How does organ donation work?

It’s often a misconception that those who require an organ transplant have in some way damaged their own body, for example, by smoking or drinking excessive alcohol. In some cases, genetics play a cruel role in the development of certain conditions, such as cystic fibrosis, meaning that transplants become the only treatment option. There are two main branches of the transplant process: organs donated by a living person, or those from a donor who has been declared brain dead.

Living donors can obviously only donate organs that they can live without, such as a single kidney or part of their liver. However, vital organs such as the heart and lungs are recovered from a patient whose brain has irreversibly lost all function, known as brain death. Being declared brain dead could mean that vital organs are still viable and undamaged. In order to maintain their viability, a ventilator artificially pumps oxygen into the deceased patient’s lungs. As the heart does not require the brain in order for it to beat, blood continues to circulate and deliver oxygen to the organs. These organs can then be removed by surgeons and transplanted into another patient who is a match. 

Finding that match, however, can be a complicated undertaking and can differ depending on the organ. More than just a compatible blood type, factors such as tissue type, body size and the patient’s condition severity can determine who receives organs. 

Once a donor and patient are matched and the transplant surgery has been a success, an internal battle begins. Organ rejection can threaten the success of any transplant. This immune response occurs because a patient’s system does not recognise the antigens (proteins) from the new organ. Instead, the new organ is viewed as a threat and the immune system attacks it. This can be prevented by trying to match a patient’s blood as closely as possible to the donor’s, and by using immunosuppressant medication to restrict the immune response.