Body Fluid Compartments

Question 1

what is the normal osmolality that we should look for

Answer 1

290 mOsm

Question 2

how do you calculate total body water TBW

Answer 2

0.6*BW(body weight)

Question 3

what is the third space

Answer 3

transcellular compartment or locations that the body should not have water

Question 4

how do you calculate ICF or intracellular fluid

Answer 4

0.4*body weight OR 2/3 of TBW(total body water)

Question 5

how do you calculate ECF or extracellular fluid

Answer 5

0.2*BW or 1/3 of TBW

Question 6

how do you calculate interstitial fluid

Answer 6

0.75*ECF

Question 7

how do you calculate plasma volume

Answer 7

0.25*ECF

Question 8

How do you calculate venous volume

Answer 8

0.8*plasma volume

Question 9

how do you calculate ECV or effective circulating volume

Answer 9

0.2*plasma volume

Question 10

what age group has the highest percentage of TBW

Answer 10

infants and this goes down with age

Question 11

where do we gain water input

Answer 11

drinking, food, and carb metab

Question 12

where do we lose water

Answer 12

feces, sweating, insensible perspiration, and urine

Question 13

what are our main extracellular ions

Answer 13

Na and Cl

Question 14

what are our main intracellular ions

Answer 14

K

Question 15

where are protein levels highest

Answer 15

in ICF and vascular compartments

Question 16

what are the main proteins we are concerned with

Answer 16

albumin and globulins

Question 17

what can be used to help measure plasma volume?

Answer 17

albumin that is radiolabeled

Question 18

what can’t we measure directly

Answer 18

ICF and ISF

Question 19

how do we measure TBW experimentally

Answer 19

heavy water or antipyrine

Question 20

how do we measure ECF experimentally

Answer 20

heavy Na, l-iothalamate, thiosulfate, inulin

Question 21

what is the gibbs donnan effect

Answer 21

the negative charge of proteins within the vasculature causes the Na+ and K+ concentrations to be slightly higher than expected

Question 22

what is ECF osmolality driven by

Answer 22

Na

Question 23

where is the most Na found

Answer 23

vasc>interstitium>ICF due to action of NaK ATPase

Question 24

what does a disrupted NaK pump cause an increase in

Answer 24

ICF [Na] this causes cellular swelling

Question 25

what is ICF osmolality driven by

Answer 25

K

Question 26

what are the two ways to estimate plasma osmolality

Answer 26

2*[Na] 2*[Na] + glucose/18 + urea/2.8

Question 27

the ECF and ICF are highly permeable to what

Answer 27

water but NOT electrolytes

Question 28

the capillary membrane is highly permeable to what

Answer 28

small ions which drive the starling forces

Question 29

what main force favors filtration? opposes filtration

Answer 29

Pc; Pi_c

Question 30

what are some common causes that increase Pc

Answer 30

- increased arterial pressure - increased venous pressure - decreased precapillary resistance - increased postcapillary resistance

Question 31

almost all capillaries have a precapillary resistance > postcapilllary resistance except for

Answer 31

glomerular

Question 32

what decreases Pc

Answer 32

- decreased arterial pressure - decreased venous pressure - increased precapillary pressure - decreased postcapillary pressure

Question 33

how are hepatic capillaries different than renal capillaries

Answer 33

hepatic are highly permeable to proteins and Pi_c plays a little role in fluid exchange for them

Question 34

what is the full formula for capillary filtration

Answer 34

Kf [(Pc-Pi)-(Pi_c-Pi_i)]

Question 35

what does Kf stand for in capillary filtration

Answer 35

permeability coefficient

Question 36

ECF ___________ controls ICF volume

Answer 36

osmolality

Question 37

what are some general factors to think of when looking at changes in ECF and ICF

Answer 37

1. All solutes and water that enter or leave the body do so via ECF. 2. ICF and ECF are in osmotic equilibrium. 3. Equilibration occurs primarily by shifts of water, not solutes.

Question 38

what are some factors that affect ECF/ICF

Answer 38

- water ingestion - dehydration - IV infusions - diarrhea or vom - sweating - diuresis - disease (IBS, DM, hypoaldosteronism, SIADH)

Question 39

what changes does excessive intake of NaCl and hyperaldosteronism cause to fluid levels

Answer 39

increased ECF, which decreases ICF and increased ECF mOsm and ICF mOsm

Question 40

what changes does water gain cause to fluid levels

Answer 40

increased ECF and ICF, decreased ECF and ICF mOsmq

Question 41

what changes does dehydration cause to fluid levels

Answer 41

decreased ECF and ICF, and increased ECF mOsm and ICF mOsm

Question 42

what change does NaCl loss (adrenal insufficiency) cause to fluid levels

Answer 42

increased ICF; decreased ECF, ECF mOsm, ICF mOsm

Question 43

what are the ranges we define as hyper natremia and hyponatremia

Answer 43

plasma >146 mEq/L | plasma < 136 mEq/L

Question 44

what changes do we see in the darrow yannet diagrams for fluid retention? excretion

Answer 44

fatter and shorter | narrower and taller

Question 45

what type of IV fluids can stay in the ECF or distribute depending on composition? which stay in the vascular space?

Answer 45

crystalloid fluids (normal saline, lactated Ringers); dextran or albumin

Question 46

isoosmotic or isotonic solutions have the same osmolatlity as _____

Answer 46

the ECF

Question 47

hyperosmotic or hypertonic solutions have an osmality (higher/lower) than the ECF

Answer 47

higher

Question 48

hypoosmotic or hypotonic solutions have an osmality (higher/lower) than the ECF

Answer 48

lower

Question 49

adding a isoosmotic solution changes what

Answer 49

only the volume in the ECF

Question 50

adding hyperosmotic solutions do what

Answer 50

increases Osm in the ECF which decreased ICF and increased ECF

Question 51

what do hyposomotic solution do

Answer 51

when added to ECF, Osm decreased and water moves out of the ECF and into the ICF to equilibrate which causes both ICF and ECF volumes to increase

Question 52

what would you administer to dilute the ECF and rehydrate cells

Answer 52

hypotonic solution

Question 53

what would you administer to replace fluid loss and expand intravascular volume

Answer 53

isotonic solution

Question 54

what would you give to treat severe hyponatremia

Answer 54

hypertonic solution

Question 55

what happens in CHF that exacerbates the edema issue

Answer 55

Pc is already increased so edema occurs, kidneys hold onto more water to increased vascular volume, this causes more edema

Question 56

what happens to fluid levels in renal disease

Answer 56

Na and H2O are inappropriately retained which causes an increase in Pc and edema results

Question 57

what causes edema in liver disease, malnutrition, and nephrotic syndrome

Answer 57

decreases in Pi_c because protein synthesis is affected