Fluids Flashcards
Water compartments in the body
65% of the body is water
2 main compartments:
intracellular: 2/3
extracellular: 1/3
- interstitial 75%
- intravascular 25%
intracellular sodium and potassium
low sodium
hi potassium
extracellular sodium and potassium
hi sodium
low potassium
hyponatremia =
water excess
hypernatremia
water loss
General types of fluid loss/reasons to give fluids
- loss of fluids from interstitial space = dehydration
- loss of fluid from intravascular space = hypovolemia
describe loss of fluids from the interstitial space
This is a result of dehydration that usually occurs slowly over days to weeks and needs to be replaced slowly
describe the loss of fluid from the intravascular space
This is a result of hypovolemia which is more rapid and will require more rapid restoration
describe crystalloid fluids
These are essentially salt water that freely moves within the extracellular space and redistributes into the interstitium rapidly.
- you will see the greatest increase in blood volume with crystalloids
- large volume with transient effect
describe colloid fluids
These contain molecules that don’t readily leave intravascular space so theoretically they stay in the intravascular space. There is a potential for interstitial leakage leading to edema formation or changes in coagulation, kidney injury and high cost.
Explain isotonic fluids and when you would use them
Isotonic fluids have the same makeup as ECF. Often these are given for dehydration and these fluids just go where they’re needed into the intravascular and interstitial compartments. We expect no net change between the ECG and ICF.
Isotonic fluids examples
Lactated ringers
Normal saline
Normasol R
Plasmalyte A
Explain hypotonic fluids and when you would use them
These is rarely administered, give to patients who don’t need a lot of salt for maintenance needs. These can still cause fluid shift into the cells so administer slowly because too fast may lead to hemolysis.
examples of hypotonic fluids
Normasol M
0.45% NaCl
D5W
Plasmalyte 56
Explain hypertonic fluids and when you would use them.
Hypertonic solutions have more sodium than the ECF. When you administer it into the IV space water will move in an out to find equilibrium and water is pulled from the interstitial and intracellular compartment. Avoid administering this to dehydrated or hypernatremic patients.
crystalloid shock bolus
10-20 ml/kg bolus
colloid shock bolus
5-10ml/kg bolus
maintenance fluid rate
~ 50 ml/kg/day
less for large, more for small dogs
