Murder-suicide by carbon dioxide (CO2) poisoning: A family case from Berlin, Germany

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This report demonstrates how carbon dioxide (CO2) may be a potent weapon in murder-suicide, where the death scene offers virtually no clues as to the lethal modality and the autopsy findings are nonspecific. Four bodies were discovered in an apartment in midsummer 2012 in Berlin, Germany. The bodies were those of a father (a 69-year-old business consultant), his wife (aged 26-years), and two sons (aged 3 and 6 years, respectively). The police found the wife and two sons lying in their beds and the husband in a supine position on the floor with a plastic bag over his head tied loosely around his neck with a rope. A 500 g single-use CO2 cylinder was standing on the floor. The container was almost empty and according to the label had been sold as a CO2-fertilizer for aquarium plants. Two synthetic inhalation face masks and tubing were also found, which tested positive for the DNA of all four deceased family members. It is hypothesized that the husband placed an inhalation mask over the mouths and noses of his wife and children while they were sleeping. Inhalation of pure CO2 ensured their rapid unconsciousness due to hypercapnia and severe anoxia. The rapid increase in CO2 concentration would render a victim helpless, with no time to wake and defend themselves, or others. The proximate cause of death in all cases was attributed to CO2 intoxication, based on the scene findings, the reconstructed sequence of events, the autopsy, and results of toxicological studies.

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... This is the most commonly reported motive in the literature [1]. In one case that involved a 69-year-old father killing his wife and his two sons by carbon dioxide poisoning, possible financial motives were mentioned in his suicide note [13]. ...
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Murder-suicides are defined as the murder of at least one person and the suicide of the offender following the murder. The intention to commit suicide must be primary. In most cases, a male offender kills a female victim after a separation. The current analysis was the first analysis of the typology of murder-suicides in Berlin. We analyzed the autopsy files of the Institute for Forensic Medicine of the Charité University Medicine Berlin and of the City Institute for Forensic Medicine Berlin. We performed descriptive and statistical analyses of cases between 2005 and 2013. We identified 17 murder-suicides. All 17 offenders were male, and 20 of the victims (90%) were female. The offenders used firearms in the majority of the cases. In seven cases, the victims and offenders were at least 80 years old. The average age of the offenders was 63 years. Disease was the motive in 6 cases involving older offenders. Our study might support the development of prevention strategies. In this regard, it is important to build a database for murder-suicides in Germany and other countries, to formulate a uniform definition of murder-suicide, to carry out nationwide interdisciplinary studies on this topic and to improve the existing health care structures, especially for older adults and people with depression.
... In August 1986, a limnic eruption at Lake Nyos in Northwestern Cameroon killed 1746 people and 3500 livestock in a matter of minutes due to release of CO 2 dissolved in the water (9). Although large quantities of CO 2 , gaseous or solid form, are rel-atively accessible to persons, very few cases of suicidal deaths from asphyxia in the setting of high concentration of CO 2 have been published (10,11). ...
Carbon dioxide (CO 2 ) therapy is the subcutaneous or transcutaneous administration of CO 2 for therapeutic purposes. Carbon dioxide therapy is used for localized lipolysis, to treat chronic skin conditions, and is a safe treatment. Full-body CO 2 baths are offered in European spa centers, in which the clients are placed into full body bags infused with CO 2 at an optimal concentration range between 1000 and 1400 mg/L (516 000-722 500 ppm). Commercially manufactured, air-tight bags and accompanying apparatus designed to provide CO 2 baths can be purchased for home use. Few human CO 2 -related deaths have been reported. They have been mostly accidental, consisting of persons trapped in a closed environment in the presence of “dry ice” or solid CO 2 . There have been no reported deaths of a human undergoing a CO 2 therapy at home. We present a case of a middle-aged male found at home completely inside an air-sealed bag wrapped tightly around his body. The bag was connected to a working pump and a CO 2 gas tank. The pump was connected through an inflow and outflow circuit to the bag. The inflow tubing for CO 2 gas delivery was partially disrupted, while the outflow tubing was intact. The autopsy and toxicology were unremarkable. The cause of death was determined to be asphyxia by vitiated atmosphere as evident by the displacement of oxygen by CO 2 and low pressure created inside a “CO 2 therapy bath.” The manner of death was accidental.
