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.     

体位性窒息对脑血管损伤的实验观察

目的 观察体位性窒息对脑血管损伤的影响。方法 家兔20只,致其中10只体位性窒息,另10只断颈处死进行对照。用兔抗人白蛋白抗体和兔抗人(von Willebrand Factor,vWF)抗体进行LSAB免疫组化法显色。结果抗人白蛋白抗体及抗人vWW、检测均显示出阳性;对照组显示不明显。秩和检验显示,两组间具有显著性差异。结论　在体位性窒息时,呼吸障碍所引起的缺氧,可损害脑血管的正常结构。     

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.     

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。     

Positional asphyxia: reflection on 2 cases

Positional asphyxia, a fatal condition arising because of the adoption of particular body positions, causing mechanical interference with pulmonary ventilation, can occur in various circumstances that are likely to come under the observation of the specialist in legal medicine (work, car accidents, torture, kidnapping, etc.). It is difficult to diagnose the cause of death in such cases because they generally present with an aspecific anatomopathologic picture. In some situations, positional asphyxia can be hard to distinguish from asphyxia because of chest compression. The main difference is in the way the event occurred: whether the particular position causing the asphyxia had been adopted by choice or by compulsion or necessity when an extrinsic mechanical action would result in traumatic asphyxia. The diagnosis of positional asphyxia is essentially based on 3 criteria: the body position must obstruct normal gas exchange, it must be impossible to move to another position, and other causes of natural or violent death must be excluded. To illustrate the main physiopathologic and diagnostic causes of positional asphyxia, the authors report 2 cases taken from the records of events that came under the observation of the Medico-Legal Sector of Bari University Hospital throughout the last 10 years.     

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.     

Autopsy Reenactment – A Useful Technique in the Evaluation of Adhesive Tape Asphyxia

A 19‐year‐old woman was found dead with her face and head wrapped in plastic adhesive tape in a cupboard beside an opened helium cylinder. Despite the alleged presence of a suicide message on a social networking website, the unusual circumstances raised the possibility at the time of autopsy of either accidental death from sexual asphyxia or homicide. A carefully monitored reenactment demonstrated, however, that the type of commercial adhesive tape that had been used did not cause complete airway obstruction and that it was possible to wrap a considerable length of tape around the head and neck with the breath held. All of the features at autopsy were, therefore, compatible with self‐infliction. Asphyxial death was attributed to the combined effects of smothering from tape and anoxia from helium, an extremely rare combination in young females.     

Posttraumatic thrombosis of the middle cerebral artery

Posttraumatic cerebral infarction resulting from carotid or cerebral artery occlusion is rare. Traumatic dissection of the carotid artery is the most frequent cause of infarction, whereas posttraumatic thrombosis of the cerebral artery is very rare. The authors describe a case of posttraumatic thrombosis of the left middle cerebral artery. Early in the morning, a 16-year-old boy was found unconscious in the parking lot of a supermarket. He had received fist blows and kicks to the head, face, body, back, and hip during the night. Computed tomography 10 hours after the violence revealed a gross cerebral infarction in the area of the left middle cerebral artery. He died 9 days after the violence. The autopsy revealed a thrombosis in the left middle cerebral artery. Microscopically, granulation tissue in the intima and a rupture of the internal elastic lamina were observed near the beginning of the artery. It was concluded that the blows to the head and face caused a partial rupture in the arterial wall, leading to thrombosis and cerebral infarction.     

Death due to unusual position of the body--an explanationfor the consequence of reduced venous reflux to the heart

The article describes the case of a 29-year-old woman who was found dead in her apartment on a bar stool with the body being maximally retroflected in the lumbar region, the head hanging down and the feet and hands barely touching the floor. On external inspection of the body the cuff-like distribution of hypostasis on the forearms and lower legs was consistent with the position in which the body was found. There were no signs of foreign intervention. At autopsy massive congestion was found in the internal organs as well as pulmonary and cerebral edema. In the ventral region of the lumbar intervertebral discs superficial hemorrhages were detected. The alcohol content was 3.40 per thousand in the blood and 4.43 per thousand in the urine. As the essential pathogenetic mechanisms responsible for death reduced venous reflux to the heart in combination with postural asphyxia and the influence of alcohol are discussed.     

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.     

大鼠限制性体位窒息模型中膈肌Fn和HSP70的免疫荧光组化观察

目的观察Fn和HSP70在限制性体位窒息死亡的大鼠膈肌中的表达情况,进一步探讨限制性体位窒息死亡的机理。方法分组建立限制性体位窒息死亡大鼠模型,采用免疫荧光组织化学方法研究大鼠膈肌的Fn和HSP70的表达情况,并将荧光照片进行灰度值分析,比较抗原在不同组别间的表达差异。结果在Fn检测中,限制性体位窒息死亡组大鼠的膈肌肌内膜上有明亮荧光,肌纤维间隙的荧光强度明显大于对照组。在HSP70检测中,肌纤维内的荧光强度随着体位性限制程度的加重而明显增加。结论采用免疫荧光组织化学检测膈肌Fn和HSP70抗原的表达,对判断限制性体位窒息死亡者膈肌的损伤是一种有意义的手段。     

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.     

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.     

