O enfermeiro e a utilização do cateter central de inserção periférica em recém-nascidos: contribuições à luz da segurança e bioética

Esta pesquisa teve como objeto de estudo a segurança do recém-nascido no processo de utilização do Cateter Central de Inserção Periférica (PICC) e, como objetivos: conhecer o significado de segurança para o enfermeiro no processo de utilização do PICC em recém-nascidos; descrever os cuidados prestados pelo enfermeiro no uso do PICC em recém-nascidos e analisar os nexos entre segurança e os princípios bioéticos no uso do PICC em recém-nascidos na prática assistencial dos enfermeiros. Trata-se de um estudo descritivo de abordagem qualitativa. O cenário foi a unidade de terapia intensiva neonatal de um Hospital Universitário localizado no município do Rio de Janeiro e os sujeitos, 11 enfermeiros plantonistas capacitados e que realizam a implantação do PICC em recém-nascidos. Para a coleta de dados realizou-se a entrevista semiestruturada, gravada em fita cassete, entre os meses de março e junho de 2012. Posteriormente estas foram transcritas e analisadas por meio da análise de conteúdo de Bardin, na modalidade temática e interpretada à luz dos princípios bioéticos e da segurança do paciente. Como resultados emergiram 04 categorias: Técnicas e Procedimentos, Cuidados com o recém-nascido, Aspectos relacionados à equipe e Aspectos relacionados à família. Para os enfermeiros, segurança no processo de utilização do PICC no recém-nascido, significa saber indicar o uso deste dispositivo de acordo com as peculiaridades de cada criança. Exercer cuidados antes, durante e após o uso do cateter, valorizar os cuidados técnicos relacionados ao procedimento, possuir conhecimento teórico-prático e ter disponibilidade de recursos materiais e humanos para desenvolver um cuidado seguro. Além de atentar para os registros e protocolos da unidade acerca desta prática assistencial. Para preservar a segurança do neonato, compreendem ser necessária a tomada de decisão em conjunto com o médico acerca do momento ideal para se implantar este dispositivo, bem como a escolha do tipo ideal de sedação para o mesmo, dentre outros aspectos. No processo de utilização do PICC, os enfermeiros entendem a manutenção da temperatura corporal, a realização de medidas de conforto perante a dor, a prevenção de infecções e o posicionamento adequado do recém-nascido durante o procedimento, como atitudes essenciais para a promoção de sua segurança. Buscam, também, esclarecer os pais quanto ao procedimento que será realizado com seu filho. Conclui-se que o enfermeiro, no que diz respeito à prática do PICC, atua de acordo com os princípios bioéticos de beneficência e não-maleficência, já que realiza sua assistência visando o bem-estar do neonato, procurando minimizar os desconfortos associados a esse procedimento. Apesar de esclarecerem os pais quanto ao procedimento que será realizado com seu filho, alguns enfermeiros, não os consultam previamente acerca da autorização para implantação deste dispositivo infringindo, assim, o princípio bioético da autonomia.

Liver genomic responses to ciguatoxin: evidence for activation of Phase I and Phase II detoxification pathways following an acute hypothermic response in mice

Ciguatoxins (CTX) are polyether neurotoxins that target voltage-gated sodium channels and are responsible for ciguatera, the most common fish-borne food poisoning in humans. This study characterizes the global transcriptional response of mouse liver to a symptomatic dose (0.26 ng/g) of the highly potent Pacific ciguatoxin-1 (P-CTX-1). At 1 h post-exposure 2.4% of features on a 44K whole genome array were differentially expressed (p ≤ 0.0001), increasing to 5.2% at 4 h and decreasing to 1.4% by 24 h post-CTX exposure. Data were filtered (|fold change| ≥ 1.5 and p ≤ 0.0001 in at least one time point) and a trend set of 1550 genes were used for further analysis. Early gene expression was likely influenced prominently by an acute 4°C decline in core body temperature by 1 h, which resolved by 8 h following exposure. An initial downregulation of 32 different solute carriers, many involved in sodium transport, was observed. Differential gene expression in pathways involving eicosanoid biosynthesis and cholesterol homeostasis was also noted. Cytochrome P450s (Cyps) were of particular interest due to their role in xenobiotic metabolism. Twenty-seven genes, mostly members of Cyp2 and Cyp4 families, showed significant changes in expression. Many Cyps underwent an initial downregulation at 1 h but were quickly and strongly upregulated at 4 and 24 h post-exposure. In addition to Cyps, increases in several glutathione S-transferases were observed, an indication that both phase I and phase II metabolic reactions are involved in the hepatic response to CTX in mice.

