Unrecognized renal damage in critically ill patients.
BACKGROUND
The objective of this study was to evaluate the percentage of unrecognized renal damage in patients with normal creatinine and urea in serum and normal creatinine clearance and to evaluate the usefulness of various proteins and enzymes as supplementary procedures for the investigation of renal function.


METHODS
Forty critically ill male patients (APACHE II-score > 20, injury severity score > 15) were daily screened for a period of five days. In the 1st group there were 30 patients with normal creatinine and urea in serum and with normal creatinine clearances. In the second group there were ten patients with increased values of these parameters. The base-line condition of all patients and any changes in hemodynamic, nutrition and ventilation were noted. Clearances of inulin, para-aminohippuric acid, and creatinine were measured and the Cockcroft-Gault equation was calculated daily for a period of five days. Excretion of alpha-1-microglobulin. Tamm-Horsfall-protein, alanine aminopeptidase, angiotensinase A, albumin and immunoglobulin G were also measured daily.


RESULTS
21 Patients of group 1 and all patients of group 2 showed the expected correlation between the routine parameters of creatinine and urea in serum and the level of protein and enzyme excretion. Nine patients of group 1 (30%) showed normal glomerular filtration rates but pathological excretion fractions of all proteins and enzymes.


CONCLUSIONS
Although all routine parameters of renal function (creatinine and urea in serum, creatinine clearance both by 24-h collection period and from the Cockcroft-Gault equation), and additionally inulin and para-aminohippuric acid clearance were measured, no references on tubular and glomerular damage were found in 30% of the investigated patients.
Dehne
M G
MG
Department of Anesthesiology and Intensive Care Medicine, Justus-Liebig University, Giessen, Germany.
Mühling
J
J
Papke
G
G
Nopens
H
H
Kuntzsch
U
U
Hempelmann
G
G
D058186:Acute Kidney Injury / Q000175:diagnosis / Q000209:etiology; D016022:Case-Control Studies; D003401:Creatine / Q000097:blood; D016638:Critical Illness; D006801:Humans; D007668:Kidney / Q000293:injuries*; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D015599:Trauma Severity Indices; D014508:Urea / Q000097:blood
D014508:Urea; D003401:Creatine