Use of Postmortem Temperature Decay Response Surface Plots of Heat Transport in the Human Eye to Predict Time of Death

A finite element heat transfer model of the human eye was previously constructed and applied to experimental postmortem temperature decay curves collected in eyeballs of ten human bodies. The model was applied in the early postmortem period of 0–24 h under conditions of natural convection–radiation. Based upon this previous model, response surfaces for postmortem temperature decay were constructed based upon variable ranges of the natural convective–radiation heat transfer coefficient from 7–13 W/m² K, ambient temperatures of 10–33°C, and times of 0–24 h. Mathematical equations to describe these response surfaces have been developed. This response surface method is demonstrated for use by coroners/medical personnel to estimate time of death from recorded field temperature data collected over a 30‐min period. Sensitivity of the model to small changes in the key variable of ambient temperature is explored. The response surface model is applied to two cases of previously collected experimental eyeball temperature data. This response surface model method is only valid for constant surrounding temperatures, conditions of natural convection, no radiation effects, and postmortem times of 0–24 h.     

Validation of a new method of providing case-specific time-of-death estimates using cadaver temperatures

The near ubiquitous presence of numerical simulation has made case-specific calculations of body temperatures following death possible so that accurate calculations of body temperatures can provide valuable information for estimating the time of death and can aid in forensic investigations. Here, a computational approach is described that has been validated against multiple, independent, and experimental investigations. The approach only requires one subjective input parameter (the heat transfer coefficient). A simple algorithm serves as a guidepost to the selection of this parameter. The algorithm incorporates clothing and the space in which the body is housed. Heat transfer coefficients that range from h = 2 W/m²/°C for bodies that are heavily clothed to h = 9 W/m²/°C for bodies that are nude (in air). The method also requires setting of ambient temperature conditions (ambient temperature)—however, that input is often available. The paucity of inputs makes this technique remarkably easy to employ. The new method is also able to calculate cadaver cooling rates for situations where the cadaver is in a timewise or spatially changing thermal environment (diurnal temperature variations, bodies partially submerged in water, changes to weather, insolation, etc.). Results from the present calculations are compared with a large body of measurements from the literature; it was found that the predictions and measurements were in excellent agreement, regardless of the ambient temperature conditions and the nature of the clothing of the body. This new calculation approach can be used with reasonable accuracy for determining cadaver cooling and time since death.     

Comment on the Marshall-Hoare-Henssge model for estimating the time since death

Timewise temperature variations in objects that are undergoing unsteady heating or cooling is a commonly encountered problem in the thermal sciences. One particular area of application is the cooling of a body post-death and the use of body temperatures to estimate the time of death. Here, a new approach based on the theory of transient heat transfer is formulated to allow efficient calculation of unsteady conduction problems. The theoretically derived unsteady temperature models are compared with experimentally based correlations (the Marshall-Hoare-Henssge model). The two approaches are found to agree very well. With this new theoretically based approach, timewise temperature variation can be calculated for both large and small Biot number transient problems.     

A New Method for Determination of Postmortem Interval: Citrate Content of Bone*

Abstract: Few accurate methods exist currently to determine the time since death (postmortem interval, PMI) of skeletonized human remains found at crime scenes. Citrate is present as a constituent of living human and animal cortical bone at very uniform initial concentration (2.0 ± 0.1 wt %). In skeletal remains found in open landscape settings (whether buried or not), the concentration of citrate remains constant for a period of about 4 weeks, after which it decreases linearly as a function of log(time). The upper limit of the dating range is about 100 years. The precision of determination decreases slightly with age. The rate of decrease appears to be independent of temperature or rainfall but drops to zero for storage temperature <0°C.     

Urinary incontinence, hyperthermia, and sudden death

An 84-year-old woman is reported whose death was associated with strenuous exercise on an extremely hot day (maximum temperature=43.1 °C, 109.6 °F). At autopsy there was evidence of exposure to high environmental temperatures with early putrefactive changes and mummification. There was underlying cardiomegaly with mild pulmonary emphysema. No significant injuries were detected. Toxicology revealed therapeutic levels of oxybutynin prescribed for urinary stress incontinence. Death was considered to be heat related, exacerbated by oxybutynin therapy, exercise, and cardiomegaly. Given that it has been predicted that there may be an increase in the number of heatwaves and in their intensity and duration, it is possible that such cases may be encountered more often in future. The assessment of all deaths occurring during conditions of extreme heat will require consideration of postmortem toxicology, particularly if there are underlying conditions such as stress incontinence that may be associated with anticholinergic drug therapy.     

