A Mount Rainier hiker is alive after he was found in whiteout conditions and brought into the emergency room at Harborview Medical Center in Seattle, Washington.

Navy crews found Michael Knapinski last weekend in Mount Rainier National Park after a night of below-freezing conditions and flew him to the hospital, WPVI-TV reports.

Shortly after his arrival, Knapinski flatlined. However, doctors began using an extracorporeal membrane oxygenation machine that pumped blood outside of his body and administered CPR. While the machine does not guarantee a full recovery, it can be life-saving.

After 45 minutes, they were able to restart the hiker’s heart. “He came back from the dead,” Dr. Jenelle Badulak, an intensive care unit doctor at the medical center, revealed. “It wasn’t a miracle though, it was science.”

Badulak added, “Michael was unconscious, had extreme hypothermia, and his heart stopped shortly after he arrived at the ER.”

“But he did have a pulse and no major injuries so we all immediately thought of ECMO,” she continued.

Upon awakening, Knapinski was unaware that he briefly died before doctors were able to revive him.

“When I woke up, I just really didn’t comprehend what had happened,” he revealed. 

“I’m extremely grateful to everybody here at the hospital for not giving up on me. I’m alive and breathing.”

The ECMO machine has been around since 2013 but is not used often.  It requires special training, but since Knapinski’s organs were so cold from the freezing conditions, they were able to function without as much oxygen and gave the doctor more time to jumpstart his heart, WDRB reports.

Although doctors were able to make his heart start again, they were worried about damage to his brain.

“We knew the heart would start beating again,” Badulak explained. “The main concern was his brain, and if there had been any permanent damage while his heart was stopped.”

Knapinski woke up two days later. Although there is a long road of physical therapy ahead of him, doctors believe the hiker will make a full recovery.

Joshua Tree Hikers The silhouette of a hiker couple on the boulders of the Joshua Tree Monument in California. Photo: Mike Powell/Getty Images