Patienter som genomgår laparoskopiska ingrepp sövs med anestesiläkemedel och behöver administration av intravenösa vätskor och inblåsning av koldioxidgas i bukhålan under operationen. Ju längre anestesitid och ju längre tid det laparoskopiska ingreppet tar desto större är risken att patienter drabbas av perioperativ hypotermi. Icke-invasiva och invasiva uppvärmningsmetoder visar kunna förebygga perioperativ hypotermin och de postoperativa komplikationer som associeras med hypotermiuppkomst vid laparoskopiska ingrepp.Syfte: Syftet är att beskriva omvårdnadsåtgärder som kan förebygga uppkomsten av perioperativ hypotermi och dess postoperativa komplikationer hos patienter som genomgår laparoskopisk kirurgi. Metod: En integrativ litteraturöversikt. Resultat: Studien visar att icke-invasiva och invasiva uppvärmningsåtgärder kan förebygga perioperativ hypotermi och minska de postoperativa komplikationerna associerade med hypotermi vid laparoskopisk kirurgi. Forcerad varmluftsbehandling visar sig vara den mest effektiva metoden för att förebygga perioperativ hypotermi. Andra icke-invasiva och invasiva värmebehandlingar är effektiva när de kombineras med varandra men inte när de administreras enskilt.Uppvärmningsmetoder visar sig förebygga uppkomst av hypotermi, bibehålla intraoperativ normotermi, öka komfort, minska postoperativa komplikationer vilket även leder till bättre återhämtning hos patienter som genomgår laparoskopisk kirurgi. Slutsats: Denna studie belyser att uppvärmnings åtgärder med invasiva och icke-invasiva uppvärmningsmetoder kan behandla och förebygga hypotermiuppkomst under den perioperativa perioden hos patienter som genomgår laparoskopisk kirurgi. Studien även visar att dessa uppvärmningsmetoder förebygger även de postoperativa komplikationer som associeras med perioperativ hypotermin vid laparoskopisk kirurgiuppkomst. / Patients undergoing laparoscopic procedures need anesthetics, intravenous fluids and insufflation of carbon dioxide gas during laparoscopic surgery. The larger the time of the anesthesia and the laparoscopic procedure is, the greater is the risk of the patients being affected by perioperative hypothermia. Non-invasive and invasive warming methods can prevent the onset of perioperative hypothermia during laparoscopic surgery. Purpose: The aim of the study is to describe the nursing interventions that can prevent the onset of perioperative hypothermia and its postoperative complications during laparoscopic surgery. Method: An integrative review. Result: The study indicates that non-invasive and invasive warming methods can prevent the onset of perioperative hypothermia and complications during laparoscopic surgery. Forced air warming turns out to be the most effective treatment to prevent perioperative hypothermia. Invasive and non-invasive warming treatments seem to be more effective in combination with each other to prevent perioperative hypothermia than when administered alone. These treatments prevent intraoperative hypothermia, maintain intraoperative normothermia, increase comfort, decrease postoperative complications and improve patient recovery after laparoscopic surgery. Conclusions: This study illustrates that non-invasive and invasive warming methods can treat and prevent the onset of perioperative hypothermia during laparoscopic surgery. The study even illustrates that these warming methods prevent the postoperative complications associated with perioperative hypothermia during laparoscopic surgery.

This thesis describes medical aspects of the expeditions of the Heroic Age of Antarctic exploration (1895-1922). It is divided into three sections. Section 1 describes the drugs and medical equipment taken to the Antarctic by these expeditions. There is an introductory discussion followed by papers on ophthalmic drugs, injections, inhalations and suppositories, oral drugs and topical preparations. Sledging medical cases are considered separately. Brandy was often used as a medicine and the medical uses of alcohol are described. Some expeditions took what were described as “medical comforts”. This term was sometimes used as a euphemism for alcoholic beverages but, in fact, encompassed a wide range of foods for invalids. Burroughs Wellcome and Co. supplied many of the expeditions with drugs and their medical chests. They used the expedition link in their advertising and the relationship between the expeditions and drug companies is described. Section 2 describes some of the medical problems encountered. The most serious problems were scurvy and a condition often called “polar anaemia”, which seems to be the same as a condition known at the time as “ship beriberi” and what is now described as “wet beriberi”. The controversy as to whether Captain Scott and his colleagues died of scurvy is also discussed. Other problems included frostbite and snow blindness. At least 11 general anaesthetics were given, including two for amputation of frostbitten toes. Psychological problems were common and there was some serious psychiatric illness including alcohol abuse. Section 3 describes the doctors and some of the research that they carried out. The most common research done by doctors was bacteriological. Most doctors collected biological data on the explorers including weights and haemoglobin measurements. This was largely for health monitoring but one doctor pursued physiological research. Three doctors and a medical student studied geology.

