Introdução: A lesão da medula espinhal é uma entidade clínica grave e extremamente incapacitante. Muitos esforços estão sendo realizados para melhorar a resposta neurológica ao trauma da medula espinhal. Dentre eles, destacamos o uso de agentes farmacológicos, a descompressão e estabilização cirúrgica precoces e a hipotermia. A hipotermia pode ser induzida de forma sistêmica ou local. Várias complicações, como arritmias cardíacas, coagulopatias e infecções, foram associadas ao uso sistêmico da hipotermia. Porém, sua aplicação local demanda a necessidade de intervenção cirúrgica de emergência e manejo pós-operatório complicado. Objetivo: Avaliar o efeito neuroprotetor da hipotermia epidural em ratos. Material e método: Foram arrolados 30 ratos Wistar pesando entre 320-360 g e divididos aleatoriamente em dois grupos: o grupo da hipotermia epidural e o grupo controle, com 15 ratos cada. Uma contusão medular produzida por queda padronizada de peso de 10 g, a 25 mm de altura, usando o New York University (NYU) Impactor, foi realizada após a laminectomia em T9-10 em todos os ratos. Os ratos do grupo da hipotermia foram submetidos ao resfriamento a 9-10 °C por um período de 20 minutos, logo após a contusão medular. Os grupos foram analisados durante seis semanas quanto à função motora utilizando-se a escala BBB e o teste do plano inclinado. Ao final da sexta semana, foi realizado ainda o exame de potencial evocado motor dos ratos, cujos resultados foram comparados entre os dois grupos. Resultados: A avaliação da função motora através da aplicação da pontuação da escala BBB ao longo das seis semanas não evidenciou diferenças estatisticamente significantes entre os dois grupos. Não encontramos diferenças estatísticas na avaliação motora através da pontuação do teste do plano inclinado ao longo das seis semanas do estudo. Os valores de latência e amplitude do potencial evocado motor não mostraram diferenças estatísticas significantes entre os grupos ao final da última semana do estudo. Conclusão: A hipotermia não apresentou efeito neuroprotetor quando aplicada no sítio da lesão, logo após a contusão medular, no espaço epidural de ratos Wistar / Introduction: Spinal cord injury (SCI) is a critical and extremely disabling clinical condition. Considerable effort has been made to improve the neurological response to the spinal cord lesion. We must highlight pharmacological agents, early surgical decompression and stabilization and hypothermia. Therapeutic hypothermia can be achieved systemically or locally. Many complications have been associated to the systemic hypothermia, such as cardiac arrhythmias, coagulopathies and infection. However, local application demands surgical intervention and difficult post operative care. Objetive: To evaluate the neuroprotective effect of epidural hypothermia in rats. Methods: Wistar rats (n = 30; weighting 320-360 g) were randomized in two groups: the hypothermia and the control group, with 15 rats in each. A spinal cord lesion was produced by the standardized drop of a 10 g-weight from a height of 2,5 cm, using the New York University Impactor, after the laminectomy at the T9-10 level. Rats of the hypothermia group underwent epidural hypothermia for 20 minutes immediately after spinal cord injury. Motor function was assessed during six weeks using the BBB motor scores and inclined plane test. At the end of the last week, neurologic status was monitored by the motor evoked potential exam and the results were compared between the two groups. Results: Analysis of the BBB scores during the six-weeks period did not show any statistically significant difference between the two groups. We did not find any significant difference between the groups in the scores of the inclined plane test during the six-weeks period. Latency and amplitude values of the motor evoked potential exam did not show any statistically significant difference between the two groups at the end of the study. Conclusion: Hypothermia did not produce any neuroprotective effect when applied immediately after spinal cord contusion, at the injury level and in epidural space of Wistar rats

