Flow and function in machine-preserved kidneys.

One hundred machine-preserved cadaver kidneys were transplanted irrespective of their flow rates on the preservation machine. Twenty-five per cent had flows of below 100 ml/min and 11 per cent had flows of below 80 ml/min. There was no correlation between the flow rate and function at 1, 3 or 12 months. There was no difference in the flow rate between those kidneys which functioned immediately and those which never functioned. A fall in flow rate was associated with acute tubular necrosis of longer duration but eventual function was not impaired. There was a higher incidence of early aggressive rejection in kidneys which functioned immediately. Preservation failure per se is a rare cause of primary non-function. Adherence to a policy of ignoring the flow characteristics of machine-preserved kidneys could make up to 25 per cent more kidneys available for transplantation.