Furosemide Stress Test

Furosemide Stress Test to clarify resuscitative goals

Urine output is minimal despite inopressors, fluids, antibiotics w/ septic shock?

what to do? 

- Volume challenge

- Vasopressor challenge

- inotrope challenge

- Furosemide stress test

Two possibilities

- Kidneys are working "smart kidney" - decrease in urine output is adaptive response to conserve volume, hemodynamic manipulation (increased MAP or cardiac output) could improve renal perfusion, increase urine output, and avoid persistent kidney injury

- Intrinsic Kidney failure "Dumb kidney" - in need of hemodialysis

Furosemide Stress test

- Furosemide naive - 1mg/kg furosemide

- Not naive 1.5mg/kg 

>200ml urine produced over two hours, tubular function is intact and short term renal recovery is likely

<200ml urine "failed" furosemide stress test, renal dysfunction requiring dialysis

Physiology of Furosemide Stress Test (FST)

- glomerulus filtering fluid, proximal tubule is intact, active transport process, loop of henle must be intact, no obstruction