Brain dead teen wakes up after parents agree to pull plug

His vital signs spiked just as US hospital was about to pull the plug

A 13-year-old American boy miraculously came back to life in March, a day after doctors declared him brain dead and his parents signed the paperwork to donate his organs.

Trenton McKinley from Alabama was at a friend's house when a utility trailer he was riding flipped over and crushed his head, reported American broadcaster CBS News on Monday.

The teenager suffered severe brain trauma and seven skull fractures.

His mother, Ms Jennifer Reindl, told local media that Trenton had been dead on the table for 15 minutes at one point.

"All I saw was a stretcher with his feet hanging out," she told American television channel Fox 10 News.

The family added that for several days, Trenton was on life support and barely breathing.

"They told me the oxidation problems would be so bad to his brain, that he would be a vegetable if he even made it," Ms Reindl said.

Ms Reindl said that she agreed to sign donation papers when she learnt that her son's organs could save five lives.

"We said yes, as that also ensured that they would continue to keep Trenton alive to clean his organs for the donation," she said.

But one day before Trenton's life support was to end, he showed signs of cognition, CBS Today reported.

"The next day he was scheduled to have his final brain wave test to call his time of death, but his vitals spiked so they cancelled the test," Ms Reindl said.

"He is a miracle," she said in a Facebook post on March 23.

According to CBS News, Trenton is now going through a slow recovery process and still suffers from nerve pain and seizures daily.

He will also eventually need surgery to reconnect half of his skull.

However, since regaining consciousness, he has been walking, talking and reading, according to Ms Reindl, who described it as a miracle.

"There's no other explanation but God," Trenton said. "There's no other way that I could have come back."