A New Approach for the Carbon Monoxide (CO) Exposure Diagnosis: Measurement of Total CO in Human Blood Versus Carboxyhemoglobin (HbCO)

The aim of the study is to present the application of a headspace–gas chromatography–mass spectrometry (HS‐GC‐MS) method for the determination of the carbon monoxide (CO) blood concentration and to compare it with carboxyhemoglobin (HbCO) saturation. In postmortem cases, the HbCO measured by spectrophotometry frequently leads to inaccurate results due to inadequate samples or analyses. The true role of CO intoxication in the death of a person could be misclassified. The estimation of HbCO from HS‐GC‐MS CO measurements provides helpful information by determining the total CO levels (CO linked to hemoglobin (HbCO) and CO dissociated from hemoglobin). The CO concentrations were converted in HbCO saturation levels to define cutoff blood CO values. CO limits were defined as less than 1 μmol/mL for living persons, less than 1.5 μmol/mL for dead persons without CO exposure, and greater than 3 μmol/mL for dead persons with clear CO poisoning.     

大鼠血液中HbCO随吸入CO浓度和时间的变化

目的研究不同一氧化碳(carbon monoxide,CO)浓度下中毒大鼠的行为学特征、存活时间、碳氧血红蛋白(carboxyhemoglobin,HbCO)饱和度变化规律,为法医学实践中CO中毒死亡案件提供实验依据。方法将160只SD大鼠随机分为4组。自制染毒装置,使大鼠分别在CO浓度为1 250、3 750、6 250 mg/m~3及持续通入CO状态下染毒致死亡。观察不同CO浓度中毒大鼠的行为学特征,记录存活时间,采用分光光度法检测心血HbCO饱和度,并提取脑、心脏、肺、肝等器官进行组织病理学观察。结果 CO中毒大鼠的行为学特征表现为肢体瘫软、反应迟钝。随着CO浓度的升高,大鼠存活时间逐渐缩短,心血HbCO饱和度逐渐升高。在CO浓度为1 250 mg/m~3条件下,发现3例心血HbCO饱和度明显低于致死饱和度,其余各组未发现心血HbCO饱和度低于致死饱和度的情况。结论建立的不同浓度下CO中毒死亡动物模型,操作简单,重复性好,为进一步研究CO中毒及其他吸入性有毒气体的法医学研究奠定了基础。     

Subarachnoid Hemorrhage and Carbon Monoxide Exposure: Accidental Association or Fatal Link?

This case study reports a fatal subarachnoid hemorrhage (SAH) with concomitant accidental carbon monoxide (CO) exposure in 32‐year‐old man. Autopsy results indicated an antemortem aspiration of smoke, and a massive SAH was identified as the cause of death. Intriguingly, the carboxyhemoglobin level was 30%, suggesting that CO could have played a specific role. Intracranial hemorrhages following CO exposure in brain areas and tissues such as the basal ganglia, globus pallidus, or white matter are rare, but well characterized, whereas SAH related to CO exposure has not been previously described. In this case report, the possible role of CO, either as a primary cause or as a facilitating factor, in the pathogenesis of SAH is discussed. In particular, we propose the hypothesis that the excessive vasodilating effects produced by CO on the cerebral endothelium results in consequential loss of microvascular integrity.     

Atherosclerotic and Hypertensive Cardiovascular Disease are Associated with Death at Sublethal Carboxyhemoglobin Levels: A Postmortem Study

Residential fires are a significant cause for morbidity and mortality in the United States. Death is often the result of soot and smoke inhalation causing carbon monoxide (CO) toxicity. The approximate lethal level of carboxyhemoglobin (COHb) in healthy adults has been well described. However, a significant number of medical examiner cases involve infirmed decedents, often elderly, with complex cardiovascular disease burdens. It is well known that death in these cases will occur at sublethal levels of COHb; however, increased lethality has been largely documented via anecdotal experience and lacks quantification. Fifty-five cases were identified where death resulted from smoke and soot inhalation suffered in a residential fire. The control group, with no cardiovascular disease, had an age-adjusted mean COHb level of 61.6% at the time of death. Presence of hypertensive cardiovascular disease showed a 30% reduction in COHb (age-adjusted mean 43.2%), atherosclerotic disease showed a 33% reduction (age-adjusted mean 41.5%), and combined disease presentation accounted for 41% reduction (age-adjusted mean 36.3%). When controlling for age, atherosclerotic and hypertensive cardiovascular diseases were each associated with statistically significant decreases in COHb (p < 0.01). Increasing age was associated with decreased COHb levels at 2.8% per 10 years of life (p < 0.01), even when modeled with hypertensive and atherosclerotic disease. These findings carry important public health significance, as well as practical significance for the medical examiner when interpreting COHb levels in cases of suspected deaths due to smoke and soot inhalation.     

