Renal equations (Pg. 552-554)

Question 1

Equation - Renal clearance

Answer 1

= UxV/Px

Question 2

Equation - GFR

Answer 2

= Uinulin × V/Pinulin = Cinulin

= Kf [(PGC – PBS) – (πGC – πBS)]

Question 3

Normal GFR (Value)

Answer 3

≈ 100 mL/min.

Question 4

Equation - eRPF

Answer 4

= UPAH × V/PPAH = CPAH

Question 5

Equation - Renal blood flow

Answer 5

= RPF/(1 − Hct).

Question 6

Equation - Filtration fraction

Answer 6

= GFR/RPF

Question 7

Normal filtration fraction

Answer 7

= 20%.

Question 8

Equation - Filtered load

Answer 8

= GFR × Px

Question 9

Equation - Excretion rate

Answer 9

= V × Ux

Question 10

Equation - Reabsorption rate

Answer 10

= filtered – excreted

Question 11

Equation - Secretion rate

Answer 11

= excreted – filtered

Question 12

Equation - FeNa

Answer 12

= Na excreted / Na filtered
= UNa × V / GFR (UCr × V/ PCr ) × PNa
= UNa × PCr / UCr × PNa

Question 13

Henderson-Hasselbach equation

Answer 13

pH = 6.1 + log ([HCO3-]/0.03 PCO2)

Question 14

Winters formula?

For what?

Answer 14

PCO2 = 1.5 [HCO3-] + 8 +/- 2

Predicted respiratory compensation for a simple metabolic acidosis

If measured PCO2 > predicted PCO2 —> concomitant respiratory acidosis

If measured PCO2 < predicted PCO2 —> concomitant respiratory alkalosis

Question 15

Anion Gap

NL?

> NL?

Answer 15

= Na - (Cl + HCO3)

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