Hypothermia and localized cold injuries

Hypothermia: Beyond the Narrative Review-The Point of View of Emergency Physicians and Medico-Legal Considerations

Hypothermia is a widespread condition all over the world, with a high risk of mortality in pre-hospital and in-hospital settings when it is not promptly and adequately treated. In this review, we aim to describe the main specificities of the diagnosis and treatment of hypothermia through consideration of the physiological changes that occur in hypothermic patients. Hypothermia can occur due to unfavorable environmental conditions as well as internal causes, such as pathological states that result in reduced heat production, increased heat loss or ineffectiveness of the thermal regulation system. The consequences of hypothermia affect several systems in the body-the cardiovascular system, the central and peripheral nervous systems, the respiratory system, the endocrine system and the gastrointestinal system-but also kidney function, electrolyte balance and coagulation. Once hypothermia is recognized, prompt treatment, focused on restoring body temperature and supporting vital functions, is fundamental in order to avert preventable death. It is important to also denote the fact that CPR has specificities related to the unique profile of hypothermic patients.

Study on thermal health and its safety management mode for the working environment

Thermal health concerns have gained significant attention due to the heightened health risks faced by workers who are exposed to extreme thermal environments for prolonged periods. To ensure the occupational health and safety of such workers, and to enhance work efficiency, it is imperative to examine the characteristics of thermal health in the working environment. This study proposes three key elements of thermal health in the working environment, namely thermal health states, absence of heat-related illnesses, and heat adaptability, which can be used to develop a safety management framework for thermal health. By exploring the interconnections between these elements, the study summarizes their features and outlines the necessary precautions to safeguard them. The PDCA (plan/do/check/action) cycle management mode is utilized as a framework, with the three components of thermal health forming the core, to establish a safety management mode for thermal health. To ensure that employees work in a safe, healthy, comfortable, and productive environment, the assessment and control objectives of the thermal environment are regularly revised through the use of labor protection technology and thermal environment control technology. This paper presents a PDCA cycle safety management mode based on the characteristics of thermal health, which offers novel insights and approaches for assessing and managing workers' thermal health.

DNA microarray analysis of hypothermia-exposed murine lungs for identification of forensic biomarkers

We used DNA microarray technology to analyze the pulmonary transcriptome of mice killed by hypothermia. This analysis identified significant differential regulation of 4094 genes; specifically, 1699 genes were upregulated, and 2395 were downregulated in response to hypothermia. The gene encoding cathelicidin antimicrobial peptide was the most upregulated gene, and that encoding BAI1-associated protein 2-like 1 was the most downregulated. Gene-set analysis identified significant hypothermia-induced variations in 101 pathways, and we discovered that pathways related to immunity are involved in the pulmonary pathogenesis of hypothermia. The present findings demonstrate some of the acute pulmonary responses to hypothermia and indicate several pulmonary genes as candidate forensic biomarkers of hypothermia. Furthermore, the present findings suggest that host defense is induced in hypothermic lungs. The present microarray data may facilitate the development of protein analyses for human forensics by immunohistochemistry, western blotting and enzyme-linked immunosorbent assay and may be beneficial in clinical research of hypothermia.

DNA microarray analysis of the mouse adrenal gland for the detection of hypothermia biomarkers: potential usefulness for forensic investigation

We analyzed the adrenal gland transcriptome of mice killed by hypothermia using DNA microarray technology. A total of 4051 significantly expressed genes were identified; 2015 genes were upregulated and 2036 were downregulated.The FBJ osteosarcoma oncogene was the most upregulated,whereas stearoyl coenzyme A desaturase 3 was the most downregulated. Validation by quantitative polymerase chain reaction revealed that results obtained by both methods were consistent. In the gene set analysis, significant variations were found in nine pathways, and we suggest that transforming growth factor β and tumor necrosis factor α would be involved in the pathogenesis of hypothermia. Gene functional category analysis demonstrated the most overexpressed categories in upregulated and downregulated genes were cellular process in biological process, binding in molecular function, and cell and cell part in cellular component. The present study demonstrated acute adrenal responses in hypothermia, and we suggest that understanding adrenal mRNA expression would be useful for hypothermia diagnosis. Furthermore, the present microarray data may also facilitate development of immunohistochemical analysis of human cases. In forensic practice, the combination of macroscopic and microscopic observations with molecular biological analyses would be conducive to more accurate diagnosis of hypothermia. Although this study is aimed at forensic practice, the present data regarding more than 20,000 genes of the adrenal gland would be beneficial to inform future clinical hypothermia research. From the viewpoint of adrenal gene activity, they could contribute to elucidating the pathophysiology of hypothermia.

Web-based hypothermia information: a critical assessment of Internet resources and a comparison to peer-reviewed literature

AIMS

Hypothermia is a medical condition characterized by a drop in core body temperature, and it is a considerable source of winter weather-related vulnerability in mid-/high-latitude areas. Heat vulnerability research, including assessments of internet-based resources, is more thoroughly represented in the peer-reviewed literature than cold-related vulnerability research. This study was undertaken to summarize available web-based hypothermia information, and then determine its scientific validity compared to the peer-reviewed literature.

