The underlying issue here, as it is in many of the cases under review, is of the extremely low level of communication and heavy reliance by Odim on what he believed to be 'standard practice' in any given situation. Cornel questioned Odim's use of a 3.5-millimetre graft, which he said was difficult to work with and could easily occlude. Cornel said that he preferred to use five-millimetre grafts. He said that the artery providing the blood, not the size of the shunt, governed the amount of blood that was shunted. I have used a 4mm graft on only 2 or 3 occasions.
Flow is controlled by the subclavian artery rather than by the graft itself.
There is a much higher failure rate in small grafts. In his testimony, Duncan said that when he wrote his report, he had not heard of anyone using a 3.5-millimetre shunt. He said that in Vancouver, however, where he had subsequently taken up a position at the British Columbia Children's Hospital, 3.5-millimetre shunts were used in that program, with good results. He testified that the issue was the length, as well as the diameter, of the shunt. A long, thin shunt, he said, was more likely to clog.