Polylactide-based polyurethane and its shape-memory behavior

A series of polylactide polyurethanes (PLAUs) were synthesized from poly(L-lactide) diols, hexamethylene diisocyanate (HDI), and 1,4-butanediol (BDO). Their thermal and mechanical properties and shape-memory behavior were studied by infrared spectroscopy (IR), differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXID), tensile testing, and thermal mechanical analysis (TMA). The T(g)s of these polymers were in the range of 33-53 degrees C, and influenced by the Mn of the PLA diol and the ratio of the soft-segment to the hard-segment. These materials can restore their shapes almost completely after 150% elongation or twofold compression. By changing the M-n of the PLA diol and the ratio of the hard-to-soft-segment, their Ts and shape-recovery temperatures can be adjusted to the neighborhood of the body temperature. Therefore, these PLAUs are expected to find practical medical applications.

高原鼠兔(Ochotona curzoniae)在生长发育过程中体温、热代谢和褐色脂肪组织(BAT)的变化

本文研究了栖息在高寒地区的高原鼠兔(Ochotona curzoniae)的体温、热代谢和肩胛部BAT随个体发育的变化，讨论了高原鼠兔热代谢发育特征及发育策略。结果表明新生个体具有初步的热调节能力，但环境温度变化时，还不能维持稳定的体温。体重为12.5克的幼体（约1－3日龄），其最低代谢离为3.028(mlO_2/g·h)，相对于Kleiber期望值的百分率为167％，热传导率为0.518(mlO_2/g·h· ℃)，相对于Bradley-Deavers期望值的百分率为200％，热中性区下临界温度为32.7 ℃。随着个体的发育，最低代谢率趋于下降，但其相对于Kleiber期望值的百分率在体重增长到大约90克前，趋于增加，其后才略有下降，热传导率及其相对于Bradley-Deavers期望值的百分率和热中性区的下临界温度随个体的发育趋于降低。所以在各环境温度下，高原鼠兔的体温随着个体发育表现出上升的变化。高原鼠兔BAT在整个发育时期都存在。刚出生时BAT发达，相对重量高，结构成熟，BAT细胞充满小而多的脂肪滴，线粒分布致密。随着个体发育，BAT相对重量和水分含量均迅速降低，结构呈退化趋势。高原鼠兔幼体主要利用小气候环境和BAT产热抵抗低温压力，高原鼠兔热调节发育的特征和对小气候环境的利用有利于减少体温调节耗能，促进生长发育。而发育到成体时，最低代谢率和热传导率对其期望值的偏离反映出高原鼠兔对西息环境的适应。另外，高原鼠兔通过行为热调节对生理调节加以补充。

Association of fever and severe clinical course in bronchiolitis

Little attention has been given to the relation between fever and the severity of bronchiolitis. Therefore, the relation between fever and the clinical course of 90 infants (59 boys, 31 girls) hospitalised during one season with bronchiolitis was studied prospectively. Fever (defined as a single recording > 38.0°C or two successive recording > 37.8°C) was present in 28 infants. These infants were older (mean age, 5.3 v 4.0 months), had a longer mean hospital stay (4.2 v2.7 days), and a more severe clinical course (71.0%v 29.0%) than those infants without fever. Radiological abnormalities (collapse/consolidation) were found in 60.7% of the febrile group compared with 14.8% of the afebrile infants. These results suggest that monitoring of body temperature is important in bronchiolitis and that fever is likely to be associated with a more severe clinical course and radiological abnormalities.

