Positional asphyxia: reflection on 2 cases.

Positional asphyxia, a fatal condition arising because of the adoption of particular body positions, causing mechanical interference with pulmonary ventilation, can occur in various circumstances that are likely to come under the observation of the specialist in legal medicine (work, car accidents, torture, kidnapping, etc.). It is difficult to diagnose the cause of death in such cases because they generally present with an aspecific anatomopathologic picture. In some situations, positional asphyxia can be hard to distinguish from asphyxia because of chest compression. The main difference is in the way the event occurred: whether the particular position causing the asphyxia had been adopted by choice or by compulsion or necessity when an extrinsic mechanical action would result in traumatic asphyxia. The diagnosis of positional asphyxia is essentially based on 3 criteria: the body position must obstruct normal gas exchange, it must be impossible to move to another position, and other causes of natural or violent death must be excluded. To illustrate the main physiopathologic and diagnostic causes of positional asphyxia, the authors report 2 cases taken from the records of events that came under the observation of the Medico-Legal Sector of Bari University Hospital throughout the last 10 years.