Classification of Asphyxia: The Need for Standardization

Abstract

The classification of asphyxia and the definitions of subtypes are far from being uniform, varying widely from one textbook to another and from one paper to the next. Unfortunately, similar research designs can lead to totally different results depending on the definitions used. Closely comparable cases are called differently by equally competent forensic pathologists. This study highlights the discrepancies between authors and tries to draw mainstream definitions, to propose a unified system of classification. It is proposed to classify asphyxia in forensic context in four main categories: suffocation, strangulation, mechanical asphyxia, and drowning. Suffocation subdivides in smothering, choking, and confined spaces/entrapment/vitiated atmosphere. Strangulation includes three separate forms: ligature strangulation, hanging, and manual strangulation. As for mechanical asphyxia, it encompasses positional asphyxia as well as traumatic asphyxia. The rationales behind this proposed unified model are discussed.

Nondrowning Asphyxia in Veterinary Forensic Pathology

“…35,129 The larynx, trachea, jugular veins, common carotid, and vertebral arteries and their branches may be partially or totally occluded: death may be due to vascular obstruction and/or airway obstruction. 111 Pressures to occlude neck vessels and trachea in people are often quoted as 2 kg for the jugular veins, 5 kg for the carotid arteries, 15 kg for the trachea, and 30 kg for the vertebral arteries, 33,117 even though these values were determined by experiments on cadavers well over a hundred years ago. 112 It is not known if these absolute values are applicable to animals, but they likely reflect the relative amount of pressure required to obstruct the vessels and trachea.…”

“…The classification of asphyxia in medical forensic pathology, including that promulgated by standard textbooks 9,33,35,84,108,117,119 and review papers, 19,78,84,103,117 is not standardized 111 and is highly variable. 103 The terminology and definitions as proposed by Sauvageau 111 (Table 1) are used in this article, although any of the above classification schemes may be used.…”

“…16,55 Hanging, ligature, and manual strangulation cause neck compression. 111 Hanging requires that a neck ligature is tightened by the body weight, whereas ligature and manual strangulation are due to forces applied to the neck other than the weight of the individual's body. 111 The duration, consistency, and type of applied force; the anatomic site of compression; and structures occluded all influence the physiological responses, the time until death, 66 and the lesions produced.…”

“…111 Hanging requires that a neck ligature is tightened by the body weight, whereas ligature and manual strangulation are due to forces applied to the neck other than the weight of the individual's body. 111 The duration, consistency, and type of applied force; the anatomic site of compression; and structures occluded all influence the physiological responses, the time until death, 66 and the lesions produced. 35,129 The larynx, trachea, jugular veins, common carotid, and vertebral arteries and their branches may be partially or totally occluded: death may be due to vascular obstruction and/or airway obstruction.…”

Immunohistochemistry of Neuronal Apoptosis in Fatal Traumas: The Contribution of Forensic Molecular Pathology in Medical Science

“…The classification of asphyxia in the forensic context is not uniform (Byard, 2011;Sauvageau & Boghossian, 2010). From a practical point of view, however, the causes of mechanical asphyxia can grossly be divided into types with and without neck compression; the former (strangulation) involves lethal factors including brain ischemia/congestion due to closure of the blood vessels and/or air passages of the neck, whereas the latter (choking and smothering) causes hypoxia due to obstruction of the air passages.…”