A sepse é sempre acompanhada de mudanças na temperatura corporal, seja esta febre ou hipotermia. O presente trabalho tem como objetivos principais (1) caracterizar o curso temporal de hipotermia em um grupo raro de pacientes sépticos; (2) desenvolver um modelo experimental bem controlado de sepse grave monobacteriana e; (3) estudar mecanicamente como o pulmão é preservado na sepse frente à virada de febre para hipotermia. Nossos resultados mostraram, pela primeira vez, que a hipotermia em pacientes sépticos é um fenômeno transitório, não terminal. Ainda desenvolvemos um modelo experimental de sepse grave, no qual observamos que a hipotermia provoca a reprogramação das principais células envolvidas na resposta inflamatória. Essas mudanças favorecem o hospedeiro, pois induzem diminuição do infiltrado inflamatório e manteve a infecção controlada. Logo, podemos concluir que a hipotermia é um fenômeno transitório, auto-limitante e não terminal, diferente da resposta desregulada e progressiva que se acreditava existir. / Sepsis is always accompanied by changes in body temperature, whether it is fever or hypothermia. The present study has as main objectives (1) to characterize the temporal course of hypothermia in a rare group of septic patients; (2) to develop a well-controlled experimental model of severe monobacterial sepsis and; (3) to mechanically study how the lung is preserved in the sepsis in the face of the onset of fever for hypothermia. Our results showed, for the first time, that hypothermia in septic patients is a transitory, non-terminal phenomenon. We have also developed an experimental model of severe sepsis, in which we observed that hypothermia causes reprogramming of the main cells involved in the inflammatory response. These changes favor the host, as they induce a decrease in the inflammatory infiltrate and kept the infection under control. Therefore, we can conclude that hypothermia is a transitory phenomenon, self-limiting and not terminal, different from the deregulated and progressive response that was believed to exist.

A hipotermia perioperatória está associada a diferentes complicações, tais como: aumento da incidência de infecção de sítio cirúrgico, arritmias cardíacas, aumento do sangramento no período intraoperatório e desconforto térmico do paciente na sala de recuperação pós-anestésica, entre outras. Na literatura há evidências de que o pré- aquecimento da superfície corporal do paciente antes da indução anestésica é efetivo para a redução da hipotermia, pela diminuição do gradiente de temperatura entre os compartimentos central e periférico do organismo humano. Assim o objetivo do estudo foi avaliar o efeito do pré-aquecimento na manutenção da temperatura corporal de pacientes submetidas a cirurgias ginecológicas eletivas. Trata-se de ensaio clínico controlado randomizado, com a participação de 86 pacientes submetidas a cirurgia ginecológica eletiva, aleatorizadas em dois grupos. Na sala de admissão do Centro Cirúrgico, as participantes do grupo experimental (n=43) foram aquecidas durante 20 minutos com o sistema de ar forçado aquecido (manta térmica para o corpo todo), o equipamento foi ligado na temperatura de 38o C, e as participantes do grupo controle (n=43) foram cobertas com lençol de algodão e cobertor, durante o mesmo tempo. No período intraoperatório, todas as pacientes foram aquecidas com o sistema de ar forçado aquecido (manta térmica para a parte superior do corpo). A temperatura timpânica foi mensurada com termômetro timpânico infravermelho nos períodos pré e intraoperatório. A partir da entrada da paciente na sala de operação, a temperatura e umidade do ar da sala cirúrgica foram mensuradas. As médias da temperatura e umidade do ar da sala cirúrgica, entre os grupos experimental e controle, foram analisadas por meio do teste t- Student. As médias da temperatura corporal, entre os grupos experimental e controle, foram analisadas por meio de modelo linear de regressão de efeitos mistos. Na análise descritiva dos dados relativos às características sociodemográficas e clínicas das pacientes e do procedimento anestésico-cirúrgico, evidenciou-se similaridade entre os grupos experimental e controle. Após o pré-aquecimento, a