This thesis focuses on how physical and biological factors influence the outcome of exposures to γ/X-rays. That the dose rate changes during real life exposure scenarios is well-known, but radiobiological data from exposures performed at increasing or decreasing dose rates is lacking. In paper I, it was found that an exposure where the dose rate decreases exponentially induces significantly higher levels of micronuclei in TK6 cells than exposures at an increasing or constant dose rate. Paper II describes the construction and validation of novel exposure equipment used to further study this “decreasing dose rate effect”, which is described in paper III. In paper I we also observed a radioprotective effect when cells were exposed on ice. This “temperature effect” (TE) has been known for decades but it is still not fully understood how hypothermia acts in a radioprotective manner. This was investigated in paper IV, where a multiparametric approach was used to investigate the underlying mechanisms. In paper V the aim was to investigate the role of biomarkers and clinical parameters as possible risk factors for late adverse effects to radiotherapy (RT). This was studied in a rare cohort of head-and-neck cancer patients that developed mandibular osteoradionecrosis (ORN) as a severe late adverse effect of RT. Biomarker measurements and clinical factors were then subjected to multivariate analysis in order to identify ORN risk factors. The results suggest that the patient’s oxidative stress response is an important factor in ORN pathogenesis, and support the current view that patient-related factors constitute the largest source of variation seen in the frequency of late adverse effects to RT. In summary, this thesis provides new and important insights into the roles of biological and physical factors in determining the consequences of γ/X-ray exposures. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 5: Manuscript.</p>

Background:  Children going through surgery are likely to develop hypothermia caused by anesthesia, which can have severer consequences both peri and postoperatively. With increased understanding and knowledge regarding the correct methods for prevention, hypothermia caused by anesthesia in children can be reduced. This in turn, will lead to better and safer care. Aim: To describe the presence of hypothermia in children undergoing anesthesia. Also, this study will look at how the nurse anesthetists’ different interventions to preserve heat affect the occurrence of hypothermia. Methods: A descriptive retrospective study was performed. Medical records were reviewed to collect data. Results: The result showed that despite interventions to preserve heat were implemented, hypothermia caused by anesthesia still occurred during surgery. Gender, age and type of operation were factors that did not correlate with the presence of hypothermia. The length of surgery was shown to have some negative correlation with presence of hypothermia. Nursing interventions to preserve heat had no significant association with hypothermia. Conclusions: Nurse anesthetist used different combinations of interventions to preserve heat and reduce the risk for hypothermia in children. The majority of children obtained three or more different interventions aimed to preserve heat. Despite this, several children developed hypothermia during surgery. By increasing the nurse anesthetists’ knowledge and awareness regarding hypothermia caused by anesthesia, it can lead to improvement in providing safe care and reduce the number of cases where hypothermia occurs. Continued similar studies could lead to more person-centered care with personalized policies and amend the methods used regarding hypothermia caused by anesthesia. / Bakgrund: Barn som opereras löper stor risk att drabbas av anestesiinducerad hypotermi. Anestesiinducerad hypotermi kan leda till allvarliga konsekvenser både peri- och postoperativt för barnet.  