The effect of changing the mode of ventilation on the arterial-to-end-tidal CO2 difference and physiological dead space in laterally and dorsally recumbent horses during halothane anesthesia

Objective - To evaluate the effect of changing the mode of ventilation from spontaneous to controlled on the arterial-to-end-tidal CO2 difference [P(a-ET)CO2] and physiological dead space (VD(phys)/VT) in laterally and dorsally recumbent halothane-anesthetized horses. Study Design - Prospective, experimental, nonrandomized trial. Animals - Seven mixed breed adult horses (1 male and 6 female) weighing 320 ± 11 kg. Methods - Horses were anesthetized in 2 positions - right lateral and dorsal recumbency - with a minimum interval of 1 month. Anesthesia was maintained with halothane in oxygen for 180 minutes. Spontaneous ventilation (SV) was used for 90 minutes followed by 90 minutes of controlled ventilation (CV). The same ventilator settings were used for both laterally and dorsally recumbent horses. Arterial blood gas analysis was performed every 30 minutes during anesthesia. End-tidal CO2 (PETCO2) was measured continuously. P(a-ET)CO2 and VD(phys)/VT were calculated. Statistical analysis included analysis of variance for repeated measures over time, followed by Student-Newman-Keuls test. Comparison between groups was performed using a paired t test; P < .05 was considered significant. Results - P(a-ET)CO2 and VD(phys)/VT increased during SV, whereas CV reduced these variables. The variables did not change significantly throughout mechanical ventilation in either group. Dorsally recumbent horses showed greater P(a-ET)CO2 and VD(phys)/VT values throughout. PaCO2 was greater during CV in dorsally positioned horses. Conclusions and Clinical Relevance - Changing the mode of ventilation from spontaneous to controlled was effective in reducing P(a-ET)CO2 and physiological dead space in both laterally and dorsally recumbent halothane-anesthetized horses. Dorsal recumbency resulted in greater impairment of effective ventilation. Capnometry has a limited value for accurate estimation of PaCO, in anesthetized horses, although it may be used to evaluate pulmonary function when paired with arterial blood gas analysis. © Copyright 2000 by The American College of Veterinary Surgeons.

Potential scenarios for Internet use in the mathematics classroom

Research on the influence of multiple representations in mathematics education gained new momentum when personal computers and software started to become available in the mid-1980s. It became much easier for students who were not fond of algebraic representations to work with concepts such as function using graphs or tables. Research on how students use such software showed that they shaped the tools to their own needs, resulting in an intershaping relationship in which tools shape the way students know at the same time the students shape the tools and influence the design of the next generation of tools. This kind of research led to the theoretical perspective presented in this paper: knowledge is constructed by collectives of humans-with-media. In this paper, I will discuss how media have shaped the notions of problem and knowledge, and a parallel will be developed between the way that software has brought new possibilities to mathematics education and the changes that the Internet may bring to mathematics education. This paper is, therefore, a discussion about the future of mathematics education. Potential scenarios for the future of mathematics education, if the Internet becomes accepted in the classroom, will be discussed. © FIZ Karlsruhe 2009.

From the classroom to the workplace: Three decades of evidence for Latin America

Includes bibliography.

Classroom discipline, classroom environment and student performance in Chile

This paper assesses the extent to which teachers’ actions in the classroom influence the school environment. The assessment is based on a statistical analysis of videotaped classroom observations of 51,329 teachers. The classroom environment was found to have a significant influence on students’ performance. More specifically, the teacher’s ability to handle the class as a group is consistently more significant than other measures of class environment. It was also founds that the overall school environment is a better predictor of students’ test results than the environment in the classrooms of the students whose test results are being reported. This suggests that the most effective course of action would be to improve the overall school environment, although individual teachers have less control over this factor.

Análise do desempenho energético de edificações: aplicação analítica do RTQ-C no Edifício do Ceamazon

Um dos grandes entraves para o desenvolvimento econômico mundial é a crescente demanda por energia e consequente aumento da utilização de recursos naturais para provê-la. Países em desenvolvimento, como o Brasil, apresentaram progressivo consumo de energia per capita nos últimos anos. Embora a sua maioria seja proveniente de usinas hidrelétricas (fontes não poluidoras) sua construção causa grande impacto ambiental. De todo o percentual energético gerado, as edificações são responsáveis pelo consumo de aproximadamente 40% e este percentual tende a aumentar mediante o crescimento da construção civil no país. Diante da problemática, o combate ao desperdício, a racionalização e o uso sustentável da energia consumida pelas edificações estão diretamente ligados à redução do impacto ao meio ambiente, postergando a necessidade de aumento da matriz energética nacional. Neste contexto é criado o Regulamento Técnico da Qualidade do Nível de Eficiência Energética de Edifícios Comerciais, de Serviço e Públicos (RTQ-C). Este trabalho consiste em uma aplicação crítica do RTQ-C utilizando a metodologia prescritiva, tendo como enfoque aspectos relativos a sua aplicabilidade e avaliação de conforto térmico e lumínico, tendo como premissa que o alto desempenho energético da edificação só é plenamente alcançado quando são garantidas condições satisfatórias de conforto ambiental aos usuários. Para tanto foi necessária uma etapa minuciosa de levantamento de dados e medições “in loco” de temperatura do ar, temperatura radiante, iluminância e umidade relativa em dois ambientes (laboratório de conforto e sala de aula 2) do edifício do Centro de Excelência em Eficiência Energética da Amazônia - CEAMAZON, subsidiando a utilização da metodologia proposta por Fanger (PMV e PPD), e verificação dos níveis de iluminância propostos pela NBR 5413. Como resultado a edificação apresentou bom desempenho, mas a não observância dos prérequisitos a classificou com nível “C”. A avaliação de conforto indicou que aproximadamente 23% dos usuários não estavam em conforto térmico e que a ventilação natural poderá ser utilizada como estratégia bioclimática para adequação. As medições de iluminância indicaram que apenas a sala de aula 2 possuia potencial de aproveitamento de iluminação natural no período da medição. Concluiu-se que, apesar de sua importância, o RTQ-C deve passar ainda por um processo de adaptação por parte da sociedade e dos profissionais envolvidos na certificação energética de edificações e que durante esse período modificações poderão ser incorporadas contribuindo para torná-lo um instrumento efetivamente válido para a garantia da eficiência energética das edificações do país.

