Dear Editor,
I read with interest the above article published recently within the Journal of Paramedic Practice. Although I agree with the introduction of this article which puts into context where a paramedic is most likely to encounter a hanging, I was somewhat surprised to see it first drift off into an area in essence irrelevant to paramedic practice within the United Kingdom, i.e. a discussion of judicial hanging and then perplexed at the section concerning the pathophysiology of hanging which fails to reference appropriate forensic pathology resources which detail, among other things, modern day considerations as to the mechanism of death related to hanging.
In 2010 a unified classification of asphyxia was proposed by the International Network for Forensic Reseach (IFOR) (Sauvageau, 2014). They proposed that hanging is one of three subtypes of strangulation and occurs when ‘pressure on the neck is applied by a constricting band tightened by the gravitational weight of the body or part of the body.’ Through the work of the Working Group on Human Asphyxia (2006), the mechanisms of death in hanging have been revaluated by studying videos of those who had videoed themselves dying of hanging. Through such work the historical proposals that deaths in hanging were due to compression of the air passages and/or vagal stimulation by carotid baroreceptor pressure have been challenged. These two mechanisms, which form two of the three sections within this paper concerning the pathothysiology of hanging are not in favour within the forensic pathology world. More so, opposing the view that ‘substantial evidence links enhanced sympathetic activation with ventricular arrhythmia and sudden death,’ a systematic review considering the published evidence base for death caused by cardioinhibitory reflex (vagal stimulation) identified only one paper between 1881 and 2009 where the authors felt that this mechanism may have played a role in the death (Schrag et al, 2011). The final mechanism of cervical spinal fracture does occur in hanging involving a long drop but will be rarely encountered in domestic or institutional settings.
The mechanism favoured to my knowledge by the forensic world in death by hanging, is that of compressive obstruction of the blood vessels of the neck, not that of compression of the airway or the tongue obstructing the airway as suggested in the article. Fractures of the hyoid bone and/or lateral components, not body, of the larynx are observed to varying amounts but these do not, to my knowledge, lead to airway compromise. Research exists into the pressures required for this to be achieved, as well as the timeframes between the pressure been applied to the neck, the time to unconsciousness, the agonal sequence, and the time to irreversibility, none of which, unfortunately, was provided by this article (Sauvageau, 2014). This mechanism explains the pathology features seen to the head and neck of such deaths and the clinical states in those who survive to hospital.
I do agree with the final conclusion that the majority of hangings attended to by paramedics will not have a cervical spinal fracture. Modern day autopsy practice all over the world increasingly incorporates post-mortem computed tomography as an adjunct if not replacement to the invasive autopsy. This is particularly so outside the UK, where hangings may be CT scanned rather than autopsied these days. This will allow those engaged in such practices to rapidly answer the question of frequency and circumstance when cervical spinal injuries occur so that they can inform pre-hospital practice (reverse translational research) as to when C-spine immobilisation may be required.