Positional Asphyxia Research Articles

Positional Asphyxia: Remains Hard to Diagnose?

Positional asphyxia is a type of asphyxia where the position of an individual compromises the ability to breathe. It is commonly caused by accidents due to alcohol or drug intoxication, diseases, and/or being in a confined space. In this study, the authors reviewed autopsy cases at their institute over the past 5 years where positional asphyxia is suspected as a contributing factor or cause of death. The autopsy cases (n=24) were divided into three groups: positional asphyxia was the cause of death (n=15); unknown cause of death but positional asphyxia was considered (n=4); and positional asphyxia was suspected to be a contributing factor (n=5). All cases of group A included postures that could interfere with breathing, but the typical jackknife or head-down postures were seen in approximately half of the cases; “classic signs of asphyxia” were also observed in approximately half of the cases. They shared features such as high blood alcohol concentration, therapeutic levels of drugs, various disease, minor head trauma, and morbid obesity; however, no definite diagnostic criteria have been established for forensic practice. Positional asphyxia is a form of mechanical asphyxia which must be differentiated from traumatic asphyxia. In addition to a complete autopsy, thorough laboratory tests and understanding of the circumstances of the case and the situation at the death scene are required for diagnosis. Special attention is required for the diagnosis of special types of positional asphyxia such as death during institutional restraint or prone restraint.

From suicide to accident – Case report – The significance of the medico-legal autopsies

IntroductionSuicide is the intentional and voluntary act of destroying one's own life, while an accident is an unintended event that involuntarily causes injury to one's health or destruction of life. Case presentationWe report a case of a 54-year-old male who was found in a forest in late November, approximately 500 m away from his car. He was positioned bent over a trunk of a tree with his head beneath the rest of his body. His pants were down to his knees, and there were soiled blades of grass and leaves on his body. Investigation of the case circumstances revealed that he had attempted suicide by carbon monoxide poisoning, using a hose connected to the exhaust pipe and running it through the window into the cabin. Window on the driver’s side was broken with glass particles on the driver's seat. Wrappers from “Rivotril” tablets, a generic benzodiazepine, were also found in the car.Autopsy revealed the following: postmortem hypostasis was of a cherry red color and well pronounced on the upper part of the front of the body and face. Numerous bruises, contusions, and erosions were present all over the body. Frostbites were especially pronounced in the knees and elbows area. The synovial membranes were partially bloodstained and reddish in color. Opening the stomach revealed erosions of the gastric mucosa (Wischnewsky sign).Chemical toxicological analysis detected presence of benzodiazepines and carboxyhemoglobin (25%). ConclusionBased on the autopsy findings, chemical toxicological analyses, and investigation of the case circumstances, it has been concluded that the death occurred due to the combined effects of hypothermia, postural asphyxia and carboxyhemoglobin and benzodiazepine intoxication. The manner of death in this case is a combination of accidental and suicidal, as the victim attempted suicide but ultimately died due to exposure to low external temperature.

Giant cervical lipoma adjacent to carotid artery: a case report and literature review

Cervical lipomas accompanied by neurovascular compression are extremely rare and require surgical treatment in case of appropriate symptoms. The preferable method is gross total resection, as otherwise they tend to recur. Invasive growth is not typical for lipomas. However, large tumors can involve adjacent nerves and vessels and significantly complicate resection. We present a 57-year-old patient who underwent resection of giant soft tissue cervical lipoma invading neurovascular bundle and compressing the oropharynx and esophagus with dysphagia and positional asphyxia. The patient was followed-up for previous 5 years. Resection was necessary due to tumor enlargement with appropriate symptoms. Searching for literature data was performed in the Pubmed, Medline, EMBASE, Cochrane Library and eLibrary databases. Gross total resection of 7-cm tumor was accompanied by mobilization of hypoglossal and vagus nerves, common, external and internal carotid arteries and jugular vein with repositioning of the oropharynx and esophagus. There was mild Horner's syndrome in early postoperative period. The patient was discharged in 4 days after surgery with regression of complaints. We found only 5 reports describing giant cervical lipomas invading neurovascular bundle. Giant cervical lipomas are extremely rare, and total resection with preservation of critical structures is possible in a specialized hospital.