Comparison of Different Analytical Methods for the Determination of Carbon Monoxide in Postmortem Blood

The determination of carbon monoxide (CO) and carboxyhemoglobin (COHb) is of utmost importance in forensic toxicology to determine the cause of death in cases of CO poisoning, fire, and explosions. To this end, reliable and updated analytical methods are required. In this paper, four different methods for the determination of carbon monoxide in postmortem blood samples were compared: (i) the spectrophotometric determination of COHb applying the method proposed by Rodkey and modified by Beutler–West, (ii) the spectrophotometric determination of CO using a micro-diffusion-based method, (iii) the determination of CO by gas chromatography coupled to a TCD detector, and (iv) the determination of COHb by blood gas analysis. Three postmortem blood samples were analyzed with all methods, and the results were comparable. The applied methodologies showed different features depending on the sensitivity, sample preparation, and volume. The HS-GC/TCD method in our hand was the most appropriate, on postmortem samples, and versatile to apply. Unfortunately, only a limited number of postmortem blood samples were available for this study due to the rarity of that kind of intoxication in our jurisdiction.     

Usefulness of Systematic Histological Examination in Routine Forensic Autopsy*

Abstract: The forensic community does not agree on the need to perform histological examination at forensic autopsy. The aim of our study was to determine the usefulness of systematic standard histology in forensic autopsies. A prospective study was carried out on 428 autopsy cases for which standard histological examination was systematic. Mechanism of death not shown by gross anatomic findings was discovered by histology in about 40% of the cases. Cause of death was established by only histology in 8.4% of the cases. Microscopic findings affected the manner of death in 13% of the cases. Histology provided complementary information about prior medical condition of the deceased in about 49% of the cases. Traumatic lesions were better documented by histology in about 22% of the cases. According to the results of our study, systematic standard histology for the main organs should be used in routine forensic autopsies.     

The Fatal Poisoning Pattern of Ankara (Turkey) and Nearby Cities from 2007 to June 2011: A Retrospective Study in Forensic Autopsies

We aimed to obtain an outline of the nature and number of fatal poisonings which still appear to affect widely the population in Turkey. A total of 5921 forensic autopsies were performed between 2007 and 2011 in Ankara and nearby cities and 366 of them were fatal poisonings (219 male, 147 female). Most of the cases were between 41 and 60 years old (n = 84). Most of the fatalities were reported during winter months (48.1%). Carbon monoxide exposure was the most common reason (66.7%) within all the causes followed by medicine and narcotics (13.9%). Postmortem blood alcohol concentrations in ethyl and methyl alcohol poisonings were 385.1 ± 61.9 and 206.8 ± 138.9 mg/dL, respectively. The most common location of deaths was home (71.3%). Fatal poisonings have been a growing global problem because of some shortcomings about the socioeconomic conditions and increasing illicit drug abuse. The level of education, socioeconomic conditions, and legal approaches are very important for the prevention fatal poisonings.     

The role of environmental factors in the causation of sudden death in infants: two cases of sudden unexpected death in two unrelated infants who were cared for by the same babysitter

We report two cases of sudden unexpected death in two unrelated African American female infants, 2 months and 4 months old. Both infants were attended to by the same babysitter in the same apartment and died 39 days apart in the same bed and in the same bedroom. The autopsy of the first infant revealed sudden unexplained death in an infant. Toxicologic analysis for carbon monoxide (CO) was not performed because it was not suspected. When the second infant died, investigation into the ambient air quality within the apartment revealed high levels of CO emanating from a poorly ventilated and defective hot water heater, which was located across a hallway from the bedroom where the two babies died. CO saturation levels in the postmortem blood samples of the two babies were elevated and were similar (13% and 14%). Nicotine and cotinine were not detected in the blood sample of the two infants. Cherry-red livor mortis was absent. Acute CO intoxication was determined to be the underlying cause of these two unexpected deaths. These two cases underscore the need to integrate ambient air analysis and postmortem CO analysis as routine components of the comprehensive death investigation of infants who die suddenly and unexpectedly.     