... However, H 2 S and CO 2 poisoning have been more extensively studied in accidental or occupational fatalities, mostly occurred in confined spaces [15][16][17][18][19][20][21][22][23][24], but also in suicidal events [25][26][27][28][29][30]. Unfortunately, few reports mention the levels of toxic gases at the death scene [13,27,31,32] although it is well known that the acute toxicity of H 2 S and CO 2 is more dependent on environmental concentration than time of inhalation. ...
The study reports the environmental, toxicological and histopathological forensic investigations applied on three victims of accidental death (father, mother and son), due to the fall in a volcanic pothole, during the touristic visit of the “Solfatara park”, near Naples (Italy). At autopsy greenish skin discolouration was observed and all bodies showed the classical signs of asphyxial deaths, such as cyanosis and hemorrhagic pulmonary edema. Focal micro-hemorrhages were found in the brain at intracranial and subpial levels. The hemogasanalysis and spectrophotometric test on blood for Methemoglobin (MetHb), Carboxyhemoglobin (HbCO) and Sulfhemoglobin (SHb) showed pCO 2 , SHb and MetHb above the physiological levels. On biological specimens, toxicological analyses performed by GC/MS revealed high concentrations of hydrogen sulfide (H 2 S) and of thiosulfate (TS), its main metabolite. The monitoring of toxic gases on the death scene showed an unsafe environment, into the pothole, able to cause the sudden loss of consciousness of the victims with subsequent asphyxiation (knockdown effect). In particular, at the bottom of the hole, the maximum levels of H 2 S and carbon dioxide (CO 2 ) were 2200 ppm and 98% respectively. For the family members, the cause of the death was assessed as acute poisoning by H 2 S and CO 2 . The fatalities, happened in quick succession as for a domino effect, were pretty similar to the asphyxial deaths by confined spaces, frequently observed in occupational setting. Fatalities secondary to accidental volcanic gases inhalation, such as H 2 S and CO 2 in geothermal areas, have been already described but often without a forensic approach. To the best of our knowledge this is the first case that reports the accidental poisoning by volcanic gases involving three people, with different caracteristic of age and sex, allowing the correlation between toxicological and pathological results with the true levels of asphyxiating gas, measured on the death scene.
... Intoxication and death with gases is reported in many cases [7,11,12], either accidents or suicides. Gases such as nitrogen [13,14], carbon monoxide [6,7], carbon dioxide [15,16], helium [8][9][10][11][12], air [4], butane [17], hydrogen sulfide [18][19][20], nitrous oxide [21] were reported as cause of death. ...
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Helium is the chemical element with atomic number 2, represented by the symbol He. It is an inert, colorless, odorless, insipid monoatomic gas. It has the lowest boiling point and the lowest melting point among the chemical elements and appears only in gaseous state, except for extreme conditions. The use of helium for suicidal purposes is extremely rare. In Romania, suicide has a frequency of 12 per 100,000 inhabitants, which classifies us in the category of countries with low suicide rates. As methods, men use hanging most often while women use more softer methods such as poisoning. Helium is rarely used for suicidal purposes because it is relatively difficult to obtain. Basically, it is not poisoning in the true sense of the word, but rather the substitution of oxygen with helium, which cannot be carried by hemoglobin, and thus transport asphyxia occurs. At the end of the paper we shall exemplify a case of helium poisoning for suicide purposes, purchased from a cylinder for inflating balloons.
... However, supporting our results are observations of inci- dents with CO 2 in humans. Survivors of CO 2 poisoning reported, besides a pungent smell and difficulty breathing, no fear, pain, or other warning signs, and unconsciousness was reached within a few seconds [71,72]. Also, a recent study comparing CO 2 , isoflurane, and pentobarbi- tal-phenytoin euthanasia in mice observed no specific behavioral signs for distress [7]. ...
