IV fluid prescribing

Question 1

Give the rough percentages of where water is found in the body

Answer 1

40% of total body weight is in intracellular fluid

20% of total body weight is in extracellular fluid - 20% of ECF is plasma and 80% of ECF is interstitial fluid

Question 2

What separates plasma from interstitial fluid?

Answer 2

capillary wall

Question 3

What separates interstitial fluid from the intracellular fluid?

Answer 3

cell membrane

Question 4

Is the cell membrane permeable to water, urea, Na, K?

Answer 4

Yes - water and urea

No - Na and K

Question 5

Is the capillary wall permeable to water, urea, na, K, plasma protein?

Answer 5

Yes - water, urea, na, K

No - plasma protein

Question 6

If you want to increase the fluid volume of the ECF but not the ICF, what would you use?

Answer 6

Saline solution IV

Question 7

if you want to increase the fluid volume of plasma only, what would you use?

Answer 7

Colloid IV

Question 8

How is thirst monitored?

Answer 8

Monitored by osmoregulators in hypothalamus. Rise in plasma osmolarity = thirst

Question 9

How does ADH and the RAAS system work to regulate body fluid?

Answer 9

Increase plasma osmolarity = ADH release, increase water reabsorption in the CD and late DCT
Low sodium and chloride concentration = RAAS system activated to increase reabsorption of ions and water