As regard the urine output during extracorporeal bypass, there was a wide variation. In most of the patients, there was minimal amount after the beginning of bypass, then suddenly increased at the end of bypass after rising of the temperature above 33°c in spite of the use of diuretics in the beginning of bypass.

The heart is connected to systemic circulation not only by SVC and IVC but also by bronchial circulation which has a significant value during extracorporeal circulation.