A 60-year-old woman is evaluated in the hospital for decreased urine output on her third day of admission for severe gastroenteritis. Her vital signs show a blood pressure of 90/60 mm Hg and a heart rate of 110/min. Physical examination reveals dry mucous membranes and poor skin turgor. Laboratory studies are obtained to determine the etiology of her acute kidney injury:
| Laboratory Test | Value |
|---|---|
| Plasma sodium | |
| Plasma creatinine | |
| Urine sodium | |
| Urine creatinine |
Based on the laboratory results provided, what is the patient's fractional excretion of sodium (FENa) expressed as a percentage?
Cevap: 0.2 %
Cevap
0.2
The correct calculation yields a fractional excretion of sodium (FENa) of . FENa measures the percentage of filtered sodium that is excreted in the urine. It is calculated as the ratio of sodium clearance to creatinine clearance. In this patient with a history of severe gastroenteritis, hypotension, and signs of volume depletion, a FENa of less than is highly indicative of a prerenal state. The kidneys appropriately reabsorb sodium in response to decreased renal perfusion to restore intravascular volume.
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Anahtar Kavram
Calculating the fractional excretion of sodium (FENa) is a crucial step in evaluating acute kidney injury to distinguish between a prerenal etiology (FENa < 1%) and intrinsic renal pathology, such as acute tubular necrosis (FENa > 2%).