A case of complex asphyxia sheds light on problems in the classification of asphyxias

Death from positional asphyxia is often an accidental event occurring when the victim’s body assumes a position which can compromise an effective respiration. Its diagnosis is usually not simple, because it needs to know the exact circumstance in which the body was found and the original positioning of all the body segments. In this case, a 41-year-old man with a history of opioid drugs abuse was found dead in a knee-chest position; the head was down on the floor with the face resting on a plastic bag. Pictures of the scene of death was taken while the body was still in its original position. At first, the main suspicion was that of a fatal overdose. Following the autopsy examination, completed by histological and toxicological examinations, the cause of death was determined as postural asphyxia secondary to intoxication by methadone, in the presence of ischemic heart disease. Some features, moreover, were typical of the death in head down position, and the prolonged knee-chest position was also associated with the obstruction of mouth and nose by the plastic bag, which may have contributed to the asphyxiation. These cases of “combined” asphyxia represent a challenge for the current classifications of asphyxia, which are very variable and not standardized, as we observe from a brief review of the literature. The elaboration of new systems of classification for asphyxias, which must be clear, simple and shareable, is necessary to avoid confusion in categorizing cases that present overlapping between several types of asphyxiation modalities.

Further explorations into the role of mast cells in deaths associated with fatal asphyxia: an immunohistochemical study utilizing CD 117 marker

Asphyxia-related deaths have always been a challenging task in the speciality of forensic pathology. Apart from helpful macroscopical signs (e.g., strangulation mark, cyanosis, petechial haemorrhage, and lung oedema), recent literature indicates that prolonged asphyxia is sufficient to induce an increase in mast cells (MC). Inflammatory cells migrate from the bone marrow to the lungs, aiding in the diagnosis of fatal asphyxial deaths. HIF1-α, a key regulator protein, is released from lung tissue capillaries during catastrophic hypoxia circumstances, as previously demonstrated in immunohistochemistry (IHC) research. The present study analyzed lung samples from 164 medico-legal autopsy cases, including 57 asphyxia/hypoxia deaths and 107 controls (non-asphyxial deaths). Peribronchial, perivascular and perialveolar MCs were detected using CD117 antibody, and the average of MCs in each of these locations was noted in each case. The results indicated a statistically significant increase in peribronchial and perialveolar mast cells (MC) in fatal asphyxial deaths, including those caused by hanging, drowning, or postural asphyxia. Peri-bronchial MC in lung sections of asphyxial deaths were in the range of 0.2–5.4 and in non-asphyxial samples were in the range of 0.0–2.2. Peri-alveolar MCs in lung sections of asphyxial deaths were in the range of 0.0–0.6 and in non-asphyxial samples were in the range of 0.0–0.2. Our data suggest that mast cells (MC) play an important role in fatal hypoxia-related mortality and CD 117 may be a reliable marker for detection of mast cells in asphyxial deaths. It could be very beneficial to forensic pathologists tasked with differentiating fatal asphyxia fatalities from other causes of death.

Analysis of Cases of Infants and Children Asphyxia at Day Care Center: Cases of Asphyxia in the Process of Teachers Putting the Infants and Children to Sleep

In the cases of infants and children, there is a special form of accidental asphyxia that occurs in an unsafe sleeping environment. Rarely, some infants and children unexpectedly die in the day care centers. This also occurs during the process when teachers put the infants and children to sleep. This analysis was performed on national forensic autopsy cases from January 1, 2001, to October 31, 2022. The 97,402 cases were selected to provide their incident overview, the cause of death and the manner of death. The cases of infants and children asphyxia at day care centers were 43 cases (0.04%). The major cause of death was sudden infants and children death syndrome which included the possibility of accidental asphyxia (31 cases). This was followed by chocking (8 cases), complicated asphyxia (2 cases), smothering (1 case), and positional asphyxia (1 case). Two cases were a result of homicide, 10 cases were accidents, and 31 cases had unknown manner of death. There were four cases of asphyxia that occurred in the process of teachers putting infants and children to sleep. In all cases, there were no specific findings in the autopsy and there were CCTV footage including contact with the day care center teacher while taking a nap. Reporting these results provides information and awareness to social members related with infants and children, specially day care centers, and serves as basis for establishing social systems such as mandatory of CCTVs, helping to reduce the occurrence of similar death on infants and children.