Med ökad förståelse, kunskap och rätt metoder kan anestesiinducerad hypotermi reduceras och öka förutsättningar till en säker vård. Syfte: Att beskriva förekomsten av hypotermi vid rutinbarnanestesi. Ett annat syfte är att studera hur anestesisjuksköterskans olika värmebevarande omvårdnadsåtgärder associeras med uppkomsten av hypotermi. Metodbeskrivning: En deskriptiv retrospektiv journalgranskningsstudie genomfördes och 147 journaler granskades. Resultat: Studiens resultat påvisade att anestesiinducerad hypotermi förekom under operationsperioden även om värmebevarande åtgärder användes. Kön, ålder och typ av operation var inte associerade med förekomst av hypotermi. Operationstiden visade sig ha en svag negativ korrelation med förekomsten av hypotermi. Värmebevarande omvårdnadsåtgärder hade ingen signifikant association med hypotermi. Slutsats: Anestesisjuksköterskan använde olika kombinationer av värmebevarande åtgärder för att minska risken för utveckling av hypotermi hos patienterna. Majoriteten av barnen erhöll tre eller fler värmebevarande åtgärder. Trots det hade flera barn hypotermi under operationen. Att försöka öka kunskapen och medvetenheten hos anestesisjuksköterskan om anestesiinducerad hypotermi, dess risker och konsekvenser samt förebyggande åtgärder kan om möjligt leda till ökade förutsättningar för en säker vård och minskat antal patientfall där oavsiktlig hypotermi förekommer. Fortsatta liknande studier inom forskningen skulle möjligt kunna leda till mer personcentrerad vård med individanpassade riktlinjer, metoder, handlingsplaner gällande anestesiinducerad hypotermi.

Status epilepticus (SE) is a type of neurological injury characterized by continuous seizure activity and can lead to molecular and pathophysiological alterations leading to plasticity changes. SE can lead to the development of AE by the process of epileptogenesis, which is a phenomenon that describes the transformation of normal brain tissue into a hyperexcitable neuronal population. It has been demonstrated both in vivo and in vitro that calcium (Ca2+) dynamics are severely altered during and after SE, and these changes play a major role in the progression of epileptogenesis. It has also been reported that preventing the rise in intracellular Ca2+ ([Ca2+]i) immediately following injury (the Ca2+ plateau) prevents the plasticity changes and ultimate development of epilepsy. Currently, there are no treatments available that can be administered following an injury to prevent the development of AE. Therefore it is clinically important to develop a therapy that can be administered after an injury to block epileptogenesis. Hypothermia is a potential therapeutic intervention. Hypothermia is used clinically to provide neuroprotection following various neurological insults such as stroke and traumatic brain injury (TBI). However, no studies have been performed to evaluate the therapeutic potential of hypothermia following SE. Hypothermia provides protection via multiple mechanisms, one of which includes modulating excitotoxic neurotransmission. It is believed to reduce Ca2+ influx by reducing NMDA receptor activation. It is unclear how hypothermia affects Ca2+ through other modes of entry. This dissertation evaluates the effects of hypothermia on the Ca2+ plateau and demonstrates the novel finding that hypothermia induced post-SE blocks the development of the Ca2+ plateau and reduces the development of AE.

Perioperative hypothermia, defined as a core body temperature lower than 36řC, is associated with increased perioperative complications and prolonged hospitalization. The aim of this thesis is to analyze measures that are taken to prevent perioperative hypothermia at the Orthopedic Clinic of one Czech hospital and compare them with the current recommendations of the American Society of PeriAnesthesia Nurses, Association of Operating Room Nurses and the National Institute for Health and Care Excellence. The study included 223 patients who underwent a planned orthopedic surgery and who were more than 18 years old. As a method of data collection I chose studying the medical documentation. The obtained data were processed quantitatively. The recommended body temperature range 36.5-37.5řC before leaving an operating room had total of 60.55% of cases. Neither one patient has been no action in terms of prevention of hypothermia. Body temperature was taken in 22.4% of cases at the beginning of and during the surgery. Except for a cotton sheet, which was used in 100% of patients, no additional measures were taken in 18,4% of patients. Thermal insulation was used in 41,7% of patients, in-line warming system of infusion fluids in 65% of patients, forced air warming system in 17.9% of patients, and disposable...