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In the European Union (EU) millions of laboratory mice are used and killed for experimental and other scientific purposes each year. Although controversially discussed, the use of carbon dioxide (CO2) is still permitted for killing rodents according to the Directive 2010/63/EU. Within the scope of refinement, our aim was to investigate if isoflurane and sevoflurane are an appropriate alternative killing method to CO2 in mice. Different concentrations of CO2 (filling rates of 20%, 60%, 100%; CO2 20, 60, 100), isoflurane (Iso 2%, 5%) and sevoflurane (Sevo 4.8%, 8%) were compared in two mouse strains (NMRI, C57Bl/6J) using a broad spectrum of behavioral parameters, including the approach-avoidance test, and analyzing blood for stress parameters (glucose, adrenaline, noradrenaline). We focused in our study on the period from the beginning of the gas inlet to loss of consciousness, as during this period animals are able to perceive pain and distress. Our results show that only higher concentrations of CO2 (CO2 60, 100) and isoflurane (5%) induced surgical tolerance within 300 s in both strains, with CO2 100 being the fastest acting inhalant anesthetic. The potency of halogenated ethers depended on the mouse strain, with C57Bl/6J being more susceptible than NMRI mice. Behavioral analysis revealed no specific signs of distress, e. g. stress-induced grooming, and pain, i. e. audible vocalizations, for all inhalant gases. However, adrenaline and noradrenaline plasma concentrations were increased, especially in NMRI mice exposed to CO2 in high concentrations, whereas we did not observe such increase in animals exposed to isoflurane or sevoflurane. Escape latencies in the approach-avoidance test using C57Bl/6J mice did not differ between the three inhalant gases, however, some animals became recumbent during isoflurane and sevoflurane but not during CO2 exposure. The rise in catecholamine concentrations suggests that CO2 exposure might be linked to a higher stress response compared to isoflurane and sevoflurane exposure, although we did not observe a behavioral correlate for that. Follow-up studies investigating other fast-acting stress hormones and central anxiety circuits are needed to confirm our findings.
... Such scenarios include closed atmospheres where oxygen is used up and carbon dioxide builds up. This has been seen in cars with catalytic converters that remove carbon monoxide, wine vat rooms with dry ice, rooms with carbon dioxide fire extinguisher mechanisms, and in some natural disasters such as volcano lake eruptions, where large amounts of carbon dioxide can be released and have resulted in multiple fatalities (20)(21)(22)(23)(24)(25)(26). In the Lake Nyos incident in Cameroon in 1986, over 1700 people were killed and there were another 5000 survivors from what was believed to be the massive release of carbon dioxide from the lake (27). ...
This paper reviews deaths in which there is an environment that is low in oxygen and/or has elevated levels of carbon dioxide. These deaths present problems to autopsy pathologists, as the autopsy is typically negative and postmortem toxicology cannot be used to detect the effects of hypoxia and raised levels of carbon dioxide. Deaths from hypoxia and raised carbon dioxide may be encountered in work-and nonwork-related environments. Typically these are accidents, but suicides may be encountered and criminal charges may follow these events. Environments that have been associated with these events include mines, tunnels, sewers, and pits. Transportation incidents may also be associated with hypoxic events, particularly aircraft and submarines. When an atmosphere low in oxygen is entered, collapse can be rapid, or immediate if the environmental oxygen is below 6%. Environments rich in carbon dioxide can also cause death, even with a high oxygen concentration. Such environments may be encountered in industrial settings, but also occur in natural disasters such as the Lake Nyos disaster. The identification of these deaths typically requires a coordinated investigation with safety inspectors and other experts in industrial- and work-related deaths.
... KEYWORDS: forensic science, forensic pathology, silage pit, accidental death, drowning, carbon dioxide, hydrogen sulfide, infrared gas analyzer Fatalities due to gas intoxication are rare in routine forensic casework. They are mostly accidental deaths (1), but cases of suicide or homicide (2,3) have also been reported. The most common is carbon monoxide (CO) intoxication (4); Intoxication by other gases is much more rare (ammonia, methane, propane and butane, hydrogen sulfide, carbon dioxide etc.). ...