média da temperatura corporal foi de 38o C no grupo experimental e de 37,8o C no grupo controle, com diferença estatisticamente não significante (p=0,27). No T150 (150 minutos após o início da cirurgia), houve diferença estatisticamente significante entre os grupos (p=0,01). No final da cirurgia, a temperatura média dos grupos estudados foi igual, ou seja, 36,8o C, com diferença estatisticamente não significante (p=0,66). Os resultados da média da temperatura da sala de operação, nos diferentes períodos mensurados, não apresentaram diferença estatisticamente significante entre os grupos estudados. Em relação à umidade do ar da sala de operação, somente no período T120 (120 minutos após o início da cirurgia), os resultados evidenciaram diferença estatisticamente significante entre os grupos (p=0,03). O pré-aquecimento com o sistema de ar forçado aquecido não teve efeito na temperatura corporal de pacientes submetidas a cirurgias ginecológicas eletivas / Perioperative hypothermia is associated with various complications, such as an increased incidence of surgical site infection, cardiac arrhythmias, increased bleeding in the intraoperative period, and thermal discomfort of the patient in the post- anesthetic recovery room, among others. In the literature there is evidence that prewarming the body surface of the patient prior to induction of anesthesia is effective in reducing hypothermia, by lowering the temperature gradient between the central and peripheral compartments of the human organism. Thus, the objective of the present study was to evaluate the effects of prewarming on maintaining the body temperature of patients undergoing elective gynecological surgery. This is a randomized controlled clinical trial involving 86 patients undergoing elective gynecological surgery, randomized into two groups. In the admission room of the Surgical Center, participants in the experimental group (n=43) were warmed for 20 minutes using the forced air heating system (thermal blanket over the whole body), the equipment was turned on at a temperature of 38o C, and the control group (n = 43) were covered with a cotton sheet and blanket for the same period. During the intraoperative period, all patients were warmed using the forced air heating system (thermal blanket for the upper body). The tympanic temperature was measured using an infrared tympanic thermometer in the pre- and intraoperative periods. From the moment of each patient\'s entry into the operating room, the temperature and humidity of the air in the room were measured. The mean temperatures and humidity levels of the operating room, between the experimental and control groups, were analyzed using the Student t-test. The mean body temperatures between the experimental and control groups were analyzed using a linear mixed effects regression model. The descriptive analysis of data on the sociodemographic and clinical characteristics of the patients and the surgical anesthetic procedure demonstrated similarity between the experimental and control groups. After prewarming, the mean body temperature was 38o C in the experimental group and 37.8ºC in the control group, with no statistically significant difference (p = 0.27). At T150 (150 minutes after the start of surgery) there was no statistically significant difference between the groups (p = 0.01). At the end of surgery, the mean temperature of the studied groups was the same, i.e., 36.8o C, with no statistically significant difference between the groups (p = 0.66). The results of the mean operating room temperatures, in the different periods measured, presented no statistically significant differences between groups. In relation to the humidity of the operating room, the results demonstrated a statistically significant difference between groups (p = 0.03) only in the period T120 (120 minutes after the start of surgery). Prewarming with the forced air heating system had no effect on body temperature of patients undergoing elective gynecological surgery

