Hospital bosses have appealed to stop a cardiology worker from being deported for claiming child benefit for his son.
Paul Ermitano, 31, from the Philippines, said he had repaid £1,138 which was claimed by mistake.
Last month, the Home Office refused to extend work visas for him and his wife. The case is now being reconsidered.
An online petition, started by a Poole Hospital colleague, said Mr Ermitano had been "failed by our complicated immigration and social care system".
Mr Ermitano was recruited in 2015 to help fill a shortage of cardiac physiologists, who operate equipment to assess patients with heart problems.
He said: "It has been a terrible experience. It was all going smoothly... until the first letter saying, 'Are you still claiming child benefit?'
"I didn't know, I didn't know, it was a mistake."
The Home Office had said he was ineligible for benefits because of his visa conditions, according to Mr Ermitano.
The Dorset hospital was forced to cancel 12 appointments on Monday because he was banned from working while he was on immigration bail, he said.
Mr Ermitano said he was "overwhelmed" more than 3,000 people had signed an online petition asking for him to be allowed to stay.
The hospital trust said: "Mr Ermitano is a valuable member of our team fulfilling an important role.
"We are liaising with the Home Office to understand if there is anything further we can do as his employer to support his visa application."
A Home Office spokesperson said: "We have contacted Mr and Mrs Ermitano to advise that their application will be reconsidered."
Cardiac physiology was removed from the government's list of shortage professions in 2013.
The British Society of Echocardiography said in 2016 there was a "major shortfall" in the profession.