Background: (Papers I and II) The objectives were to first determine incidence and contributing factors to cold-related injuries in northern Sweden, both those that led to hospitalization and those that led to fatality.  (Papers III and IV) A further aim was to assess post-cooling hand-rewarming responses and effects of training in a cold environment, both on fingertip rewarming and on function of the autonomic nervous system, to evaluate if there was adaptation related to prolonged occupational cold exposure. Methods:  In a retrospective analysis, cases of accidental cold-related injury with hospital admission in northern Sweden during 2000-2007 were analyzed (Paper I).  Cases of fatal hypothermia in the same region during 1992-2008 were analyzed (Paper II).  A cohort of volunteers was studied before and after many months of occupational cold exposure. Subject hand rewarming response was measured after a cold hand immersion provocation and categorized as slow, moderate or normal in rewarming speed.  This cold provocation and rewarming assessment was performed before and after their winter training.  (Paper III).  Heart rate variability (HRV) was analyzed from the same cold provocation/recovery sequences (Paper IV). Results:  (Paper I) For the 379 cases of hospitalization for cold-related injury, annual incidences for hypothermia, frostbite, and drowning were 3.4/100,000, 1.5/100,000, and 1.0/100,000 inhabitants, respectively.  Male gender was more frequent for all categories.  Annual frequencies for hypothermia hospitalizations increased during the study period.  Hypothermia degree and distribution of cases were 20 % mild (between 32 and 35ºC), 40% moderate (31.9 to 28ºC), and 24% severe (&lt; 28ºC), while 12% had temperatures over 35.0ºC.  (Paper II) The 207 cases of fatal hypothermia showed an annual incidence of 1.35 per 100,000 inhabitants, 72% in rural areas, 93% outdoors, 40% found within 100 meters of a building.  Paradoxical undressing was documented in 30%.  Ethanol was detected in femoral vein blood in 43%. Contributing co-morbidity was common including heart disease, previous stroke, dementia, psychiatric disease, alcoholism, and recent trauma.  (Paper III) Post-training, baseline fingertip temperatures and cold recovery variables in terms of final rewarming fingertip temperature and vasodilation time increased significantly in moderate and slow rewarmers.  Cold-related injury (frostbite) during winter training occured disproportionately more often in slow rewarmers (4 of the 5 injuries).  (Paper IV) At ‘pre- winter-training’, normal rewarmers had higher power for low frequency and high frequency heart rate variability.  After cold acclimatization (post-training), normal rewarmers showed lower resting power values for the low frequency and high frequency heart rate variability components.  Conclusions: Hypothermia and cold injury continues to cause injury and hospitalization in the northern region of Sweden.  Assessment and management is not standardized across hospitals.  With the identification of groups at high risk for fatal hypothermia, it should be possible to reduce the incidence, particularly for highest risk subjects; rural, living alone, alcohol-imbibing, and psychiatric diagnosis-carrying citizens.  Long-term cold-weather training may affect hand rewarming patters after a cold provocation, and a warmer baseline hand temperature with faster rewarming after a cold provocation may be associated with less general risk for frostbite.  Heart rate variability results support the conclusion that cold adaptation in the autonomic nervous system occurred in both groups, though the biological significance of this is not yet clear.