Fatalities due to gas intoxication are rare in routine forensic casework. The most common gas is carbon monoxide, with other gases (ammonia, methane, propane and butane, carbon dioxide, hydrogen sulfide) encountered only very rarely. In this report, we describe the accidental death of two maintenance workers who were found in the silage pit at a biogas plant. The autopsy revealed signs of asphyxia in both the deceased. Analysis of the gaseous mixtures in the tank using an infrared gas analyzer showed slightly elevated concentrations of carbon dioxide. Toxicological examination of the blood of both the deceased using gas chromatography with a flame ionization detector, spectrophotometry and liquid chromatography‐mass spectrometry did not detect any toxicologically significant substance that would explain the sudden collapse. Both the autopsy and the toxicology analyses suggest CO2 intoxication as the most likely cause for the collapse of the two men, which then led to sudden asphyxia.
... Während von Sautter et al. [20] ein 4 Personen betreffender erweiterter Sui-zid unter Verwendung einer CO2-Gasflasche berichtet wurde und Duncanson [6] einen "iatrogenen Homizid" durch Inhalation einer 60 %igen CO2-Narkose beschreibt, ist eine homizidale Anwendung der Noxe in Form von Trockeneis in der Literatur bisher nicht beschrieben. Demgegenüber ist der "Mordmethode" Trockeneis hingegen bereits ein Fernsehfilm der Reihe "Tatort" gewidmet und damit einem großen Publikum bekannt gemacht worden ("Tatort: Auskreuzung", Folge 811, Erstausstrahlung 25.09.2011) ...
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Deaths associated with dry ice are rare. After a change of its aggregate state from solid to gaseous form (sublimation), CO2 accumulates on the ground in closed rooms and inspiration of high concentrations leads to respiratory distress and a potentially fatal outcome. We report the death of a 25-year-old man, who was found with signs of putrefaction after an order of 30 kg of dry ice. After autopsy, the cause of death was classified as suicidal CO2 intoxication, which is already reported in suicide internet fora. If the crime scene investigation failed to demonstrate a possible influence of dry ice on the manner of death, the diagnosis would be nearly impossible, because neither autopsy findings nor toxicological analyzes can provide evidence in such cases. The present article aims to familiarize all doctors who perform postmortem examinations with the known hazards of dry ice and sensitize them for such investigations.
The acute toxicity of high concentrations of carbon dioxide (CO2) was investigated in anesthetized rats using physiological parameters. At an oxygen concentration of 21%, the survival time decreased in a concentration-dependent manner from ≥7.3 h at 20% CO2 to 1.0 h at 50% CO2. The animals were divided into groups that were exposed to 40% CO2 and 21% O2 balanced with nitrogen (CO2 group), 40% CO2 and 12.6% O2 (CO2-Hypoxia group), 0% CO2 and 12.6% O2 (Hypoxia group), and 0% CO2 and 21% O2 (Control group) for 3 h. In the CO2 group, mean blood pressure (MBP) increased temporarily in the first 60 min followed by a gradual decrease, while breathing rate (BR) decreased immediately up to 3 h and the concentration of serum indicators reflecting organ damage increased. Most of these effects progressed in the CO2-Hypoxia group. The Hypoxia group showed a contrasting response to the CO2 groups in MBP and BR, and a slight partial increase in the serum indicators. Histological changes were not observed in any primary organs of any group, except for eosinophilic or necrosis of pyramidal cells in the hippocampal CA1 region of the CO2 group. These results indicate that high concentrations of CO2 inhalation are toxic, likely due to BR suppression, and that hypoxia produced under a high CO2 environment, while showing little effect on its own, enhances the toxic effects of CO2.
Carbon dioxide capture and storage (CCS) is regarded as a powerful technology in mitigating the impacts of climate change and is considered as interim solution until other sustainable energy technologies can be used on a broader scale. Despite the fact that well conducted geological risk analyses exists, a major toxicological risk assessment including all components of the process is missing. Therefore, a literature study was undertaken with its focus on potential toxicological risks. These could appear in all parts of the CCS chain: in the capture process when chemicals are used for scrubbing, during transportation in case of accidents, and during geological storage when a leakage of CO2 or brine occurs. Toxicological hazards of special concern emerge not from CO2, but degradation products of scrubbing chemicals (nitrosamines and nitramines) or H2S-co-transportation. Additionally, contamination of potable aquifers due to mobilisation of hazardous trace elements, such as arsenic, nickel, and lead could become relevant in case of a leakage. Overall, to achieve further safety for the implementation of CCS as a mitigation technology, investigations in acute CO2-toxicity (with derivation of mass-intoxications threshold values), acute emergency management, and contaminants should be prime objectives for future CCS risk assessment research.
