Accidental hypothermia: direct evidence for consciousness as a marker of cardiac arrest risk in the acute assessment of cold patients.

BACKGROUND: Rapid stratification of the risk of cardiac arrest is essential in the assessment of patients with isolated accidental hypothermia. Traditional methods based on measurement of core temperature are unreliable in the field. Behavioural observations have been used as predictors of core temperature and thus indirect predictors of cardiac arrest. This study aims to quantify the direct relationship between observed conscious level and cardiac arrest. METHODS: Retrospective case report analysis identified 114 cases of isolated accidental hypothermia meeting inclusion criteria. Level of consciousness in the acute assessment and management phase was classified using the AVPU system with an additional category of "Alert with confusion"; statistical analysis then related level of consciousness to incidence of cardiac arrest. RESULTS: All patients who subsequently suffered cardiac arrest showed some impairment of consciousness (p < < .0001), and the risk of arrest increased directly with the level of impairment; none of the 33 fully alert patients arrested. In the lowest impairment category, Alert confused, a quarter of the 12 patients went on to arrest, while in the highest Unresponsive category, two thirds of the 43 patients arrested. Where core temperature was available (62 cases), prediction of arrest by consciousness level was at least as good as prediction from core temperature. CONCLUSIONS: This study provides retrospective analytical evidence that consciousness level is a valid predictor of cardiac arrest risk in isolated accidental hypothermia; the importance of including confusion as a criterion is a new finding. This study suggests the use of consciousness alone may be at least as good as core temperature in cardiac arrest risk prediction. These results are likely to be of particular relevance to the management of accidental hypothermia in the pre-hospital and mass casualty environment, allowing for rapid and accurate triage of hypothermic patients.

The influence of hypothermia prevention by application of skin moisture absorbent on the value of body temperature, body weight and blood parameters in piglets / A influência da prevenção da hipotermia pela aplicação de absorvente de umidade da pele no valor da temperatura corporal, peso corporal e parâmetros sanguíneos em leitões

Reducing the mortality rate is of a great economic importance for pig farming. Therefore, it is necessary to define the conditions in the farrowing unit based on the performance of the piglets, and specific hematological and biochemical parameters. Therefore, the aim of this paper is to examine the importance of using skin moisture absorbent and its influence in preventing hypothermia, which causes great economic losses in pig production. The experiment was set up on a commercial farm in Serbia and included 92 pigs divided into the experimental and control group. Body temperature values, body weight and blood parameters were monitored. The obtained values indicate that there is a significantly positive correlation of body temperature change and body weight values, and body temperature showed a significantly higher increase in the experimental group compared to the control group. The results obtained from hematological and biochemical parameters provide a clearer picture of the metabolic processes in piglets in the farrowing unit and can be used to further improve pig production and as a complement to genetic enhancement.(AU)

A redução da taxa de mortalidade é de grande importância econômica para a suinocultura. Portanto, é necessário definir as condições na unidade de parto com base no desempenho dos leitões, para serem parâmetros hematológicos e bioquímicos específicos. Portanto, o objetivo deste trabalho é examinar a importância do uso de absorvente de umidade na pele e sua influência na prevenção da hipotermia, que causa grandes perdas econômicas na produção de suínos. A experiência foi montada em uma fazenda comercial na Sérvia, e incluiu 92 porcos divididos no grupo experimental e de controle. Os valores de temperatura corporal, pesos corporais e parâmetros sanguíneos foram monitorados. Os valores obtidos indicam que existe uma correlação significativamente positiva entre os valores da temperatura corporal e dos pesos corporais, e a temperatura corporal mostrou um aumento significativamente maior no grupo experimental em comparação com o grupo de controle. Os resultados obtidos a partir de parâmetros hematológicos e bioquímicos fornecem uma imagem mais clara dos processos metabólicos em leitões na unidade de parto e podem ser usados para melhorar ainda mais a produção de suínos e como um complemento ao melhoramento genético.(AU)

The accuracy of tactile assessment of canine nose temperature to identify rectal hyperthermia and hypothermia in dogs presenting on an emergency basis.

