Brittanie Cecil, who would have turned 14 on Wednesday, was hit by a shot early in the Blue Jackets' 3-1 victory.
According to the coroner, when the girl's head snapped back from the impact of the puck, she damaged an artery which runs from the spine to the back of the brain, which led to a ``vicious cycle'' of clotting in the artery and swelling of the brain.
The Blue Jackets, in a statement released on Tuesday, said the club was "deeply saddened by the tragic accident."
"Our thoughts, prayers and condolences go out to Brittanie's family and friends during this time of anguish. Our fans mean the world to us and this loss has had a profound affect on the entire Blue Jackets family."
NHL Commissioner Gary Bettman also expressed grief at news of the accident
"Our fans are our family, and this tragic accident fills us all with a deep sense of sorrow," Bettman said.
"We extend heartfelt condolences to the grieving family and friends on this day of profound sadness."
NHL spokesman Frank Brown said he could not recall any other fan being killed by a puck at an NHL game.