Uma das causas mais importantes de lesão encefálica em neonatos na atualidade é a anóxia neonatal. Este é um dos problemas mais graves e comuns nos serviços de perinatologia dos hospitais no mundo, sendo ainda pior em países subdesenvolvidos, devido à carência de precauções e cuidados requeridos. Há relativamente pouco tempo estudos têm indicado que a hipotermia promove um importante efeito neuroprotetor, podendo ser usada como tratamento alternativo promissor para danos causados pela anóxia neonatal. Porém, embora diversas pesquisas mostrem a ação neuroprotetora da hipotermia, não existem evidencias consistentes do seu papel preventivo em relação as alterações comportamentais decorrentes da anóxia neonatal. O objetivo deste trabalho foi avaliar se a hipotermia previne alterações comportamentais decorrentes da anóxia neonatal, incluindo funções de memória espacial, condicionamento aversivo e ansiedade. Foram incluídos no estudo 91 ratos Wistar machos organizados em 4 grupos: anóxia com hipotermia (AH), anóxia sem hipotermia (AC), controle (para anóxia) com hipotermia (CH) e controle sem hipotermia (CC). O protocolo de anóxia neonatal foi iniciado 24 horas após o nascimento dos ratos, usando uma câmara semi-hermética saturada com nitrogênio gasoso. A temperatura da câmera foi mantida a 37°C e o tempo de exposição à anóxia foi de 25 minutos. Animais controle para anóxia foram expostos à mesma câmera, exceto pelo nitrogênio que foi substituído por ar. O tratamento com hipotermia foi iniciado imediatamente após da anóxia em uma câmara a 30°C, onde os animais permaneceram durante 5 horas. O tratamento controle para hipotermia envolveu o mesmo protocolo, exceto pela temperatura da câmera que foi mantida a 37°C. No final do período, os neonatos foram colocados em uma câmara aquecida a 37°C por 40 minutos até se recuperarem. Quando os animais atingiram 70 dias de idade foram submetidos ao paradigma teste-reteste no labirinto em cruz elevado, para avaliar níveis de ansiedade, atividade locomotora e memória aversiva. Subsequentemente, quando os animais fizeram 75 dias, iniciou-se o teste de memória espacial no Labirinto Aquático de Morris. Finalmente, quando os animais atingiram 115 dias de idade, realizou-se o teste de condicionamento de medo ao som e ao contexto. A anóxia neonatal e a hipotermia não interferiram nos níveis de ansiedade no Labirinto em cruz elevado. Porém, a hipotermia aumentou a atividade locomotora e comportamentos de avaliação de risco. Os resultados obtidos no Labirinto Aquático de Morris indicam que a hipotermia previne prejuízos na memória espacial induzidos pela anóxia neonatal. Finalmente, a anóxia neonatal reduziu a taxa de extinção de memória aversivas, efeito que foi prevenido pela hipotermia. No conjunto, esses resultados mostram, por um lado, que a hipotermia previne alterações da memória espacial e de medo condicionado. Por outro lado, eles mostram que a hipotermia induz aumento da atividade locomotora e de comportamentos de avaliação de risco em ratos / Neonatal anoxia is one of the main causes of brain injury in newborns. This is among the most serious problems in many hospitals around the world and is even worse in developing countries due to the lack of required precautions and care. Recent studies have indicated that hypothermia promotes important neuroprotective effects. Thus, it could constitute a promising alternative treatment to dysfunctions caused by neonatal anoxia. Although there have been studies demonstrating that hypothermia promotes neuroprotection following neonatal anoxia, there is no solid evidence showing to which extent this neuroprotection prevents behavioral changes. This study aimed at evaluating to which extent behavioral changes induced by neonatal anoxia are prevented by hypothermia, focusing on anxiety, spatial memory and fear conditioning, in rats. The study included 91 male Wistar rats organized in 4 groups: anoxia with hypothermia (AH), anoxia without hypothermia (AC), control (for anoxia) with hypothermia (CH) and control without hypothermia (CC). Neonatal anoxia protocol started 24 hours after birth, using a semi-hermetic chamber saturated with nitrogen gas. The chamber temperature was maintained at 37°C and the time of exposure to anoxic conditions was 25 minutes. Hypothermia treatment started immediately after the anoxia protocol, within a chamber at 30°C, where the newborns remained for 5 hours. At the end of this period, newborns were transferred to a chamber at 37°C for 40 minutes until its recovery. Control treatment for anoxia involved the same protocol except for the nitrogen that was substituted for air. Control treatment for hypothermia involved to maintain the subjects in the same chamber at 37°C for 5 hours. When the animals were 70 days old, they were subjected to the elevated plus maze, in order to evaluate their anxiety, locomotor activity and aversive memory. Subsequently, when the animals were 75 days old, their spatial memory was evaluated in the Morris Water Maze. Finally, when the animals were 115 days old, they were subjected to an auditory and contextual fear conditioning task. Neonatal anoxia did not interfere with anxiety as evaluated in the elevated plus maze. In contrast, hypothermia by itself increased risk assessment behavior in the elevated plus maze. Performance in the Morris water maze task indicated that hypothermia prevents anoxia-induced disruption of spatial memory. Extinction of both auditory and contextual fear conditioning were slowed by anoxia, and this effect was prevented by hypothermia treatment. Therefore, the present experiments show that hypothermia prevents anoxia-induced (1) disruption of spatial memory and (2) slowing of extinction of fear conditioning; however, by itself, hypothermia increases risk assessment, in rats