不同来源一氧化碳中毒死亡者血液中COHb含量分析

目的探索一氧化碳中毒存在的个体差异性,分析女性可能存在的抵御一氧化碳中毒的机制。方法收集207例不同来源的一氧化碳中毒死亡者血液,测量COHb含量,将案例按照不同的因素分类进行统计学分析。结果不同一氧化碳的来源对于死者的COHb浓度影响显著,而性别对于COHb浓度影响不显著,少年儿童和老年人有可能对COHb的抵御能力差于成年人。     

Globus Pallidus Necrosis Unrelated to Carbon Monoxide Poisoning: Retrospective Analysis of 27 Cases of Basal Ganglia Necrosis

Bilateral globus pallidus necrosis is said to be characteristic of carbon monoxide (CO) poisoning. However, there has been no scientific test of this hypothesis. To examine the assertion that globus pallidus necrosis is typical of CO poisoning, this study examined autopsy cases from the King County Medical Examiner's Office (KCMEO) between 1994 and 2013. Twenty-seven cases with bilateral basal ganglia lesions were identified and examined for associated or causative disease or injury with the following results: 10 cases of drug overdose, seven heart disease, three asphyxia, two chronic ethanolism, two Huntington-like disorder, and one case each of remote trauma, rheumatic heart disease, and cerebral artery gas embolism. Additionally, review of all known cases at KCMEO of CO poisoning found no evidence of globus pallidus or basal ganglia necrosis. Thus, this study provides no support for the assertion that globus pallidus necrosis is characteristic of CO poisoning.     

一氧化碳中毒血分光光度定量分析法比较

目的比较7种一氧化碳中毒血样分光光度含量测定方法的特点及适用性。方法用空白血添加一氧化碳配制不同浓度的样品,采用双波长法、还原法（3种）、切线法和导数光谱法（2种）进行检测,对各种方法线性范围、重现性和操作中注意事项等内容进行考察,并用实际案件检材验证和比较。结果还原法一在30%~70%、还原法三在20%~100%,其他方法在20%~70%范围内,线性关系良好;样本浓度超过或低于50%,采用切线法有一定误差;导数法及还原法三因需要制备CO饱和样本,操作略微繁琐,但导数光谱法计算结果准确性好。结论几种方法均可用于一氧化碳中毒血的检测,实验结果可为方法的实际应用提供借鉴和帮助。     

Carbon Monoxide Poisoning and Death in a Large Enclosed Ventilated Area

A 55‐year‐old man with a medical history of tobacco use suddenly collapsed while power washing an empty indoor pool in a hotel. The decedent was transported to the local hospital where he was pronounced. A postmortem examination revealed atherosclerotic heart disease and bilateral pulmonary edema and congestion. A postmortem blood carbon monoxide (CO) level was 27% saturation, and a CO performed on hospital admission blood was 49% saturation. CO poisoning is a common cause of toxicological morbidity and mortality in the United States. The circumstances most often occur in an enclosed environment and may be intentional or unintentional. CO poisoning has been reported in open, well‐ventilated spaces, but rarely results in death. A warning label was present on the engine clearly stating the dangers of CO emission. However, there was a false sense of security due to the large size of the pool room and the presence of industrial blowers that were being used for ventilation.     

Intracoronary Thrombus Formation Following Carbon Monoxide Poisoning

Thromboembolic events in the context of carbon monoxide (CO) exposure have been well described in the literature. Six cases of clinically significant coronary thrombosis following CO exposure were previously reported. However, factors affecting the development of coronary thrombus in CO exposure are poorly understood, and the significance of this finding in a forensic context is not clear. This article discusses a case of coronary thrombosis found at autopsy following a death in which CO poisoning was suspected. A 67‐year‐old man was found dead in his garage with four vehicles with their ignition in the “on” position and their tanks empty. At autopsy, severe coronary atherosclerosis and an acute nonocclusive coronary thrombus were found. Given the dissimilarities among cases and the presence of CO exposure, it was suggested that the coronary artery thrombosis is likely due to the inherent prothrombotic mechanism of CO, the only common denominator in all the cases.     

Concentration of carbon monoxide (CO) in postmortem human tissues: effect of environmental CO exposure

We studied how carbon monoxide (CO) is distributed within the human body through quantitation of CO concentrations in postmortem tissue samples from fatalities including possible CO exposure. Stored, frozen tissues were diced, sonicated in water, and 0.01-8.0 mg wet weight (ww) tissues were incubated with sulfosalicylic acid in CO-purged, septum-sealed vials. CO released into the headspace was quantitated by reduction gas chromatography. Mean tissue CO concentrations (pmol/mg ww) from subjects diagnosed to have no known CO exposure (control, N=14), died from fire (N=13), and CO asphyxiation (N=7), respectively, were: adipose (2;13;9), brain (3;13;65), muscle (15;97;297), heart (30;99;371), kidney (22;432;709, lung (54;690;2638), spleen (73;1366;3548), and blood (162;2238;5070). Carboxyhemoglobin concentrations were 1.4%, 25.2%, and 69.1% of total hemoglobin, respectively. We conclude that measurements of CO concentration in a variety of tissues can be used as markers for the degree of exogenous CO exposure and the identification of possible causes of death.     