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Given that most fatal hangings are suicidal and occur in locations that have been selected to conceal this activity (thus maximizing the chances of a lethal outcome), there has been very little corroboration of the speed with which unconsciousness and death may occur. A 35-year-old male is reported who committed suicide by hanging immediately after talking to his spouse. Police investigations confirmed her reliability as a witness indicating that lethal anoxia in this case had occurred within a very short time (most likely in less than 1 min) of suspension. The speed with which death may result from hanging not only gives an insight into fatal pathophysiological mechanisms, but also provides useful information for situations where a lethal outcome is to be avoided, or is not intended. For example, individuals at risk of suicide who are being monitored in institutional facilities need to be constantly under direct visual surveillance as significant hypoxia can be rapidly induced, parents and caregivers with infants and children in potentially unsafe sleeping environments need to realize how swiftly death or irreversible anoxic brain damage may occur from neck compression, and those who engage in recreational asphyxia should be informed just how quickly a fatal outcome may ensue.
The life-threatening danger of neck compression results from — obstruction of cervical blood vessels, — obstruction of respiratory ducts, and — a complex of cardiac reflex mechanisms. The contribution of these pathophysiological components, in each case, depends on the particular location, the pressure and the continuous/discontinuous duration of the violence. Cardiac reflex mechanisms are present during the act of violence to the neck and can lead to death even after the violence has ended. During the post-ischemic period local obstructive vascular lesions occur in the brain such as the “no-reflow-phenomenon” and the “maturation phenomenon” which could be responsible for death during a defined interval after the end of neck compression. Some morphological findings of the lungs may be suggestive of (Brinkmann 1978) or provide evidence of (Janssen 1963) such a protraction. The traditional concept of pathophysiological mechanisms must be enlarged due to the findings of recent experimental neuropathophysiology (recovery after complete brain ischemia). The importance of disturbed regulation of blood flow in the post-ischemic period must especially be considered. The traditional classification of violence to the neck (e.g. hanging, manual strangulation or throttling, strangulation by ligature) indicates preferences for particular pathophysiological components, but is insufficient for progress of knowledge in this field. The pathophysiological aspects are indispensable for reconstruction of the course of violence and are the basis of the expert’s opinion.
Carbon dioxide (CO(2) ) is an odorless constituent of air. Higher concentrations can be detected in geothermal and automotive emissions, fermentation, and sublimation of dry ice. An unskilled worker entered a fermentation tank to clean it, which had not been done for about 5 months allowing for high concentrations of CO(2) to build up. A second worker entered the tank to rescue the first one. Shortly after both were found the first worker was rescued directly whereas the tank had to be rotated to pull the second worker out. Cardiopulmonary resuscitation was successful only for the first worker. Medico-legal autopsy showed bruises, hematoma, myocardial hemorrhage, and edema of the lungs. The right lung was vacuum degassed in an argon atmosphere and quadrupole-mass-spectrometry showed an elevated CO(2) content in lung gases. Thus, CO(2) intoxication/asphyxia in a vitiated atmosphere due to fermentation of wine mash was established as the cause of death.
For a better understanding of circumstantial and toxicological findings of fatalities resulting from self-administration of intravenous anesthetic/narcotic agents, medico-legal autopsy files of the State Institute of Legal and Social Medicine Berlin from 1998 to 2011 were reviewed retrospectively. Of a total of 15,300 autopsies, 9 cases of such deaths were identified, and all were health care professionals. Medical supplies for injection were found still on, or near, the body at the scene. Anesthetic/narcotic agents detected were classified into 3 categories, and administered solely or in combination. Propofol was the most common agent, being detected in 6 cases. In 2 out of 6 cases, propofol was detected substantially above therapeutic levels and was considered the cause of death. In the remaining 4 cases, propofol levels were within the therapeutic range, but propofol intoxication was considered as lethal due to it being administered by rapid continuous injection. In 5 cases, injection of opioid narcotics was fatal. Alongside the 2 propofol-detected cases, there was one case where a higher-than-therapeutic level of piritramide and a therapeutic level of alfentanil was identified. Despite suspected usage, remifentanil was not detected due to its rapid metabolism by elastases in one case, and sufentanil was undetectable due to putrefaction in another, but death was attributed to their potent respiratory depressant effects without respiratory assistance. Benzodiazepines were detected in 4 cases. All of them were used together with propofol or opioids, and contributed to death by inhibiting respiration. It is essential to consider means of administration as well as additive or synergistic effects of combined agents when interpreting toxicological results in such cases.
