Fluids

Question 1

Describe the distribution of the total body water in dogs/cats

Answer 1

TBW- 66% in the cell 34% is extracellularly

25% (70% of ECF) is interstitial; and 9% (30% oftheECF) is in the vessel

Question 2

What are the approximate values of the major electrolytes in the extracellular and intracellular fluid compartments

Answer 2

Extracellular: Na 145; Cl 110 Intracellular: K 140 mEq/L and Mg 35 mEq/L

Question 3

What is electroneutratility

Answer 3

is the concept that intracellular and extracullular will add up to zero (mEq/L)

Question 4

Gibbs Donan effect

Answer 4

the behavior of charged particles near a semi-permeable membrane that sometimes fail to distribute evenly across the two sides of the membrane

Question 5

Convert mEq to milimoles

Answer 5

mEq = milimoles x valance

Question 6

Discuss effective vs. ineffective osmoles and toncitiy

Answer 6

Tonicity- ability to hold water; osmolarity; Isotonic replacement (solution that does cause achange in the size of red cell); Effect osmolarity
Osmolalrity: The concentration of a solution expressed as the total number of solute particles per kilogram

Question 7

What is the total osmolality

Answer 7

2 (Na+K) + BUN/2.8 + Glu/18

Question 8

Effective osmolality caluclation

Answer 8

2 (Na+K) + Glu/18

Question 9

Whate is the osmolal gap

Answer 9

Difference is between the measured and calculated. Normal -2 to 5

Question 10

Define Colloid

Answer 10

Osmotically active > 32 kdaltons

Question 11

Whate is normal plasma COP for dogs and cats

Answer 11

~20

Question 12

Describe net filtration of fluid in the capillary including a being able to discuss and apply Starling’s law

Answer 12

Out is 0.3-.5 filtration in the arteries; In is 0.3-0.5 favors reabsorption in venules

Question 13

What is the effect of the endothelial glycocalyx on fluid flux in the capillary and how does this differ from fluid movement originally described by the starling equation

Answer 13

The endothelial glycocalyx is the primary barrier to microvascular filtration
Colloid osmotic pressure of the fluid on the interstitial side of the glycocalyx and within the endothelial clefts has a more direct effect on filtration than that of the free interstitial fluid.
Reversal of fluid flow across the microvascular barrier upsets this colloid osmotic pressure gradient and limits fluid reabsorption by the microvasculature

Question 14

Describe the net effect on the effective circulating volume if loss is a hypotonic fluid

Answer 14

will result in increases in ECF osmolality, reflected by increased in serum sodium concentration. As a consequence, water will move from the ICF compartment to the ECF compartment until osmolality is equalized. The loss of ICF volume has the greatest impact on the central nervous system, and if the degree of soule-free water loss is severe and acute it can result in neurologic abnormalities and possibly death ias a result of neuronal cell shrinkage. The effective circulating volume is preserved- overall though less total body water

Question 15

Describe the net effect on the effective circulating volume if loss is a isotonic fluid

Answer 15

The ECF will cause changes in the ECF volume with little change in ECF osmolality, and hence there will be no change in the ICF volume. Will lead to interstitial dehydration. Isotonic fluid gain would cause interstitial overhydration

Question 16

Describe the net effect on the effective circulating volume if loss is a hypertonic fluid

Answer 16

: a drop in ECF osmolality results and provides a gradient for water to move into the ICF compartment leading to cell swelling- net decrease

Question 17

Describe the effects of administration of hypotonic on the effective circulating Volume.

Answer 17

lower of osmolarity and sodium concentration. 5% dextrose in free water is a unique isosmotic solution with hypotonic effects because dextrose is rapidly metabolized and free water remains. Replenish free water deficits and useful for treating animals with hypernatremia . hypotonic fluids distribute throughout both intracellular and extracellular fluid compartments, with less remaining extracellularly in comparison to isotonic fluids. Should not be bolused. Depends on the fluid type that you give

Question 18

Describe the effects of administration of isotonic on the effective circulating Volume.

Answer 18

useful for hypovolemic shock; does not cause significant fluid shifts between intracellular and extracellular fluid compartments in normal animals. Used for dehydration with losses that are hypotoic/isotonic

Question 19

Describe the effects of administration of hypertonic on the effect on circulating volume

Answer 19

high osmolarity and sodium concentration such as 7.5% saline. Causes a free water shift from the intracellular space to the extracellular space; expands the extracellular fluid volume by 3-5 times volume administered. Hypertonic saline is used for the therapy of hypovolemic shock, intracranial hypertension and severe hyponatremia. The intravascular volume expansion effect to hypertonic saline is transient (<30 mins) because of the redistribution of electrolytes throughout the extravascular space.

