Pharmacology Ii- Fluids Used In Dehydration And Hypovolemic Shock

Front 1

How are crystalloids classified and what are some examples of each?

Back 1

replacement (lactated ringers, 0.9% sodium chloride, Normasol R)
Maintenance (Plasmalyte 56, Normasol M)
Dextrose solutions
by strict definition hypertonic saline is considered a hyperosmolar cystalloid

Front 2

How do different crystalloids differ in composition

Back 2

replacement= has electrolyte levels similar to normal values in plasma

maintenance- has an electrolyte level similar to that of the amount of electrolyts lost per liter of fluid or filtered in kidneys

Dextrose solution - have no electrolgytes and a large amount of dextrose to create an osmolality similar to that of plasma. The glucose is also converted to water once metabolized (some maintenance solutions will have dextrose and are a cross of a dextrose and maintenance solution)

Front 3

Why can replacement solutions be given quickly but not maintenance r dextrose solutions?

Back 3

replacement solutions have an electrolyte composition similar to plasma so they can be given quickly withou causing harmful electrolyte imbalance. Maintenance solutions have an increased amt of potassium which may quickly elevate potassium levels if given to quickly. They also have less Na and Cl so if given rapidly they would decrease Na and Cl. Some are hyposmolar and this may cause damage to red cells.
-Dextrose solutions would cause an excessive increase in dextrose if given to quickly and would decrease all electrolyte levels if givens quickly

Front 4

How are replacement, maintenance and dextrose solutions used in treatment of dehydration and hypovolemia?

Back 4

Replacement solutions are solutions that have electrolyte levels similar to plasma. They are used in patients with evidence of interstitial fluid loss to replace the replacement requirements and ongoing losses. Best for treating hypovolemic shock because they can replace vascular volume in shcok (improve preload) without altering the electrolyte composition

Maintenance- has an electrolyte composition similar to that of the amount of electrolytes lost per a liter of fluids lost or filtered in the kidneys. Maintenance solutions are used to replace normal daily fluid and electroyte losses. They are not used in shock.

Dextrose solutions- provides free water without giving a hyposmolar solution. Dextrose is rapidly converted to free water via metabolism in the body. It is used to repalce fluid in al lcompartments caused by pure water loss. Pure water loss can occur due to no access to water or other reasons. It will result in more evere intracellular losses. Pure water losses cause increases in electrolytes like sodium therefore these fluids can replace these losses without increasing electolytes.

Front 5

What effect will replacement fluids have on preload, afterload, heart rate and cardiac output in hypovolemic shock?

Back 5

Increase preload by restoring vascualr volume which will improve cardiac contractility and increase stroke volume and therefore cardiac output.

They will reflexly decrease afterload because as vascular volume is restored there will be less vasoconstriction.

Heart rate will decrease
The end result will be improved blood pressure and blood flow with less work load on the heart

Front 6

Why are buffers added to some replacement and maintenance solutions?

Back 6

they provide a buffer that is converte to bicarbonate to counteract any metabolic acidosis.
Examples: sodium lactate, gluconate, and acetate

Front 7

By what routes can replacement solutions be given?

Back 7

all routes

Front 8

By what route can maintenance solutions be given?

Back 8

all routs but typicall IV slowly

Front 9

By what routes are dextrose solutions given?

Back 9

only IV and Orally when used in treatment of pure water loss dehydration and hypoglycemia.

Front 10

What are complications of crystalloids?

Back 10

Fluid overload
dilution of clotting factors, red blood cells and proteins,
hyperkalemia with maintenance solutions
hyperglycemia with dextrose solutions
dextrose can irritate vein and cause skin sloughing if given SC

Front 11

Can dextrose solutions be given as a nutritional fluid?

Back 11

No, they do not have enough energy but can be used to maintain normoglycemia in hypoglycemic patients

Front 12

How are replacement solutions sometimes made into a maintenance like solution?

Back 12

by adding KCl. This will increase potassium so that there is enough potassium to repalce losses. The excess Na+ and Cl- will be excreted by fxnal kidneys

Front 13

What are some examples of synthetic and natural colloids

Back 13

Synthetic= dextrans hetastrach, pentastrach

natural: plasma or human albumin

Front 14

how do colloids differ from crystalloids?

Back 14

colloids contain large molecules that cannot cross the endothelial surface. These molecules increase osmoality without being able to cross the endothelium they are called colloids. They are able to hold fluid in vessel

Front 15

What are synthetic colloids used for?

Back 15

shock

Front 16

why do some people feel colloids are superior to crystalloids in hypovolemic shock?

Back 16

they fill vascular space more rapidly with less volume

Front 17

what is the duration of most synthetic colloids?

Back 17

12-24 but may be less based on colloid used and disease process (less if have vasculitis or protein losing diarrhea)

Front 18

why are colloid doses generally limited to 20ml/kg in 24 hours?

Back 18

-larger doses may cause bleeding abnormalities (by decreasing vWF)
Stay in vascular space so less need to be given compared to a crystalloid and they willallow you to reduce the dose of crystaloids

Front 19

Why is plasma not generally used as a colloid?

Back 19

one unit does not contain enough albumin to give a significant oncotic effect in particular with large dogs or large animals.

Front 20

What is the problem with human albumin in veterinary medicine?

Back 20

it has been shown to cause life threatening allergic reaction (type 1 and 3 reaction) in dgos
-canine albumin is new on the market

Front 21

Other side effects of colloids include:

Back 21

fluid overload
may be contraindicated in renal disease because small molecules may ostruct renal tubules when filtered

Front 22

how does hypertonic saline differ from a colloid?

Back 22

it can cross the intravascular space and therefore is not a colloid. However, rapid infusion will increase sodium levels enough to pull fluid into the vessel for a short period of time
- It may be combined with a colloid to increase volume rapidly and have a substained effect

Front 23

when is hypertonic saline used and not used?

Back 23

- used in shock (blood loss, gastric dilatation and volvulus) except for shock due to severe dehydration. This is because in dehydrated the patient has no fluid to pull from the intracellular space.

Front 24

Why may hypertonic saline be good in head trauma?

Back 24

head trauma is often associated with swelling of the brain cells which can be harmful (cerebral edema). It can remove this excess fluid from the brain

Front 25

what are side effects of hypertonic saline?

Back 25

reflex bradycardia, bronchoconstriction and hypotension if given too quickly
- hypernatremia if give too much.