In report of Surveillance Systems for Adverse Events and Medical Errors in the Unites States, there were many possible explanations for undereporting. The most commonly mentioned ones included the fear of being blamed, the possibility of legal an expectation that reports will be futile. Moreover, the necessity of establishment of a confidential environment without "blame and shame" culture was highlighted [33] Study on 700 hospital beds in 2007, revealed that achievement to an acceptable safety level in hospitals needs a close working relationship between clinical staff and support teams of hospital [34]