Anything that interferes with oxygen transfer can be called asphyxia, though etymologically the word means absence of pulsation. Non-specific autopsy signs include abnormal fluidity of blood, post-mortem clotting. Traumatic asphyxia is caused by an intense compression of the thoracic cavity.
Suffocation is a death caused by reduction of the oxygen concentration in the respired atmosphere, formerly called a vitiated atmosphere. Another type of death which is caused from mechanical occlusion of the mouth and nose is classified as smothering.