A infecção de sítio cirúrgico (ISC) é uma complicação frequente que pode acometer o paciente submetido ao procedimento anestésico cirúrgico, acarretando o aumento da morbidade, mortalidade e dos custos hospitalares, bem como do sofrimento emocional e físico do paciente. Este estudo teve como objetivos estimar a incidência de ISC em pacientes submetidos à cirurgia abdominal, identificar as taxas de ISC segundo fatores relacionados ao paciente, ao procedimento anestésico cirúrgico e ao ambiente da sala cirúrgica, identificar os fatores de risco e de proteção, e identificar o efeito independente da hipotermia sobre a incidência de ISC. Para o alcance dos objetivos propostos, conduziu-se estudo de coorte com 484 pacientes submetidos à cirurgia abdominal. Para a coleta de dados elaborou-se instrumento, submetido à validação aparente e de conteúdo por cinco juízes. A coleta de dados foi realizada na unidade de internação ou na sala de recepção do centro cirúrgico, no período intraoperatório, no período de internação e reinternação, e no retorno no 30° dia após a cirurgia. A hipotermia foi avaliada a partir de três mensurações distintas, a saber: 1 - temperatura Delta; 2 - número de vezes em que a temperatura do paciente foi <36,0°C; 3 - tempo de exposição, em minutos, em que o paciente esteve submetido a temperaturas <36,0°C. A incidência bruta de ISC foi de 20,25% (98 casos). A incidência de ISC apresentou maior magnitude nos participantes do sexo feminino (22,43%), nos pacientes na faixa etária de 60 anos e mais (27,22%), e com obesidade classe II (25,71%). As médias de duração da anestesia e da cirurgia foram maiores no grupo com ISC, a incidência de ISC apresentou maior magnitude naqueles pacientes submetidos a cirurgias de porte III (85,71%) e anestesia combinada (41,10%). A incidência de ISC apresentou maior magnitude naquele participante que no final da cirurgia estava exposto à temperatura da sala de operação < 20°C (33,33%), e naqueles expostos à umidade do ar entre 45-55 kg/m3 (22,18%). Na mensuração 1 (modelo final), a hipotermia não apresentou relação causal com a ISC, e as variáveis classificação ASA, porte cirúrgico e tipo de anestesia permaneceram independentemente associadas à ISC. Na mensuração 2 (modelo final), identificou-se o efeito causal independente da hipotermia sobre a ISC, os pacientes que estiveram submetidos mais de cinco vezes a temperaturas <36,0°C apresentaram maior probabilidade (89%; RR=1,89) de desenvolverem ISC, as variáveis classificação ASA e tipo de anestesia mantiveram-se independentemente associadas à ISC. Na mensuração 3 (modelo final), também identificou-se o efeito causal independente da hipotermia sobre a ISC, os pacientes que estiveram submetidos a mais de 75 minutos a temperaturas <36,0°C apresentaram maior probabilidade (89%; RR=1,89) de desenvolverem ISC, as variáveis classificação ASA e tipo de anestesia permaneceram independentemente associadas à ISC. A raquianestesia foi fator de proteção independente para ISC, nos três modelos finais. Os resultados evidenciados poderão subsidiar a tomada de decisão dos profissionais de saúde na implementação de ações direcionadas para a prevenção e controle de ISC, com ênfase em medidas para a prevenção da hipotermia perioperatória / Surgical site infection (SSI) is a frequent complication that can affect the patient undergoing surgical anesthetic procedure, leading to increased morbidity, mortality and hospital costs, as well as emotional and physical suffering of the patient. This study aimed to estimate the incidence of SSI in patients undergoing abdominal surgery; to identify SSI rates according to factors related to the patient, to the surgical anesthetic procedure and to the operating room environment; to identify risk and protective factors; and to identify the independent effect of hypothermia on the incidence of SSI. To reach the proposed objectives, a cohort study was conducted with 484 patients undergoing abdominal surgery. An instrument was developed for data collection, and submitted to face and content validation by five judges. Data collection was performed in the inpatient care unit or in the surgical center reception room, during the intraoperative period, the hospitalization and readmission period, and on the 30th postoperative day. Hypothermia was evaluated from three different