The purpose of the investigators' study is to determine whether the production of heat shock proteins has an effect on the development and the outcome of acute renal failure in children.

A prognostic factor for the development of acute renal failure (ANR) in children would be very valuable for therapy regulation. So-called chaperones out of the family of heat shock proteins (HSP) are promising candidates which are involved in the development of ANR as well. This could be a starting point for the development of new therapeutic approaches.

ANR occurs in up to 50 percent of all critical ill patients and has a high rate of morbidity and mortality despite advances in symptomatic therapy. Following severe sepsis, septic shock or other shocks, combined with multiple organ failure, the ANR is an autonomous prognosis worsening factor.

Should the results of our study show a correlation between the production of HSP and the outcome of children with ANR, further studies would be required, to examine the pathophysiological relevance of HSP in ANR. We would then be able to determine a high risk population for ANR. A modulation of ANR therapy might be a result of further studies.

Inclusion Criteria:

• Between 0 and 18 years of age.
• Either severe sepsis, shock of any origin or asphyxia.
• Operated patients with operative or post-operative transfusion requirement of at least 0.5 x 80 ml/kg body weight of erythrocyte concentrate.

Exclusion Criteria:

• Existing affection of the kidney.
• Kidney transplantation.
• Missing written consent of the parents or guardian (if applicable).

Patients on paediatric intensive care units.