Methane asphyxia. Coal mine accident investigation of distribution of gas

Death from asphyxia due to substitution of air by methane gas may occur in coal mine by gas outburst. In such a case, it is required to determine methane gas contents from cadaveric blood and tissues for diagnosing cause of death and estimating conditions of the accident. The methane concentration in blood and tissue samples of 22 male victims by a gas outburst accident was measured by gas chromatography. The level of methane in the cardiac blood was in the range of 6.8-26.8 microliters/g. As a model of gas outburst in coal mine, rats were exposed experimentally to various concentrations of methane. Their course of death and methane distribution in the bodies were observed. From these findings, diagnostic criteria for asphyxia from substitution of air by methane are also discussed.     

Forensic and chemical determination of methane in cadaveric samples

Conditions were elaborated for the determination of methane, through gas chromatography, in blood and the lung by using a 2% methanol solution as an internal standard and with the below gas-chromatography column being applied: dimensions--200 x 0.3 cm, 15% di-2-ethylhexyl sebacate on Dinochrome II (0.16 x 0.21 mm) at 110 0 degree C. The detector is of the flame-ionization type. The normal content of methane was determined for blood and for the lung--0.122 +/- 0.0074 microgram/ml and 0.20 +/- 0.04 microgram/g, respectively. Biological samples from cadavers of other persons who died due to trauma were suggested for use as controls. The method was used to examine expertise objects, blood and the lung from the cadavers of peoples who died in fire.     

Incidence and forensic value of liver cell hydrops in external asphyxia and sudden infant death

A histological examination was carried out in 108 cases of asphyxia, 28 cases of SIDS, and 33 cases with other causes of death to assess the occurrence of liver-cell hydrops. In almost all cases of violent suffocation of newborns and children up to 10 years of age hydrops of the hepatocytes were found, whereas these results could be verified only exceptionally after violent suffocation of adults. Eighteen cases or 64.3% of SIDS showed a diffuse distribution of liver-cell hydrops over each liver lobule. Liver-cell hydrops seems to represent a frequent morphological equivalent of acute oxygen deficiency in asphyxia in childhood and is a common finding in SIDS.     

The pathological features and circumstances of death of lethal crush/traumatic asphyxia in adults--a 25-year study

A 25-year retrospective study of cases of crush/traumatic asphyxia autopsied at Forensic Science SA, Adelaide, Australia from 1980 to 2004 was undertaken. A total of 79 cases of crush asphyxia was found consisting of 63 males (80%) and 16 females (20%). The age range of the males was 19-86 years (mean=41.8 years) and of the females was 19-75 years (mean=38.6 years). In 18 cases the exact circumstances of death were unclear, leaving 61 cases in which details of the fatal episode were available. Major categories included vehicle crashes (N=37), industrial accidents (N=9), farm accidents (N=6) and entrapment beneath vehicles (N=5). Forty of the 79 victims (51%) had only very minor bruises and abrasions; 28 (35%) had evidence of chest compression with rib and sternal fractures and large areas of soft tissue bruising of the chest; 7 cases (9%) had other significant injuries or findings that had contributed to death. All of these victims had signs of crush asphyxia in the form of intense purple congestion and swelling of the face and neck, and/or petechial hemorrhages of the skin of the face and/or conjunctivae. The pattern of pathological findings of crush asphyxia was not influenced by the presence or absence of concomitant serious or lethal injuries. In 4 cases (5%) where the circumstances of the lethal episode were those of crush asphyxia there were no characteristic pathological findings. This study has shown that a high percentage of crush asphyxias may be caused by vehicle accidents. It has also demonstrated that on occasion fatal crush asphyxia may have to be a diagnosis of exclusion, made only when there are characteristic death scene findings, and no evidence of lethal natural diseases or injuries at autopsy, with negative toxicological screening.     

2633例机械性窒息法医尸检资料回顾性研究

本文根据湖北省部分地区1957～1986年间尸检记录,收集并分析了2633例机械性窒息死的出现率、案情性质、城市与乡村的差别等问题,为法医学实践提供了可供参考的资料。     

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

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

Studies on asphyxia: on the changes of the alveolar walls of rats in the hypoxic state. II. The hypoxic state produced by carbon dioxide and methane gases

Experimental studies were presented here concerning death by asphyxia due to the inhalation of carbon dioxide and methane gases. The morphological changes were almost the same as those demonstrated in our previous report. The authors concluded that the morphological changes in the lung tissue were not attributable to the chemical specificity of gases used in the experiment but to the decrease of oxygen.     

What is the incidence and significance of "dry-lungs" in bodies found in water?