Detection of methamphetamine in mouse femurs exposed to high temperature

Bone samples are valuable for examining the cause of death and circumstance leading up to death when body fluids are not available for forensic toxicological analysis. Examined were heat-induced changes in methamphetamine and amphetamine concentrations in femurs removed from methamphetamine-injected mice to determine if the burned bones could be used for toxicology testing. The femurs were heated at 100°C, 300°C, or 500°C for 10 or 30 min. The tissue structure of the heated femurs was preserved at 100°C for 30 min but was destructed at higher temperatures. Methamphetamine and amphetamine were detected in femurs heated at 100°C for 10 min, 100°C for 30 min, and 300°C for 10 min (with methamphetamine and amphetamine concentrations ranging from 0.36 to 35 μg/g and 0.54 to 47 μg/g, respectively). Methamphetamine and amphetamine were detectable when heated above their decomposition temperature as a result of limited heat transfer do to protection provide by the femoral muscle. Thus, the bone could be a useful analytical sample in cases of burn-related deaths, where it is difficult to collect body fluids.     

Natural,Unexpected Deaths: Reliability of a Presumptive Diagnosis*

Abstract: We retrospectively analyzed 100 deaths because of suspicions and concerns expressed by the family. We compared the preautopsy cause of death, as determined by a thorough review of the clinical data and circumstances, to the autopsy‐derived cause of death. In the majority (91/100), the preautopsy and postautopsy proximate causes of death were in agreement. In 9%, the autopsy provided information that resulted in a proximate cause of death different than anticipated. In four instances, the manner of death also was incorrect and was determined to be an accident rather than the originally presumed natural. No homicide or suicide would have been misclassified. In another nine instances, where the premortem and postmortem proximate causes of death were in agreement, the autopsy provided a specific mechanism of death. With a quality initial medicolegal death investigation, a subset of sudden deaths in adults may be reliably certified without an autopsy.     

Does a Draft Really Influence Postmortem Body Cooling?*

Estimation of the time of death (TOD) is a very important task of forensic pathologist, and measurement of body temperature is a method deemed to be most precise during the initial postmortem period. The study aimed at verification of the significance of airflow present in the room where a corpse is found on body cooling process and hence on determination of the TOD. The experiment was performed in pigs during which the postmortem temperature of the eye, muscles, and rectum was recorded--in still air and with generated draft in the room. The results showed that the moderate airflow present in the experimental conditions did not significantly affect the course of cooling of the investigated body sites. Despite moderate wind generated in the room, the air movement close to pigs' bodies was actually minimal. This allowed to conclude that to evaluate the TOD most precisely, one should first have reliable data on the actual velocity of air in the direct vicinity of the body rather than relying on subjective sensation of the draft and using various unnecessary corrective coefficients for TOD calculation.     

Death in sauna

Bathing in sauna is common in Finland, where there are approximately 2 million saunas among the population of 5.2 million. In this paper, deaths occurring while in a sauna in 1990-2002 in Finland were studied by analyzing police and forensic autopsy reports, death certificates, and toxicological results. The annual rate of death occurring while in a sauna was less than 2 per 100,000 inhabitants. Close to half (51%) of the cases were determined to be natural deaths and exposure to heat was the cause of death in 25%. Overall, 50% of all cases were under the influence of alcohol. The main conclusion is that death in the sauna is a rare event even in Finland where the frequency of sauna bathing is high. The role of alcohol as a risk factor has grown. The prevention of these deaths should focus on less drinking of alcohol and avoid leaving a drunken bather alone in the sauna.     