A prevenção da hipotermia do paciente cirúrgico é um desafio para o enfermeiro. Na literatura há diferentes medidas que podem ser implementadas para a manutenção da temperatura corporal do paciente no perioperatório, salientamos os sistemas de aquecimento cutâneo. O presente estudo teve como objetivo avaliar as evidências disponíveis na literatura sobre qual é o sistema de aquecimento cutâneo mais eficaz para a prevenção da hipotermia, no paciente submetido à cirurgia cardíaca sem circulação extracorpórea, no período intra-operatório. O método de revisão adotado foi a revisão sistemática. As bases de dados PubMed, Cinahl, Embase, Central e Lilacs foram selecionadas para a busca dos estudos primários. Os descritores controlados e não controlados foram delimitados para cada uma das bases de dados. Dos 1.604 estudos localizados e considerando os critérios de inclusão e exclusão adotados, 25 estudos foram selecionados e oito foram incluídos na revisão sistemática. Dos oito estudos primários incluídos, quatro ensaios clínicos testaram o sistema de ar forçado aquecido e o sistema de circulação de água aquecida, sendo que em um destes estudos, a cobertura elétrica de fibra de carbono também foi estudada. Em dois ensaios clínicos, os autores investigaram o sistema de ar forçado aquecido e o sistema de transferência de energia com dispositivos adesivos. Em um ensaio clínico, o sistema de ar forçado aquecido e o sistema Thermogard foram estudados e um estudo primário investigou o pré-aquecimento, na indução anestésica, com o sistema de ar forçado aquecido. Os resultados evidenciados apontaram que o sistema de circulação de água aquecida é o mais eficaz para a manutenção da temperatura corporal do paciente submetido à revascularização do miocárdio sem circulação extracorpórea em comparação ao sistema de ar forçado aquecido. Em relação aos outros sistemas de aquecimento cutâneo há necessidade de novas pesquisas para determinar a eficácia destes em cirurgia cardíaca. A adoção de medidas para a prevenção da hipotermia é de responsabilidade de todos os profissionais que prestam cuidado ao paciente cirúrgico; entretanto, ressaltamos a atuação do enfermeiro perioperatório. Compete a esse profissional o planejamento e implementação de intervenções direcionadas para a melhoria da qualidade do cuidado de enfermagem e promovam a segurança do paciente. / Hypothermia prevention in surgical patients represents a challenge of nurses. Literature discusses different measures that can be put in practice to maintain patients\' perioperative body temperature, among which we highlight cutaneous warming systems. This study aimed to assess available evidence in literature on the most effective cutaneous warming system for hypothermia prevention in patients submitted to cardiac surgery without extracorporeal circulation, during the intraoperative period. The systematic review method was adopted. The databases PubMed, Cinahl, Embase, Central and Lilacs were selected to seek primary studies. Controlled and non-controlled descriptors were delimited for each of the databases. Out of 1,604 studies that were located, in view of the adopted inclusion and exclusion criteria, 25 were selected and eight included in the systematic review. Out of eight primary studies included, four clinical trials tested the forced-air warming system and the circulating-water garment system. In one of these, the carbon fiber resistive heating blanket was also studied. In two clinical trials, the authors investigated the forced-air warming system and the energy transfer pads system. In one clinical trial, the forced-air warming system and the Thermogard system were studied, and one primary study investigated prewarming during induced anesthesia, using the forcedair warming system. The evidenced results appointed that the circulating-water garment system is the most effective to maintain the body temperature of patients submitted to coronary artery bypass graft surgery without extracorporeal circulation in comparison with the forced-air warming system. As for other cutaneous warming systems, further research is needed to determine their efficacy in case of cardiac surgery. All professionals who deliver care to surgical patients are responsible for the adoption of hypothermia prevention measures; nevertheless, perioperative nurses\' actions are highlighted. These professionals are responsible for planning and putting in practice interventions aimed at improving nursing care quality and enhancing patient safety.