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。     

Sudden Unexpected Death due to Chiari Type I Malformation in a Road Accident Case

This case concerns a sudden death of a patient with Chiari I malformation. A 17‐year‐old female was seen unconscious then fell off a motorbike during the vehicle acceleration. The girl was confirmed dead on the way to hospital, being previously asymptomatic and with a clean medical record. Autopsy findings showed an extremely extra‐long cerebellar tonsillar herniation in the left side and unexplained multiple small cavities in cerebral hemispheres. Microscopic findings revealed loss and abnormal migration of the Purkinje cells, as well as capillary congestion in the herniated tonsil. The cause and mechanisms of this sudden death are considered as the cardiopulmonary dysfunction and arrest resulted from compression of the medulla and cervical cord, which was induced by both the positional insult and minor head trauma. In addition, this study stresses the importance of cervical cord examination in the case of unexpected sudden death following road accidents.     

固定双上肢并悬挂家兔死亡机理的研究

目的观测固定双上肢并悬挂家兔的血气变化及膈肌的肌电变化,探讨体位性窒息死亡的发生机制。方法建立家兔体位性窒息死模型,在实验前、后分别抽取家兔耳缘动脉和左心室血2m l进行血气分析,并监测实验过程中家兔膈肌肌电图(EMGd i)的变化。结果实验组与对照组均有缺氧、二氧化碳储留以及氧饱和度下降,但是实验组的二氧化碳储留比对照组低,氧饱和度比对照组高,缺氧情况比对照组低。在连续记录的EMGd i中,早期EMGd i较晚期EMGd i的高频与低频(H/L)比值显著降低,超过20%。结论固定双上肢并悬挂家兔死亡与膈肌疲劳导致缺氧窒息有关     

Computer Simulations to Investigate the Consequence of Blunt Head Impact

Blunt head impact as sustained in falls or punches against the head can result in rupture of bridging veins. Computer simulations were performed to simulate three different types of falls and punches against the head. The relative brain‐skull motion was recorded. The falls resulted in impact on the backside of the head, whereas the punches struck the face. The maximum resultant translational and rotational acceleration, the Head Injury Criterion (HIC), and the characteristics of the relative brain‐skull motion, as well as the coup and contre‐coup regions were determined. The maximum resultant translational acceleration was found to be between 2982 and 3541 m/s² for falls and between 814 and 942 m/s² for punches. The maximum resultant rotational acceleration reached 632–1000 rad/s² for falls and 252–620 rad/s² for punches. The HIC for falls was found to be at least 1357 and at most 130 for punches. The major brain‐skull displacement calculated for falls and punches was 6.6 and 4.2 mm, respectively. The results of this study suggest that falls are associated with a higher risk for bridging vein ruptures than punches and that cerebral contusions at the contre‐coup side are more serious.     

Spontaneous fractures in the differential diagnosis of fractures in children

A four-year-old male with cerebral palsy and spasticity, as a result of a non-accidental head injury sustained when he was two years old, died of pneumonia. Postmortem full body X-rays revealed fractures of varying ages of the left humerus and both femora, tibiae, and fibulae. This led to a thorough investigation of the case by the Office of the Chief Medical Examiner. Child abuse, accidents, metabolic bone disorders, other primary or secondary diseases of the bones, and pathological fractures were ruled out. The final diagnosis was spontaneous fractures secondary to osteopenia. The term spontaneous fractures is used to define fractures that occur without any known external cause, especially in cerebral palsy patients with spasticity.     

Sudden Death from Cardiopulmonary Arrest on Arrival of a Patient with Pulmonary Tuberculosis: A Case Diagnosed by Postmortem CT and Autopsy

Sudden death due to massive hemoptysis during management of tuberculosis occurs in a considerable number of patients. However, when massive airway hemorrhage occurs in a patient in whom tuberculosis has not been confirmed and a blood is not apparent externally on the face/body, it is difficult to immediately identify the cause of death as airway obstruction by tuberculous bleeding in the airway. We encountered an 83‐year‐old Japanese woman with her medical history included treatment of tuberculosis in her 20s who was in cardiopulmonary arrest on arrival (CPAOA), and the cause of sudden death could not initially be identified. Postmortem CT (PMCT) and autopsy revealed that the cause of sudden death was airway obstruction/asphyxia by tuberculous massive airway hemorrhage. Identification of the cause of death facilitated a subsequent active contact investigation and led to prevention of secondary tuberculosis infection.     

Virtopsy--fatal motor vehicle accident with head injury

A man wearing no protective helmet was struck by a motor vehicle while riding a bicycle. He was loaded on his left side, and the impact point of his head was his occiput on the car roof girder. He was immediately transported to the general hospital, where he passed away. Postmortem examination using multi-slice computed tomography (MSCT) revealed an extensively comminuted fracture of the posterior part and the base of the skull. Observed were deep direct and contrecoup brain bruises, with the independent fractures of the roof of the both orbits. Massive subdural and subarachnoidal hemorrhage with cerebral edema and shifting of the mid-line towards left side were also detected. MSCT and autopsy results were compared and the body injuries were correlated to vehicle damages. In conclusion, postmortem imaging is a good forensic visualization tool with great potential for documentation and examination of body injuries and pathology.