The goals of this study were to evaluate whether touch can identify a warm nose as opposed to a cold nose, to examine the correlation between thermographically measured nose temperatures and rectal temperatures, and to calculate the accuracy of tactile assessment of nose temperature in detecting rectal hyperthermia and hypothermia in dogs. A total of 100 dogs presenting to an emergency room was prospectively enrolled. Tactile nose assessment was carried out on triage. Noses were subjectively categorized as warm, cold, or intermediate (neither warm nor cold). Thermographic nose temperatures were recorded using a thermal imaging camera. Tactile assessment categorized noses as warm, intermediate, or cold (P < 0.01). There was no correlation between thermographically measured nose temperature and rectal temperature (r = 0.02). Tactile assessment of noses as warm had a sensitivity of 29.4% and a specificity of 79.5% for detecting rectal hyperthermia; calculated test accuracy was 71%. Tactile assessment of noses as cold had a sensitivity of 54.5% and a specificity of 62.9%; calculated test accuracy was 62%. It was concluded that nose temperatures do not correlate with rectal temperatures. Tactile assessment of nose temperature is inaccurate for identifying rectal hyperthermia or hypothermia.

Les objectifs de cette étude étaient d'évaluer si le toucher peut identifier un nez chaud par opposition à un nez froid, d'examiner la corrélation entre les températures nasales mesurées thermographiquement et les températures rectales, et de calculer la précision de l'évaluation tactile de la température nasale dans la détection de l'hyperthermie et l'hypothermie rectale chez le chien. Un total de 100 chiens se présentant aux urgences a été enrôlé de manière prospective. Une évaluation tactile du nez a été réalisée lors du triage. Les nez ont été classés subjectivement comme chaud, froid ou intermédiaire (ni chaud ni froid). Les températures thermographiques du nez ont été enregistrées à l'aide d'une caméra thermique. L'évaluation tactile a classé les nez comme chauds, intermédiaires ou froids (P < 0,01). Il n'y avait pas de corrélation entre la température nasale mesurée par thermographie et la température rectale (r = 0,02). L'évaluation tactile des nez chauds avait une sensibilité de 29,4 % et une spécificité de 79,5 % pour détecter l'hyperthermie rectale; la précision calculée du test était de 71 %. L'évaluation tactile des nez froids avait une sensibilité de 54,5 % et une spécificité de 62,9 %; la précision calculée du test était de 62 %. Il a été conclu que les températures nasales ne sont pas corrélées avec les températures rectales. L'évaluation tactile de la température du nez est imprécise pour identifier l'hyperthermie ou l'hypothermie rectale.(Traduit par les auteurs).

ThermoLabAnimal - A high-throughput analysis software for non-invasive thermal assessment of laboratory mice.

Body temperature changes in laboratory mice are often assessed by invasive and stressful methods, which may confound the measurement. Infrared thermography is a possible non-invasive alternative, but the cost of standard thermal cameras, lack of dedicated software for biomedical purposes, and labour-intensiveness of thermal image analysis have limited their use. An additional limitation lies on the scarcity of research on the causing factors of differences between body surface and core body temperature. We propose a method for automatic assessment of mean body surface temperature in freely-moving mice, using dedicated software for thermal image analysis. While skin surface temperature may not necessarily be linearly correlated with core body temperature (in itself an imprecise concept), under standardized environmental conditions, such as those in which laboratory animals are kept, mean body surface temperature can provide useful information on their thermal status (i.e. deviations from normothermia, namely hypo- and hyperthermia). We developed a publicly available software that includes an imaging analysis workflow/algorithm for automatic segmentation of the pixels associated with the animal from the pixels associated with the background, removing the need for manually defining the area of analysis. A batch analysis mode is also available, for automatic and high-throughput analysis of all image files located in a folder. The software is compatible with the most widespread thermal camera manufacturer, 'FLIR Systems', as well as with the low-cost 'Thermal Expert TE-Q1' miniaturized high-resolution thermal camera used for this study. Furthermore, the software has been validated in a mouse model expressing non-transient hypothermia, where the thermal analysis results were compared with readings from implanted thermo-sensitive passive integrated transponders tags. Thermography allows for thermal assessment of laboratory animals without the effect of handling stress on their physiology or behaviour. Our automatic image analysis software also removes observer errors and bias, while speeding up the data processing.

"Cold Card" to Guide Responders in the Assessment and Care of Cold-Exposed Patients.

INTRODUCTION: A concise, easy-to-use decision aid "Cold Card" that can be carried in the field by wilderness search and rescue teams or medical responders to advise on assessment and care of cold-exposed patients was created. METHODS: A 2-sided card was designed to summarize the important principles established by the Wilderness Medical Society practice guidelines for hypothermia. The card was continually updated through feedback from several content experts. The card was then distributed for further feedback from members of the Search and Rescue Volunteer Association of Canada and enrollees of the Baby It's Cold Outside web-based educational program. This additional feedback was used to create the final iteration of the card. RESULTS: On the front "ASSESS COLD PATIENT" side, the level of cold exposure or hypothermia is accomplished by evaluating (as either normal or impaired function) consciousness, movement, shivering, and alertness on a series of concentric rings. The important treatment actions are provided for each cold-exposure level. The back "CARE FOR COLD PATIENT" side provides the required elements and principles of use for a hypothermia wrap. The Cold Card is available for free download and unlimited use for education or in-field instruction by any individual or group. The card should be printed on heavy, waterproof stock (13×18 cm) for use in all weather conditions. CONCLUSIONS: Key elements of hypothermia evaluation and field care have been summarized on a small portable card for laypersons, trained rescuers, and first responders.