INTRODUÇÃO: A hipotermia é um fator de risco independente no aumento da mortalidade em recém-nascidos pré-termos muito baixo peso (RNPTs MBP). A prática de envolver o corpo do RNPT MBP em película de polietileno ou saco plástico durante a reanimação neonatal após o nascimento é uma medida recomendada visando prevenir a hipotermia neonatal. É necessário avaliar o impacto da introdução dessa prática sobre a estabilidade térmica do RNPT MBP nas primeiras 24 horas de vida. OBJETIVO: Comparar a variação da temperatura corporal nas primeiras 24 horas de vida de RNPTs MBP envoltos e não em saco plástico durante a reanimação neonatal ao nascimento. MÉTODO: Estudo longitudinal com coleta retrospectiva de dados de prontuários. Foram analisados prontuários de 282 RNs com idade gestacional menor que 33 semanas ou peso inferior a 1500 gramas, nascidos no período de 2004 a 2007 e 2009 a 2012, respectivamente antes e após a introdução da prática de envolver o RNPT MBP em saco plástico no Hospital Universitário da Universidade de São Paulo. A análise estatística das variáveis maternas, perinatais, neonatais e a variável dependente, temperatura corpórea do RN nas primeiras 24 horas de vida e ocorrência de hipotermia foram relacionadas às variáveis de exposição e ao grupo de RNPT MBP envolto em saco plástico (ESP) ou não envolto em saco plástico (NESP). A existência de associação entre as variáveis independentes e dependente foi determinada para as variáveis nominais com o teste Qui-quadrado e Exato de Fisher e teste t de Student para as variáveis discretas. As variáveis contínuas foram analisadas com o teste ANOVA. Para analisar a existência de relação entre variável de exposição e ocorrência de hipotermia neonatal em diferentes períodos de aferição da temperatura nas primeiras 24 horas de vida, foi utilizado o teste de Breslow-Day-Tarone. O teste de Cochran-Mantel-Haenszel foi empregado para analisar a existência de associação entre hipotermia e uso do saco plástico controlado pelo intervalo de aferição da temperatura corpórea. A estimativa da razão de chance de ocorrer hipotermia entre os recém-nascidos que foram envoltos em saco plástico foi obtida mediante o uso de teste de Mantel-Haenszel Common Odds Ratio Estimate. Foi adotado nível de significância estatística de p < 0,05 e intervalo de confiança de 95%. O projeto de pesquisa recebeu aprovação do Comitê de Ética e Pesquisa da instituição campo do estudo. RESULTADOS: Houve distribuição homogênea entre os grupos NESP e ESP quanto às variáveis maternas, perinatais e neonatais com exceção da idade gestacional e do peso do RN ao nascimento, com média de idade do grupo NESP de 29,29 semanas e do ESP de 27,79 semanas, p=0,000; médias de peso ao nascimento dos grupos NESP e ESP, respectivamente, de 1287,47 gramas e 1115,29 gramas, p=0,000. As médias das temperaturas dos RNPTs MBP apresentaram diferenças significativas ao longo das primeiras 24 horas de vida para ambos os grupos, sendo p=0,000, e na comparação dos grupos NESP e ESP, de p=0,002. A evolução da temperatura ao longo das primeiras 24 horas não foi igual nos dois grupos (p = 0,032). Não se encontrou associação entre o uso do saco plástico e a idade gestacional com relação à hipotermia, p=0,772, mas no grupo de RN com idade gestacional até 28 semanas envoltos em saco plástico a prevalência de hipotermia ao longo das primeiras 24 horas de vida foi menor em comparação ao grupo não envolto em saco plástico (p = 0,009). A evolução da temperatura também não foi igual quando da análise dos grupos NESP e ESP com até 28 semanas, sendo as médias das temperaturas do ESP maiores, p=0,028. A variável peso ao nascimento apresentou relação estatística significante com a ocorrência de hipotermia, p = 0,000, OR = 0,999 [IC 95%, 0,999 0,999]. CONCLUSÕES: O uso do saco plástico não mostrou mais efetividade na prevenção de hipotermia em RNPT com idade gestacional entre 29 e 32 semanas, porém nos com idade menor que 28 semanas houve menor prevalência de hipotermia nas primeiras 24 horas de vida, indicando efeito benéfico do uso de saco plástico. Os resultados indicam que apesar da implementação da prática de envolver os RNPTs MBP em saco plástico, medidas complementares necessitam ser adotadas na prevenção da hipotermia