measurements: 1) delta temperature; 2) number of times the patient temperature was <36.0°C; 3) exposure time, in minutes, in which the patient was submitted to temperatures <36.0°C. The crude incidence of SSI was 20.25% (98 cases). The incidence of SSI presented higher magnitude in female participants (22.43%), in patients aged 60 years and over (27.22%), and with class II obesity (25.71%). The mean duration of anesthesia and surgery were higher in the SSI group, the SSI incidence was higher in patients undergoing surgery III (85.71%) and combined anesthesia (41.10%). The incidence of SSI presented higher magnitude in participants who were exposed, in the end of surgery, to temperature <20°C (33.33%) at the operating room; and in those exposed to air humidity between 45-55 kg/m3 (22, 18%). In the measurement 1 (final model), hypothermia did not present a causal relationship with SSI, and the variables ASA classification, surgical size and type of anesthesia remained independently associated with SSI. In the measurement 2 (final model), the independent causal effect of hypothermia on SSI was identified; patients who were submitted more than five times to temperatures <36.0°C were more likely (89%; RR=1.89) to develop SSI, the variables ASA classification and type of anesthesia remained independently associated with SSI. In the measurement 3 (final model), the independent causal effect of hypothermia on SSI was also identified; patients who were submitted to more than 75 minutes to temperatures <36.0°C were more likely (89%; RR = 1.89) to develop SSI, the variables ASA classification and type of anesthesia remained independently associated with SSI. Spinal anesthesia was an independent protective factor for SSI in the three final models. The found results may support the decision-making of health professionals in the implementation of actions directed to the prevention and control of SSI, with emphasis on measures for the prevention of perioperative hypothermia

A participação da COX-1 na inflamação sistêmica tem sido questionada. Nós investigamos os mecanismos pelos quais a COX-1 participa da inflamação sistêmica mais grave. O inibidor da COX-1 (SC-560) atenuou a hipotermia, o hipometabolismo e a hipotensão induzidos por LPS. Este efeito atenuante teve duas fases: 30-60 min e 60-100 min. Em animais esplenectomizados, o efeito do SC-560 foi observado apenas na primeira fase. O SC-560 não alterou o nível plasmático das citocinas TNF-&#945;, IL-1&#946; e IL-10 em ambas as fases. No entanto, reduziu a expressão de IL-10 no baço, com tendência a aumentar IL-1&#946; (80 min). Eicosanoides (PGE2, PGD2, PGF2, TXB2 e LTC4) foram detectados no baço e na circulação (80 min). Nossos resultados indicam que o mecanismo da COX-1 no choque endotóxico tem duas fases: (i) na fase inicial a COX-1 não é proveniente do baço e age independentemente de citocinas; (ii) na fase tardia da resposta a COX-1 parece agir de forma dependente do baço e através da produção de eicosanoides, independentemente de TNF-&#945;, mas modulando a síntese de IL-10 e IL-1&#946;. / The participation of COX-1 in systemic inflammation has been questioned. We investigated the mechanisms by which COX-1 participates in the most severe systemic inflammation. The COX-1 inhibitor (SC-560) attenuated the hypothermia, hypometabolism and hypotension induced by LPS. This attenuating effect had two phases: 30-60 min and 60-100 min. In splenectomized animals, the effect of SC-560 was observed only in the first phase. SC-560 did not alter the plasma levels of cytokines TNF-&#945;, IL-1&#946; and IL-10 in both phases. However, it reduced IL-10 expression in the spleen, with tendency to increase IL-1&#946; (80 min). Eicosanoids (PGE2, PGD2, PGF2, TXB2 and LTC4) were detected in spleen and circulation (80 min). Our results indicate that the mechanism of COX-1 in endotoxic shock has two phases: (i) COX-1 does not originate from the spleen and acts independently of cytokines; (ii) in the late phase the COX-1 it seems to act in a spleen-dependent manner and through the production of eicosanoids, independently of TNF-&#945;, but modulating the synthesis of IL-10 and IL-1&#946;.

