Large Animal Medicine Fluid Therapy

Front 1

What are 2 ways water and electrolytes are lost from the body everyday?

Back 1

-Excretion of body fluids: ocular, nasal & oral discharges, urine, feces, sweat, milk.
-Evaporative losses through body surfaces and the respiratory tract

Front 2

Non-excretable body fluids exist in what two discrete compartments within the body?

Back 2

-Intracellular fluid (ICF)
-Extracellular fluid (ECF): IV-ECF and EV-ECF pools

Front 3

What do you call the water in that makes up body fluids such as glomerular filtrate and intestinal luminal fluid that are still being modified by the body prior to excretion of the remained?

Back 3

Transcellular water

Front 4

The ECF has a high concentration of what 3 electrolytes?

Back 4

Sodium, chloride and albumin

Front 5

The ICF has a high concentration of what 2 electrolytes?

Back 5

Potassium & phosphorus

Front 6

True or false. Fluid & electrolytes move relatively freely between the IV-ECF & EV-ECF.

Back 6

True

Front 7

What draws fluid into the vascular space from the interstitium?

Back 7

The plasma oncotic force created by albumin and other proteins

Front 8

As the intravascular fluid creates pressure against the blood vessel walls, _____ pressure causes fluid to exude into the interstitium.

Back 8

Hydrostatic

Front 9

What causes electrolyte changes in the ICF?

Back 9

Severe enough changes in the ECF

Front 10

Depleting the intravascular pool of fluid may have a negative impact on __________ and ____________function.

Back 10

Cardiovascular & respiratory function

Front 11

Loss of electrolytes into the _____may result in electrolyte derangements.

Back 11

Transcellular space

Front 12

What separates the ECF from the ICF?

Back 12

semi-permeable cellular membrane

Front 13

What fluid compartment is most commonly measured?

Back 13

*IV-ECF

Front 14

What are some examples of fluids that are sampled to examine the EV-ECF? What do we look at when evaluating the EV-ECF?

Back 14

Lymph, peritoneal fluid, pericardial fluid, CSF
-look at protein count, cell count

Front 15

In a normal cow/horse the IV-ECF is what percent of body weight?

Back 15

6% (8% in neonates)

Front 16

The extracellular fluid comprises _____% of large animal body weight. What's the equation for ECF?

Back 16

30%, so ECF= 0.3 x BW

Front 17

What is the goal of fluid replacement?

Back 17

To correct all deficits (electrolytes, acid/base, water loss) as rapidly as possible without iatrogenic complications

Front 18

When is an animal's dehydration considered "subclinical"?

Back 18

When the animal has loss <6% of its BW
-Eye normal, normal skin tent, normal mucus membranes

Front 19

How will the eye, skin tent and mucus membranes appear in an animal that has lost 6-8% of its BW in water?

Back 19

Sunken eye: mild
Skin tent: 2-4 sec
Mucus membranes: tacky

Front 20

How will the eye, skin tent and mucus membranes appear in an animal that has lost 8-10% of its BW in water?

Back 20

Sunken eye: moderate
Skin tent: 6-10 seconds
Mucus membranes: tacky

Front 21

How will the eye, skin tent and mucus membranes appear in an animal that has lost >10% of its BW in water?

Back 21

-Sunken eye: severe
-Skin tent: > 10 seconds
-Mucus membranes: dry
*Signs more obvious in ruminants than horses

Front 22

*Horses are commonly afflicted with _________, whereas cattle are commonly afflicted by overt fluid loss.

Back 22

Horses= severe shifts to the interstitium bc more prone to protein issues
-hence estimates of cardiovascular function (HR, CRT,) become important estimators (of IV-ECF deficits) in horses

Front 23

What are 4 clinicopathologic parameters that can be measured to diagnose dehydration (or at least loss of IV-ECF)?

Back 23

1) PCV
2) Hemoglobin
3) Serum protein fractions
4) Azotemia

Front 24

Why can't a single laboratory value be used to diagnose dehydration in large animals?

Back 24

Because RBC indices and blood total protein are variable in LAs (splenic contractions in the horse, and variable globulin concentrations in all LAs)

Front 25

**How do you calculate the volume of replacement fluids to administer to a large animal?

Back 25

% dehydration x body weight (kg) = L of fluid needed (Kg=L)

Front 26

A 450 kg horse is 10% dehydrated, how many fluids should be given? How long should the fluids be given over?

Back 26

450 x .10= 45 L of fluid given within 4 hours of time

Front 27

**How do you calculate how much fluid to give a large animal in shock? Over how long?

Back 27

Up to one blood volume (5-8% BW) as fast as possible-20 minutes (within 1 hour)

Front 28

What happens to the BUN & creatinine when an herbivore goes off its feed for a few days?

