An Arizona 2-year-old boy had made a full recovery after his  heart stopped for almost 40 minutes.  Released from the hospital after a week, Caleb Teodorescu now runs circles around his  family's living room, acting like any other toddler. Doctors say he  has no long-term medical or brain injuries.

Caleb was considered technically dead when his mother found  his lifeless body lying face-down in the family's outdoor swimming pool. His heart had stopped, and he was unable to breathe when he arrived at the hospital.

"He quite literally died outside the hospital," Dr. Corey Philpot, a pediatric critical care physician at the Banner Thunderbird Medical Center in Glendale, Ariz., told ABC News.

Caleb's mother, Mihaela Teodorescu, became hysterical when she realized her son wasn't breathing.

"I was crying out to God," Teodorescu told ABC 15 in Phoenix. "I was saying, 'God you cannot take him from me!'"

Teodorescu screamed  for help and a neighbor began CPR.

When Philpot began treatment, Caleb was in a comatose state and on a breathing machine. He had been given blood pressure medication.

But doctors  believe their decision to use therapeutic hypothermia, a cutting- edge technique, was what saved Caleb's life and reduced the risk of  brain damage.

"Therapeutic hypothermia slows down the metabolic rate of the body and, in this case, of the brain,"  Philpot told ABC News. "We cooled him down to 32 degrees and put him in cold hybernatory state to prevent ongoing brain injury."

It took 24 hours to cool down Caleb's body to this point of hypothermia. Then doctors slowly rewarmed his body for four days. During this time, Caleb's heart started to function better, and he required less blood pressure medication. But doctors still wondered whether  he would ever function normally again.

Caleb's father, Ovy Teodorescu, told ABC 15 in Phoenix that doctors told the family that  Caleb would never be the same.

"[Our doctor] told us in his 23 years of being with the hospital in the pediatric intensive care unit, they did not have a case like this," Teodorescu said. "Not even close. He said out of the good outcomes, Caleb is the best  of the best  of the best."

Doctors began to notice that Caleb was improving once the rewarming began.

"It was about five days after Caleb arrived and three days after we rewarmed his body that Caleb began showing a drastic and quick recovery,"  Philpot told ABC News.

"He started to move, and then his movements became purposeful , and then he opened his eyes. We could tell that he was on the quick road to recovery."

Long-term brain damage is extremely common for patients who stop breathing. The lack of air to the brain and stoppage of blood flow often require machines to keep some patients alive.

"What was shocking was his quick recovery and his going-home state. The average person may not notice anything wrong with him at all. In a couple months you wouldn't even notice  what he went through," Philpot told ABC News.

The Teodorescus, who never gave up hope during the week their son was in the hospital,  told ABC 15 that having Caleb home,  alive and healthy, was the perfect early Christmas gift.