Fire exposure after lethal hypothermia.

A 49-year-old woman was found dead in her apartment after a fire began in her building. During the forensic autopsy, 3rd to 4th degree burns were found on the woman's body, but there were no indications that she was alive when the fire started. Interestingly, hemorrhagic gastric mucosa erosions, as well as bloody contents in the esophagus, stomach, and intestines, were observed. However, the source of the bleeding could not be found. The cause of death was therefore determined to be hypothermia with postmortem fire exposure. The cause of the hypothermia could possibly have been high internal blood loss. The organs showed early signs of putrefaction. It was theorized that the woman had not died immediately before the fire began, but rather a few days before. Examination of heat shock proteins (HSPs) to evaluate premortem thermal influences did not reveal HSP 27, 60, or 70 expression in renal tissue, possibly because of the putrefaction. However, Sudan staining of this tissue revealed a fatty degeneration of renal tubular cells. Opposing temperature influences, as in this case, are rather rare and require thorough investigations.

Autopsy findings in fire deaths in relation to manner of death: Analysis of autopsy records in Friuli, Italy (1993-2020).

The determination of the cause and manner of death can be particularly difficult in burned and charred bodies and autopsy remains a key element in the investigation. In this study, 39 autopsy records of fire deaths were reviewed in relation to the manner of death (25 accidents, 8 suicides, 3 homicides and 3 instances in which the manner of death remained undetermined). The analysis focused on the study of the burns, the degree to which the bodies were consumed by fire and the evidence of signs of vital exposure to fire and of non-fire-related injuries. Total surface body area (TBSA) was found to be significantly higher (p = 0.02) in suicides than in accidents. Moreover, the degree of destruction according to the Crow-Glassman Scale and the presence of a pugilistic posture tended to be higher in suicides compared to accidental deaths, whereas such parameters were found to be variable in homicides. With regard to the anatomical distribution of burns, in contrast with the literature, the feet were affected by burning in all suicides, with a significantly higher prevalence than in accidents (p < 0.01). Traumatic non-fire related injuries were noted in all homicides (with no signs of vital exposure to fire), 1 complicated suicide, 1 undetermined death and 13 accidents. We found that very few studies have focused on the analysis of burn distribution and extension according to manner of death and that there is currently no standardised anatomical model with which to study these variables for forensic purposes.

The impacts of thermocouple insulation failure on the accuracy of temperature measurement data in forensic fire-death scenarios-Part I: Physical disintegration.

Thermocouples are utilized to monitor a wide range of temperatures in industrial applications. They are also used in both fire and forensic science research to measure temperatures of fires and of materials exposed to fire. Taking accurate temperature measurements during forensic fire-death scenarios is very difficult due to direct fire exposure to thermocouples, shrinkage and destruction of tissues, and movements from pyre collapse and pugilistic posturing of human donors. This two-part study investigates the impacts on the accuracy of temperature data if the selected thermocouples are unable to withstand fire exposure. Part I (this article) provides an overview of thermocouple theory along with evidence of the physical deterioration that occurs when glass fiber-insulated thermocouple wires are overheated by exposure to fire-level temperatures in a muffle furnace. This study verified that insulation overheating causes embrittlement and disintegration, which can cause the indicated temperature to reflect a new location of measurement located far away from the original measuring junction at the thermocouple tip. Part II will discuss the measurement errors that occurred due to low electrical resistance of insulation when three different thermocouple models were passed through fire-level temperatures to measure an ice bath at a constant temperature of 0°C.

The impacts of thermocouple insulation failure on the accuracy of temperature measurement data in forensic fire-death scenarios-Part II: Low electrical resistance and contamination.

Part II of this two-part article investigates the impact of thermocouple insulation failure on temperature measurement data in forensic fire-death scenarios. Two different models of glass fiber-insulated thermocouple wires (GG-K-24-SLE and HH-K-24 from Omega Engineering) were passed through a ceramic kiln at temperatures up to 1093°C to measure an ice bath at a constant 0°C. In a separate experiment, the same two models of thermocouple wire plus a BLMI-XL-K-18U-120 mineral-insulated metal-sheathed thermocouple probe were passed through a wood pallet fire to measure an ice bath. In the ceramic kiln, the effect on measurement errors was determined for short vs. long exposure lengths and clean insulation vs. insulation contaminated with pork fat. Glass fiber-insulated thermocouple wires showed severe failure in both experiments, with errors ranging from -270°C to almost 2200°C. The metal-sheathed probe showed no evidence of insulation failure and continued to accurately measure the ice bath temperature within expected margins of error around 0°C. This study highlights how exposure of inadequate thermocouples to fire-level temperatures produces severe errors in temperature data. Consequently, it will not be possible to use this data to draw any accurate conclusions about the effects of fire exposure to human donors or animal proxies.

Examination of misconceptions surrounding fatal fire victims.

Fire deaths are not unusual in forensic investigative practice but due to the destructive nature of fire they are often very difficult to investigate. With the need to identify the deceased and the events surrounding the manner and cause of death, knowledge of thermally induced alteration to the human body is important. Within the fire investigation community, a number of misconceptions have been present for years regarding the protrusion of the tongue as an indicator of life during the fire, and fractured skulls as the result of brains boiling and skulls exploding. This work presents qualitative analysis on the experimental burning of 42 unembalmed human donated cadavers by the San Luis Obispo Strike Team (SLOFIST) on their annual Forensic Fire Death Investigation Course (FFDIC) between 2017 and 2019. Prior to burning, the position of the tongue within the dental arch was confirmed and sharp, blunt, surgical and gunshot trauma to the cranium documented. Temperature was recorded from ignition through to suppression with thermocouples present both within the scene and the body. Post burn analysis on the position of the tongue, observation of cranial fractures and presence of brain tissue were recorded and analysed in conjunction with thermocouple data, fire scene dynamics and body demographics. The results provide a more comprehensive understanding of the thermal environmental factors involved in producing the phenomena that facilitate these misconceptions, identifying that a more thorough understanding of individual fire scenes and their development is essential when interpreting alteration and injury to the body of the fatal fire victim.

Supravital expression of heat-shock proteins.

Heat-shock proteins (HSPs) are expressed during cellular stress, especially thermal stress, to support protein homeostasis. Extensive investigations have revealed that HSP27 is rapidly and intensively expressed in the pulmonary and renal tissues of most cases of death due to fire, contrary to cases without premortem thermal influences, which are negative for HSP expression. As such, HSP27 can be used as a marker of vitality in the investigation of fire-related deaths. Without positive HSP27 expression or only slight expression, one can conclude that the deceased was not alive at the time of heat stress. This is presented in two case reports of men who were shot and later burned. HSP espression could not be found in these cases. In the very early supravital period, particularly the latency and supravital periods, metabolic processes can continue after irreversible cardiac arrest. Extensive cellular stress can lead to an immunohistochemically detectable expression of HSP in this portmortem period. This is shown in the case report of a 49-year-old man who immediately died and burned following the massive detonation of an air mine. Immunohistochemical studies of recovered renal tissues have revealed HSP27 expression in the vessel walls as well as renal tubules, as presented in a third case report. This HSP expression can be considered as a phenomenon of supravitality. Heat stress induces massive cellular stress and the expression of HSP under global ischemic conditions. When vitality is to be determined in cases of suspected fire deaths, the possibility of supravital expression has to be considered.

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.