According to Sports Illustrated, Bills assistant athletic trainer Denny Kellington administered CPR that was "absolutely vital" in saving Hamlin's life after he collapsed on the field from cardiac arrest following a tackle early in the first quarter of Monday night's game.
Kellington is involved in the NFL's emergency action plan, which each team rehearses annually before the season. The EAP is rarely used in an NFL game, but medical personnel at Monday's game performed the plan admirably.
The story might have been a very different one had Kellington not quickly recognized that Hamlin needed CPR, but fortunately, he did.