Condições hemodinâmicas, respiratórias e sua segurança na realização de exercícios em unidade de terapia intensiva / Hemodynamic, respiratory conditions and their safety when performing exercises in an intensive care unit

Introdução: A permanência prolongada na Unidade de Terapia Intensiva (UTI) compromete a funcionalidade e a qualidade de vida dos pacientes. Programas de exercícios podem contribuir na melhora do status funcional e aceleração do retorno às atividades. Objetivo: avaliar a segurança de exercícios em pacientes na UTI, descrevendo as condições hemodinâmicas e respiratórias e a ocorrência de efeitos adversos. Métodos: trata-se de um estudo não controlado, do tipo "antes e depois", realizado com 42 pacientes internados em UTI, submetidos à mobilização através de cinesioterapia passiva, cinesioterapia ativa, sedestração e deambulação. Além dos dados epidemiológicos e clínicos, foram avaliados os efeitos adversos da mobilização. As variáveis hemodinâmicas e respiratórias foram mensuradas à beira do leito, em três momentos: antes, durante e imediatamente após a mobilização. Resultados:Foram estudados pacientes idosos (65,8±13,7 anos), predominantemente mulheres (59,5%), com diagnóstico admissional de natureza clínica (64,3%). Os pacientes em ventilação mecânica realizaram predominantemente cinesioterapia passiva (57,1%) e aqueles em ventilação espontânea realizaram predominantemente sedestração (28,6%) e deambulação (28,6%). Dentre os efeitos adversos, observou-se padrão muscular ventilatório insatisfatório (7,1%), saturação periférica de oxigênio inferior a 90% (4,8%), alteração da pressão arterial (7,1%). Não houve registro de alteração da frequência cardíaca, extubação acidental ou perda de acesso venoso durante as mobilizações, assim como não foram observadas alterações no comportamento hemodinâmico, respiratório e da oxigenação antes, durante e após a mobilização. Conclusão: exercícios físicos demonstraram-se seguros, viáveis em qualquer âmbito clínico, respeitando-se os limites de segurança, podendo trazer benefícios potenciais para pacientes internados em UT (AU).

Introduction: The prolonged stay in the Intensive Care Unit (ICU) compromises the functionality and quality of life of patients. Physical exercise can contribute to improving functional status and accelerating return to activities. Objective: to assess the safety of patient mobilization in the ICU, describing the hemodynamic and respiratory conditions and the occurrence of adverse effects. Methods: This is an uncontrolled, "before and after" study, carried out with 42 patients hospitalized in the ICU, submitted to mobilization through passive kinesiotherapy, active kinesiotherapy, seating and walking. In addition to epidemiological and clinical data, the adverse effects of mobilization were evaluated. Hemodynamic and respiratory variables were measured at the bedside, at three times: before, during and immediately after mobilization. Results: Elderly patients (65.8±13.7 years), predominantly women (59.5%), with a clinical admission diagnosis (64.3%) were studied. Patients on mechanical ventilation predominantly performed passive kinesiotherapy (57.1%) and those on spontaneous ventilation predominantly performed seating (28.6%) and walking (28.6%). Among the adverse effects, there was an unsatisfactory ventilatory muscle pattern (7.1%), peripheral oxygen saturation less than 90% (4.8%), and changes in blood pressure (7.1%). There was no record of changes in heart rate, accidental extubation or loss of venous access during mobilizations, as well as changes in hemodynamic, respiratory and oxygenation behavior before, during and after mobilization were not observed. Conclusion: physical exercises proved to be safe, viable in any clinical environment, respecting safety limits, and may bring potential benefits to patients admitted to the ICU (AU).

Variation in upper thermal tolerance among 19 species from temperate wetlands.

Communities usually possess a multitude of interconnected trophic interactions within food webs. Their regulation generally depends on a balance between bottom-up and top-down effects. However, if sensitivity to temperature varies among species, rising temperatures may change trophic interactions via direct and indirect effects. We examined the critical thermal maximum (CTmax) of 19 species from temperate wetlands (insect predators, amphibian larvae, zooplankton and amphipods) and determined if they vary in their sensitivity to warming temperatures. CTmax differed between the groups, with predatory insects having higher CTmax than amphibians (both herbivorous larval anurans and predatory larval salamanders), amphipods and zooplankton. In a scenario of global warming, these differences in thermal tolerance may affect top-down and bottom-up processes, particularly considering that insect predators are more likely to maintain or improve their performance at higher temperatures, which could lead to increased predation rates on the herbivores in the food web. Further studies are needed to understand how the energy flows through communities, how species' energy budgets may change and whether other physiological and behavioral responses (such as phenotypic plasticity and thermoregulation) can buffer or increase these changes in the top-down regulation of wetland food webs.