The onset and severity of acute opioid toxicity in heroin overdose cases: a retrospective cohort study at a supervised injecting facility in Melbourne, Australia

Aim To differentiate the severity of acute opioid toxicity and describe both the clinical and physiological features associated with heroin overdose in a cohort of witnessed overdose cases. Methods Witnessed heroin overdose cases over a 12-month period (30 June 2018 – 30 June 2019) at the Medically Supervised Injecting Room (MSIR) in Melbourne, Australia were examined. The severity of acute opioid toxicity was classified according to the level of clinical intervention required to manage the overdose cases where an escalating level of care was provided. Heroin overdose cases were classified into one of three graded severity categories and a fourth complicated heroin overdose category. Results A total of 1218 heroin overdose cases were identified from 60,693 supervised injecting visits over the study period. On the spectrum of toxicity, 78% (n = 955) of overdose cases were classified as Grade 1 severity, 7% (n = 83) as Grade 2 severity, and 13% (n = 161) as Grade 3 acute opioid toxicity severity cases, as well as 2% (n = 19) classified as complicated heroin overdose cases. The median onset time for heroin overdose cases was 17 min (IQR 11–28 min) from the time the individual was ready to prepare and inject heroin until clinical intervention was initiated. Conclusion We demonstrated that heroin overdose is a dynamic illness and cases differ in the severity of acute opioid toxicity. The risk of airway occlusion including positional asphyxia was an early and consistent feature across all levels of toxicity, while exaggerated respiratory depression together with exaggerated depression of consciousness was increasingly observed with greater levels of toxicity. We also demonstrated the importance of early intervention in overdose cases, where in a large cohort of heroin overdose cases there were no fatal outcomes, a very low hospitalisation rate and most cases were able to be managed to clinical resolution on-site.

Forensic Research Progress on Postural Asphyxia.

In recent years, the increase in the number of cases of postural asphyxia has gradually attracted the attention and discussion of forensic scientists domestically and internationally, but a systematic, comprehensive and recognized expert consensus and identification standard has not been established at home and abroad. This paper reviews the case characteristics, occurrence, mechanism of death, and identification criteria of postural asphyxia, to provide reference for future research.

Sudden Death Caused by Positional Asphyxia Related to Forensic and Clinical Medicine

Positional asphyxia refers to a special type of mechanical asphyxia, which can lead to death under severe circumstances. It can be found in clinical practice and medico-legal expertise such as sudden infant death syndrome (SIDS) in the sleeping, unexplained sudden death in alcoholics and seniors of weak physiques, as well as violence-related sudden death in special physical position. However, the death cases of positional asphyxia were failed to be given more focuses in clinical practice. Most of the cases associated with positional asphyxia are mainly subject to forensic medical identification, and the death mechanism and the expertise standard have been discussion in forensic medicine. But both clinical medicine or forensic medicine, positional asphyxia can be classified into violence and non-violence, having some associated high-risk factors such as age, temulence, heart disease etc. Therefore, it is very important to correctly identify the causes and related risk factors of positional asphyxia and to make scientific clinical diagnosis and correct forensic experts opinions for correctly judging the cause of death of victims.