Back 28

Microbes in gut start using urea for short term energy production, so urea decreases w/ acute anorexia (2-3 d)

Front 29

Most fluid that is loss in animals is roughly (hypotonic/isotonic/ hypertonic).

Back 29

Isotonic - meaning animal is losing water and salt in roughly the same proportions to plasma amounts

Front 30

What is the Na+, Cl-, K+, and bicarbonate concentration of plasma?

Back 30

Na+: 140 mEq/L
Cl-: 115 mEq/L
K+: 5 mEq/L
Bicarbonate: 25 mEq/L

Front 31

What are the 3 polyionic, pH balanced fluids?

Back 31

Normosol, lactated ringer's, plasmalytes
-polyionic= lots of different electrolytes, like plasma but no proteins

Front 32

What is the base present in lactated ringer's and normosol?

Back 32

Lactated Ringer's= lactate
Normosol= acetate

Front 33

What fluids do you give if you don't want to give salt?

Back 33

5% dextrose

Front 34

Saline (0.9% NaCl + water) is considered acidifying or basic?

Back 34

Acidifying

Front 35

What hypertonic fluid is typically used?

Back 35

Saline (Na+=154 (plasma=140) and Cl-=154, plasma=115)
OR 5-7% NaCl (1200 mEq/L of Na+ & Cl-)

Front 36

What happens when hypertonic fluids are used? What are hypertonic fluids used for?

Back 36

Very selective use: by increasing salt in vascular compartment water is sucked from intracellular compartment and EV-ECF into IV-ECF to dilute the salt, salt only stays there for ~20 m.
-Used for emergency treatment that needs to be followed by more conventional fluids, most effective for shock caused by acute blood loss

Front 37

What are 3 fluids that are administered orally?

Back 37

water, milk, calf electrolytes

Front 38

What are the 2 main "groups" of metabolic acidosis?

Back 38

-Bicarbonate loss (secretional)
-Organic acid production (lactic, keto-)= titrational

Front 39

**What fluids are used to treat metabolic acidosis due to bicarbonate loss?

Back 39

Bicarbonate loss is most responsive to fluids containing a base (LRs, normosol)

Front 40

**What is the approach to treating metabolic acidosis due to organic acid production with fluids?

Back 40

Treated by enhancing excretion or metabolism of the acid and halting its production

Front 41

True or false. Respiratory acidosis responds to fluids.

Back 41

False, ventilation!

Front 42

**How can the bicarbonate deficit per liter be estimated?

Back 42

Measured bicarbonate can be subtracted from desired bicarbonate (24 mEq/L)
-*total deficit=(24-x) x ECF % x BW

Front 43

A 500 kg cow has a blood bicarbonate of 12 mEq/L. What is the total bicarbonate deficit?

Back 43

total deficit= (24-12) x 0.3 x 500= 1800 mEq/L= what you need to give to animal to reach normal, realistically give over 4 hours

Front 44

Why do you have to be extremely careful when deciding on the rate of infusion of bicarbonate? When is this a big issue?

Back 44

If the infusion is too rapid than paradoxic cerebral acidosis will result
-HCO3- + H+ <------> H2CO3 <------> CO2 + H2O, CO2 is very permeable so it goes everywhere, once CO2 is in the brain then combines H2O---> H+ production
*big issue when not ventilating well, not an issue w/ normal ventilation
-Why you give bicarbonate deficit over 4 hours not 20 minutes

Front 45

When is acidosis considered an emergency? Why?

Back 45

pH <7.25, out of range for enzymatic function

Front 46

What is a base deficit when looking at a blood gas analysis?

Back 46

When the base excess is a negative number

Front 47

What form of bicarbonate is administered to replace a deficit? (2)

Back 47

-Alone as isotonic (1.3%) NaHCO3
-Added to another isotonic fluid, making it hypertonic

Front 48

True or false. Metabolic acidosis is rarely as severe or life-threatening as metabolic alkalosis.

Back 48

False, metabolic alkalosis is rarely as severe or life threatening as metabolic acidosis

Front 49

What is usually the treatment for metabolic alkalosis? What do you have to be careful of?

Back 49

administer fluids without any base buffer, like NaCl (saline), and correct the cause of the alkalosis
-remember NaCl doesn't have K+ so don't worsen hypokalemia

Front 50

What causes hypernatremia and hyperchloremia?

Back 50

-Loss of water without salt
-Too high of salt diet

Front 51

What fluids are given to animals with hyperchloremia/ hypernatremia?

Back 51

Fluids that mimic normal plasma (let kidneys pee out to return to normal)
-plasma, normosol
-oral fluids have low salt too

Front 52

What fluids are given to an animal in extreme cases (acute derangements) of hypernatremia/ hyperchloremia? Why?

