The evaluation of an accurate occurrence rate for AKI is of great importance for health policy, quality initiatives as well as for designing clinical trials.

The primary objective is to prospectively evaluate the incidence of AKI within 72 h after extended surgical procedures that require admission to an observation unit.

Acute kidney injury (AKI) is a severe clinical complication with increasing incidence and is associated with adverse short- and long-term outcomes resulting in a major health care burden worldwide. The introduction of consensus classification systems has enhanced the awareness for AKI. The evaluation of an accurate occurrence rate for AKI is of great importance for health policy, quality initiatives as well as for designing clinical trials. However, analyzing AKI from existing databases is often limited by missing data elements, especially the inclusion of the urine output criteria. Missing data and the use of different definitions before the consensus classification are the reasons for large variations in reported occurrences of surgical induced AKI.

The primary objective is to prospectively evaluate the incidence of AKI within 72 h after extended surgical procedures that require admission to an observation unit (e.g., Intensive Care Unit, Intermediate Care, Post Anesthesia Care Unit) using the latest consensus definition for AKI (Kidney Disease: Improving Global Outcomes criteria) and a standardized data collection instrument and to assess the dependence of AKI on preoperative and intraoperative factors.

Method: International prospective, observational, multi-center, cross-sectional cohort study

Eligible patients will be identified during preoperative assessment. All eligible patients will be approached to obtain written consent.

Inclusion Criteria:

• major elective or emergency surgery procedures with a duration of at least 2 h
• admission to the intensive care unit, intermediate care unit after surgery informed consent

Exclusion Criteria:

• preexisting acute kidney injury
• acute kidney injury within the last 3 months
• end stage renal disease with dialysis dependency
• kidney transplant

Adult patients undergoing extended surgical procedure and the need for postoperative observation