Respiratory mechanics behavior after heart surgery: an experimental study

Changes in ventilatorymechanics and their consequent pulmonary complications are common after surgical procedures, particularly in cardiac surgery (CS), and may be associated with both preoperative history and surgical circumstances. This study aims to compare ventilatory mechanics in the moments before and after cardiac surgery (CS), describing how pulmonary complications occurred. An experimental, uncontrolled study was conducted, of the before-and-after type, and with a descriptive and analytical character. It was carried out in a private hospital in the city of Salvador, Bahia, Brazil, and involved 30 adult patients subjected to CS. In addition to clinical and epidemiological variables, minute volume (VE), respiratory rate (RR), tidal volume (VT), forced vital capacity (FVC), maximum inspiratory pressure (MIP), and peak expiratory flow (PEF) were also recorded. Data were collected in the following moments: preoperative (PRE-OP) period, immediate postoperative (IPO) period, and 1stpostoperative day (1stPOD). The sample was aged 48.1 ± 11.8 years old and had a body mass index of 25.5 ± 4.9 kg m-2; 60% of the patients remained on mechanical ventilation for less than 24 hours (17.5 [8.7-22.9] hours). There was a significant reduction in VT, FVC, MIP and PEF when PRE-OP versus IPO, and PRE-OP versus 1stPOD were compared (p < 0.05). There were no significant changes between IPO and the 1stPOD. The highest incidence of pulmonary complications involved pleural effusion (50% of the patients). This study showed that patients subjected to CS present significant damage to ventilatory parameters after the surgery, especially in the IPO period and on the 1stPOD. It is possible that the extension of this ventilatory impairment has led to the onset of postoperative pulmonary complications.

Recrutamento alveolar com suspiro: impacto na mecânica respiratória e oxigenação de pacientes ventilados mecanicamente / Alveolar recruitment: impact on respiratory mechanics and oxygenation of mechanically ventilated patients

INTRODUÇÃO: O suspiro caracteriza-se pela realização de uma inspiração lenta e profunda, seguida de uma expiração lenta. Estudos sugerem que a adição de um suspiro por minuto em pacientes com síndrome do desconforto respiratório agudo, ventilados em PSV, melhora a oxigenação e a mecânica pulmonar. OBJETIVO: Avaliar o impacto da manobra de recrutamento alveolar através de suspiro na mecânica pulmonar e oxigenação em pacientes ventilados mecanicamente, além de verificar o impacto hemodinâmico e a incidência de intercorrências associadas à utilização da técnica. MATERIAIS E MÉTODOS: Estudo experimental com 17 pacientes em ventilação mecânica, apresentando relação entre pressão parcial de oxigênio alveolar e fração inspirada de oxigênio (PaO2/FiO2) inferior a 300mmHg. Avaliou-se dados respiratórios, de mecânica pulmonar e hemodinâmicos. Os dados foram coletados durante três períodos: antes do suspiro, imediatamente após e 15 minutos depois da técnica. Dois suspiros por minuto foram administrados utilizando pressão em vias aéreas limitada em 40cmH2O, durante um tempo inspiratório de quatro segundos. RESULTADOS: Após o suspiro, observou-se aumento da PaO2, pressão resistiva, complacência estática e relação PaO2/FiO2, além de diminuição da pressão de platô e pressão parcial de gás carbônico alveolar (PaCO2). Após 15 minutos da retirada do suspiro observou-se que a PaO2, pressão resistiva, complacência estática e relação PaO2/ FiO2 mantiveram-se acima do valor basal, enquanto que a pressão de platô manteve-se abaixo. Não foi observada alteração significante nas variáveis hemodinâmicas. CONCLUSÃO: O suspiro em pacientes ventilados mecanicamente foi capaz de melhorar a oxigenação e a mecânica pulmonar sem comprometer a estabilidade hemodinâmica.

