Essentials of Autopsy Practice by Guy N. Rutty

Author:Guy N. Rutty
Language: eng
Format: epub
ISBN: 9783030243302
Publisher: Springer International Publishing

In healthy people, triggering a major (lethal) cardiac reflex appears to be impossible, even with strong bilateral pressure on the carotid bifurcations [30, 31]. No death occurred in pressure experiments on approximately 8000 subjects aged 15–95 years [13]. Additionally, in animal experiments, lethal irritation of the carotid sinus was impossible [32]. In martial arts, directed blows on the lateral neck are used for temporary knock out of the opponent induced by syncopal events, but events of death have not been reported [22]. In medicine practice, the cardiac reflex by massage or pressure on the carotid bifurcation is used to decrease a high heart rate, but it also occurs unintentionally (e.g., in case of moderate pressure on the carotid artery after accidental carotid puncture).

Studies have shown that an effect on heart rate and blood pressure by pressure of the carotid bifurcation only occurs under certain conditions [31, 33, 34]. In a few cases, ventricular fibrillation was induced [33, 35, 36]. However, in these cases, increased hypersensitivity of the carotid sinus was present because of pre-existing cardiac arrhythmia and digitalis medication. An increase in carotid sinus activity (hypersensitive carotid sinus) occurs from the age of 40 years; from the age of 60 also with asystole [31, 34, 37–39]. The reason for increased carotid sinus activity is the age-dependent development of atherosclerosis of the carotid vessel wall. In the case of pressure on the carotid bifurcation, baroreceptors in the adventitia of the internal carotids are pushed against plaques in the media. In this manner, atherosclerotic alterations and diseases that promote atherosclerosis (hypertension, diabetes mellitus) lead to a hypersensitive carotid sinus. Space-consuming tumors of the head and neck [40], which press on the carotid bifurcation, as well as icteric disease [34] and medication (insulin, digitalis), can also increase reflex activity of the carotid sinus [41]. In contrast, alcohol may reduce sensitivity of the carotid sinus [21, 42]. Susceptibility of the carotid sinus is of considerable importance. Franke showed that, in 3500 people, a hypersensitive carotid sinus was present in 9% [34]. During autopsy, known pre-existing conditions and findings may be indicative for a hypersensitive carotid sinus. In our study group, considerable atherosclerosis or disease was not present. There was not any evidence of a hypersensitive carotid sinus. Sigler reported the occurrence of reflex-based death in cases of heart disease [43].

Many factors need to be considered if a lethal reflex might have occurred. These factors include the history (e.g., witness statements), and macroscopic and microscopic findings of violence against the neck (e.g., haemorrhage). Other possible factors are general macroscopic and microscopic findings (cyanosis, petechiae, haemorrhagic pulmonary edema, acute pulmonary emphysema, and cerebral edema), including signs of prolonged circulation and hypoxia [14, 27].

In the presented cases, a history that suggested a rapid death (sudden collapse) was not present. Most of the cases were suicides that were committed alone (sudden unconsciousness is normal for hanging) with mild trauma of the neck. In case of hanging, haemorrhagic lesions of the neck tissue are typically not observed. However, a rope above the larynx can lead to pressure on the carotid bifurcation.

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