NONINVASIVE DIAGNOSIS OF ACUTE-RENAL-FAIL URE IN INTENSIVE-CARE PATIENTS

Acute renal failure is a common and severe complication in ICU. Renal laboratory examinations like creatinine and urea are late signs of ren al 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 th e order of appearance,the cause of acute renal failure and the value o f the measured parameters. Methods: After agreement of the local ethic committe, 21 patients of the ICU were investigated. They were devided into two groups: 1 st (n = 14) with no signs of renal dysfunction and were regarded as control group and 2nd (n = 7) were examined until th e beginning of acute renal failure. For five days the glomerular filtr ation rate, proteinuria (immunglobulin G, Tamm-Horsfall protein, alpha -1- and beta-2 microglobulin, lysozyme), the brush border enzymes angi otensinase A and the lysosomal enzyme N-acetyl-beta-d-glucosaminidase were daily measured and compared with clinical standards like the excr etion of albumin, the clearances of creatinine and urea and the fracti onal excretion of sodium. Results: Both groups were comparable with re spect to drug therapy,APACHE-Il-score (with the exception of the last day before ARF),and infusion therapy. There were differences in tubula r functions between the 2 groups. Patients developing renal insufficie ncy showed an increased excretion of a-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 glo merular functions (glomerular filtration rate), albumin, and immunoglo bulin G. Discussion: Only a short time intervall (1 to 2 days) between tubular and glomerular damage were detectable in patients with renal insufficiency. Renal failure must be due to circulatory problems becau se of the nearly simultaneous increase of tubular and glomerular param eters after RPF decreased. The parameters alpha 1-microglobulin, angio tensinase A and Tamm-Horsfall-protein gave early indications for the a cute renal failure. They showed satisfactory sensitivity and specifity , but the positive predictive value was poor.