A infecção de sítio cirúrgico (ISC) é uma complicação frequente que pode acometer o paciente submetido ao procedimento anestésico cirúrgico, acarretando o aumento da morbidade, mortalidade e dos custos hospitalares, bem como do sofrimento emocional e físico do paciente. Este estudo teve como objetivos estimar a incidência de ISC em pacientes submetidos à cirurgia abdominal, identificar as taxas de ISC segundo fatores relacionados ao paciente, ao procedimento anestésico cirúrgico e ao ambiente da sala cirúrgica, identificar os fatores de risco e de proteção, e identificar o efeito independente da hipotermia sobre a incidência de ISC. Para o alcance dos objetivos propostos, conduziu-se estudo de coorte com 484 pacientes submetidos à cirurgia abdominal. Para a coleta de dados elaborou-se instrumento, submetido à validação aparente e de conteúdo por cinco juízes. A coleta de dados foi realizada na unidade de internação ou na sala de recepção do centro cirúrgico, no período intraoperatório, no período de internação e reinternação, e no retorno no 30° dia após a cirurgia. A hipotermia foi avaliada a partir de três mensurações distintas, a saber: 1 - temperatura Delta; 2 - número de vezes em que a temperatura do paciente foi <36,0°C; 3 - tempo de exposição, em minutos, em que o paciente esteve submetido a temperaturas <36,0°C. A incidência bruta de ISC foi de 20,25% (98 casos). A incidência de ISC apresentou maior magnitude nos participantes do sexo feminino (22,43%), nos pacientes na faixa etária de 60 anos e mais (27,22%), e com obesidade classe II (25,71%). As médias de duração da anestesia e da cirurgia foram maiores no grupo com ISC, a incidência de ISC apresentou maior magnitude naqueles pacientes submetidos a cirurgias de porte III (85,71%) e anestesia combinada (41,10%). A incidência de ISC apresentou maior magnitude naquele participante que no final da cirurgia estava exposto à temperatura da sala de operação < 20°C (33,33%), e naqueles expostos à umidade do ar entre 45-55 kg/m3 (22,18%). Na mensuração 1 (modelo final), a hipotermia não apresentou relação causal com a ISC, e as variáveis classificação ASA, porte cirúrgico e tipo de anestesia permaneceram independentemente associadas à ISC. Na mensuração 2 (modelo final), identificou-se o efeito causal independente da hipotermia sobre a ISC, os pacientes que estiveram submetidos mais de cinco vezes a temperaturas <36,0°C apresentaram maior probabilidade (89%; RR=1,89) de desenvolverem ISC, as variáveis classificação ASA e tipo de anestesia mantiveram-se independentemente associadas à ISC. Na mensuração 3 (modelo final), também identificou-se o efeito causal independente da hipotermia sobre a ISC, os pacientes que estiveram submetidos a mais de 75 minutos a temperaturas <36,0°C apresentaram maior probabilidade (89%; RR=1,89) de desenvolverem ISC, as variáveis classificação ASA e tipo de anestesia permaneceram independentemente associadas à ISC. A raquianestesia foi fator de proteção independente para ISC, nos três modelos finais. Os resultados evidenciados poderão subsidiar a tomada de decisão dos profissionais de saúde na implementação de ações direcionadas para a prevenção e controle de ISC, com ênfase em medidas para a prevenção da hipotermia perioperatória / Surgical site infection (SSI) is a frequent complication that can affect the patient undergoing surgical anesthetic procedure, leading to increased morbidity, mortality and hospital costs, as well as emotional and physical suffering of the patient. This study aimed to estimate the incidence of SSI in patients undergoing abdominal surgery; to identify SSI rates according to factors related to the patient, to the surgical anesthetic procedure and to the operating room environment; to identify risk and protective factors; and to identify the independent effect of hypothermia on the incidence of SSI. To reach the proposed objectives, a cohort study was conducted with 484 patients undergoing abdominal surgery. An instrument was developed for data collection, and submitted to face and content validation by five judges. Data collection was performed in the inpatient care unit or in the surgical center reception room, during the intraoperative period, the hospitalization and readmission period, and on the 30th postoperative day. Hypothermia was evaluated from three different measurements: 1) delta temperature; 2) number of times the patient temperature was <36.0°C; 3) exposure time, in minutes, in which the patient was submitted to temperatures <36.0°C. The crude incidence of SSI was 20.25% (98 cases). The incidence of SSI presented higher magnitude in female participants (22.43%), in patients aged 60 years and over (27.22%), and with class II obesity (25.71%). The mean duration of anesthesia and surgery were higher in the SSI group, the SSI incidence was higher in patients undergoing surgery III (85.71%) and combined