What is the name for someone who has an obsession with preventing death?

OCD: Obsessive compulsive disorders can take many forms and whether its an obsession with counting numbers or preventing death, its usually called an ocd, and "obsessive compulsive disorder".

Physician :-): Some feel that physicians are too bent on preventing death, sometimes causing unnecessary suffering at the end of life through unhelpful procedures. An obsession is a persistent disturbing preoccupation with an often unreasonable idea or feeling. Anything taken to this degree -- even a wish to help others or prevent death -- is unhealthy and unsustainable. The cycle of life does include death.