Dr. Mark Forrest knew he had to act fast to save the life of a man he watched go into cardiac arrest after a motorcycle accident — so he opened up the man's chest right there on the road and brought him back from the dead.

The incident happened in October 2018 in Delamere, England, where Forrest is medical director at the Cheshire Fire and Rescue Service.

This weekend, Forrest is sharing his story and expertise with other emergency responders at the Emergency Summit Conference in Nelson, B.C.

"That was quite a day," said Forrest, who arrived at the accident scene after the air ambulance team. As he arrived, he witnessed a man go into cardiac arrest and his colleagues began performing CPR.

Forrest knew what he had to do and that he had to do it quickly.

"When they arrest in front you, they literally die in front of you … you can't wait 10 or 15 minutes, it's got to be now," he said.

So he performed emergency heart surgery right then and there.

'I gave everyone a heads-up we were going to do it, but I don't think people quite realized what we meant," said Forrest. "I opened the chest up completely at the roadside."

The last time our Medical Director Dr Mark Forrest met John O’Brien he, quite literally, had his heart in his hand performing lifesaving roadside surgery. John's made a remarkable recovery, even able to walk his daughter down the aisle.<br><br>Full story here <a href="https://t.co/9Pd7cTRpim">https://t.co/9Pd7cTRpim</a> <a href="https://t.co/E8QJJm5caV">pic.twitter.com/E8QJJm5caV</a> —@CheshireFire

Forrest said he managed to get a pulse and the man, identified as John O'Brien, made a full recovery.

"I think we were all quite stunned we'd managed to get this guy back," Forrest said.

'Drastic, radical move'

Nick Sparrow, an emergency-room doctor at Kootenay Lake Hospital in Nelson, said his mobile critical care vehicle carries the equipment necessary to do what Forrest did, but he has never performed such a surgery on the roadside.

"It's a very drastic, radical move to make … Mark Forrest has shown the world," said Sparrow, who helped bring Forrest to Nelson to talk about his experience.

Forrest, too, said he had never performed heart surgery under such conditions until he sprang into action that day, and had only practised and taught on-the-spot surgeries using mannequins and simulations.

But he has good news for other first responders who might be in the same situation one day.

"You drill for it and drill for … and that really helps when you have to do it," he said.

Forrest and O'Brien met in May at a ceremony where Forrest received recognition from the local fire chief.

O'Brien recovered from his injuries in time to walk his daughter down the aisle at her May wedding.