It is not unusual for a transplant unit to require a colonoscopy as part of the pre- transplant assessment because of the icreased risk of cancer as a result of immunosupressant therapy. If they still insist, despite what your GI doc. Says, I agree with other people that you should ask for twilight anaesthesia/conscious sedation.Does your transplant doc. Know aboutyour past medical history with regard to anaesthetic because the duration/nature of the operation means that a deeper anaesthetic tends to be used.