Figure 1: Consort flow chart of enrollment characteristics. 1- In 9 children consent could not be obtained because of language problems or absent legal representative. 2- Other reasons: One child’s operation was cancelled, one child suffered from cerebral ischemia preoperatively, 4 patients were not included due to lack of resources of staff. 3- 2 patients did not receive intervention because of left ventricular failure and parental consent withdrawal respectively. n: number of patients.