[Role of Institutional Review Boards for multi-centre studies in national health services research - a cross-sectional study of the effort to obtain secondary ethical approvals for the DACAPO study].

Background: Health services research (HSR) is of fundamental importance for the continuous improvement of preventive, diagnostic or therapeutic measures. The conduct of multi-centre HSR studies requires that ethical approval by Institutional review boards (IRB's) is obtained. We documented the effort, the complexity and the man power necessary to obtain secondary ethical approval for a national HSR in Germany ("Surviving the Acute Respiratory Distress Syndrome" [DACAPO-study]).