限制性体位窒息死亡的法医学鉴定

限制性体位窒息是一种特殊类型的窒息,其死亡机理、过程复杂,体表损伤轻微,尸体表现缺乏特异性,鉴定难度大,目前还没有一个客观、准确、公认的鉴定标准,通过文献复习总结有关体位性窒息的研究成果,结合窒息死亡的组织病理改变和鉴定实践,提出限制性体位窒息的检验鉴定要点,在确定有长时间限定在某一影响呼吸的体位,且自己不能解脱;有明显的窒息尸体征象;排除损伤、疾病致死;常见毒物检测阴性;膈肌Fn免疫荧光检测阳性或透射电镜检查证明有膈肌损伤的可以诊断。如果合并有损伤或疾病,还应该有肺SP-A检查阳性或HIF1-α免疫组化染色核阳性表达。某些特定部位的损伤检查有助于分析体位关系。     

An unusual accidental death from positional asphyxia

Death from postural or positional asphyxia takes place in circumstances when the victim's body assumes an abnormal position compromising the process of respiration. The diagnosis is usually based on circumstantial evidence in conjunction with excluding other significant underlying causes of death. This case report is about a 37-year-old man who had been drinking the previous night and was found dead in the morning in a knee-chest position. The forensic medical examiner had the opportunity to examine and photograph the scene of death while the body was still in its original position. Apart from a blood alcohol level of 290 mg/100 mL, marked congestion of the face, and petechial hemorrhages on the conjunctivae, autopsy findings were unremarkable. There were no injuries or pathological findings to account for his death. Death was certified as due to postural asphyxia secondary to intoxication by alcohol.     

Death due to positional asphyxia under severe alcoholisation: pathophysiologic and forensic considerations

In contrary to "physical restraint", describing a fixed body position due to external devices, "positional restraint" is defined as an abnormal body position, resulting from accidental fixation under unfortunate circumstances. We report on a remarkable case of positional asphyxia of an alcoholised young man after a fall down a staircase. On external examination, the body showed petechiae of the conjunctivae and oral mucosa, abrasions on the left zygomatic region and scratch marks, respectively. Neither broken fingernails, etc. nor signs of external violence against the neck were found. Autopsy revealed haemorrhages in the praevertebral cervical musculature and Simon's sign. Haemorrhagic pulmonary edema and cerebral edema were observed; blood alcohol concentration: 2.60 g/l, urine alcohol concentration: 3.26 g/l. As cause of death, positional asphyxia after blunt head trauma has to be considered as well as lethal ethanol intoxication. To us, alcoholisation attributed to the fall and together with unconsciousness following blunt head trauma circumvented self-rescue efforts, and therefore, aggravated the potentially lethal impact of positional restraint.     

Model for the prediction of mechanical asphyxia as the cause of death based on four biological indexes in human cardiac tissue

Determination of mechanical asphyxia as the cause of death has always been difficult for forensic pathologists, particularly when signs of asphyxia are not obvious on the body. Currently, depending on only physical examination of corpses, pathologists must be cautious when making cause-of-death appraisals. In a previous study, four biomarkers—dual-specificity phosphatase 1 (DUSP1), potassium voltage-gated channel subfamily J member 2 (KCNJ2), miR-122, and miR-3185—were screened in human cardiac tissue from cadavers that died from mechanical asphyxia compared with those that died from craniocerebral injury, hemorrhagic shock, or other causes. Expression of the markers correlated with death from mechanical asphyxia regardless of age, environmental temperature, and postmortem interval. However, a single biological index is not an accurate basis for the identification of the cause of death. In this study, receiver operating characteristic curves of the ΔCq values of the four indexes were generated. The diagnostic accuracy of the indexes was judged according to their area under the curve (DUSP1: 0.773, KCNJ2: 0.775, miR-122: 0.667, and miR-3185: 0.801). Finally, a nomogram was generated, and single blind experiment was conducted to verify the cause of death of mechanical asphyxia.     