Accidental boric acid poisoning following the ingestion of household pesticide

Borate-containing compounds were formerly used as topical antiseptics and were components of many medicinal preparations including skin powders and ointments used for the treatment of burns and diaper rash. These compounds were also used as irrigants for body cavities, including the pleural, vaginal, and rectal cavities. These applications were subsequently discontinued by the medical community when the toxicity and potential lethality of borates were recognized. Although documented cases of borate poisoning are now rare, the chemical is still an active component commonly used in high concentrations in household disinfectants/cleaners, pesticides, and wood preservatives. While the majority of documented borate-related deaths have occurred in infants, the toddler population is currently at risk due to possible exposure to these household products. We present the case of an 18-month-old child who died following the accidental ingestion of a boric acid-containing, commercially available roach pesticide product.     

Accuracy of 3D Scanners in Tooth Mark Analysis

The objective of this study was to compare the accuracy of contact and laser 3D scanners in tooth mark analysis. Ten dental casts were scanned with both 3D scanners. Seven linear measurements were made from the 3D images of dental casts and biting edges generated with DentalPrint© software (University of Granada, Granada, Spain). The uncertainty value for contact 3D scanning was 0.833 for the upper dental cast and 0.660 mm for the lower cast; similar uncertainty values were found for 3D-laser scanning. Slightly higher uncertainty values were obtained for the 3D biting edges generated. The uncertainty values for single measurements ranged from 0.1 to 0.3 mm with the exception of the intercanine distance, in which higher values were obtained. Knowledge of the error rate in the 3D scanning of dental casts and biting edges is especially relevant to be applied in practical forensic cases.     

一氧化碳（CO）中毒检测方法

作者查阅近20年国内外相关文献的基础上,对一氧化碳(CO)中毒的检验方法进行了全面的阐述,同时对每种方法的优缺点和适用条件作了比较,并对适用于我国国情的顶空气质联用法进行了改良.     

Evidence of Premeditation in Skin Messages in Suicide

A 34‐year‐old man with manic‐depressive disorder was found dead sitting in a vehicle with a hose running from the exhaust pipe to the cabin. Numerous suicide notes were found inside his house. At autopsy, the decedent was wearing jeans and a long‐sleeved windcheater. Upon removal of his clothes, a series of messages were also found written on the legs and forearm. Death was due to carbon monoxide toxicity with a blood level of carboxyhemoglobin of 84%. Skin messages represent a rare form of suicide note that may suggest that a suicide has not been planned, as the decedent may have used the nearest surface to write on. This case demonstrates, however, that skin messages may be more organized, being written prior to dressing and setting up the fatal episode. They also may compliment other notes and messages.     

Diesel fumes do kill: a case of fatal carbon monoxide poisoning directly attributed to diesel fuel exhaust with a 10-year retrospective case and literature review*

While it is known that diesel fuel combustion engines produce much lower concentrations of carbon monoxide (CO) than gasoline engines, these emissions could certainly generate lethal ambient concentrations given a sufficient amount of time in an enclosed space and under suitable environmental conditions. The authors report a case of CO poisoning which was initially referred for autopsy as a presumed natural death of a truck driver found in the secure cab of a running diesel tractor trailer truck. Completion of the preliminary investigation ascribed death to complications of ischemic heart disease (IHD), pending toxicological analysis that included quantification of CO. When the toxicology results showed lethal blood COHbg, the cause of death was re-certified as CO intoxication secondary to inhalation of (diesel) vehicular exhaust fumes. Because of the unique source of fatal CO intoxication in this case, the contributory IHD and the possible contaminants in the putrefied blood, a 10-year retrospective review was conducted on all nonfire related CO deaths autopsied (n = 94) at the Office of the Chief Medical Examiner in Louisville, KY from 1994 to 2003. For validation of the COHbg detection method used by the Kentucky Office of Forensic Toxicology (KYOFT), blood samples from these cases along with controls were submitted to three laboratories using various analytical methods yielding no statistically significant differences. Lastly, an extensive literature review produced no scientifically reported cases of fatal CO poisoning attributed to diesel fuel exhaust.