INTRODUCTION: The sigh is characterized by a slow and deep inhalation, followed by a slow exhalation. Studies suggest that the addition of one breath per minute in patients with acute respiratory distress syndrome, ventilated on PSV, improves oxygenation and pulmonary mechanics. OBJECTIVE: Analyze the impact of the alveolar recruitment maneuver through breath in pulmonary mechanics and oxygenation in mechanically ventilated patients, in addition to checking the hemodynamic impact and the incidence of complications associated with the use of the technique. MATERIALS AND METHODS: Experimental study with 17 patients on mechanical ventilation, showing a relationship between partial pressure of alveolar oxygen and fraction of inspired oxygen (PaO2/FiO2) below 300mmHg. Respiratory, pulmonary mechanics, and hemodynamic data were evaluated. Data were collected during three periods: before sigh, immediately after, and 15 minutes after the technique. Two sighs per minute were administered using airways pressure limited to 40 cmH2O, during an inspiratory time of four seconds. RESULTS: After the sigh, there was an increase in PaO2, resistive pressure, static compliance, and PaO2/FiO2 ratio, in addition to a decrease in plateau pressure and partial pressure of alveolar carbon dioxide (PaCO2). After 15 minutes of sigh removal, it was observed that PaO2, resistive pressure, static compliance, and PaO2/ FiO2 ratio remained above the baseline, while the plateau pressure remained below. There was no significant change in hemodynamic variables. CONCLUSION: The sigh in mechanically ventilated patients was able to improve oxygenation and pulmonary mechanics without compromising hemodynamic stability

Ventilação não invasiva profilática, desfechos e seus impactos ­ uma revisão sistemática / Non-invasive prophylactic ventilation, outcomes and their impacts - a systematic review

Ventilação Não Invasiva Profilática (VNIP) é uma modalidade de VNI aplicada a pacientes que foram eleitos para extubação, porém possui alto risco de falha. OBJETIVO: descrever e analisar populações favorecidas pela VNIP, impactos e desfechos. MÉTODO: Revisão sistemática, buscaram- -se ensaios nas bases de dados PubMed, EMBASE e Cochrane Library com os seguintes critérios de inclusão: publicação nos últimos 20 anos, escrito em inglês, espanhol ou português; idade ≥ 18 anos; ventilação mecânica ≥ 48 horas; comparação da VNIP com terapia padrão. Critérios de exclusão: VNIP < 4 horas; e VNIP intermitente. RESULTADOS: Resultaram-se oito estudos. Os desfechos foram: reintubação, Insuficiência Respiratória Pós Extubação (IRPE), mortalidade e permanência na UTI. Características relevantes extraídas: uso de VNIP de resgate, níveis de PaCO2, pressão inspiratória máxima e índice de respiração rápida superficial. Os estudos relatam que a aplicação de VNIP em população heterogênea reduz o risco de desenvolver IRPE, porém parece não haver consistência referente à reintubação, mortalidade na UTI, permanência na UTI e hospitalar. Estes marcadores foram apresentados através de resultados controversos entre os estudos revisados. Em pneumopatas especificamente, VNIP parece não ter impacto direto em reintubação e permanência na UTI. CONCLUSÃO: Os estudos divergem sobre uso da VNIP em prevenir principais desfechos, mesmo em pneumopatas, porém, seu uso em evitar IRPE é positivo. Sendo assim, necessitam-se estudos em populações com melhor predisposição a sucesso na extubação para comprovar a eficácia da VNIP.

Noninvasive Ventilation Prophylactic (NIVP) is a modality of NIV applied to patients who have planned extubation but has a high risk of failure. OBJECTIVE: The objective of this study was to describe and analyze populations favored by NIVP, impacts and outcomes. MATERIAL AND METHODS: For this, essays were searched in the Pubmed, EMBASE and Cochrane Library databases with the following inclusion criteria: publication in the last 20 years, written in English, Spanish or Portuguese; age ≥ 18 years; mechanical ventilation ≥ 48 hours; and compare NIVP with standard therapy. Exclusion criteria: NIVP < 4 hours and intermittent NIVP. RESULTS: Eight studies were resulted. The outcomes were: reintubation, Respiratory Failure Post Extubation (RFPE), mortality and ICU permanence. Relevant features extracted: use of rescue NIV, PaCO2 levels, maximal inspiratory pressure and rapid superficial respiration index. Studies report that the application of NIVP in a heterogeneous population reduces the risk of developing RFPE, but there seems to be no consistency regarding reintubation, ICU mortality, permanence in the ICU and hospital. These markers were presented through controversial results among the reviewed studies. In lung disease specifically, NIPV seems to have no direct impact on reintubation and ICU stay. CONCLUSIONS: It is possible conclude that the present studies differ on the use of NIPV to prevent major outcomes such as reintubation and mortality, even in lung disease, but its use in preventing RFPE is positive. Therefore, studies in populations with better predisposition to successful extubation are necessary to prove the efficacy of NIPV.

