A hiker who was rescued after he spent the night lost in Mount Rainier National Park "came back from the dead" after his heart stopped for 45 minutes.

Michael Knapinski, 45, of Woodinville, died in the emergency room at Harborview Medical Center after being airlifted off the mountain.

He was found unresponsive in a river drainage on the edge of a mountain, the Seattle Times reported. Though he arrived with a pulse, Knapinski suffered cardiac arrest moments later and died in the emergency room, said Dr. Jenelle Badulak, one of the first people who treated him.

"He came back from the dead," said Dr. Saman Arbabi, medical chief of Harborview's intensive-care unit in Seattle, where Knapinski was treated.

Badulak said they saved Knapinski's life by bypassing his heart and lungs, which is "the most advanced method of artificial life support that we have in the world," Fox News quoted him as saying.

Knapinski remembers little beyond being lost on the mountain Nov. 7. When he opened his eyes two days later, he was crying and so were his family and the nursing staff, at his amazing recovery.

The doctors pumped blood out of his body using an extracorporeal membrane oxygenation machine that took out carbon dioxide from his system and then pumped it back into his body.

The procedure is being used to treat some COVID patients - but it is costly and a risky form of treatment with many complications.

While the medical staff was working on him, Knapinski's heart stopped beating for 45 minutes while teams repeatedly administered CPR.

Knapinski said he is still having some delay in his cognitive functions but is in good spirits.