Flashcards in 12. Effective renal plasma flow Deck (13):

1

## Effective renal plasma flow ( eRPF) is ised to

### calculate plasma flow (RPF) and hence estimate renal function

2

## Effective renal plasma flow (eRPF) can be estimating using ... (why)

### para- aminohippurinc ( PAH) clearance because filtration and secretion is nearly 100% excretion of all PAH that enter kidney

3

## Effective renal plasma flow ( eRPF) calculation

### para- aminohippurinv ( PAH ) clearance = Upah x V/ Ppah

4

## renal blood flow (RBF) is the

### volume of blood delivered to the kidneys per unit time

5

## renal blood flow (RBF) - calculation

###
renal blood flow (RBF) = RPF / (1-Hct)

1-Hct =plasma

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## eRPG vs true renal plasma flow

### eRPF underestimates true renal plasma flow slightly

7

## • What substance's clearance is used to estimate renal plasma flow? Why?

### Para-aminohippurate (PAH); 100% of PAH is actively secreted from the proximal tubule into the urine (the renal vein PAH concentration is 0)

8

## • What is the formula for estimating the effective renal plasma flow (ERPF) using para-aminohippuric acid (PAH)?

### ERPF = urine PAH concentration times the urine flow rate divided by the plasma PAH concentration (UPAH × V/PPAH)

9

## • What is the formula for estimating renal blood flow (RBF) if renal plasma flow (RPF) is known?

### RBF = RPF divided by (1 - the hematocrit) (normally, RBF is double the RPF)

10

## • You infuse para-aminohippuric acid (PAH) into a patient. An hour later, you still detect a trace of PAH in the patient's blood. Why?

### Ten percent of renal blood flow goes to the kidney parenchyma rather than through the glomerulus; PAH in this blood is not filtered

11

## • Effective renal plasma flow ____ (overestimates/underestimates) true renal plasma flow by approximately ____%.

### Underestimates; 10 (because 10% of renal blood flow supplies the kidney parenchyma rather than passing through the glomerulus)

12

## • A man gets PAH. Plasma level (PPAH) is 2 mg/mL, urine level (UPAH) 550 mg/mL, urine flow (V) 4 mL/min. What is his ERPF (mL/min)?

### ERPF = CPAH (mL/min) = (UPAH × V)/PPAH = (550 × 4)/2= 1100 mL/min

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