Back 52

-Hypotonic fluids: 5% dextrose, .045% saline
-Acute so there has not been enough time for brain to generate idiogenic osmoles

Front 53

How does the rate of fluid administration vary b/w acute hypernatremia/ hyperchloremia and severe, chronic hypernatremia/ hyperchloremia? Why?

Back 53

If chronic and severe then the fluids must be given slowly to prevent fluid shifts into the CNS. In some cases hypertonic fluids are best

Front 54

What type of fluids do you give to correct hyponatremia?

Back 54

-Isotonic, polyionic fluids usually contain enough sodium to correct hyponatremia
-Hypertonic fluids containing supplemental NaCl or NaHCO3 are also safe

Front 55

What fluids do you NOT want to use to correct hyponatremia? What's the exception?

Back 55

In general we do not like to give solutions that are more than 2x normal tonicity (7% NaCl-hypertonic saline). Exception is hypertonic saline for shock.

Front 56

What is the treatment for hypochloremia?

Back 56

Usually best treated by treating concurrent hyponatremia or metabolic alkalosis

Front 57

***When is hypokalemia extremely common in large animals?

Back 57

Extremely common finding in hoofstock that have been off feed for any length of time
-most herbivores eat lots of K+ in diet and organic anions so pee out these organic acids and take a cation with them since Na+ is so well perserved its usually K+ so LAs tend to excrete lots of K+ when stop eating

Front 58

Anorexic large animals almost always develop hypokalemia, what are 3 exceptions?

Back 58

1) Horses w/ hyperkalemic periodic paralysis
2) Tumor lysis syndrome: releases intracellular K+ (usually means dying)
-also w/ severe, acute tissue necrosis
3) **Foals with a ruptured bladder bc K+ is extremely high in milk, so if can't pee but keeps drinking milk= hyperkalemia
-animals on high K+ diets that can't urinate

Front 59

Why don't we usually calculate the potassium deficit?

Back 59

Because blood concentration is a poor estimator of intracellular deficit (most of K+ is intracellular)

Front 60

What is the result of too rapid intravenous (or oral) infusion of potassium?

Back 60

Bradycardia and cardiac arrest

Front 61

****What is the general rule for the rate of administration of potassium?

Back 61

No more than 0.5 mEq/kg BW/ h of potassium
-REMEMBER PER HOUR, more cautious in horses

Front 62

How would you administer potassium to a 600 kg horse that is 10% dehydrated?

Back 62

0.5 mEq/kg/h x 600 kg = 300 mEq/h
0.1 x 600 kg= 60 L over 4 hours of time = 15 L per hour
300 mEq/hour / 15 L/ hour= 20 mEq/L
-In horses we don't give any more than 20-30 mEq/L per hour

Front 63

Do we worry more about the rate of K+ administration with maintenance or replacement?

Back 63

Replacement

Front 64

True or false. Hyperkalemia is very infrequent in hoofstock because their requirement for potassium is so high.

Back 64

true

Front 65

What can be given to combat severe hyperkalemia?

Back 65

Dextrose-containing fluids and insulin

Front 66

**How do you calculate the calcium deficit?

Back 66

Same method as bicarbonate
0.3 x BW (kg) x (normal-measured)

Front 67

What is normal calcium in all species?

Back 67

10 mg/dL

Front 68

You have a 400 kg horse that has a calcium level of 7 mg/dL. What is the calcium deficit?

Back 68

0.3 x 400 kg x (10 mg/dL - 7 mg/dL) x 10 dL/ L= 3600 mg= 3.6 g

Front 69

Why do you have to administer calcium slowly?

Back 69

Calcium is cardiotoxic, usually given over 2-4 hours added to other intravenous fluids

Front 70

How can you monitor for signs of hypercalcemia when administering calcium?

Back 70

Heart will slow down and speed up, then start to convulse

Front 71

***What can calcium NOT be given with? Why?

Back 71

Banamine- because banamine has bicarbonate and combines with calcium to form minerals= bad!!!!!
-don't combine banamine w/ lactated ringer's for same reason

Front 72

*What are the 2 types of calcium that are measured?

Back 72

-Blood gas tends to measured ionized calcium
-Panel looks at total calcium

Front 73

What are the units for calcium?

Back 73

mg/dL, but can switch machines to measure in mEq/L, LOOK AT UNITS

Front 74

What are 4 general causes of hypoproteinemia?

Back 74

1) Lack of production
2) Protein catabolism
3) Loss of protein
4) Leakage of protein into the EV-ECF

Front 75

How does hypoproteinemia complicate fluid therapy?

Back 75

B/c w/o blood protein crystalline solutions are poorly retained within IV-ECF and such fluids are either lost or leak into the interstitium--> edema (pulmonary)

Front 76

Hypoproteinemia complicates fluid therapy, so what is the rule of thumb when treating a patient in shock that also has hypoproteinemia?

