"A death is attributed to asphyxia only when the asphyxia itself is the condition that directly causes the death.... Asphyxia (Greek for “breathlessness”) is defined as the lack of oxygen in the blood or the failure of cells to utilize oxygen, and a failure of the body to eliminate carbon dioxide. Asphyxial deaths are commonly divided into different categories based on the nature of the cause for inadequate respiration. Asphyxial deaths include suffocation, smothering, choking, positional asphyxia, mechanical asphyxia, traumatic asphyxia, hanging, strangulation, and “chemical” asphyxia."