anesthesia (41.10%). The incidence of SSI presented higher magnitude in participants who were exposed, in the end of surgery, to temperature <20°C (33.33%) at the operating room; and in those exposed to air humidity between 45-55 kg/m3 (22, 18%). In the measurement 1 (final model), hypothermia did not present a causal relationship with SSI, and the variables ASA classification, surgical size and type of anesthesia remained independently associated with SSI. In the measurement 2 (final model), the independent causal effect of hypothermia on SSI was identified; patients who were submitted more than five times to temperatures <36.0°C were more likely (89%; RR=1.89) to develop SSI, the variables ASA classification and type of anesthesia remained independently associated with SSI. In the measurement 3 (final model), the independent causal effect of hypothermia on SSI was also identified; patients who were submitted to more than 75 minutes to temperatures <36.0°C were more likely (89%; RR = 1.89) to develop SSI, the variables ASA classification and type of anesthesia remained independently associated with SSI. Spinal anesthesia was an independent protective factor for SSI in the three final models. The found results may support the decision-making of health professionals in the implementation of actions directed to the prevention and control of SSI, with emphasis on measures for the prevention of perioperative hypothermia

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 54-58).

Background: Protection against cold is vitally important in prehospital trauma care to reduce heat loss and prevent body core cooling. Objectives: Evaluate the effect on cold stress and thermoregulation in volunteer subjects byutilising additional insulation on a spineboard (I). Determine thermal insulation properties of blankets and rescue bags in different wind conditions (II). Establish the utility of wet clothing removal or the addition of a vapour barrier by determining the effect on heat loss within different levels of insulation in cold and warm ambient temperatures (III) and evaluating the effect on cold stress and thermoregulation in volunteer subjects (IV). Methods: Aural canal temperature, sensation of shivering and cold discomfort was evaluated in volunteer subjects, immobilised on non-insulated (n=10) or insulated (n=9) spineboards in cold outdoor conditions (I). A thermal manikin was setup inside a climatic chamber and total resultant thermal insulation for the selected ensembles was determined in low, moderate and high wind conditions (II). Dry and wet heat loss and the effect of wet clothing removal or the addition of a vapour barrier was determined with the thermal manikin dressed in either dry, wet or no clothing; with or without a vapour barrier; and with three different levels of insulation in warm and cold ambient conditions (III). The effect on metabolic rate, oesophageal temperature, skin temperature, body heat storage, heart rate, and cold discomfort by wet clothing removal or the addition of a vapour barrier was evaluated in volunteer subjects (n=8), wearing wet clothing in a cold climatic chamber during four different insulation protocols in a cross-over design (IV). Results: Additional insulation on a spine board rendered a significant reduction of estimated shivering but there was no significant difference in aural canal temperature or cold discomfort (I). In low wind conditions, thermal insulation correlated to thickness of the insulation ensemble. In greater air velocities, thermal insulation was better preserved for ensembles that were windproof and resistant to the compressive effect of the wind (II). Wet clothing removal or the use of a vapour barrier reduced total heat loss by about one fourth in the cold environment and about one third in the warm environment (III). In cold stressed wet subjects, with limited insulation applied, wet clothing removal or the addition of a vapour barrier significantly reduced metabolic rate, increased skin rewarming rate, and improved total body heat storage but there was no significant difference in heart rate or oesophageal temperature cooling rate (IV). Similar effects on heat loss and cold stress was also achieved by increasing the insulation. Cold discomfort was significantly reduced with the addition of a vapour barrier and with an increased insulation but not with wet clothing removal. Conclusions: Additional insulation on a spine board might aid in reducing cold stress inprolonged transportations in a cold environment. In extended on scene durations, the use of a windproof and compression resistant outer cover is crucial to maintain adequate thermal insulation. In a sustained cold environment in which sufficient insulation is not available, wet clothing removal or the use of a vapour barrier might be considerably important reducing heat loss and relieving cold stress.