nas primeiras 24 horas de vida do RN. / BACKGROUND: Hypothermia is an independent risk factor for increased mortality in very low birth weight preterm infants (VLBWPI). The practice of involving the body of VLBWPI in polyethylene film or plastic bag during neonatal resuscitation after birth is a recommended measure to prevent neonatal hypothermia. It is necessary to evaluate the impact of the implementation of this practice on the thermal stability of VLBWPI within the first 24 hours of life. OBJECTIVE: To compare the variation of VLBWPI body temperature in the first 24 hours of life of wrapped (WPG) and non-wrapped in plastic bag (NWPG) during neonatal resuscitation at delivery room. METHODS: A longitudinal study with retrospective collection data. It was analyzed 282 medical records of preterm infants with gestational age less than 33 weeks or birth weight less than 1500 grams, born from 2004 to 2007 and from 2009 to 2012, respectively before and after the implementation of the practice of wrapping the VLBWPI in plastic bag at the University of Sao Paulo University Hospital. Statistical analysis of maternal, perinatal and neonatal variables and the dependent variable, VLBWPI body temperature within the first 24 hours of life and occurrence of hypothermia were related to the exposure variables - group of VLBWPI (WPG) or group of not wrapped in plastic bag (NWPG). The existence of an association between the independent and dependent variables were analyzed, and for nominal variables, the chi-square test was used and Fisher\'s exact and Student\'s t test were used to analyze discrete variables. Continuous variables were analyzed with ANOVA. To analyze the relationship between the independent variable and the occurrence of neonatal hypothermia in different periods of body temperature measures in the first 24 hours of life, was used the test of Breslow-Day-Tarone. To analyze the association between hypothermia and use of plastic bag controlled by body temperature measurement range, it was used the Cochran-Mantel-Haenszel test. The estimated ratio of hypothermia occurrence among infants were wrapped in plastic bags was obtained by the test of Mantel-Haenszel Common Odds Ratio Estimate. The statistical significance level adopted was < 0.05 and confidence interval 95%. The University of Sao Paulo School of Nursing and University Hospital Research Ethics Committee approved the research project. RESULTS: There were homogeneous distributions between the WPG and NWPG regarding maternal, perinatal and neonatal variables except for gestational age and birth weight, mean gestational age for NWPG 29.29 weeks and for WPG, 27.79 weeks, p=0.000; mean birth weight for NWPG and WPG, respectively 1287.47 grams and 1115.29 grams, p=0.000. The mean body temperature showed significant differences over the first 24 hours of life for both groups, p=0.000 and when compare NWPG with WPG, p=0.002. The evolution of the body temperature throughout the first 24 hours was not similar for both groups, p=0.032. There was no association between the use of plastic bag and gestational age with occurrence of hypothermia, p= 0.772, but in the group of VLBWPI with gestational age up to 28 weeks wrapped in plastic bag (WPG) the prevalence of hypothermia over the first 24 hours of life was lower compared to the NWPG with same gestational age, p = 0.009. The evolution of the body temperature also was not equal when it examined the NWPG and WPG of up to 28 gestational weeks, the mean temperature of WPG was higher, p=0.028. The variable birth weight showed a statistically significant relationship with the occurrence of hypothermia , p = 0.000 , OR = 0.999 [95% CI , 0.999 to 0.999 ] . CONCLUSIONS: The use of plastic bag not shown to be more effective for preventing hypothermia in VLBWPI, with gestational age between 29 to 32 weeks, but for those up 28 weeks the hypothermia prevalence was in the first 24 hours of life, indicating a beneficial effect of wrapping them in the plastic bag during the neonatal resuscitation at birth. The results indicate that although the practical implementation of involving VLBWPI in a plastic bag, additional measures need to be adopted in the prevention of hypothermia in the first 24 hours of life of the newborn