Identification of mechanical asphyxiation in cases of attempted masking of the homicide

Five homicides are described that had remained unexplained as to the causes of death after gross pathology. Although general signs of asphyxiation were present, they were lacking injuries specific of strangulation or oro-nasal occlusion. The diagnoses of asphyxiation were established by microscopical investigation of the lung and confirmed by subsequent police inquiries. An oro-nasal occlusion was involved in three cases, a strangulation or an oro-nasal occlusion, in another case. The victims were young and healthy. Toxicological investigations remained negative in four cases; one victim was anaesthetized by bromazepam and ether and had a blood alcohol concentration of 80 mg/100 ml. Lung histology and electron microscopy revealed acute emphysema, the development of a haemorrhagic-dysoric syndrome and a microembolism syndrome. With regard to the haemorrhagic-dysoric syndrome, the development of alveolar-interstitial edema is particularly important. This finding may also be diagnosed by light microscopy in semi-thin sections. It is emphasized that the combined action of several pathomechanisms is responsible for the rapid manifestation of the pulmonary lesions. Especially, the haemorrhagic-dysoric syndrome is brought about by the combined action of inspiratory intrapulmonary vacuum and raised intracapillary pressure. The complex pattern allows to compile the diagnosis of mechanical asphyxia even if there is no corresponding injury.     

Suicidal asphyxiation by inhalation of automobile emission without carbon monoxide poisoning

Reported herein is the suicidal asphyxiation of a young man due to exhaustion of oxygen in the interior of a sealed automobile into which the exhaust emissions were diverted. His blood carboxyhemaglobin concentration was less than 5% saturation. The car was equipped with a catalytic converter and when tested, the exhaust carbon monoxide concentration was 0.01%.     

Animal-related fatalities--part II: characteristic autopsy findings and variable causes of death associated with envenomation, poisoning, anaphylaxis, asphyxiation, and sepsis

In addition to blunt and sharp trauma, animal-related fatalities may result from envenomation, poisoning, anaphylaxis, asphyxiation, and sepsis. Although the majority of envenomation deaths are caused by hornets, bees, and wasps, the mechanism of death is most often anaphylaxis. Envenomation resulting from the injection of a poison or toxin into a victim occurs with snakes, spiders, and scorpions on land. Marine animal envenomation may result from stings and bites from jellyfish, octopus, stonefish, cone fish, stingrays, and sea snakes. At autopsy, the findings may be extremely subtle, and so a history of exposure is required. Poisoning may also occur from ingesting certain fish, with three main forms of neurotoxin poisoning involving ciguatera, tetrodotoxin ingestion, and paralytic shellfish poisoning. Asphyxiation may follow upper airway occlusion or neck/chest compression by animals, and sepsis may follow bites. Autopsy analysis of cases requires extensive toxinological, toxicological, and biochemical analyses of body fluids.     

Suicidal Nitrogen Inhalation by use of Scuba Full‐Face Diving Mask

A 29‐year‐old man was found dead lying on the bed in a hotel room in a famous Slovak mountain resort. He had a full‐face diving mask on his face, connected through a diving breath regulator to a valve of an industrial (nondiving) high‐pressure tank containing pure 100% nitrogen. The breath regulator (open‐circuit type) used allowed inhalation of nitrogen without addition of open air, and the full‐face diving mask assured aspiration of the gas even during the time of unconsciousness. At autopsy, we found the typical signs of suffocation. Toxicological analysis revealed 94.7% content of nitrogen in alveolar air. Following the completion of the police investigation, the manner of death was classified as a suicide. Within the medico‐legal literature, there has been only one similar case of suicidal nitrogen inhalation described (1).     

An unusual blunt force trauma pattern and mechanism to the cranial vault: Investigation of an atypical infant homicide

This case report presents an unusual fracture pattern in the cranium of a four-month-old infant indicative of child abuse. Upon postmortem examination, the infant presented with numerous bilateral linear cranial fractures running perpendicular to the sagittal suture with depressed and curvilinear fractures apparent on the supra-auricular surfaces of the cranium. Histological evidence indicates multiple traumatic events to the cranium. In addition, the stair-step pattern of a parietal fracture may represent multiple contiguous fractures from repeated loading of the head at different times with variation of the focal points of compressive force. Additionally, the left humerus, left radius, and left ulna have healing metaphyseal fractures, and the left ulna also has an antemortem diaphyseal fracture which resulted in the distal metaphysis being rotated 45 degrees medially. Integration of autopsy, anthropological, and neuropathological reports for this case suggest multiple inflicted injury episodes with a repeated atypical mechanism(s) to the cranial vault of the infant. During investigative interviews, the caretaker admitted to squeezing the infant's head and neck on multiple occasions to quiet the child. This reported abusive mechanism is consistent with the pattern of symmetric cranial fractures and soft tissue injuries indicating asphyxiation. This case report provides forensic investigators with a potential trauma mechanism to explore in cases when a similar pattern of cranial trauma is observed and highlights the need for greater research on fracture propagation and fracture healing in the infant cranium.     

Asphyxiation by Occlusion of Nose and Mouth by Duct Tape: Two Unusual Suicides

Abstract:  The most recent U.S. statistics (2005) determined that 22.2% of suicides are by suffocation. This number likely includes suicidal hanging. Based on previous reports the majority of nonhanging suicidal asphyxiations are accomplished by securing a plastic bag over the head. We report two instances of a far less common method of suicidal asphyxiation, occlusion of the nose and mouth by duct tape. One was a 47-year-old man with a history of paranoid schizophrenia with suicidal ideation and the other was a 52-year-old man who was depressed due to gambling debts. The value of scene investigation, including review of available video surveillance to determine the manner of death is highlighted.     

Nitrous Oxide Determination in Postmortem Biological Samples: A Case of Serial Fatal Poisoning in a Public Hospital*

Abstract: In a public hospital, eight cases of fatal poisoning by nitrous oxide (N₂O) occurred under oxygen administration, due to an erroneous swapping of the lines in the gas system. The aim of the study was to clarify the factors involved in asphyxia by characterizing gases from different lines and measuring N₂O concentrations in postmortem biological samples from bodies exhumed. Analyses carried out on the gas system confirmed the erroneous substitution of O₂ line with N₂O and air line with O₂. Consequently, high N₂O amounts were revealed in several tissues and gaseous biological samples. All specimens were analyzed by headspace gas chromatography technique. A rigorous quantitative analysis was possible only in blood (11.29–2152.04 mg/L) and urine (95.11 mg/L) and in air samples from stomach and trachea (from 5.28 to 83.63 g/m³). This study demonstrates that N₂O can be detected in biological samples even 1 month after death.     

Physical Restraint and Near Death of a Psychiatric Patient

Physical restraint is used as a last resort emergency measure to calm and safeguard agitated and/or aggressive psychiatric patients. This can sometimes cause injuries, and rare fatalities have occurred. One mechanism of injury and death while in physical restraint is that of severe asphyxiation. We present the case of a hospitalized man in his mid‐30s, suffering from schizophrenia. The patient was obese. He became aggressive and had to be manually restrained with a “takedown.” After having been put in the prone position on the floor with a significant weight load on his body, he lost respiration and consciousness. Subsequently, he was given CPR. He regained consciousness and respiration, while the cyanosis receded in 1–2 min. Psychiatrists and pathologists should be aware that physically restraining a patient in the prone position with a significant weight load on the torso can, in rare cases, lead to asphyxiation.