METHODS

This research takes a similar approach used by Hajat et al. for web-based heat vulnerability research, and utilizes this framework to assess hypothermia information found on the internet. Hypothermia-related search terms were used to obtain websites containing hypothermia information, and PubMed (medical literature search engine) and Google Scholar were used to identify peer-reviewed hypothermia literature. The internet information was aggregated into categories (vulnerable populations, symptoms, prevention), which were then compared to the hypothermia literature to determine the scientific validity of the web-based guidance. The internet information was assigned a Strength of Recommendation Taxonomy (SORT) grade (developed by the American Academy of Family Practitioners) of A, B, or C based on the peer-reviewed evidence.

RESULTS

Overall, 25 different pieces of guidance within the three categories were identified on 49 websites. Guidance concerning hypothermia symptoms most frequently appeared on websites, with six symptoms appearing on 50% or greater of websites. No piece of guidance within the vulnerable population categories appeared on greater than 60% of the websites, and prevention-related guidance was characterized by varied SORT grades.

CONCLUSIONS

Hypothermia information on the internet was not entirely congruent with the information within the peer-reviewed medical literature. Several suggestions for improving web-based hypothermia resources include clearly listing sources for users to see and eliminating guidance with lower SORT grades and replacing with evidence-based information.

Successful resuscitation from cardiopulmonary arrest due to profound hypothermia using noninvasive techniques

Profound hypothermia is defined as a core body temperature of 20.0 °C or less. Successful resuscitation from this degree of hypothermia is rare. We present a case of successful resuscitation in a 2-year-old boy found in cardiac arrest due to profound hypothermia. Invasive techniques such as cavity lavage, extracorporeal membrane oxygenation, and cardiopulmonary bypass were not used.

National Athletic Trainers' Association position statement: environmental cold injuries

OBJECTIVE

To present recommendations for the prevention, recognition, and treatment of environmental cold injuries.

BACKGROUND

Individuals engaged in sport-related or work-related physical activity in cold, wet, or windy conditions are at risk for environmental cold injuries. An understanding of the physiology and pathophysiology, risk management, recognition, and immediate care of environmental cold injuries is an essential skill for certified athletic trainers and other health care providers working with individuals at risk.

RECOMMENDATIONS

These recommendations are intended to provide certified athletic trainers and others participating in athletic health care with the specific knowledge and problem-solving skills needed to address environmental cold injuries. Each recommendation has been graded (A, B, or C) according to the Strength of Recommendation Taxonomy criterion scale.

Successful treatment of profound hypothermia of the newborn

We report a case of a profoundly hypothermic newborn with a core temperature of 25 degrees C with a successful recovery and normal neurological outcome at 3 and 6 months. This term male infant had been exposed to a temperature of -3 degrees C for approximately 30 min. Slow re-warming, using external modalities was used in addition to volume expansion, heparinization, antibiotics and sedation. There is limited information available concerning the safest and most effective method of re-warming hypothermic newborns. Slow re-warming has been advocated as it replicates the normal physiological process in a neonate, which minimizes a negative therapy impact.

CONCLUSION

The most significant decision regarding treatment is the identification of the most appropriate method and speed of re-warming. This report supports recommendations for gradual re-warming of a severely hypothermic newborn. Physiological cardiovascular mechanisms seemed to be intact during slow re-warming; this might be applicable to the treatment of profound hypothermia of the newborn.

Environmental issues for team physicians

As outdoor sports continue to gain popularity, understanding the environmental factors that may influence athletes is becoming a more important aspect of medical care for team physicians. Temperature, ultraviolet light, lightning, and altitude are some of the most common elements that cause illness. Understanding how to prevent, diagnose, and promptly treat conditions caused by environmental factors is essential to optimizing athletic performance in outdoor sports and avoiding morbidity.

Hypothermia and Hyperthermia Medicolegal Investigation of Morbidity and Mortality From Exposure to Environmental Temperature Extremes

Context.—The determination of the cause of death from exposure to extreme temperatures is a diagnosis of exclusion. Because both clinical and autopsy findings are nonspecific, a thorough investigation of the background and scene, evaluation of temporally relevant environmental conditions, and assessment of the victim's underlying state of health with appropriate laboratory studies, which frequently include autopsy, are essential to establish the cause of injury and/or death with reasonable medical probability. Individuals may encounter environmental extremes in many settings during any season. Both constitutional and external factors exacerbate the stress brought about by extreme temperature.

Objective.—This article reviews guidelines for forensic investigation into environmental temperature extremes that contribute to an important seasonal grouping of morbidity and mortality in the United States.

Data Sources.—Articles on clinical and pathologic aspects of hyperthermia and hypothermia were collected and reviewed.

Conclusions.—Recognition of multiple risk factors predisposing humans to both cold-related and heat-related morbidity and mortality enhances prevention. Awareness of the susceptibility of these exposed at-risk individuals is crucial to investigations by both clinicians and medicolegal death investigators.

[Pathology related to altitude: the experience on K2]

The pathology related with the altitude is a common entity above 3000 m. It includes mild symptoms to severe illness such as cerebral or pulmonary edema. Cold-induced injuries may produce permanent tissue loss and surgical amputation. Recognition is made mainly through symptoms. Adequate treatment of these patients allows for rapid resolution of the symptoms and improves outcome.