The presented studies were performed to investigate the effects of motion sickness (MS) on human autonomic and behavioural thermoregulatory mechanisms during cold stress and in a thermoneutral environment. The roles of histaminergic and cholinergic neuron systems in autonomic thermoregulation and MS-dependent dysfunction of autonomic thermoregulation were studied using a histamine-receptor blocker, dimenhydrinate (DMH), and a muscarine-receptor blocker, scopolamine (Scop). In addition, the effects of these substances on MS-induced nausea and perceptual thermoregulatory responses were studied. MS was found to lower core temperature, during cold stress by attenuation of cold-induced vasoconstriction and decreased shivering thermogenesis, and in a thermoneutral environment by inducing sweating and vasodilatation. The increased core cooling during cold stress was counteracted by DMH but not by Scop. In a thermoneutral environment, the temperature was perceived as uncomfortably warm during and after the MS provocation despite decreases in both core and skin temperature. No such effect was seen during cold-water immersion. Both pharmacologic substances had per se different effects on autonomic thermoregulatory responses during cold stress. Scop decreased heat preservation, but did not affect core cooling, while DMH reduced the rate of core cooling through increased shivering thermogenesis. Both DMH and Scop per se decreased thermal discomfort during cold-water immersion.Findings support the notion of modulating roles of histamine (H) and acetylcholine (Ach) in autonomic thermoregulation and during MS. MS activates cholinergic and histaminergic pathways, thereby increasing the levels of H and Ach in several neuro-anatomical structures. As a secondary effect, MS also elevates blood levels of several neuropeptides, which in turn would influence central and/or peripheral thermoregulatory responses.In conclusion, MS may predispose to hypothermia, by impairment of autonomic thermoregulation in both cold and thermoneutral environments and by modulation of behavioural thermoregulatory input signals. This might have significant implications for survival in maritime accidents. / <p>Medicine doktorsexamen</p>

Abstract Syftet med denna studie var att påvisa effekter av ofrivillig hypotermi samt beskriva anestesisjuksköterskans omvårdnadsåtgärder för att belysa vilka förebyggande faktorer som bibehåller normotermi i den perioperativa vården. Metod: Studien genomfördes som en litteraturöversikt. Artiklarna har sökts via Cinahl och Medline. Studiens resultat baserades på sjutton vetenskapliga artiklar med kvantitativ ansats, dessa grupperades under olika teman. Resultatet redovisas i följande huvudteman fysiologiska effekter, komplikationer, perioperativa teamet, aktiv uppvärmning, administrering av intravenösa vätskor, miljön i operationssalen samt riktlinjer för bibehållande av normotermi. Ofrivillig hypotermi i samband med ett kirurgiskt ingrepp ökade risken för komplikationer i form av ökad infektionsbenägenhet, påverkan på koagulationen med ökad blödningsrisk och hjärtpåverkan med risk för myocardischemi. Hypotermi påverkade också läkemedelsmetabolismen. Dessa effekter av ofrivillig hypotermi under den perioperativa vården orsakade patienten onödigt lidande, förlängd sjukhus vistelse och ökade kostnader för samhället.Slutsats: Anestesisjuksköterskans mest framgångsrika omvårdnadsåtgärder i den perioperativa fasen för att bibehålla normotermi var att använda aktiv uppvärmning, (värmetäcke) vätskevärmare och förhöjd rumstemperatur i operationssalen. Därigenom minskade värmeförlusten via strålning från patientens hud till omgivande miljö. Dessa omvårdnadsåtgärder förutsätter gott samarbete och ska vara självklara i det perioperativa teamet.