The family of a 16-year-old Dublin student who is being kept alive on a mechanical heart machine at the Mater Misericordiae University Hospital have made a special plea for heart donors to save her life.

Kiva Humphries from Deansgrange in south Dublin contracted an infection last February which seriously damaged her heart muscles.

She is the only person in the country on a mechanical heart machine and after over 250 days doctors say time is running out for a life-saving heart transplant.

Her parents, Joe and Avril Humphries, say she is a fighter who has been through the most difficult year of her life with the support of family and friends.

National Cardiac Surgery Unit Director, Freddie Wood said that in the past a patient was on the machine for 310 days but the longer Kiva remains on it the greater the risk of infection or a major stroke.

He said that if any family is in the tragic situation where a loved one has died from irreversible brain damage and is prepared to consider organ donation, it would be of great help.

Mr Wood said there was a lot of difficulty in obtaining heart organs for transplantation.