Unexpected Human Fatality Associated with Bed Bug (Hemiptera: Cimicidae) Heat Treatment

Thermal insect treatments can be an effective method of controlling cryptic insect pests, particularly bed bugs, in residential settings. The treatments require high heat over a sustained timeframe. Residents are not present during treatment but return after completion. An unexpected death was investigated following heat treatment for bed bugs in the home of an elderly female, found with a postmortem axillary temperature of 106.2°F (41.2°C) approximately 8 h after returning home. The cause of death was classified as hyperthermia with a contributory cause of hypertensive cardiovascular disease. The manner of death was an accident. The decedent had medical history and medications that could have impaired her ability to dissipate heat. Furthermore, the air conditioning inside the residence was not functional following treatment. Recommendations including education regarding heat stroke and treatment, re‐entry timeframes, and/or temperature thresholds are suggested to reduce the risk of heat‐related injury or death in vulnerable populations.     

Entomological and Cardiologic Evidence of Time Since Death in Short Postmortem Intervals

Estimating the time since death of the deceased is a main goal in forensic investigations, but this can be challenging due to contradictory results derived from different investigations at the scene of death. We present a case of a 78‐year‐old woman, found dead in a small forest with broad‐leaved trees, whose husband had a history of domestic violence. Routinely performed investigations, such as postmortem rectal temperature and lividity, yielded inconsistent time since death results between only a few and longer than 20 h. This difficulty was most likely caused by high ambient temperatures of up to 38.0°C, which negatively influenced the informative value of the applied nomogram method. Additionally, performed entomological investigation of fly maggots (Lucilia illustris) recovered from the corpse and the assessment of heart pacemaker data revealed consistent and incontrovertible results. The presented case highlights the benefits of information provided by entomological investigations and data evaluation of cardiac implantable electronic devices and the combined use of the two techniques.     

A Nonlinear Least Squares Approach to Time of Death Estimation Via Body Cooling

The problem of time of death (TOD) estimation by body cooling is revisited by proposing a nonlinear least squares approach that takes as input a series of temperature readings only. Using a reformulation of the Marshall–Hoare double exponential formula and a technique for reducing the dimension of the state space, an error function that depends on the two cooling rates is constructed, with the aim of minimizing this function. Standard nonlinear optimization methods that are used to minimize the bivariate error function require an initial guess for these unknown rates. Hence, a systematic procedure based on the given temperature data is also proposed to determine an initial estimate for the rates. Then, an explicit formula for the TOD is given. Results of numerical simulations using both theoretical and experimental data are presented, both yielding reasonable estimates. The proposed procedure does not require knowledge of the temperature at death nor the body mass. In fact, the method allows the estimation of the temperature at death once the cooling rates and the TOD have been calculated. The procedure requires at least three temperature readings, although more measured readings could improve the estimates. With the aid of computerized recording and thermocouple detectors, temperature readings spaced 10–15 min apart, for example, can be taken. The formulas can be straightforwardly programmed and installed on a hand‐held device for field use.     

Accidental Ligature Strangulation by an Ironing Machine: An Unusual Case*

Abstract: In this paper, we present a case of a 53‐year‐old woman who had her headscarf catch on the cylinder ironing machine in the laundry of the hospital where she worked. The hospital workers found the woman dead with her head stuck to the ironing machine. After the death scene investigation and autopsy were completed, it was determined that the death occurred as a result of accidental ligature strangulation. Accidental ligature strangulation in which an article of clothing is caught in such an electrical machine and strangles the wearer is very rare. This case highlights the fact that these kinds of machines can be hazardous to work around and that increased safety measures should be taken to insure worker safety; additionally, the people who use these machines should be educated on the potential hazards.     

Estimating the Time of Death in Domestic Canines

Abstract:  Because 36.1% of U.S. households have dogs, the time of death (TOD) of dogs at crime scenes can be useful to forensic investigators. However, there are few published studies based on postmortem changes in dogs. This study, conducted indoors in still air at approximately room temperature, monitored the postmortem reduction in rectal, liver, brain, and aural temperatures in 16 dogs for 32 h after death. Graphs of temperature reduction were prepared to estimate the TOD of dogs within the first 32 h postmortem. Sex, body mass, and hair coat density did not affect the rate of body temperature reduction, but increased body weight and volume slowed it. Rectal temperature was the most convenient, reasonable site for measuring body temperature. Vitreous humor potassium ion concentration [K⁺] was measured in both eyes at c.  1.5 and 7 h after death. Both eyes had the same [K⁺] when measured simultaneously, and [K⁺] increased after death.     