Entrapment within an ottoman storage bed: an unusual accidental asphyxial death

Herein, we present an uncommon forensic case of death by asphyxia. The victim was a woman whose body at death scene investigation (DSI) was discovered beside an ottoman storage bed. According to the rescue team, who had moved the body before our arrival, the body was originally found in the prone position and stuck with the neck, thorax and arms within the bed. Examination of the body showed hypostasis that was mainly distributed to the face and the lower chest while sparing the neck and the upper chest. The face was markedly swollen, and the eyes were congested with blood. Dissection and histology revealed pulmonary oedema and emphysema of both lungs. Integrating circumstantial, radiology and autopsy data, it was established that the victim, while trapped between the mattress and the edge of the ottoman storage bed, died by mechanical asphyxia due to cervical-thoracic compression and postural asphyxia acting simultaneously.

Deaths due to suffocation in an oxygen deprived environment onboard a marine vessel – A case report

Suffocation deaths may be due to mechanical obstruction of the airways such as smothering and choking, restriction of respiration from traumatic and positional asphyxia, or from a lack of environmental oxygen. The latter may be due to entrapment in a nearly or completely air-tight container, or from consumption or replacement of the environmental oxygen by other means. Enclosed spaces onboard marine vessels are potential workplace hazards due to consumption of oxygen from rusting of the walls. Autopsy findings are typically non-specific.

Excited Delirium Syndrome (ExDS): emergence and emergency management

The Excited Delirium Syndrome (ExDS) is a state of maximum psychophysiological excitation far beyond mental agitation. Patients themselves are at an acute risk and put others at a high risk. We present data from eleven patients and a short literature review. Results: 9 of 11 patients were acutely intoxicated (alcohol, magic mushrooms, THC, ecstacy, or "flakka"). Eight had a history of substance abuse and 4 of other mental illness. None of the patients responded to attempts at verbal de-escalation. Seven had significant injuries at the time of admission to the hospital. The aggressive "psychiatric" presentation of ExDS can lead to vital risks being overlooked (hyperexcitation, acidosis, rhabdomyolysis, hypoxemia, and cardiovascular decompensation), which may even be increased by severe methods of restraint (hogtie; positional asphyxia). Early recognition of ExDS and its risks, comprehensive management and the prevention of inappropriate treatment will help to reduce fatal outcomes.

Prone restraint cardiac arrest: A comprehensive review of the scientific literature and an explanation of the physiology.

Deaths occurring among agitated or violent individuals subjected to physical restraint have been attributed to positional asphyxia. Restraint in the prone position has been shown to alter respiratory and cardiac physiology, although this is thought not to be to the degree that would cause asphyxia in a healthy, adult individual. This comprehensive review identifies and summarizes the current scientific literature on prone position and restraint, including experiments that assess physiology on individuals restrained in a prone position. Some of these experimental approaches have attempted to replicate situations in which prone restraint would be used. Overall, most findings revealed that individuals subjected to physical prone restraint experienced a decrease in ventilation and/or cardiac output (CO) in prone restraint. Metabolic acidosis is noted with increased physical activity, in restraint-associated cardiac arrest and simulated encounters. A decrease in ventilation and CO can significantly worsen acidosis and hemodynamics. Given these findings, deaths associated with prone physical restraint are not the direct result of asphyxia but are due to cardiac arrest secondary to metabolic acidosis compounded by inadequate ventilation and reduced CO. As such, the cause of death in these circumstances would be more aptly referred to as "prone restraint cardiac arrest" as opposed to "restraint asphyxia" or "positional asphyxia."

An Illustrative Review of Positional Asphyxiation in Infants Secured Upright in Car Seats

Sudden Unexpected Infant Death (SUID) includes the full spectrum of all causes of infant death, which include “Determined” causes [e.g. Sudden Infant Death Syndrome (SIDS) at 42% and Accidental Suffocation and Strangulation at 24%], as well as “Undetermined” causes at 34% [1]. Literature is replete with studies that address the risk factors associated with SIDS, accounting for at least 42% of infant mortality,[1] but scarcely do published reports address risk factors associated with Positional Asphyxia (PA).This illustrative narrative addresses the 2.8 – 3.0% (98-105) healthy infants who have no pre-existing medical conditions, including prematurity, who die from SUID primarily in car seats, and whose suspected cause of death is PA. Webster’s Dictionary defines PA as, “A condition of deficient oxygen supply to the body which occurs when a person’s physical position prevents adequate breathing.” This tragic phenomenon is suspected when the autopsy of an infant reveals no discovery of a traumatic injury, when there is no pre-existing medical pathology, and when the cause of death is determined to be “Undetermined or Unknown.”