Question 20

Define urine osmolality

Answer 20

is the number of molecules (unaffected by the size of the molecules) per kilogram of water and must be measured by an osmometer. Used to assess the concentrating ability of the kidney and should be interpreted along with the hydration and volume status of the patient

Question 21

Define urine specific gravity

Answer 21

assess renal concentrating ability because it is easier to measure. Is a ratio of the density of a susbatance compared to water, so it is affected by the number of molecules and their molecular weights.

Question 22

How are urine osmolality and urine specific gravity related? And when does this relationship fail?

Answer 22

Normally USG and urine osmol are linearly correlated. If many high molecular weight molecules are present in the urine, USG will overestimate the urine solute concentration whereas the urine osmolality remains accurate. Interfere with USG include albumin, synthetic colloids and iohexal, lipoproteins. Synthetic colloids- at 6 hrs at difference, differengce at 18 hrs- not in reading reading list; first pee okay, not the second

Question 23

What is urine osmolality was useful for?

Answer 23

differentiating sodium disorders, identifying the syndrome of inappropriate antidiureic hormone, differentiating perrenal from renal causes of azotemia and diagnosing diabetes insipidus

Question 24

Whate are the 3 general phases of fluid therapy

Answer 24

Resuscitation, rehydration, and maintence

Question 25

What is the law of physics that governs the flow of fluids through a tube

Answer 25

Poiseuille’s Law: that the flow of fluid is related to a number of factors: the viscosity of the fluid, the pressure gradient across the tubing the length and diameter of the tubing. Doubling the diameter of a catheter increases the flow rate by 16 (r4). The larger the IV catheter the greater the flow; Also want the shortest length of tubing to maximize flow

Question 26

Discuss the methods (physical exam, or labs) of monitoring IV fluid therapy

Answer 26

Body weight gain. Assessment of hydration: plasma osmolality, urine osmolality, urine specific gravity, PCV, total protein, serum sodium concentration

Question 27

What physical exam findings are associated with overhydration/volume overload

Answer 27

Serous nasal discharge, chemosis, juguar venous distension, interstitial pitting edema; increased respiratory rate/ crackles wheezes.

Question 28

What are some of the complications of IV fluid therapy

Answer 28

Organ edema with volume overload; electrolyte imbalances, changes to the gastrointestinal tract resulting in decreased motility, increased interstitial permeability. Increased risk of ventricular arrhythmias, disruption of cardiac contractility, decreased cardiac output. Starling’s myocardial performance curve

Question 29

What buffers are used in the currently available IV fluid preparations/ metabolized?

Answer 29

LRS- Lactate- liver; Norm-R - acetate- Gluconate; Plyte- acetate/lactate

Question 30

What is the most common complication of rapid administration of hypertonic saline

Answer 30

hypernatremia; risk for hypernatremia induced central pontine myelolysis when administered to patients with pre existing chronic hyponatremia; Used cautiously in patients with cardiac or pulmonary abnormalities because of the increase in intravascular volume and hydrostatic pressure may lead to volume overload and pulmonary edema. Also may cause significant interstitial volume depletion, particularly in patients that are already dehydrated

Question 31

Whate complications have been associated with the use of synthetic colloid fluids

Answer 31

Acute kidney injry, coagulopathy, pulmonary edema

Question 32

Discuss the pros and cons of the use of human serum albumin in canine and feline patients

Answer 32

Immune mediated reactions have been noted for up to 4 weeks afterwards, therefore needs to be monitored even after improved. Studies in healthy dogs show anaphylactoid reactions after a single infusion and after a second infusion; however in critically ill dogs, results in survivors showed improved albumin and total protein. Acute hypersensitivity type 1 reactions were not reported in critically ill dogs

Question 33

What are the mechanisms of coagulopathy associated with use of synthetic colloids?

Answer 33

Either through hemodilution – non specific vs. specific actions of macromolecules on platelet function, coagulation proteins and fibrinolytic system. High molecular weight starches can cause decrease in the activity of von Willebrand’s factor and its associated factor VIII and risotcetin cofactor activities. And platelet dysfunction

Question 34

Whate is pressure diuresis

Answer 34

urine output can double when intravascular volume and pressure increase even a few millimeters of mercury above normal. Concomitant sodium loss occurs- if diuresis goes undetected then all electrolytes may be excreted in urine because of decreased reabsorption in the proximal and distal renal tubules.

Question 35

Whate dictates the rate and total volume of fluid shift after administration of IV fluids?

Answer 35

Starling forces, types of fluid, disease process- ex. Sepsis

Question 36

Over approximately how long do rehydration fluids need to be administered

Answer 36

4-24 hrs