Back 76

Initial protein values can be halved in the short term, but long term maintenance of an animal's total serum protein below 4 g/dL is likely to result in edema
-treat shock & follow with plasma
-ABCs of shock: airways, breathing, circulation- no protein involved!

Front 77

What is the best treatment for panhypoproteinemia or deficiency of specific proteins such as immunoglobulin or clotting factors?

Back 77

-Plasma (best)
-Synthetic colloids: mainly 6% hetastarch

Front 78

What kind of plasma do you give to replace immunoglobulins? clotting factors?

Back 78

-Immunoglobulins: fresh or frozen
-Clotting factors: fresh

Front 79

How do you calculate the protein deficit?

Back 79

-Protein deficit= .06 x bw x (1-PCV) x (desired(normal)-observed (bld wk or refractometer))
-looking at intravascular space (plasma volume- everything except RBCs)

Front 80

What is usually our goal for treating hypoproteinemia?

Back 80

Too expensive to replace entire deficit so just shoot to get over the 4 g/dL

Front 81

You have a 600 kg horse that has a total protein of 3 g/dL and a PCV of 33%. What is the protein deficit? If 1 L of plasma from a horse= 6g/dL how much plasma needs to be given?

Back 81

protein deficit= 0.06 x 600 x (1-.333) x (5 g/dL -3 g/dL)= 480 g
6 g/dL x 10 dL/L= 60 g/ L
60 g/L / 480 g = 8 L

Front 82

What's a normal total protein?

Back 82

6 g/dL

Front 83

What is the treatment for blood loss/ anemia?

Back 83

Crystalloids
-If oxygen carrying capacity affected transfusion should be considered

Front 84

When should a blood transfusion be performed w/ acute blood loss? Chronic blood loss?

Back 84

-Acute blood loss: when PCV in high teens
-Chronic: PCV can be as low as about 12% and appear clinically normal

Front 85

What needs to be done before a horse receives a blood transfusion?

Back 85

Cross-matching

Front 86

What should you look for in a horse blood donor?

Back 86

Donor that has had minimal opportunities to develop alloantibodies against other blood types (previous transfusion, exposure to fetal RBCs during gestation or parturition)
-typically use geldings

Front 87

What are the signs of an adverse reaction to a blood transfusion in a horse?

Back 87

Salivate, sweat, tremor, hives, tenesmus (so pass lots of feces), collapse, fever
-give slow for first 15 minutes, then speed up

Front 88

How should a blood transfusion be administered?

Back 88

Through filtered IV sets

Front 89

What are the 3 routes fluids can be administered?

Back 89

IV, SQ, or PO

Front 90

What are the advantages of oral fluids? Disadvantages?

Back 90

-Advantage: Cheaper, don't need to be sterile; hypo-, iso-, and hypertonic fluids may all be given
-Disadvantage: GI tract must be functioning somewhat for them to be absorbed

Front 91

What are the advantages of administered SQ fluids? Disadvantages?

Back 91

-Advantages: Do not require venous access
-Disadvantage: volume is often limited, most horse owners don't tolerate the blebs, don't give hypertonic fluids this way bc suck water out of IV-ECF, give dextrose fluids with caution bc potential for infection is high

Front 92

What are the advantages and disadvantages of IV fluids?

Back 92

-Advantages: can give any tonicity if given slowly- can go rapidly into blood stream (isotolic and small volumes of hypertonic can be given rapidly), most rapid correction
-Disadvantages: Require skill & equipment, fluids must be sterile

Front 93

What is the goal of maintenance fluids?

Back 93

Making up for what they're using & losing (supply day's needs rather than deficits)

Front 94

**What is the daily water requirement for horses? Cows?

Back 94

Horses: 4-6% of BW/d
Cows: 7-10% BW /d

Front 95

**What is the daily fluid requirement of neonatal calves and foals?

Back 95

~10% BW /d

Front 96

*What is the daily requirement of K+ in hoofstock?

Back 96

~ 1.2 mEq/kg/d
-this increases 20-50% for work or about 100% for lactation

Front 97

*What is the daily requirement of Ca+ for horses?

Back 97

40 mg/kg/d
-increases 50-100% for work, or about 150% for lactation

Front 98

*What is the daily requirement of Ca+ in cattle?

Back 98

30 mg/kg/d

Front 99

*How much calcium does each kg of milk contain?

Back 99

2 g

Front 100

*What is the typical administration of maintenance fluids to a horse?

Back 100

5% BW/d or 2 mL/kg/h
-many hospitalized cases require 2-3 times that to make up for higher demand or loss

Front 101

How do maintenance fluids differ b/w a horse and cow?

Back 101

similar for cow, but less calcium and K+ would be used