Three things are critical on the recipients side(aside of donor related issues e.g. CIT and qualtiy of the graft): 1. volume load, i.e. CVP around 10 mm mercury and 2. systolic blood pressure > 100 mm mercury, 3. WIT during anastomsis (should not exceed 30 min) to reperfusion. I would suggest you do an analysis of your procedure and identify potential weaknesses.