The course of respiration and circulation in death due to typical hanging

Abstract

Experiments were carried out on 15 dogs to investigate the course of respiration and circulation during the agonal period of death due to typical hanging. Animals were asphyxiated by a method simulating typical hanging. Electrocardiogram (ECG), electroencephalogram (EEG), blood pressure (BP) in the femoral artery and intrathoracic pressure (ITP) were registered. In typical hanging, the course of respiration was characterized by shorter stages of dyspnoea and initial apnoea and a longer stage of the terminal respiration when compared with obstructive asphyxia. However, the whole time of the course of respiration and circulation in typical hanging was almost the same as that in obstructive asphyxia. The BP increased rapidly, was maintained during the dyspnoea stage, and then decreased gradually. EEG disappeared with, or a short time after, the end of the dyspnoea stage. The increased heart rate in the dyspnoea stage remained until circulatory collapse. The analysis of the ECG complexes revealed that the heart muscle adapted to oxygen deficiency during typical hanging.

Asphyxia-activated corticocardiac signaling accelerates onset of cardiac arrest

“…Experimental asphyxia in animal models results in cardiac arrest within a few minutes. In all cases following the onset of asphyxia, electroencephalogram (EEG) amplitudes become extremely low before the disappearance of electrocardiogram (EKG) signals (5)(6)(7)(8). Although no reports of EEG and EKG recordings are available from asphyxia in humans, loss of external consciousness and sensory responsiveness is often the first sign of clinical cardiac arrest and always precedes the termination of all cardiac electrical signals.…”

Nondrowning Asphyxia in Veterinary Forensic Pathology

“…13 Based on these papers, the general sequence of physiological responses is respiratory distress and tachycardia, followed by bradycardia, then apnea, an isoelectric (EEG), terminal or agonal respirations, and cardiac arrest. 13 and then terminal respiratory movements for 2 to 3 minutes, 63,123 was observed. The EEG was isoelectric at 1.5 to 2 minutes, roughly half of the time than with simple obstructive asphyxia, 63,123 and cardiac arrest occurred between 4 and 6 minutes.…”

“…13 and then terminal respiratory movements for 2 to 3 minutes, 63,123 was observed. The EEG was isoelectric at 1.5 to 2 minutes, roughly half of the time than with simple obstructive asphyxia, 63,123 and cardiac arrest occurred between 4 and 6 minutes. 63 To differentiate ligature strangulation from hanging, a similar model was used but with patent vertebral arteries.…”

“…80 In dogs and cats, the maxillary and vertebral arteries contribute significantly to the cerebral blood supply. 51,120 It is difficult to occlude the vertebral arteries, 63,68 and even when occluded, the numerous extracranial vascular anastomoses in dogs and cats maintain an adequate vascular supply to the brain.…”

“…17 Only after the larynx was also manually compressed was asphyxia produced, resulting in an isoelectric electroencephalogram (EEG) at 40 seconds to 2 minutes, apnea at 4 minutes, and cardiac arrest at 9 to 10 minutes. 17 Many of the experiments in dogs, cats, rabbits, and rats simulating ligature and manual strangulation and hanging 12,50,55,56,62,[66][67][68] are reviewed by Boghossian. 13 Based on these papers, the general sequence of physiological responses is respiratory distress and tachycardia, followed by bradycardia, then apnea, an isoelectric (EEG), terminal or agonal respirations, and cardiac arrest.…”