A physician is treating a patient exhibiting symptoms of impaired renal function following a massive hemorrhage.The physician orders a serum sodium and a PAH clearance test.The patient has a serum PAH of 1.0 mg/dL,urine PAH of 200 mg/dL,and a urine volume of 240 mL in 2 hours.The serum sodium is decreased.
-Calculate the patient's renal blood flow using the information provided.
A) 100 mL/min
B) 200 mL/min
C) 300 mL/min
D) 400 mL/min

Question

Quizplus · Accepted Answer

Renal blood flow (RBF) can be calculated using the PAH clearance method. PAH clearance = (Urine PAH concentration x Urine flow rate) / Plasma PAH concentration. Urine flow rate = 240 mL/120 min = 2 mL/min. PAH clearance = (200 mg/dL x 2 mL/min) / 1 mg/dL = 400 mL/min. Since PAH clearance approximates renal plasma flow, and renal blood flow = renal plasma flow / (1 - hematocrit), assuming a typical hematocrit, the RBF is approximately 400 mL/min.

A Physician Is Treating a Patient Exhibiting Symptoms of Impaired