限制性体位窒息死亡的国内外研究进展

限制性体位窒息是指被限制于某种异常体位,造成了自主呼吸功能的障碍引起的窒息,严重时可引起死亡,属机械性窒息中的特殊类型。从国内外有关案例报道来看,限制性体位窒息死亡可以发生在多种环境、体位下。由于早年限制性体位窒息死亡的案例没有引起足够的重视,其作为一个法医学课题起步较晚。近年来由于发生率猛增,已引起国内外法医学家们的极大关注,并对其发生机理、鉴定标准等方面进行了大量研究,但从研究的成果来看,尚不能形成一些客观的鉴定指标,由此,国外关于限制性体位窒息的研究重点已转向其发生的危险因素评估及如何预防。本文就其死亡机理、危险因素及预防、鉴定标准和展望等方面作一综述。     

PMCT在机械性窒息方面的研究进展

机械性窒息是公安法医日常检案中最常见的死因之一。如何快速准确的判断死者是否为机械性窒息死亡、以及作案手段是判断案件性质、指引案件侦破方向的重要因素。在法医鉴定过程中,诊断机械性窒息需要结合尸体体表征象、尸体内部征象、组织病理学检验等多方面综合判断。PMCT在骨折的检测、异物的检测和气体的检测方面具有极大的优势,在许多国家和地区已作为常规检验手段。本文综述了国内外近年来使用PMCT研究机械性窒息案例中舌骨骨折、甲状软骨骨折、椎间盘真空现象等多个征象的成果,讨论了PMCT诊断机械性窒息的应用价值与潜力,并对国内PMCT的发展前景进行了展望。     

Positional Asphyxia in Opioid-Related Deaths: Is It Being Overlooked?

The contribution of positional asphyxia in opioid-related deaths is currently unknown. Diagnostic criteria for positional asphyxia include finding the decedent in a position that does not allow for adequate respiration and an inability to extricate themselves from the position due to various conditions. Our primary objective was to assess whether positional asphyxia and the resulting airway compromise were a contributing factor to death due to the toxic effects of opioids. We evaluated 225 deaths where the death scene investigation contained adequate information to evaluate for positional asphyxia and performed a Pearson chi-square test to determine if the proportion of deaths found in an airway compromising position was higher when opioid(s) caused the death. The proportion of decedents found in a potential airway compromising position was greater when the death was related to opioid use (p < 0.0001). Further, narrowing the dataset to decedents who were definitely in an airway compromising position [Yes (24.49%) vs. No (11.02%)] showed a statistically significant association between positional asphyxia and deaths related to opioid use (p = 0.0021). Carefully documenting the position in which the decedent was initially found may be a significant factor in accurate reporting and in harm reduction efforts to decrease the opioid mortality rate.     

Metal Railing Fences and Accidental Death

Two cases of accidental deaths caused by the sharp ends of fence or gate posts are reported. Case 1: A 47‐year‐old man was found hanging by his ankle in an inverted position on fencing. He had attempted a shortcut to a railway platform by climbing over a metal rail fence. He had slipped and been impaled through his ankle by the sharp end of the fence post, resulting in death from positional asphyxia. Case 2: An 18‐year‐old male slipped while climbing over a gate and died after being impaled on a spear tip finial, which had lacerated his external iliac vein. Death was due to exsanguination. These cases demonstrate two rare examples of accidental deaths from impalement by the ends of sharp fence posts. Mechanisms of death in such circumstances involve suspension with positional asphyxia and vascular injury with exsanguination.     

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.     