The energetics of huddling in two species of mole-rat (Rodentia: Bathyergidae)

Small rodents with a large surf ace-area-to-volume ratio and a high thermal conductance are likely to experience conditions where they have to expend large: amounts of energy in order to maintain a constant body temperature at low ambient temperatures. The survival of small rodents is thus dependent on their ability to reduce heat loss and increase heat production at low ambient temperatures. Two such animals are the social subterranean rodents Cryptomys damarensis (the Damaraland mole-rat) and Cryptomys hottentotus natalensis (the Natal mole-rat). This study examined the energy savings associated with huddling as a behavioural thermoregulatory mechanism to conserve energy in both these species. Individual oxygen consumption (VO2) was measured in groups ranging in size from one to 15 huddling animals for both species at ambient temperatures of 14, 18, 22, 26 and 30 degrees C. Savings in energy (VO2) were then compared between the two species. Significant differences in VO2 (p

Seasonal acclimatization of non-shivering thermogenesis in common spiny mice (Acomys cahirinus) from different habitats

We compared non-shivering thermogenesis between two adjacent populations of freshly captured common spiny mice (Acomys cahirinus) during both winter and summer. Mice were captured from north- and south-facing slopes (NFS and SFS) of the same valley that represent 'Mediterranean' and 'Desert' habitats, respectively. Oxygen consumption and body temperature responses to an injection of exogenous noradrenaline (NA) were higher during the winter than during the summer. in addition, SFS mice had a lower body temperature response to NA during the summer than the other groups of mice. This suggests that heat dissipation is likely to have been greatest in SFS mice during the summer. Overall this study shows that seasonal acclimatization of NST mechanisms is an important trait for small mammals that inhabit the Mediterranean ecosystem. Differences in physiological capabilities can occur temporally within populations across seasons, and spatially between populations that are only a short distance (200-500 m) apart.

Non-shivering thermogenesis in common spiny mice Acomys cahirinus from adjacent habitats: response to seasonal acclimatization and salinity acclimation

1. We compared resting metabolic rate (RMR) and non-shivering thermogenesis (NST) values between founder and F1-populations of winter-acclimatized Acomys cahirinus that originated from north- and south-facing slopes (NFS and SFS) of the same valley, representing mesic and xeric habitats. 2. NST was measured by the increase in oxygen consumption (VO2) and body temperature (T-b) after a noradrenaline (NA) injection (VO2 NA, TbNA). 3. Body mass and TbNA values were higher in SFS F1-mice, while RMR and VO2 NA values were higher in NFS F1-mice. Differences were not apparent in founders. 4. Results are consistent with NFS and SFS mice being considered as

Resting energy expenditure in non-ventilated, non-sedated patients recovering from serious traumatic brain injury: Comparison of prediction equations with indirect calorimetry values

Background & aims: Little is known about energy requirements in brain injured (TBI) patients, despite evidence suggesting adequate nutritional support can improve clinical outcomes. The study aim was to compare predicted energy requirements with measured resting energy expenditure (REE) values, in patients recovering from TBI.

Methods: Indirect calorimetry (IC) was used to measure REE in 45 patients with TBI. Predicted energy requirements were determined using FAO/WHO/UNU and Harris–Benedict (HB) equations. Bland– Altman and regression analysis were used for analysis.

Results: One-hundred and sixty-seven successful measurements were recorded in patients with TBI. At an individual level, both equations predicted REE poorly. The mean of the differences of standardised areas of measured REE and FAO/WHO/UNU was near zero (9 kcal) but the variation in both directions was substantial (range 591 to þ573 kcal). Similarly, the differences of areas of measured REE and HB demonstrated a mean of 1.9 kcal and range 568 to þ571 kcal. Glasgow coma score, patient status, weight and body temperature were signi?cant predictors of measured REE (p < 0.001; R²⁼ 0.47).

Conclusions: Clinical equations are poor predictors of measured REE in patients with TBI. The variability in REE is substantial. Clinicians should be aware of the limitations of prediction equations when estimating energy requirements in TBI patients.