Penetrating and blunt trauma to the neck: clinical presentation, assessment and emergency management.

Penetrating and blunt trauma to the neck: clinical presentation, assessment ana emergency management. In Belgium, and even in Western Europe, penetrating and blunt injury to the neck is relatively uncommon in both the civilian and military populations. Pre-hospital and emergency assessment and management will therefore always prove challenging, as individual exposure to this specific type of injury remains low. Historically, the neck has been divided into three anatomical zones with specific landmarks to guide the diagnostic and therapeutic approach to penetrating neck injuries. Most penetrating injuries need to be explored surgically, although with the advent of multi-detector computed tomographic angiography (MDCTA), which yields high diagnostic sensitivity, this inflexible approach has recently changed to a more targeted management, based on clinical, radiographic and, if deemed necessary, endoscopic findings. However, some authors have addressed their concern about this novel, 'no-zone' approach, since the risk of missing less apparent aerodigestive tract injuries may increase. It is recommended, therefore, that all patients with penetrating neck injuries be closely observed, irrespective of the initial findings. The incidence of blunt neck injury is much lower, and this makes risk assessment and management even more difficult in comparison with penetrating injuries. Again, MDCTA is most often the first diagnostic tool if a blunt neck injury is suspected, due to its good sensitivity for blunt cerebrovascular injuries (BCVI) as well as for aerodigestive tract injuries. Specific patterns of injury and unexpected neurological and neuro-radiological findings in trauma patients should always warrant further investigation. Despite ongoing debate, systemic anticoagulation is recommended for most BCVI, sometimes combined with endovascular treatment. Aerodigestive tract injuries may present dramatically, but are often more subtle, making the diagnosis more difficult than other types of neck injuries. Treatment may be conservative if damage is minimal, but surgery is warranted in all other cases.

Value of extended warming in patients undergoing elective surgery.

Perioperative temperature management is imperative for positive surgical outcomes. This study assessed the clinical and wellbeing benefits of extending normothermia by using a portable warming gown. A total of 94 patients undergoing elective surgery were enrolled. They were randomized pre-operatively to either a portable warming gown or the standard warming procedure. The warming gown stayed with patients from pre-op to operating room to postrecovery room discharge. Core temperature was tracked throughout the study. Patients also provided responses to a satisfaction and comfort status survey. The change in average core temperature did not differ significantly between groups (P = 0.23). A nonsignificant 48% relative decrease in hypothermic events was observed for the extended warming group (P = 0.12). Patients receiving the warming gown were more likely to report always having their temperature controlled (P = 0.04) and significantly less likely to request additional blankets for comfort (P = 0.006). Clinical outcomes and satisfaction were improved for patients with extended warming.

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.

Validity and reliability of the Cold Discomfort Scale: a subjective judgement scale for the assessment of patient thermal state in a cold environment.

Complementary measures for the assessment of patient thermoregulatory state, such as subjective judgement scales, might be of considerable importance in field rescue scenarios where objective measures such as body core temperature, skin temperature, and oxygen consumption are difficult to obtain. The objective of this study was to evaluate, in healthy subjects, the reliability of the Cold Discomfort Scale (CDS), a subjective judgement scale for the assessment of patient thermal state in cold environments, defined as test-retest stability, and criterion validity, defined as the ability to detect a difference in cumulative cold stress over time. Twenty-two healthy subjects performed two consecutive trials (test-retest). Dressed in light clothing, the subjects remained in a climatic chamber set to -20 °C for 60 min. CDS ratings were obtained every 5 min. Reliability was analysed by test-retest stability using weighted kappa coefficient that was 0.84 including all the 5-min interval measurements. When analysed separately at each 5-min interval the weighted kappa coefficients were was 0.48-0.86. Criterion validity was analysed by comparing median CDS ratings of a moving time interval. The comparison revealed that CDS ratings were significantly increased for every interval of 10, 15, and 30 min (p < 0.001) but not for every interval of 5 min. In conclusion, in a prehospital scenario, subjective judgement scales might be a valuable measure for the assessment of patient thermal state. The results of this study indicated that, in concious patients, the CDS may be both reliable and valid for such purpose.

