Her Heart Stopped for 6 Hours. Now She’s Ready to Go Back to Work.

LONDON — Audrey Mash’s life was hanging in the balance. Her heart had stopped beating when she was caught in a snowstorm on a hike in the Spanish Pyrenees with her husband, and when she arrived at a Barcelona hospital she had no vital signs.

“I was trying to feel a pulse,” her husband, Rohan Schoeman, told the Catalonian news Channel TV3. “I couldn’t feel a breath. I couldn’t feel a heartbeat.”

When Ms. Mash, a 34-year-old English-language teacher, arrived at the Vall d’Hebron hospital last month, “she was blue and cold and she had no vital signs,” Dr. Eduard Argudo, who helped treat her, said in an interview on Friday.

But after she spent six hours in cardiac arrest, doctors managed to restart Ms. Mash’s heart with the aid of a highly specialized tool and saved her life.

Ms. Mash’s experience will go down in the record books in Spain as the longest period of cardiac arrest in which the patient survived, the doctors said.

On Thursday, she appeared at a news conference in Barcelona and stood smiling while surrounded by the doctors and members of the rescue teams that had worked to save her life. She said she felt happy and grateful to be alive.

“I am the lucky one,” she said. “I’m the one who didn’t have to do anything.”

Ms. Mash, a Briton who lives in Barcelona, had gone on the hike in early November with her husband but was caught in a snowstorm on the trail. They lost their way in the inclement weather and clung to each other, trying to shelter from the wind and cold.

Her body temperature dropped sharply, she developed severe hypothermia, and she ultimately went into cardiac arrest.

First, she began to “talk nonsense,” her husband told Channel TV3. Then, she had trouble moving. Later, she became unconscious.

By the time the emergency workers rescued the couple, Ms. Mash’s body temperature was 64 Fahrenheit.

A helicopter rescue team airlifted her to Vall d’Hebron, where a team of doctors mobilized to save her life.

Medical journals have long noted the cases of people who have emerged from yearslong comas. And medical studies of hypothermic cardiac arrests in Norway have explored the cases of patients who have survived after their core body temperature dropped to 13.7 degrees Celsius (56 degrees Fahrenheit) and they spent nearly seven hours in that condition.

Ms. Mash’s hypothermic condition not only stopped her heart for six hours, but it also protected her brain and other organs from damage, the doctors said.

“If she had been in cardiac arrest for that long with a normal body temperature, she would have died,” Dr. Argudo said

Dr. Argudo, who had been called back to the hospital to attend to the unusual case after ending a 24-hour shift, said his team deployed a specialist tool that has never before used on a patient in hypothermic cardiac arrest in Spain: an extracorporeal membrane oxygenation machine, known as Ecmo.

The tool is more commonly used to treat infants with breathing or heart problems.

The machine takes blood from the patient, infuses it with oxygen and then reintroduces it to the body and circulates it around the bloodstream. It is more commonly used to treat infants with breathing or heart problems.

It also allows doctors to control the blood’s temperature, so they slowly increased it until Ms. Mash’s body temperature reached a point where they could use a defibrillator to shock her heart into beating normally again.

The medical team had prepared her husband for the possibility that she could experience brain damage when she woke up, but that was dispelled when she was taken off sedation two days after the rescue.

“We were really happy and surprised when she woke up and immediately asked, ‘What am I doing here?’ and ‘Who are you?’ ” Dr. Jordi Rivera, the director of the Ecmo program at Vall d’Hebron Hospital, said in an interview on Friday.

But beating all expectations of a long period of healing, she has made a near-full recovery. Ms. Mash was discharged from the hospital 12 days after her rescue. And she now plans to return to work on Wednesday.

Ms. Mash remembers nothing about the traumatic experience. Her last memory before waking up in the intensive care unit is of heading off to hike with her husband.

Born in Britain, she spent part of her childhood in South Africa, where she met her husband, and has also lived in China. They moved to Barcelona two years before the hiking rescue.

She is a keen hiker and tries to go to the mountains with her husband at least once a month, and has previously trekked in the Himalayas. Doctors said that her experience there might have helped her to survive, in addition to her young age and active lifestyle.

“There is very low levels of oxygen in the Himalayas, so her body was in some way prepared for this,” Dr. Jordi Rivera said.

The hypothermia has left Ms. Mash with some mobility and sensitivity issues in her fingers, which means she cannot do up buttons on her own or put earrings in herself, she said, but she hopes that will improve.

While near-death experiences can prompt some people to reassess their priorities in life, she said in a video interview that that was not her style.

“When I woke up, I realized it was not a moment to change my life,” Ms. Mash explained. “It was a moment to realize that there isn’t anything that I want to change. I like my life.”

The experience has also not deterred her from one of her favorite activities.

“I hope that in spring we will be able to start hiking again,” Ms. Mash said. “I don’t want this to take away that hobby from me.”

But she will steer clear of the mountains in winter.