Insights into torpor and behavioural thermoregulation of the endangered Juliana's golden mole

The cryptic, subterranean ways of golden moles (Chrysochloridae) hamper studies of their biology in the field. Ten species appear on the IUCN red list, but the dearth of information available for most inhibits effective conservation planning. New techniques are consequently required to further our understanding and facilitate informed conservation management decisions. We studied the endangered Juliana's golden mole Neamblysomus julianae and aimed to evaluate the feasibility of using implantable temperature sensing transmitters to remotely acquire physiological and behavioural data. We also aimed to assess potential body temperature (T-b) fluctuations in relation to ambient soil temperature (T-a) in order to assess the potential use of torpor. Hourly observations revealed that T-b was remarkably changeable, ranging from 27 to 33 degrees C. In several instances T-b declined during periods of low T-a. Such 'shallow torpor' may result in a daily energy saving of c. 20%. Behavioural thermoregulation was used during periods of high T-a by selecting cooler microclimates, while passive heating was used to raise T-b early morning when T-a was increasing. In contrast to anecdotal reports of nocturnal patterns of activity, our results suggest that activity is flexible, being primarily dependent on T-a. These results exemplify how behavioural patterns and microclimatic conditions can be examined in this and other subterranean mammal species, the results of which can be used in the urgently required conservation planning of endangered Chrysochlorid species.

Hibernation and non-shivering thermogenesis in the Hottentot golden mole (Amblysomus hottentottus longiceps)

Although heterothermy (hibernation and torpor) is a common feature among mammals, there is debate over whether it is a derived or ancestral trait relative to endothermic homeothermy. Determination of the physiological characteristics of primitive mammals is central to understanding the evolution of endothermy. Moreover, evaluation of physiological mechanisms responsible for endothermic heat production [e.g. non-shivering thermogenesis (NST)] is key to understanding how early mammals responded to historical climate changes and colonised different geographical regions. Here we investigated the capacity for NST and heterothermy in the Hottentot golden mole, a basal eutherian mammal. NST was measured as the metabolic response to injections of noradrenalin and heterothermy by recording body temperature in free-ranging animals. We found that hibernation and torpor occurred and that the seasonal phenotypic adjustment of NST capacity was similar to that found in other placental mammals. Using phylogenetically independent contrasts, we compared measured values of NST with those obtained from the literature. This showed that all variation in NST was accounted for by differences in phylogeny and not zoogeography. These findings lend support to the observation that NST and heterothermy occur in the Afrotheria, the basal placental mammalian clade. Furthermore, this work suggests that heterothermy, rather than homeothermy is a plesiomorphic trait in mammals and supports the notion that NST mechanisms are phylogenetically ancient.

Transmission characteristics of a vaginally-worn UHF radio telemeter

A vaginally-worn temperature telemeter may be used by women to chart their basal body temperature for ovulation detection. The telemeter uses a temperature to pulse width converter to key a Colpitts oscillator which is controlled in frequency by a 418 MHz SAW resonator. The circuit’s tank inductor acts as a compact, multi-turn loop antenna with a radiated power in isolation of around 1 uW. The transmission characteristics of the system are affected by the proximity of the human body, which acts as an electrically-large lossy dielectric. The RF link-budget must allow for the reduction in total emitted power, directional body-induced fading, and polarization effects. The polar power patterns of the telemeter were measured for both isolated and in-situ cases, using horizontal and vertical polarization. The power patterns were numerically integrated to determine relative emitted power, and a reference dipole used to determine the emitted power for the isolated device. In isolation the telemeter radiation is vertically polarized and isotropic in nature. With the telemeter in-situ, total body absorption was found to be over 20 dB, with directional fades of up to 40 dB; there was extensive cross-polarization, with up to 60% of radiated power horizontally polarized. With limited radiated power and directional fading, the operating range for the telemeter is limited to single room operation (less than 10m). The majority of RF radiation is absorbed by the body, but the radiation hazard is negligible due to the low power level of the device. The high level of cross-polarization suggests that either horizontal or vertically polarized base-station antennas may be used.