Segurança na aplicação da eletroestimulação neuromuscular no doente crítico: estudo piloto / Safety in application of neuromuscular electrical stimulation in critically ill patients: pilot study

INTRODUÇÃO: A Neuromuscular Electrical Stimulation (NMES) é um importante aliado do paciente crítico, favorecendo contrações ativas mesmo em estado que requer imobilidade. OBJETIVO: Verificar a segurança da aplicação da NMES em Unidades de Terapia Intensiva (UTIs) de um hospital público da cidade de Salvador. MÉTODO: Trata-se de estudo piloto, de intervenção. Os dados foram coletados no período de fevereiro a junho de 2018, com amostra por conveniência em uma população de pacientes críticos intubados e em uso de vasopressores. Foi aplicada uma única sessão de 45 minutos de NMES em ambos os quadríceps (músculo reto femoral e vasto lateral), sendo coletados os seguintes dados hemodinâmicos 5 minutos antes da aplicação e logo após a terapêutica: frequência cardíaca, pressão arterial sistólica, diastólica e média; e frequência respiratória. Estes dados foram avaliados seguindo recomendações de segurança já descritas previamente. Para análise estatística, as variáveis foram descritas através de médias e desvio-padrão, mediana e intervalo interquartílico e percentuais obtidos nas variáveis do estudo. A distribuição dos dados foi avaliada pelo teste Shapiro-Wilk, e os testes Mann Whitney e T de student foram utilizados. RESULTADOS: A amostra foi composta por 8 pacientes sendo 1 excluído. Destes, 85,7% era do sexo feminino, sendo o diagnóstico clínico de Sepse evoluindo para choque em 85,7%, média da idade de 61±9,5 anos e APACHE II de 29±5,5. Não foram evidenciadas diferenças estatísticas em relação aos dados hemodinâmicos coletados pré e pós eletroestimulação. Estes dados são semelhantes aos resultados encontrados por outros autores em populações sem uso de vasopressores. CONCLUSÃO: É possível sugerir que a aplicação da NMES no doente crítico em uso de vasopressores é uma técnica segura e viável desde que respeitando os limites estabelecidos e parâmetros corretos baseados em evidências

INTRODUCTION: Neuromuscular Electrical Stimulation (NMES) is an important ally of the critically ill patient, favoring active contractions even when in a state that requires immobility. OBJECTIVE: The objective of this study was to verify the safety of NMES application in Intensive Care Units (ICUs) of a public hospital in the city of Salvador. MATERIAL AND METHODS: This is a pilot, study of intervention. Data were collected from February to June 2018, having as population critically ill intubated patients using vasopressors. A single 45-minute NMES session was applied to both quadriceps (rectus femoris and vastus lateralis), and the following hemodynamic data were collected 5 minutes before application and soon after therapy: cardiac frequency, systolic, diastolic and medium blood pressure and respiratory frequency. Data were collected following security recommandations, described earlier. For statistical analysis, the variables were described by mean and standard deviation, median and interquartile interval and percentages obtained for the variables of the study. The distribution of data was evaluated by the Shapiro-Wilk test and Mann Whitney test and t test were used. RESULTS: The sample consisted of 8 patients, being 1 excluded. Of these, 85.7% were female, with a clinical diagnosis of Sepsis in 85.7%, mean age of 61±9.5 years and APACHE II of 29±5.5. No statistical differences were observed in relation to hemodynamic data collected before and after electrostimulation. These data are similar to those found by other authors in populations without vasopressors usage. CONCLUSION: It is possible to suggest that the application of NMES in critically ill patients using vasopressors is a safe and viable technique as long as respecting the established limits and correct evidence-based parameters.

Population Approach to Efavirenz Therapy.

