L3 Body Fluids

Question 1

What is the 60-40-20 rule?

Answer 1

60% of body weight is total body water

40% of body weight is ICF

20% of body weight is ECF

(So 2/3 of total body water is ICF)

Question 2

What percentage of the extra cellular fluid is institial fluid v plasma?

Answer 2

3/4 interstitial fluid

1/4 plasma

Question 3

What is the equation for Total Body Water (in someone whose % body fat is known)

Answer 3

TBW= 0.7LBM + 0.1AT

Question 4

What is the equation for TBW in someone whose Lean body mass is not known?

Answer 4

TBW= 0.6(Weight)

Question 5

What are the major cations and anions in ECF?

Answer 5

Cation: Na+

Anions: Cl- and HCO3-

Question 6

What are the major cations and anions in ICF?

Answer 6

Cation: K+

Anion: proteins and organic phosphates

Question 7

What is the calculation for estimating plasma osmolarity?

Answer 7

Osmolarity= 2Na + Glucose/18 + BUN/2.8

Question 8

Where must any gain of water/electrolytes initially occur?

Answer 8

ECF

Question 9

What happens to TBW, Plasma protein and hematocrit if you give a pt 1 liter of isotonic saline?

Answer 9

TBW: increase

Plasma protein: decrease

Hematocrit: decrease

Question 10

What is it called when you gain isotonic fluid?

Answer 10

Isosmotic volume expansion

Question 11

What happens to TBW, Plasma protein and hematocrit if a pt loses isotonic solution ( ex. Diarrhea)

Answer 11

TBW: decrease
Plasma protein: increase
Hematocrit: increase

Question 12

What is it called when a pt loses isotonic solution

Answer 12

Isosmotic volume contraction

Question 13

What happens to TBW, Plasma protein, and hematocrit if a pt gains hypotonic solution? Ex drinking pure water

Answer 13

TBW: increases
Plasma protein: decreases
Hematocrit: decreases slightly due to RBCs swelling

Question 14

What is it called when you gain hypotonic solution?

Answer 14

Hyposmotic volume expansion

Question 15

What would happen to TBW, plasma protein, and hematocrit if you lose hypotonic solution? Ex sweating

Answer 15

TBW; decrease
Plasma protein: increase
Hematocrit: increases slightly, because RBCs are also shrinking

Question 16

What is it called when you lose hypotonic solution like from sweating?

Answer 16

Hyperosmotic volume contraction

Question 17

What happens to TBW, plasma protein and Hematocrit if you gain a lot of sodium?

Answer 17

TBW: unchanged (just moves from ICF to ECF)
Plasma protein: decrease
Hematocrit: Really decreased because water moves into ECF and RBCs shrink as well

Question 18

What is it called when you gain a lot of sodium?

Answer 18

Hyperosmotic volume expansion

Question 19

What would happen to TBW, Plasma protein, and hematocrit if you were to lose sodium (Ex aldosterone insufficiency)

Answer 19

TBW: unchanged (would just move from ECF to ICF)

Plasma protein: decreased

Hematocrit: increased a lot because water leaves ECF into ICF and the RBCs swell

Question 20

What is it called when you lose a lot of sodium/

Answer 20

Hyposmotic volume contraction

Question 21

What would happen to TBW, Plasma protein, and hematocrit if you gave a pt an isotonic glucose infusion?

Answer 21

TBW: Increases! Due to byproducts of glucose metabolism

plasma protein: decreases

Hematocrit: decreases slightly, due to water from metabolism going to ECF, but RBCs swell because it is hypotonic

Question 22

High NaCl intake would have what effect on ECF volume?

Answer 22

Volume expansion

Question 23

Aldosterone insufficiency would have what effect on ECF volume?

Answer 23

Volume contraction (it’s like losing salt)