A portable miracle machine that breathes life into ailing livers outside the body could revolutionise organ transplants.
The device, set on wheels and the size of a supermarket trolley, can keep a donor liver alive for 24 hours or more at body temperature.
As well as preserving the organ, it helps damaged tissue repair itself by delivering a carefully balanced combination of blood, oxygen and nutrients.
Doctors believe the machine, which could be ready to market in Europe next year, could double the number of livers available for transplant.
In five years, it could be replacing the current method of flushing an organ with preservative, cooling it to 4C, and then racing to do the transplant before deterioration sets in.
Modified versions of the device may also assist transplants of other organs, including kidneys and lungs, and provide a tool for testing the toxicity of new medicines.
Two patients are said to be recovering well after taking part in a pilot trial to test the machine at London's King's College Hospital.
Ian Christie (62) from Devon, the first person in the world to benefit from the technology, said: "I feel better than I've felt for 10 to 15 years, even allowing for the pain and wound that's got to heal."
Another female liver recipient has also delighted surgeons with her progress. Neither patient has suffered any complications.
To operate the machine, surgeons place the donor liver into a holding container, plug in tubes carrying blood and bile, and press a start button. The device runs itself, supplying the tissue with the right balance of oxygen and nutrients.
In the pilot trial, the device was used to preserve donor livers for just 10 hours. But experts from the Oxford University design team are confident they can keep organs functioning outside the human body for 24 hours, and pre-clinical tests suggest 72 hours may be possible.
Using the standard cooling technique, an 'ideal' liver can be stored for a maximum of 20 hours, but in practice most surgeons dare not wait longer than 14. Every hour that passes causes the organ to suffer some degree of irreparable damage.
Professor Constantin Coussios, co-inventor of the machine and technical director of Oxford University spin-out company OrganOx, set up to commercialise the device, said: "These first clinical cases confirm that we can support human livers outside the body, keep them alive and functioning on our machine and then, hours later, successfully transplant them.
"It was astounding to see a cold grey liver flushing with colour once hooked up to our machine and performing as it would within the body.
"What was even more amazing was to see the same liver transplanted into a patient who is now walking around."