Morphometric Investigation of Death by Asphyxia

Abstract:  The aim of this study was to investigate the possibility of distinguishing deaths by asphyxia from those due to natural causes by comparing morphometric measurements in lungs. The study population comprised 27 subjects: 14 cases of death by asphyxia (hanging or drowning) and 13 cases of sudden natural death. Eighty parenchyma sections were used for each subject. Data were collected by computerized image analysis. Measurements aimed at quantifying, as percentages, pulmonary parenchyma (mean values of positive-fraction areas [PFA] and their standard deviations). Subjects who died of natural causes and of drowning showed a relative internal homogeneity compared to those who hanged. Results show significant discrimination between drowned subjects and those dying of natural causes (mean of PFA p  = 0.01) and between hanged and drowned subjects (SD of PFA p  = 0.04). Attention must be paid to the possible role played by senile emphysema. The method is proposed as a complementary tool in forensic cases.     

Obturation, aspiration, and inhalation in case of mechanical asphyxia

This paper aims at updating terminology employed for the characteristic of selected forms of mechanical asphyxia. The medical terms "obturation", "aspiration", and "inhalation" are not infrequently used by forensic medical experts and pathological anatomists engaged in diagnostics of mechanical asphyxia, elucidation of the mechanism of the accompanying injury and causes underlying its fatal outcome. It is argued that the use of these terms for the purpose is sometimes either unjustified or incorrect or both. To begin with, they have different meanings in different situations. Second, the mechanism of death from mechanical asphyxia is variable and associated with specific morphological features that are directly dependent not only on the route by which a foreign body enters the respiratory tract but also on its size, weight, structure, shape, properties, and aggregated state. Third, it is necessary to differentiate between inhalation of a toxicant in case of poisoning and inhalation of a gaseous substance leading to mechanical asphyxia.     

Forensic medical specificity of death in atypical sexual behavior: asphyxiophilia, autoerotism

The diagnosis of death of autoerotic asphyxia has not been virtually stated by Russian forensic medical expert. All such cases were interpreted as mechanical asphyxia entailing suicide, and "accidental" or "fatal" death. The authors observed, during the recent 5 years, 10 lethal cases in different-type autoerotic practice. Strangulation asphyxia was the death cause in 7 cases. Compression asphyxia, inhaling of glue vapor and electric shock caused death, each in one case. Death of asphyxia seizes to be exceptional; it is rather a regular phenomenon in the present-day life, which needs a proper research from 2 standpoints--etiopathogenesis, and forensic medical diagnosis.     

Sudden death due to asphyxia by esophageal polyp: two case reports and review of asphyxial deaths

Asphyxia, not an uncommon cause of sudden death, may result from numerous etiologies. Foreign-body aspiration and strangulation are 2 extrinsic causes. Airway obstruction may also be caused by laryngeal edema, asthma, infection, or anaphylaxis. Chronic causes of asphyxia include musculoskeletal diseases (eg, muscular dystrophy, amyotrophic lateral sclerosis), neurologic disorders (eg, myasthenia gravis, multiple sclerosis), respiratory disease (eg, emphysema, chronic bronchitis), or tumors. The manner of death in cases of asphyxiation may be natural, accidental, homicide, or suicide. For the death investigator, determining the cause and manner of death can often be quite challenging.We report here 2 cases of an esophageal fibrovascular polyp causing sudden asphyxial death, review of the literature, and discussion of other differential diagnoses in the case of asphyxial death.     

An original cause of drowning in an industrial environment

We describe an original case of drowning in a wax tank in an industrial setting. The causes of death were multiple, with the association of drowning, mechanical asphyxia, and extensive superficial burns. To our knowledge, it is the first report of drowning in wax, and only 7 previous related observations of drowning in industrial environments were reported in the international literature. These accidents are more often fatal, with multiple associated causes of death due to the incriminated media. Although exceptional, these serious accidents must be prevented in potentially risky industries.     

Positional asphyxia during law enforcement transport.

Three cases of positional asphyxia are described that occurred while victims were in a prone position in rear compartments of police patrol cars. These deaths are attributed to positional asphyxia. Autopsy findings and specific scene and circumstantial correlations of the investigation are discussed with emphasis placed on the limitations of interpretation of the anatomic changes at autopsy.     