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

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

Importance and Approach to Manner of Death Opinions in Opioid-Related Deaths

The majority of opioid-related deaths are accidental. However, the number of opioid-related suicidal deaths is likely under recognized. Presented here is a case of suicide by heroin overdose. The manner of death would have likely been deemed accidental if not for critical information shared by the decedent’s family during follow-up telephone interviews between the forensic pathologist and the decedent’s family, which included text messages that were sent by the decedent just before his death that were not known at the time of the initial medicolegal death scene investigation. This case highlights that when a forensic pathologist establishes an engaged relationship with the decedent’s family, the information elucidated can prove to be invaluable in reaching an informed opinion about the manner of death. For overdose cases, identifying an accurate manner of death allows the design of public health efforts that adequately address the health risks in the community. For aid in the determination of the manner of death for overdose cases, we propose a five-step checklist that may assist forensic pathologists and medicolegal death investigators when approaching similar cases.     

Trigemino‐Cardiac Reflex as Lethal Mechanism in a Suicidal Fire Death Case

In the vast majority of immediate fire deaths, the mechanism of death is inhalation of toxic gases (especially carbon monoxide), direct thermal injury, or neurogenic shock due to the redistribution of the body's blood volume produced by surface heat on the skin. We present a suicidal case that is unusual because the mechanism of immediate fire death could arguably be explained in terms of a primitive autonomic reflex/the trigemino‐cardiac reflex. Although this reflex is well known to surgeons and anesthetists, with possible lethal consequences in the course of invasive surgical procedures on the head and neck region, it is much less familiar to forensic pathologists.     

Influence of electricity on post-mortal body temperature

In a case of suicidal application of electricity differences between the rectal temperature of the body and the suspected time of death were observed.In order to answer the question whether an electric current from hand to hand over >30 min led to a rise in body temperature FEM-based computer simulations and animal experiments were carried out. Both resulted in a warming of the soft parts in the arm without warming the body core. Thus a temperature-based estimation of the time since death can also be used in cases with electricity as the cause of death. Besides, in the animal experiment we found a spontaneous rise in the body core temperature even without application of electricity which may be a reason for the typical temperature plateau after death.     

The Optimal Combination of Cartilage Source and Apparatus for Long‐Term In Vitro Chondrocyte Viability Analysis

Abstract: Most studies of long‐term chondrocytes survival were for tissue banks. They showed a gradual reduction in the viable chondrocytes percentage as a function of time and ambient temperature, but the samples were harvested under optimal conditions. The aim of our study was to determine the most reliable combination of cartilage source and assay for the in vitro postmortem chondrocyte viability analysis in the conditions that imitate a dead body. Osteochondral cylinders were procured from femoral condyles and talar trochleas of three male donors and stored in the cell culture media at 4 ± 2°C and 23 ± 2°C. The samples were analyzed by a cell viability analyzer and a confocal laser scanning microscope (CLSM) initially 24–36 h after death and then in 4‐week intervals. The results reconfirmed the significant influence of time (p = 0.0002), but not of the temperature (p = 0.237). The largest reproducibility was presented for the knee joint and the CLSM.     

Sudden death due to an unrecognized cardiac hydatid cyst: three medicolegal autopsy cases

Echinococcosis is a human infection caused by the larval stage of Echinococcocus granulosus. The most common sites of infection are the liver and the lungs. Cardiac hydatid cysts are very rare, even in regions where hydatic cysts are endemic (the Mediterranean, South America, Africa, and Australia). It has been reported that cardiac involvement is seen in about 0.5-3% of human echinococcosis cases. Three cases of cardiac hydatid disease that caused sudden death and which were histopathologically diagnosed are reported. Cardiac echinococcosis is rare, but due to its insidious presentation and affinity to cause sudden death, it is important that it be identified in the histopathological examination.