Unrecognized renal damage in critically ill patients

Introduction: The objective of this study was to evaluate the percentage of unrecognized renal damage in patients with normal creatinine and urea in s erum and normal creatinine clearance and to evaluate the usefulness of vari ous proteins and enzymes as supplementary procedures for the investigation of renal function Material and Methods: Forty critically ill male patients (APACHE II-score > 20 injury severity score > 15) were daily screened for a period of five da ys. In the Ist 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 ven tilation were noted Clearances of inulin, para-aminohippuric acid and creat inine were measured and the Cockcroft-Gault equation was calculated daily f or a period of Jive clays. Excretion of alpha-1-microglobulin, Tamm-Horsfal l-protein, alanine amino-peptidase, angiotensinase A, albumin and immunglob ulin G were also measured daily Results. 21 Patients of group I and all patients of group 2 showed the expe cted correlation between the routine parameters of creatinine and urea in s erum and the level of protein and enzyme excretion. Nine patients of group 1 (30%) showed normal glomerular filtration rates but pathological excretio n fi-actions 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-aminoh ippuric acid clearance were measured, no references on tubular and glomerul ar damage were found in 30% of the investigated patients.