BACKGROUND: Drowning without aspiration of liquid, generally attributed to death from asphyxia while submerged and in laryngospasm, has been reported to occur in approximately 10% to 15% of drowning victims. OBJECTIVES: The occurrence of "dry-drowning" recently has been questioned and the hypothesis developed that "dry-lungs" in bodies found dead in the water could conceal more natural deaths than previously recognized. METHODS: Based on 578 selected adult victims who presumably drowned, we analyzed the correlation between the cases with a low combined lung/pleura liquid weight (< 1000 g and < 750 g) and a wide set of individual, circumstantial, and postmortem (PM) variables, using multivariate logistic regression analysis. Victims with lung weight < 1000 g were screened for long-QT syndrome (LQTS) founder mutations in KCNQ1 and KCNH2 genes. RESULTS: Of the 578 victims, 120 (20.7%) had a lung weight of < 1000 g, and 22 of these (3.8%) of < 750 g. Multivariate analysis showed a significant correlation for women (P < 0.001), for women aged 65 years or older (P < 0.001), and for men with prolonged PM submersion time (P < 0.001). "Normal" lungs were found in only 8 (1.4%) victims. Low-weight (< 1000 g), overdistended lungs with no sign of liquid penetration were seen in 11 (1.9%). No LQTS founder mutations were detected. CONCLUSIONS: The actual incidence of death of persons found in water who have normal lungs or do not have penetration of liquid into their airways, based on our study, is much lower (below 2%) than currently assumed.     

Plastic bag asphyxia in southeast Scotland

Death resulting from plastic bag asphyxia has been recognized for >40 years, but relatively little is known about either its epidemiology or its pathophysiology. Over 15 years (1984-1998), 30 deaths were attributed to plastic bag asphyxia among the 14,560 autopsies performed in the Forensic Medicine Unit in Edinburgh. These 30 deaths involved 20 male and 10 female subjects, with an age range of 13 to 81 years. Eleven had some alcohol measurable in the blood, with four having levels >80 mg/dl. Only one individual appeared to have ingested a drug overdose, but inhaled substances within the plastic bag may have contributed to death in five cases. The absence of childhood accidental deaths may reflect successful preventive measures. The 3 accidental deaths involved adults (including 2 who died of autoerotic asphyxia), and the remaining deaths were 27 suicides. Of those who committed suicide, most (59%) had chronic psychiatric illness rather than chronic debilitating or terminal physical illness. In contrast with reports from the United States, publicity associated with "self-deliverance" did not result in an increased number of deaths from plastic bag asphyxia (4 deaths in this series). Analysis of the circumstances of all the deaths revealed them to be difficult to predict and hence prevent.     

Odor analysis of decomposing buried human remains

This study, conducted at the University of Tennessee's Anthropological Research Facility (ARF), lists and ranks the primary chemical constituents which define the odor of decomposition of human remains as detected at the soil surface of shallow burial sites. Triple sorbent traps were used to collect air samples in the field and revealed eight major classes of chemicals which now contain 478 specific volatile compounds associated with burial decomposition. Samples were analyzed using gas chromatography-mass spectrometry (GC-MS) and were collected below and above the body, and at the soil surface of 1.5-3.5 ft. (0.46-1.07 m) deep burial sites of four individuals over a 4-year time span. New data were incorporated into the previously established Decompositional Odor Analysis (DOA) Database providing identification, chemical trends, and semi-quantitation of chemicals for evaluation. This research identifies the "odor signatures" unique to the decomposition of buried human remains with projected ramifications on human remains detection canine training procedures and in the development of field portable analytical instruments which can be used to locate human remains in shallow burial sites.     

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.     

Accidental autoerotic death by volatile substance abuse or nonsexually motivated accidents?

In contrast to typical autoerotic fatalities, when death is due to asphyxia mostly by mechanical compression of the neck, atypical autoerotic accidental deaths (AADs) involve sexual self-stimulation by other means such as electrocution or inhalation of chemical agents. Especially in lethal cases of volatile substance abuse (VSA), a differentiation between suicide or sexually or nonsexually motivated accident is often complicated in practical casework. Considering the small number of AADs involving chemical substance abuse reported in the literature, the number of unreported cases seems to be very high. We report about 5 lethal cases of VSA; analysis was performed using headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS). When headspace sampling is not performed at autopsy, the analysis of volatile substances can be very complicated. In 2 cases, an AAD was diagnosed considering findings at the scene, reconstruction of the event, and discussion of the circumstances of the death. These findings demonstrate the importance of VSA in atypical autoerotic asphyxia. Therefore, in cases of suspected lethal inhalational intoxications, as a matter of principle, headspace asservation should be performed at autopsy and an autoerotic motivational background should be taken into consideration for differential diagnosis.     

