[Acute kidney failure. Non-invasive diagnosis of acute kidney failure in operative intensive care patients]

Abstract

Acute renal failure is a common and severe complication in ICU. Renal laboratory examinations like creatinine and urea are late signs of renal dysfunction: Most of the functional abilities are reduced and there is no time for therapeutical interventions. The aim of this study was to find some earlier sensitive parameters of renal dysfunction and the order of appearance, the cause of acute renal failure and the value of the measured parameters.

Methods: After agreement of the local ethic committee, 21 patients of the ICU were investigated. They were divided into two groups: 1st (n = 14) with no signs of renal dysfunction and were regarded as control group and 2nd (n = 7) were examined until the beginning of acute renal failure. For five days the glomerular filtration rate, proteinuria (immunoglobulin G, Tamm-Horsfall protein, alpha-1- and beta-2 microglobulin, lysozyme), the brush border enzymes angiotensinase A and the lysosomal enzyme N-acetyl-beta-d-glucosaminidase were daily measured and compared with clinical standards like the excretion of albumin, the clearances of creatinine and urea and the fractional excretion of sodium.

Results: Both groups were comparable with respect to drug therapy, APACHE-II-score (with the exception of the last day before ARF), and infusion therapy. There were differences in tubular functions between the 2 groups. Patients developing renal insufficiency showed an increased excretion of alpha-1-microglobulin, and decreased excretions of Tamm-Horsfall-protein, angiotensinase A as well as a low renal blood flow. Significant differences were also detectable in glomerular functions (glomerular filtration rate), albumin, and immunoglobulin G.

Discussion: Only a short time interval (1 to 2 days) between tubular and glomerular damage were detectable in patients with renal insufficiency. Renal failure must be due to circulatory problems because of the nearly simultaneous increase of tubular and glomerular parameters after RPF decreased. The parameters alpha 1-microglobulin, angiotensinase A and Tamm-Horsfall-protein gave early indications for the acute renal failure. They showed satisfactory sensitivity and specificity, but the positive predictive value was poor.