Efavirenz (EFV) is a nonnucleoside reverse transcriptase inhibitor commonly used as first-line therapy in the treatment of human immunodeficiency virus (HIV), with a narrow therapeutic range and a high between-subject variability which can lead to central nervous system toxicity or therapeutic failure. To characterize the sources of variability and better predict EFV steady-state plasma concentrations, a population pharmacokinetic model was developed from 96 HIV-positive individuals, using a nonlinear mixed-effect method with Monolix® software. A one-compartment with first-order absorption and elimination model adequately described the data. To explain between-subject variability, demographic characteristics, biochemical parameters, hepatitis C virus-HIV coinfection, and genetic polymorphisms were tested. A combination of the single-nucleotide polymorphisms rs2279343 and rs3745274, both in the CYP2B6 gene, were the only covariates influencing clearance, included in the final model. Oral clearance was estimated to be 19.6 L/h, 14.15 L/h, and 6.08 L/h for wild-type, heterozygous mutated and homozygous mutated individuals, respectively. These results are in accordance with the current knowledge of EFV metabolism and also suggest that in homozygous mutated individuals, a dose adjustment is necessary. Hepatitis C virus-HIV coinfection does not seem to be a predictive indicator of EFV pharmacokinetic disposition.

An Intelligent Weather Station.

Accurate measurements of global solar radiation, atmospheric temperature and relative humidity, as well as the availability of the predictions of their evolution over time, are important for different areas of applications, such as agriculture, renewable energy and energy management, or thermal comfort in buildings. For this reason, an intelligent, light-weight, self-powered and portable sensor was developed, using a nearest-neighbors (NEN) algorithm and artificial neural network (ANN) models as the time-series predictor mechanisms. The hardware and software design of the implemented prototype are described, as well as the forecasting performance related to the three atmospheric variables, using both approaches, over a prediction horizon of 48-steps-ahead.

Local divergence of thermal reaction norms among amphibian populations is affected by pond temperature variation.

Although temperature variation is known to cause large-scale adaptive divergence, its potential role as a selective factor over microgeographic scales is less well-understood. Here, we investigated how variation in breeding pond temperature affects divergence in multiple physiological (thermal performance curve and critical thermal maximum [CTmax]) and life-history (thermal developmental reaction norms) traits in a network of Rana arvalis populations. The results supported adaptive responses to face two main constraints limiting the evolution of thermal adaptation. First, we found support for the faster-slower model, indicating an adaptive response to compensate for the thermodynamic constraint of low temperatures in colder environments. Second, we found evidence for the generalist-specialist trade-off with populations from colder and less thermally variable environments exhibiting a specialist phenotype performing at higher rates but over a narrower range of temperatures. By contrast, the local optimal temperature for locomotor performance and CTmax did not match either mean or maximum pond temperatures. These results highlight the complexity of the adaptive multiple-trait thermal responses in natural populations, and the role of local thermal variation as a selective force driving diversity in life-history and physiological traits in the presence of gene flow.

Swimming with predators and pesticides: how environmental stressors affect the thermal physiology of tadpoles.

To forecast biological responses to changing environments, we need to understand how a species's physiology varies through space and time and assess how changes in physiological function due to environmental changes may interact with phenotypic changes caused by other types of environmental variation. Amphibian larvae are well known for expressing environmentally induced phenotypes, but relatively little is known about how these responses might interact with changing temperatures and their thermal physiology. To address this question, we studied the thermal physiology of grey treefrog tadpoles (Hyla versicolor) by determining whether exposures to predator cues and an herbicide (Roundup) can alter their critical maximum temperature (CTmax) and their swimming speed across a range of temperatures, which provides estimates of optimal temperature (Topt) for swimming speed and the shape of the thermal performance curve (TPC). We discovered that predator cues induced a 0.4°C higher CTmax value, whereas the herbicide had no effect. Tadpoles exposed to predator cues or the herbicide swam faster than control tadpoles and the increase in burst speed was higher near Topt. In regard to the shape of the TPC, exposure to predator cues increased Topt by 1.5°C, while exposure to the herbicide marginally lowered Topt by 0.4°C. Combining predator cues and the herbicide produced an intermediate Topt that was 0.5°C higher than the control. To our knowledge this is the first study to demonstrate a predator altering the thermal physiology of amphibian larvae (prey) by increasing CTmax, increasing the optimum temperature, and producing changes in the thermal performance curves. Furthermore, these plastic responses of CTmax and TPC to different inducing environments should be considered when forecasting biological responses to global warming.