Positional asphyxiation in adults. A series of 30 cases from the Dade and Broward County Florida Medical Examiner Offices from 1982 to 1990.

Over a 9-year period, 30 cases of positional (or postural) asphyxia were identified in the Dade and Broward County (Florida) Medical Examiner Offices. The victims had an average age of 50.6 years with no significant sex or racial differences as compared with the general medical examiner population. Chronic alcoholism or acute alcohol intoxication was a significant risk factor in 75% of cases and these had an average postmortem ethanol concentration of 0.24 g%. Signs of mechanical asphyxiation (petechiae and/or combined lung weights greater than 900 g) were present in 93% of cases. Victims were commonly (43%) found in a restrictive position producing hyperflexion of the head and neck. Two deaths involved restraint vests ("poseys") in elderly, demented, wheel-chair-confined victims. Scene photographs of the undisturbed decedent are extremely helpful in confirming a suspicion of postional asphyxia.     

mRNA和microRNA在机械性窒息死推断中的研究进展

机械性窒息死的推断是法医学鉴定的难点之一。利用实时荧光定量PCR（fluorogenic quantitative RT-PCR,RT-qPCR）技术检测RNA表达水平变化规律,并据之推测机械性窒息死亡的原因,近年来已成为研究热点。本文对mRNA和microRNA（miRNA或miR）在机械性窒息死推断的研究文献进行复习综述,并重点探讨miRNA在该类死因推断中的应用,以期为机械性窒息死推断提供新的思路。     

35例胰腺出血案例死亡原因分析

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Death by overlaying and wedging: a 15-year retrospective study

Overlaying, the accidental death by smothering caused by a larger individual sleeping on top of an infant, is a cause of death that has been documented for centuries. The hazard of death has been reported to be greater in infants less than 5 months of age but may occur in children up to the age of 2 years. When an adult or older child rolls on top of an infant, mechanical asphyxia results. The face may be pressed into the mattress or into the body of the sleeping adult or older child. The infant's air may be expressed, and he or she is unable to cry due to pressure on the thorax and the inability to inhale. Some pathologists and investigators believe that the victims of overlaying have no pertinent physical findings at autopsy and that any injury is indicative of inflicted trauma. Others believe that one may see contusions and abrasions from overlaying in and of itself. Wedging is another form of accidental mechanical asphyxia that may have negative autopsy findings. The prevalence of bruising, contusions, or facial and ocular petechiae is not clear. The author reviewed all pediatric forensic cases referred for autopsy to the Forensic Section of the Medical University of South Carolina/Medical Examiners' Office over the past 15 years, from 1985 to 1999. Of these, all cases of overlaying, cases listed as undetermined sudden infant death syndrome versus overlaying, and wedging were included. The cases were analyzed as to victims' age, sex, race, location/bedding, bed-sharer, and whether the bed-sharer was known to have ingested drugs or alcohol before sleep. Postmortem physical findings were also reviewed, particularly for documentation of contusions, abrasions, or facial or ocular petechiae. By clarifying not only the victim, bed-sharer, and scenario but also the presence or absence of physical findings in cases of overlaying, wedging, and other accidental asphyxia, we can better categorize these cases.     

Complex autoerotic death with full body wrapping in a plastic body bag

Autoerotic deaths are normally classified as accidental deaths occurring during individual, and usually solitary, sexual activity in which a device, apparatus, or prop used to enhance sexual stimulation of the deceased somehow causes unintended death. The most common methods of autoerotic practices are asphyxia by hanging, ligature, plastic bag, chemical substances, or a mixture of these. However, atypical methods such as overdressing/body wrapping have also been reported. In fact, overdressing/body wrapping is so rare that it is implicated in only 1.5% of published cases. Although plastic bags are often implicated in autoerotic deaths, there has been only one previous case that involved a plastic covering the victim's body from head to toe. We here report the case of a 34-year-old man who died due to asphyxia, secondary to body wrapping in the largest and most complex plastic bag ever involved in a published case of autoerotic death.