5 - Fluid and Electrolytes

Question 1

effective arterial blood volume is regulated by ___ balance

Answer 1

sodium

Question 2

ratio of ICF:ECF

Answer 2

2:1

Question 3

nl osmolarity

Answer 3

280-290

Question 4

formula for osmotic pressure

Answer 4

2*Na + gluc/18 + BUN/2.8

Question 5

osmolar gap

Answer 5

measured minus calculated

nl = 10 mosm/L

Question 6

substances that cause inc osmolar gap

Answer 6

methanol, ethanol, isopropanol, ethylene glycol
mannitol
contrast media
glycine

Question 7

effective solute

Answer 7

confined to 1 compartment > causes water to shift
ex hyperglycemia (w/ low insulin), contrast media, mannitol

Question 8

adding isotonic fluid will expand which volume compartment?

Answer 8

ECF

Question 9

how is ADH release controlled?

Answer 9

sense osmolarity - inc > ADH secretion

Question 10

V1 vs V2 effects of ADH

Answer 10

V1 - vasoconstriction, inc PG synth by kidneys

V2 - inc water reabs in kidney (inc AQP in DCT)

Question 11

PGs and ADH

Answer 11

PGs reduce action of ADH on collecting duct

Question 12

NSAIDs effect on water balance

Answer 12

water retention (via dec PGs > inc ADH action)

Question 13

2 scenarios in which ECV is expanded by EABV is diminished

Answer 13

CHF and cirrhosis

Question 14

3 renal indicators of low EABV

Answer 14

low FENA
low urine Na
high urine specific grav

Question 15

physical signs of dehydration

Answer 15

low bp
shock
orthostasis
dec skin turgor
dec CVP
tachycardia
hemoconcentration

Question 16

what does urine Na conc most closely represent?

Answer 16

EABV