary edema
Weight gain
Measure “ins and outs”: in a stable patient, urine volume that comes out should be similar to the fluid volume that you put in
Lung sounds: avoid crackles
Central venous pressure is controversial: it is good acutely, but not as useful for ongoing assessment

Question 44

Which colloids are used for volume expansion?

Answer 44

All colloids

Question 45

Which colloids are used for clotting factors?

Answer 45

Plasma

Question 46

Which colloids are used for anemia?

Answer 46

Whole blood, packed RBC

Question 47

Which colloids are used for hypoproteinemia?

Answer 47

Albumin, hetastarch, plasma

Question 48

Which colloids are used for failure of passive transfer?

Answer 48

Plasma, serum, immunoglobulin concentrates

Question 49

Why should blood products not be given simultaneously with Ringer’s solution or dextrose solutions?

Answer 49

The anticoagulants in blood products work by chelating Ca+. RIngers and other balanced electrolytes will antagonize these anticoagulants because they have Ca+ in them. Likewise, dextrose solutions cause hemolysis issues because of their glucose content

Question 50

What is the proposed mechanism of benefit in using intravenous therapy for ivermectin toxicity or local anesthetic overdose?

Answer 50

Lipid-soluble drugs/toxins will get pulled from circulation by the IV lipids and get trapped in a “lipid sink” withing the plasma and are then eliminated

Question 51

After how many days of anorexia should nutritional support be required?

Answer 51

3-4 days without food: nutritional support is likely needed if recovery is not imminent
5 days without food: nutritional support is required

Question 52

What species and body conditions may warrant early intervention with nutritional support?

Answer 52

Animals in poor body conditions (low glycogen and fat reserves) or obese animals (risk of hypertriglyceridaemia and hyperlipemia) especially cats and ponies) may need earlier intervention

Question 53

What are the components used to make Total Parenteral Nutrition supplement?

Answer 53

Hypertonic dextrose solution
Amino acid solution
Lipid emulsion
Multivitamins and trace metals often added

Question 54

How do partial parenteral nutrition formuals differ from TPN?

Answer 54

They are composed of:
No lipid emulsions
Some premade commercial dextrose and AA solutions exist
Lower concentrations of dextrose and AA to decrease risk of phlebitis

Question 55

What complication of parenteral nutrition is the most common and, arguable, of greatest importance?

Answer 55

Septic complications

Question 56

What conditions are likely to lead to “refeeding syndrome”?

Answer 56

Due to reinstitution of nutrition to patients who are starved, severely malnourished, or metabolically stressed due to severe illness
Biggest cause of death in refeeding is cardiac arrythmia related to electrolyte disturbances

Question 57

Be able to calculate the required fluid volume for intravenous replacement therapy based on percent deficit, maintenance fluid requirements, and ongoing losses. (Already addressed in Calculations lecture.)

Be able to calculate how much blood to give an anemic dog or cat when supplied with the patient’s PCV, the donor PCV, the weight of the patient, and the targeted PCV. (Already addressed in Calculations lecture.)

Answer 57

Be able to calculate the required fluid volume for intravenous replacement therapy based on percent deficit, maintenance fluid requirements, and ongoing losses. (Already addressed in Calculations lecture.)

Be able to calculate how much blood to give an anemic dog or cat when supplied with the patient’s PCV, the donor PCV, the weight of the patient, and the targeted PCV. (Already addressed in Calculations lecture.)