Fatal and non-fatal injuries due to suspension trauma syndrome: A systematic review of definition, pathophysiology, and management controversies.

Suspension trauma syndrome is a life-threatening event that occurs when a person is "trapped" in a prolonged passive suspension. It is most commonly seen in people who engage in occupational or sport activities that require harness suspension. The aim of this study is to identify the predisposing factors, pathophysiology, and management of suspension trauma. A review and analysis of the literature published in English and Spanish from 1972 to 2020 on suspension trauma were performed. Search sources were PubMed, Medline, Cochrane Library, MeSH, UpToDate, and Google Scholar. Articles referring to suspension trauma associated with other injury mechanisms (traumatic impact injuries, drowning, asphyxiation, or bleeding), case reports, and pediatric population were excluded. Forty-one articles were identified. Of these, 29 articles related to mechanism, pathophysiology, and management of individuals who suffered prolonged suspension trauma without associated traumatic injuries were included in the study. We encountered several controversies describing the putative pathophysiology, ranging from blood sequestration in the lower extremities versus accumulation of metabolic waste and hyperkalemia to dorsal hook-type harness as a trigger cause of positional asphyxia; to vascular compression of femoral vessels exerted by the harness causing decreased venous return. Pstients suspended in a full-body harness with dorsal hook showed more hemodynamic alterations in response to the compressive effect on the rib cage, causing a reduction in perfusion by presenting a decrease in pulse pressure. Management strategies varied across studies. Progress has been made in individualizing the population at risk and in the management of suspension trauma. We recommend the formation of consensus definitions, larger cohort or registry studies to be conducted, and experimental animal models to better understand the mechanisms in order to develop management and life support guidelines from a trauma and emergency medicine perspective.

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.

Impact of statewide safe sleep legislation on hospital practices and rates of sudden unexpected infant deaths

BackgroundSudden Unexpected Infant Death (SUID) is the leading cause of death in the post-neonatal period in the United States. In 2015, Connecticut (CT) passed legislation to reduce the number of SUIDs from hazardous sleep environments requiring birthing hospitals/centers provide anticipatory guidance on safe sleep to newborn caregivers before discharge. The objective of our study was to understand the barriers and facilitators for compliance with the safe sleep legislation by birthing hospitals and to determine the effect of this legislation on SUIDs associated with unsafe sleep environments.MethodsWe surveyed the directors and/or educators of the 27 birthing hospitals & one birthing center in CT, about the following: 1) methods of anticipatory guidance given to parents at newborn hospital discharge; 2) knowledge about the legislation; and 3) barriers and facilitators to complying with the law. We used a voluntary online, anonymous survey. In addition, we evaluated the proportion of SUID cases presented at the CT Child Fatality Review Panel as a result of unsafe sleep environments before (2011–2015) and after implementation of the legislation (2016–2018). Chi-Square and Fisher’s exact tests were used to evaluate the proportion of deaths due to Positional Asphyxia/Accident occurring before and after legislation implementation.ResultsAll 27 birthing hospitals and the one birthing center in CT responded to the request for the method of anticipatory guidance provided to caregivers. All hospitals reported providing anticipatory guidance; the birthing center did not provide any anticipatory guidance. The materials provided by 26/27 (96%) of hospitals was consistent with the American Academy of Pediatrics (AAP) Guidelines. There was no significant change in rates of SUID in CT before (58.86/100,000) and after (55.92/100,000) the passage of the legislation (p = 0.78). However, more infants died from positional asphyxia after (20, 27.0%) than before the enactment of the law (p < 0.01).ConclusionsDespite most CT hospitals providing caregivers with anticipatory guidance on safe sleep at newborn hospital discharge, SUIDs rates associated with positional asphyxia increased in CT after the passage of the legislation. The role of legislation for reducing the number of SUIDs from hazardous sleep environments should be reconsidered.