Analytical investigations in a death case by suffocation in an argon atmosphere

A 31-year-old engineer was found dead in a reaction vessel (diameter 0.8 m, height 1.8 m) of a bulb factory some minutes after he had entered it for repair work. Resuscitation attempts with artificial respiration were unsuccessful. Despite autopsy and usual toxicological analyses, no cause of death could be found. Since in the normal production process, argon was used as a protecting gas, the possibility of suffocation in an argon atmosphere was investigated. This was rendered more difficult because of the natural content of 0.93 vol.% argon in air and since the excessive argon could have been removed by the resuscitation attempts. Gas samples from larynx, esophagus, bronchi, and stomach, separated blood samples from both ventricles of the heart and from the vena iliaca externa as well as tissue samples from lung and liver were collected during autopsy into headspace vials in such a way that the loss of gas and a dilution by surrounding air was avoided as far as possible. The samples were analyzed by headspace GC-MS. The abundance of Ar+ (m/z = 40) was used for quantification with N2(2+) (m/z = 14) as internal standard. The following argon concentrations were measured (mean values, case under investigation/comparison cases): gas from larynx 1.79/0.96 vol.%, stomach gas 1.58/0.89 vol.%, heart blood (left ventricle) 7.2/2.7 microg/mL, heart blood (right ventricle) 5.8/2.7 microg/mL, blood from vena iliaca externa 3.6/2.7 microg/mL. A clearly increased concentration was also found in lung tissue, whereas in liver tissue no significant difference in comparison to other cases was measured. From the results, it follows that the deceased inhaled an increased amount of argon a short time before death. The concentrations are consistent with asphyxia and subsequent resuscitation attempts. They cannot be explained by a long-term inhalation of an atmosphere enriched with argon before the incident as it is likely to have occurred in this factory hall.     

Dirty diving. Sudden death of a SCUBA diver in a water treatment facility.

We report a case of a sudden death in a SCUBA diver working at a water treatment facility. The victim, an employee of the facility with a specialty in electronics, was a sport diver not qualified in commercial diving. While attempting to clean sludge from a blocked drain 25 ft under water, the diver was suddenly pinned against the drain valve when the sludge plug was broken up. We review the mechanics of the incident and the actual cause of death, asphyxia, as opposed to drowning. We believe this to be the first reported case of traumatic (pressure) asphyxia in a SCUBA diver.     

Screening for drug use among Norwegian drivers suspected of driving under influence of alcohol or drugs

Two hundred and seventy blood samples selected at random from Norwegian drivers apprehended on the suspicion of drunken or drugged driving were screened for the presence of amphetamine, benzodiazepines, cannabinoids, tetrahydrocannabinol (THC) and cocaine. Of the samples tested, 223 were from drivers suspected of driving under the influence of alcohol only (A-cases). In the rest (n = 47) of the cases, the police also suspected drugs as a possible reason for driving impairment (D-cases). In the A-cases, benzodiazepines were found in 17%, cannabinoids in 26%, THC in 13% and amphetamine in 2% of the blood samples. One or more drugs besides ethanol were found in 38% of the A-samples. In the D-cases, benzodiazepines were found in 53%, cannabinoids in 43%, THC in 43%, amphetamine in 13% and 77% of these samples contained one or more drugs. Cocaine was not detected in any sample. Blood alcohol concentrations (BAC) above the legal limit of 0.05% were found in 80% of the drug positive A-cases and in 28% of the drug positive D-cases. The frequency of drug detection in A-samples was similar (40%) in samples with BAC above and below 0.05%, while this frequency was much higher (above 90%) in D-samples with BAC below 0.05% than in D-samples with BAC above 0.05% (53%). Benzodiazepines were most frequently found among drivers above 25 years of age, while cannabinoids were most frequently found among drivers below 35 years. For about 15-20% of the A-cases with BAC below 0.05%, other drugs were detected at concentrations which may cause driving impairment. It was concluded that analysis of alcohol only might often be insufficient in A-cases to reveal driving impairment.     

Acute flurazepam intoxication: a case report

A fatality due to ingestion of flurazepam is reported. Flurazepam is a benzodiazepine, a widely prescribed hypnotic drug for use in sleep disorders. There are only few documented reports of the disposition of flurazepam in deaths due to overdose. A 68-year-old woman was found deceased at home with no evidence of trauma or asphyxia. Toxicologic analyses were performed and drug levels measured by means of gas chromatography coupled to mass spectrometry. The flurazepam concentration in each specimen was as follows: heart blood 2.8 microg/mL, bile 323 microg/mL, and urine 172 microg/mL. Presence of flurazepam into gastric content was observed too. Based on the autopsy findings, patient history, and toxicologic results, the cause of death was determined to be acute intoxication of flurazepam and the manner, suicide.     

A study on house fire victims: age, carboxyhemoglobin, hydrogen cyanide and hemolysis.

