Joel Bueno shed tears of joy as his four-legged guests entered the intensive care unit where he had been admitted due to a blood clot.

Bueno, 34, said being showered with affection by therapy dogs Vida and Lu reminded him of his own dog back home.

"It’s great to have someone that loves you more than anything else in the world,” he told Reuters with a broad smile. "They give everything for you, no matter how you are with them."

The visit was part of a trial launched by the Hospital del Mar in Barcelona and the Affinity Foundation, which specialises in pet therapy, to improve the emotional well-being of patients in intensive care units (ICU).

Patients in the programme receive two visits each week of 15 to 20 minutes each.

"For now it's just a perception, but it seems to us that there's a benefit for patients," said Lucia Picazo, an ICU doctor.

The project will analyse saliva samples collected from patients before and after a therapy session, to check whether stress indicators like cortisol decrease while those related to wellbeing like oxytocin and serotonin increase, she said.

Patients aren't the only ones benefiting from the project: many members of staff in the emergency ward also enjoy having the canines around and bond with them, said Maribel Vida, who leads Affinity's animal therapy projects.

Bueno has no doubts about the benefits of the trial. Just the news that some dogs might pop by for a visit was an immediate morale boost, he said.

(Reporting by Guillermo Martinez; Writing by Pietro Lombardi Editing by Aislinn Laing and Frances Kerry)