Near death experiences could be down to carbon dioxide

People who say they have experienced the phenomenon describe sensations such as life flashing before their eyes, feelings of peace and joy, and supernatural encounters.

Slovenia-based scientists studied 52 patients who had suffered cardiac arrest, using questionnaires to determine if they had had near-death experiences.

They also looked at data including carbon dioxide levels.

According to the study, published in Critical Care, higher concentrations of carbon dioxide in the breath and arteries were found among the 11 who reported near death experiences.

It concluded that as many as one fifth of out-of-hospital cardiac arrest patients reported near death experiences.

As well as higher C02 levels higher serum levels of potassium also appeared to be important.

These associations have not been found before and could be an important clue to the phenomena, the scientists claim

Zalika Klemenc-Ketis, who worked with a team of researchers from the University of Maribor, said there were several competing theories for the experience.

She added: "We found that in those patients who experienced the phenomenon, blood carbon dioxide levels were significantly higher than in those who did not."

She said further studies were required, using larger sample sizes to investigate the possible link. "The association with carbon dioxide has never been reported before, and deserves further study," she added.