Correlation among age, concentrations of carboxyhemoglobin and hydrogen cyanide, oxygen density and hemolysis were studied in 120 house fire victims. Victims aged over 60 years comprised approximately 50% of the pooled subjects. Blood samples were mainly collected from the left ventricle, but sometimes from both the right and left ventricles. The concentration of carboxyhemoglobin ranged from 1-95%, of which 71 persons (59.7%) died with carboxyhemoglobin concentrations below 60%. Carboxyhemoglobin concentrations below 10% were found in 9 persons (7.5%). Most of these cases involved the elderly persons. In this paper, we report on the death of elderly victims as a result of low carboxyhemoglobin concentrations. A significant correlation of blood carboxyhemoglobin concentrations existed between the right and left ventricles. The concentration of carboxyhemoglobin in the left ventricle was significantly higher than that in the right. Two out of 31 victims whose hydrogen cyanide concentrations were determined, succumbed to hydrogen cyanide poisoning, having a high concentration of hydrogen cyanide and a low concentration of carboxyhemoglobin. On analysis, oxygen density was found to be low in 13 persons. A negative correlation was shown between carboxyhemoglobin concentration and hemolysis. Inasmuch as hemolysis may indicate the extent of heat dissociation, hemolysis should provide an index of carbon monoxide dissociation from carboxyhemoglobin. In the present study of victims, possible causes of death i.e., carbon monoxide gas poisoning, hydrogen cyanide poisoning, oxygen deprivation, burning, shock due to burns and others were estimated. The survival time for elderly victims was considered to be short.     

Asphyxial homicide in two Scandinavian capitals

In the Oslo and Copenhagen capital areas, 94 asphyxial homicides were committed in the 10-year period 1985-1994, accounting for 22% of all homicides in that period. Sixty-nine (73%) of the asphyxia victims were female. The most common method of asphyxiation was manual strangulation. Seventeen (18%) of the victims were below the age of 10, accounting for 59% of all homicides in that age group. Whereas 38% of the female victims were killed by their spouse, this was the case for only one male victim. The motive was not known in a great proportion of cases. Fifty-seven percent of the victims had been subjected to additional violence, and in this respect there was no difference between the sexes. In 12 of the cases the offender was female; in 9 such cases the victim was her offspring. More than half of the victims had no blood alcohol. When disregarding the victims less than 10 years of age, 33% of the male and 49% of the female victims had no blood alcohol. The crime scene was the victim's domicile among 72% of female and 52% of male victims. Forty-two percent of the female and 11% of the male victims above the age of 10 years were married or cohabitant.     

Carbon monoxide concentrations in the 2009 Victorian Bushfire disaster victims

Blood was available for the estimation of carboxyhemoglobin saturation (COHb) in 30 of the 173 persons who died in the Victorian bushfires in February 2009. The ages of these 30 deaths ranged from 3 to 80 years and there were 8 females. 13 cases (43%) were considered negative (less than 5% COHb), 12 (40%) were between 5 and 40% COHb, 2 (6.7%) between 40 and 50% and 3 (10%) were greater than 50% COHb. There were 6 persons either found within a building or a car and the COHb in these cases ranged up to 69% (mean 50%). There were 5 cases where the location was unable to be determined as either indoor or outdoor due to the extensive nature of the fire. The remaining 19 deceased persons were all located outside in the open and the concentration of COHb in these cases ranged up to 30% (mean 19%). Hydrogen cyanide was only detected in two deceased persons at concentrations of 0.5 and 2.7 mg/L, respectively. 13 deceased were found to have soot in the airways following necropsy but this did not correlate with the COHb levels.     

Homicidal asphyxia

Homicides due to asphyxia are relatively uncommon. To better understand the presentation of such cases, the files of the Bexar County Medical Examiner's Office were reviewed from January 1, 1985, through December 31, 1998, for all such homicides. A total of 133 cases were found. The largest category was ligature strangulation with 48 deaths (21 male, 27 female). Petechiae were present in the conjunctivae and/or sclerae in 86% of the cases; fractures of the hyoid and/or thyroid cartilage were present in 12.5%. There were a total of 41 deaths from manual strangulation (27 female, 14 male). Petechiae were present in 89% of the cases. In cases of manual strangulation, fractures of the hyoid, thyroid, or cricoid cartilage were found in all the male victims and slightly more than one half of the female victims. Twenty-six cases of suffocation were found; 20 of the victims were < or =2 years of age. Only 1 of these children had petechiae and/or scleral hemorrhage. Five deaths were due to choking. Three of the deaths involved adults who were gagged; 2 deaths involved infants with foreign material pushed into the mouth. Other categories of asphyxia were as follows: 9 deaths due to more than one form of asphyxia; 1 death due to hanging, and 3 deaths due to drowning. Rape was the motive in 66% of the female victims of ligature strangulation and 52% of those due to manual strangulation.