Renal sonography in the intensive care unit: when is it necessary?
OBJECTIVE
To evaluate the efficacy of renal sonography performed in intensive care units on patients with the diagnosis of acute or acute-on-chronic renal failure.


METHODS
We reviewed all renal sonograms performed in our institution during 1 year on critically ill patients for evaluation of renal failure. Renal failure was defined as a serum creatinine level greater than 1.5 mg/dL or an increase of greater than 20% from the baseline creatinine level. Exclusion criteria included patient age younger than 18 years and signs or symptoms of obstructive uropathy. Using the electronic medical record, we recorded patient age, sex, blood urea nitrogen level, serum creatinine level, blood urea nitrogen-creatinine ratio, and clinical indication for intensive care unit admission. Sonographic reports were reviewed for the presence or absence of hydronephrosis. The total cost of these examinations was estimated with the use of Medicare reimbursement rates for 2000.


RESULTS
One hundred five renal sonographic examinations were performed on 104 patients meeting all inclusion criteria. Only 1 study had positive results for hydronephrosis, which was graded as mild. Incidental findings not immediately affecting patient care and including ascites and simple renal cysts were identified in 91 patients. The estimated total cost of the examinations was $13,350.75.


CONCLUSIONS
In critically ill patients with acute renal failure and no physical findings suggesting obstructive uropathy, renal sonography to evaluate for hydronephrosis is probably not indicated. This holds true regardless of patient age, sex, medical or surgical disposition, and blood urea nitrogen-creatinine ratio.
Keyserling
Harold F
HF
Department of Radiology, University of North Carolina at Chapel Hill, 27501, USA.
Fielding
Julia R
JR
Mittelstaedt
Carol A
CA
D058186:Acute Kidney Injury / Q000000981:diagnostic imaging* / Q000191:economics / Q000209:etiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001806:Blood Urea Nitrogen; D003365:Costs and Cost Analysis; D003404:Creatinine / Q000097:blood; D016638:Critical Illness; D005260:Female; D006300:Health Services Misuse; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging* / Q000191:economics; D007362:Intensive Care Units; D007668:Kidney / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography / Q000191:economics; D014481:United States
D003404:Creatinine