A woman was kept alive for six days without her lungs in what has been called a medical world-first.

Melissa Benoit, was born with cystic fibrosis — a genetic disease that can cause phlegm build-up in the lungs and affect the digestive system.

After she came down with a bout of flu last year, she was rushed from her home in Burlington, Canada to the intensive care unit at hospital in nearby Toronto.

Bacteria in the 32-year-old mother-of-one's lungs became resistant to most antibiotics and as a result the disease spread throughout her body, causing her to slip into septic shock.

As her blood pressure plummeted to dangerously low levels and, one by one, her organs began to shut down.

Although it had never been carried out before, doctors decided to remove her lungs entirely.

A risky procedure, it was unclear whether Ms Benoit's blood pressure and oxygen levels could be sustained during surgery and there was the possibility that she could bleed into the empty chest cavity.

But at the same time they knew that removing them could potentially eliminate the source of bacterial infection.

“What helped us is the fact that we knew it was a matter of hours before she would die,” said Dr Shaf Keshavjee, one of three surgeons who operated on her. “That gave us the courage to say — if we’re ever going to save this woman, we’re going to do it now.”

Ms Benoit's family then had to make the final decision whether she went under the knife.

“It didn’t take very long for us to insist that Melissa would want to go right to the end and fight with experimental surgery," said her husband, Christopher. “We needed this chance. Things were so bad for so long, we needed something to go right.”

Ms Benoit, who was “within hours of death” before the operation, survived and nine-months on, she said it could have been a "death sentence" but it was the "best feeling ever" to be alive.

"Essentially, trying this procedure could have been a death sentence,” Ms Benoit told a press conference in Toronto.

“I was within hours of death when the decision was made. It’s a very fine balance on deciding ‘okay, is now the time we removed her lungs?' because the procedure may not have even worked.

“Without the doctors coming up with this procedure I wouldn’t be sitting here today. I wouldn’t be reading stories to my daughter. I wouldn’t be with my family. I still don’t believe it happened. It seems very surreal.

“For the first time in my life, I can actually say that I feel like I’m living, despite the little consequences of the surgery. In the grand scheme of things, it doesn’t matter.