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.
A 49-year-old male captain fell and unfortunately died in a hold tank where he had entered to rescue his fainting co-worker on the disposing waste fluid left there. An autopsy revealed that the captain died from drowning in the waste fluid. In order to clarify the cause of their falling in the tank, the gas in the hold tank was analyzed. The concentration of oxygen was 18.86 to 19.31%, carbon dioxide was 7.28 to 9.07% and the other gases, including hydrogen sulfide, were assessed to be under the normal level. It was concluded that the intoxication of carbon dioxide generated from the waste fluid fermentation was the cause of this fatal accident through loss of consciousness. It is necessary to recognize that carbon dioxide is a dangerous and deleterious gas in circumstances where the gas can be produced.
We had a suicide case suspected to result in death from carbon dioxide poisoning by dry ice in the car. A clay cooking stove with charcoal was in the car, but the charcoal had no burning sign. CO hemoglobin saturation degree of the suicide victim's blood was 0%. Moreover, there were signs that 50 kg of dry ice was brought in the car. To clarify the cause of death, reproducibility testing was carried out by using a car under the same conditions. CO2 concentration in it increased to 22% and O2 concentration decreased to 16% within 20 minutes. From these observations, his death was considered to be caused by hypoxia and CO2 narcosis. CO2 in the suicide victim's blood was higher than those in the blood of healthy persons, and the same range was visible in the blood of fire victims. These data might support above supposition concerned with the cause of death. Blood analysis will be helpful in clearing the cause of death by CO2 poisoning.
This report documents a rare case of carbon dioxide intoxication in a young healthy male. The deceased hid in a small plastic container, size 1.5 x 1 x 1 m, and within 5 min he was located suffering convulsions and was reported as dead within minutes. Scene investigation revealed dry ice in the container. Autopsy findings were unremarkable. The probable cause of the convulsions was carbon dioxide intoxication due to both the dry ice sublimation and the small confined space in which he was hiding. This report emphasizes the significance of scene investigation in establishing the cause of the death.
Exposure to a high concentration of environmental carbon dioxide (CO2) can result in poisoning through direct toxicity and by displacing atmospheric oxygen (O2). Dry ice undergoes sublimation to a gaseous state at -78.5 degrees C (-109.3 degrees F), which is heavier than air and can accumulate in dependent areas. We report the case of a 59-year-old man found in cardiac arrest shortly after entering a recently repaired walk-in freezer that contained dry ice. First responders and bystanders did not recognize the proximate hazardous environment but were fortunately uninjured. A careful Emergency Department history coupled with rapid case investigation by the Medical Examiner's Office led to the determination of the cause of death and the elimination of the ongoing hazard. This case illustrates the lethal consequences of improper storage of dry ice and the need to consider toxic environmental exposure as a cause of sudden cardiac arrest.
The authors describe a case of suicide in the workplace. A 45-year-old man employed by a fruit and vegetable packing company was found dead in a room containing a modified atmosphere for the packaging of fruits and vegetables. The rescue team measured the carbon monoxide (CO) concentration of the ambient air with a digital CO tester and found a level higher than 600 particles per million. Analysis of an arterial blood sample taken with an airtight syringe revealed the absence of CO but high levels of carbon dioxide (CO(2)). Autopsy revealed no significant injury and police investigators found a handwritten note of intent, describing a recent personal crisis. The authors concluded that the cause of death was suicide by asphyxiation secondary to CO(2) intoxication and notably oxygen (O(2)) depletion. This manner of suicide is rare and most cases previously described in the literature were accidental intoxications. To the best of our knowledge, this is the first case of suicide by CO(2) intoxication and O(2) depletion in a room with a modified atmosphere.
