Newly released 911 recordings reveal confusion and delays in the emergency response after Christa Pike survived a lethal injection attempt at a Tennessee prison on September 30.

The recordings show dispatchers initially questioning whether the emergency call was genuine, with prison officials later confirming that medical assistance was needed.

Pike, 50, received at least two doses of pentobarbital but remained alive. Emergency responders were allowed into the prison about 30 minutes after the initial call.

She was hospitalised and placed on a ventilator before regaining consciousness and beginning to speak last week, according to her lawyers.