The sympathetic release test: a test used to assess thermoregulation and autonomic control of blood flow

When a subject is heated, the stimulation of temperature-sensitive nerve endings in the skin, and the raising of the central body temperature, results in the reflex release of sympathetic vasoconstrictor tone in the skin of the extremities, causing a measurable temperature increase at the site of release. In the sympathetic release test, the subject is gently heated by placing the feet and calves in a commercially available foot warming pouch or immersing the feet and calves in warm water and wrapping the subject in blankets. Skin blood flow is estimated from measurements of skin temperature in the fingers. Normally skin temperature of the fingers is 65-75 degrees F in cool conditions (environmental temperature: 59-68 degrees F) and rises to 85-95 degrees F during body heating. Deviations in this pattern may mean that there is abnormal sympathetic vasoconstrictor control of skin blood flow. Abnormal skin blood flow can substantially impair an individual's ability to thermoregulate and has important clinical implications. During whole body heating, the skin temperature from three different skin sites is monitored and oral temperature is monitored as an index of core temperature. Students determine the fingertip temperature at which the reflex release of sympathetic activity occurs and its maximal attainment, which reflects the vasodilating capacity of this cutaneous vascular bed. Students should interpret typical sample data for certain clinical conditions (Raynaud's disease, peripheral vascular disease, and postsympathectomy) and explain why there may be altered skin blood flow in these disorders.

Environmental Challenges and Physiological Solutions: Comparative Energetic Daily Rhythms of Field Mice Populations from Different Ecosystems

Daily and seasonal variations in physiological characteristics of mammals can be considered adaptations to temporal habitat variables. Across different ecosystems, physiological adjustments are expected to be sensitive to different environmental signals such as changes in photoperiod, temperature or water and food availability; the relative importance of a particular signal being dependent on the ecosystem in question. Energy intake, oxygen consumption (VO) and body temperature (T) daily rhythms were compared between two populations of the broad-toothed field mouse Apodemus mystacinus, one from a Mediterranean and another from a sub-Alpine ecosystem. Mice were acclimated to short-day (SD) 'winter' and long-day (LD) 'summer' photoperiods under different levels of salinity simulating osmotic challenges. Mediterranean mice had higher VO values than sub-Alpine mice. In addition, mice exposed to short days had higher VO values when given water with a high salinity compared with mice exposed to long days. By comparison, across both populations, increasing salinity resulted in a decreased T in SD- but not in LD-mice. Thus, SD-mice may conserve energy by decreasing T during ('winter') conditions which are expected to be cool, whereas LD-mice might do the opposite and maintain a higher T during ('summer') conditions which are expected to be warm. LD-mice behaved to reduce energy expenditure, which might be considered a useful trait during 'summer' conditions. Overall, increasing salinity was a clear signal for Mediterranean-mice with resultant effects on VO and T daily rhythms but had less of an effect on sub-Alpine mice, which were more responsive to changes in photoperiod. Results provide an insight into how different populations respond physiologically to various environmental challenges.

Recent advances in thermoregulation

Thermoregulation is the maintenance of a relatively constant core body temperature. Humans normally maintain a body temperature at 37°C, and maintenance of this relatively high temperature is critical to human survival. This concept is so important that control of thermoregulation is often the principal example cited when teaching physiological homeostasis. A basic understanding of the processes underpinning temperature regulation is necessary for all undergraduate students studying biology and biology-related disciplines, and a thorough understanding is necessary for those students in clinical training. Our aim in this review is to broadly present the thermoregulatory process taking into account current advances in this area. First, we summarize the basic concepts of thermoregulation and subsequently assess the physiological responses to heat and cold stress, including vasodilation and vasoconstriction, sweating, nonshivering thermogenesis, piloerection, shivering, and altered behavior. Current research is presented concerning the body's detection of thermal challenge, peripheral and central thermoregulatory control mechanisms, including brown adipose tissue in adult humans and temperature transduction by the relatively recently discovered transient receptor potential channels. Finally, we present an updated understanding of the neuroanatomic circuitry supporting thermoregulation.