A cloud of carbon dioxide gas, with an estimated volume of 1 km3 was released from Lake Nyos, a volcanic crater lake in Cameroon, Africa, causing 1700 to 2000 human fatalities as well as killing thousands of livestock and wild animals. At the request of the Cameroonian Government, the Office of Foreign Disaster Assistance of the U.S. Department of State sent a multidisciplinary team which included 2 forensic pathologists to assist the Government of Cameroon in investigating this natural disaster. The medical evaluation was concentrated in 3 areas: the autopsy of human and animal fatalities, examination and interview of survivors, and examination of the scene of the disaster. Toxicologic specimens were obtained at autopsy, and numerous samples of lake water were collected. The autopsy findings were consistent with asphyxia. The results of chemical analyses excluded many volatiles but not carbon dioxide as the toxic agent. The exact source of this gas continues to be a subject of a heated geologic debate, but fermentation of organic materials in the lake water has been eliminated on the basis of C14 isotope studies. This investigation underlines the value of forensic pathologists in epidemiological studies and in the examination of living persons.
A 44-year-old male, engaged in the transportation of dry ice, was found dead on the floor of the freezer of his refrigerator car which was parked in front of the place where he was scheduled to make a delivery. Autopsy was performed to investigate the cause of death. Apart from the signs of acute death, no other significant findings were obtained, either macro or microscopically; carbon dioxide poisoning was thus strongly suspected. We created a simulation experiment by using the refrigerator car to reproduce the events of the accident. The oxygen concentration in the freezer was 21.0% as indicated by oxygen sensors, but decreased to 17.1-17.4% when the engine was stopped. This decrease in oxygen concentration supposedly results from the production of carbon dioxide by the vaporization of dry ice. Carbon dioxide concentration in the air could be calculated from the change in the oxygen concentration in the closed space of the freezer. The concentration was assessed at 17.1-18.6%. An oxygen concentration of 17.1-17.4% does not of itself cause serious hypoxia, but a carbon dioxide concentration of 17.1-18.6% probably causes serious intoxication, because this value is beyond that of intoxication levels published in references. Therefore, we concluded that the cause of death in this case was carbon dioxide intoxication.
The authors describe three accidental deaths resulting from occupational hazards involving environmental gas alterations. One involved the displacement of oxygen caused by leakage of liquid nitrogen during the installation of a magnetic resonance imaging system. Two involved elevated environmental carbon dioxide concentrations: dry ice sublimation in a walk-in refrigerator in a research laboratory, and activation of a carbon dioxide fire alarm-extinguisher system by a woman locked in a bank vault. The autopsy findings, scene investigations, and certifications of these deaths, as related to the mechanisms of death, are discussed.
Carbon dioxide is a physiologically important gas, produced by the body as a result of cellular metabolism. It is widely used in the food industry in the carbonation of beverages, in fire extinguishers as an 'inerting' agent and in the chemical industry. Its main mode of action is as an asphyxiant, although it also exerts toxic effects at cellular level. At low concentrations, gaseous carbon dioxide appears to have little toxicological effect. At higher concentrations it leads to an increased respiratory rate, tachycardia, cardiac arrhythmias and impaired consciousness. Concentrations >10% may cause convulsions, coma and death. Solid carbon dioxide may cause burns following direct contact. If it is warmed rapidly, large amounts of carbon dioxide are generated, which can be dangerous, particularly within confined areas. The management of carbon dioxide poisoning requires the immediate removal of the casualty from the toxic environment, the administration of oxygen and appropriate supportive care. In severe cases, assisted ventilation may be required. Dry ice burns are treated similarly to other cryogenic burns, requiring thawing of the tissue and suitable analgesia. Healing may be delayed and surgical intervention may be required in severe cases.
This updated edition of Care Practice Paper #2 presents the evidence for the benefits of allowing freedom of movement in labor. Physiologic and anatomical principles that support the benefits of movement are explained. The authors review common obstacles to movement in labor, including the routine use of interventions that inhibit women's ability to walk or change position. Women are encouraged to plan to be active in labor and to select care providers and birth settings that provide the full range of options for using movement in labor.
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