Impaired ability to turn in bed in parkinson’s disease as a potential rare cause of positional asphyxia: a sensor-based analysis

BackgroundNocturnal hypokinesia commonly affects Parkinson’s disease (PD) patients, manifesting primarily as an impaired ability to turn in bed and sleeping in specific positions, such as prone that potentially poses the risk of positional asphyxia. ObjectiveTo objectively evaluate, using axial inertial sensors (the NIGHT-Recorder), the ability of PD patients and controls to turn in bed from prone to supine position and to correlate these parameters with disease severity scores. Patients and MethodsTurning in bed from prone to supine position was assessed in 16 PD patients with a moderate disease stage and 16 age-matched controls using the NIGHT-Recorder. Successful turning was defined as a full 180 ° turn from prone to supine position as evidenced by the NIGHT-Recorder. Objective parameters included duration, velocity, and acceleration of turn. The ability to turn in bed was determined by torque per kilogram body weight (T/kg). ResultsTwo out of 16 PD patients (12.5%) could not initiate their turns. PD patients turned with a significant longer duration (p = 0.04), slower velocity (p = 0.04), and acceleration (p = 0.04) compared to controls. Although PD patients had lower T/kg than controls, the difference was not significant. Several significant correlations were demonstrated between turning parameters and clinical rating scales (Duration vs. UPDRS axial: r=0.51, p = 0.04; T/kg vs. PDSS-2: r=0.53, p = 0.03; T/kg vs. NHQ: r=0.52, p = 0.03). ConclusionOur study provides objective evidence of impaired turning in bed from prone to supine position in PD patients with nocturnal hypokinesia. Appropriate measures should be taken to improve nocturnal mobility in those at risk.

The relationship between positional asphyxia and increasing body mass index.

Review of the files of the Pathology section of Forensic Science SA over 17 yrs (January 2003-December 2019) revealed 32 adult cases of positional asphyxia (age range 18-87years; average 49years - m:f ratio 3:1). Predisposing/causative conditions were accidents, N=8, alcohol intoxication N=7, neurological disease N=7, drug intoxication N=5, morbid obesity N=2, combinations of factors N=2, and a single homicide N=1. There was one case with below normal weight (BMI 17.9), with 6 cases having normal weights (BMI range 18.9-24.6, average 22.3), 9 being overweight (BMI range 25.3-29.5, average 27.9), and 16 being obese (BMI range 30-66.2, average 40.9). Only 7 cases (22%) had either under/normal weight compared to 25 (78%) who were overweight/obese (p<0.05). Increasing body mass appears to be a risk factor to be considered in all forms of positional asphyxia; BMI should, therefore, be routinely taken into account in the forensic evaluation of such cases.

Accidental death in a jack-knife position

Postural (or “positional”) asphyxia occurs due to a person being in a prolonged abnormal body position that prevents adequate breathing. Its diagnosis is based on several criteria, in particular the exclusion of involvement of other people and other causes of death. This case report is about a 73-year-old woman whose body was found in a jack-knifed position by her son. She was on the floor, wedged into the space between the legs and seat of a chair. The man attempted unsuccessfully to extricate her from that position and called for medical assistance. The rescuers took pictures of the scene before freeing the victim from the chair and providing unsuccessful resuscitation. External examination disclosed abrasions on the thighs and the back of the victim, which corresponded to parts of the chair, ecchymoses on the upper limbs (ascribed to the gripping attempts), conjunctival petechiae, facial congestion and swelling. Autopsy disclosed brain and lung congestion and edema and atherosclerotic coronary disease without acute cardiac lesions. All these considerations contributed to the cause of death being determined as being due to postural asphyxia.