Assessment of body temperature measurement options.

Assessment of body temperature is important for decisions in nursing care, medical diagnosis, treatment and the need of laboratory tests. The definition of normal body temperature as 37°C was established in the middle of the 19th century. Since then the technical design and the accuracy of thermometers has been much improved. Knowledge of physical influence on the individual body temperature, such as thermoregulation and hormones, are still not taken into consideration in body temperature assessment. It is time for a change; the unadjusted mode should be used, without adjusting to another site and the same site of measurement should be used as far as possible. Peripheral sites, such as the axillary and the forehead site, are not recommended as an assessment of core body temperature in adults. Frail elderly individuals might have a low normal body temperature and therefore be at risk of being assessed as non-febrile. As the ear site is close to the hypothalamus and quickly responds to changes in the set point temperature, it is a preferable and recommendable site for measurement of body temperature.

Diagnosis, prevention and treatment of accidental and perioperative hypothermia.

Accidental hypothermia and its variant, perioperative hypothermia, is a rather common clinical phenomenon in patients. This is surprising because the negative effects on clinical outcomes are well described and effective patient-warming devices are available today. The aim of this paper is to describe the physiologic background of accidental and perioperative hypothermia, the clinical relevance and existing prophylaxis and treatment options. Patient warming techniques will be discussed in detail. Remaining technical and clinical challenges and the need for further research will be addressed. We will present existing guidelines and standards and analyse the impact of accidental and perioperative hypothermia on cost effectiveness.

Evaluation of cold workplaces: an overview of standards for assessment of cold stress.

Many persons world wide are exposed to cold environments, either indoors for example in cold stores, or outdoors. Cold is a hazard to health and may affect safety and performance of work. Basis for the creation of safe and optimal working conditions may be obtained by the application of relevant international standards. ISO 11079 presents a method for evaluation of whole body heat balance. On the basis of climate and activity a required clothing insulation (IREQ) for heat balance is determined. For clothing with known insulation value an exposure time limited is calculated. ISO 11079 also includes criteria for assessment of local cooling. Finger temperatures should not be below 24 degrees C during prolonged exposures or 15 degrees C occasionally. Wind chill temperature indicates the risk of bare skin to freeze for combinations of wind and low temperatures. Special protection of airways is recommended at temperatures below -20 degrees C, in particular during heavy work. Additional standards are available describing evaluation strategies, work place observation checklists and checklist for medical screening. Risks associated with contact with cold surfaces can be evaluated with ISO 13732. The strategy and principles for assessment and prevention of cold stress are reviewed in this paper.

A clinical evaluation of the cost and time effectiveness of the ASPAN Hypothermia Guideline.

It is known that perioperative hypothermia increases the cost of care and places surgical patients at increased risk for adverse outcomes. The American Society of PeriAnesthesia Nurses (ASPAN) developed the Clinical Guideline for the Prevention of Unplanned Perioperative Hypothermia to specify a systematic approach to the maintenance of normothermia in surgical patients, making use of newer active warming technologies as well as passive warming techniques. The purpose of this study was to test the cost and time effectiveness of the ASPAN Hypothermia Guideline as compared with usual care. Our findings indicate that the Hypothermia Guideline, which is known to employ practices effective for maintaining normothermia, is clinically feasible and can be implemented without significant increases in cost or time for an ambulatory surgical unit.

Proposed guidelines for skin-to-skin treatment of neonatal hypothermia.

Hypothermia is not uncommon in full-term, low-risk newborns during the first days of life. Standard care for treating hypothermia often involves the separation of the mother and the newborn while the infant is placed under a warmer and observed in the nursery. Because one important role of the postpartum nurse is to promote mother-infant attachment by encouraging the mother to spend time "getting to know" her infant, this separation can be problematic. This article proposes that skin-to-skin (STS) care, also called kangaroo care, an intervention in which the unclothed, diapered infant is placed on the mother's bare chest, be used to promote thermoregulation instead of using separation and a warmer. STS care has been recognized as a way to facilitate maternal-infant attachment and promote thermoregulation. The literature review here provides an analysis of the available evidence and the author's conclusion that the research supports the use of STS care as an alternative to traditional rewarming. The evidence was graded and organized into an evidence-based practice guideline for the use of STS care in the treatment of mild hypothermia in the low-risk infant. Suggestions for further research and outcomes measurement are included.

Hypothermia: assessment, treatment and prevention.

Hypothermia is a condition that can have serious consequences, yet its symptoms are often unrecognised in older people because they can be easily confused with symptoms of other age-related illnesses. Nurses should know how to treat the condition, as well as be able to offer health promotion and health education advice about keeping warm.