Towards criterion validity in classroom language analysis: methodological constraints of metadiscourse and inter-rater agreement

This paper reports on a process to validate a revised version of a system for coding classroom discourse in foreign language lessons, a context in which the dual role of language (as content and means of communication) and the speakers' specific pedagogical aims lead to a certain degree of ambiguity in language analysis. The language used by teachers and students has been extensively studied, and a framework of concepts concerning classroom discourse well-established. Models for coding classroom language need, however, to be revised when they are applied to specific research contexts. The application and revision of an initial framework can lead to the development of earlier models, and to the re-definition of previously established categories of analysis that have to be validated. The procedures followed to validate a coding system are related here as guidelines for conducting research under similar circumstances. The advantages of using instruments that incorporate two types of data, that is, quantitative measures and qualitative information from raters' metadiscourse, are discussed, and it is suggested that such procedure can contribute to the process of validation itself, towards attaining reliability of research results, as well as indicate some constraints of the adopted research methodology.

Intravenous versus inhalation anaesthesia for one-lung ventilation

BackgroundThis is an update of a Cochrane Review first published in The Cochrane Library, Issue 2, 2008.The technique called one-lung ventilation can confine bleeding or infection to one lung, prevent rupture of a lung cyst or, more commonly, facilitate surgical exposure of the unventilated lung. During one-lung ventilation, anaesthesia is maintained either by delivering an inhalation anaesthetic to the ventilated lung or by infusing an intravenous anaesthetic. It is possible that the method chosen to maintain anaesthesia may affect patient outcomes. Inhalation anaesthetics may impair hypoxic pulmonary vasoconstriction (HPV) and increase intrapulmonary shunt and hypoxaemia.ObjectivesThe objective of this review was to evaluate the effectiveness and safety of intravenous versus inhalation anaesthesia for one-lung ventilation.Search methodsWe searched the Cochrane Central Register of Controlled Trials (CENTRAL); The Cochrane Library (2012, Issue 11); MEDLINE (1966 to November 2012); EMBASE (1980 to November 2012); Literatura Latino-Americana e do Caribe em Ciencias da Saude (LILACS, 1982 to November 2012) and ISI web of Science (1945 to November 2012), reference lists of identified trials and bibliographies of published reviews. We also contacted researchers in the field. No language restrictions were applied. The date of the most recent search was 19 November 2012. The original search was performed in June 2006.Selection criteriaWe included randomized controlled trials and quasi-randomized controlled trials of intravenous (e. g. propofol) versus inhalation (e. g. isoflurane, sevoflurane, desflurane) anaesthesia for one-lung ventilation in both surgical and intensive care participants. We excluded studies of participants who had only one lung (i.e. pneumonectomy or congenital absence of one lung).Data collection and analysisTwo review authors independently assessed trial quality and extracted data. We contacted study authors for additional information.Main resultsWe included in this updated review 20 studies that enrolled 850 participants, all of which assessed surgical participants no studies investigated one-lung ventilation performed outside the operating theatre. No evidence indicated that the drug used to maintain anaesthesia during one-lung ventilation affected participant outcomes. The methodological quality of the included studies was difficult to assess as it was reported poorly, so the predominant classification of bias was 'unclear'.Authors' conclusionsVery little evidence from randomized controlled trials suggests differences in participant outcomes with anaesthesia maintained by intravenous versus inhalational anaesthesia during one-lung ventilation. If researchers believe that the type of drug used to maintain anaesthesia during one-lung ventilation is important, they should design randomized controlled trials with appropriate participant outcomes, rather than report temporary fluctuations in physiological variables.

Interactive effects of mechanical ventilation, inhaled nitric oxide and oxidative stress in acute lung injury

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determinant factors for mortality of patients receiving mechanical ventilation and effects of a protocol muscle training in weaning

Introduction: Prognostic factors are used in the Intensive Care Unit (ICU) to predict morbidity and mortality , especially in patients on mechanical ventilation (MV ) . Training protocols are used in MV patients with the aim of promoting the success of the weaning process. Objective: To assess which variables determine the outcome of patients undergoing mechanical ventilation and compare the effects of two protocols for weaning. Method: Patients under MV for more than 48 hours had collected the following information: sex, age , ideal weight, height , Acute Physiology and Chronic Health Evaluation (APACHE II), risk of mortality, Glasgow Coma Scale (GCS) and index Quick and perfunctory (IRRS) breathing. Patients with unsuccessful weaning performed one of weaning protocols: Progressive T - tube or tube - T + Threshold ® IMT. Patients were compared for outcome (death or non- death in the ICU ) and the protocols through the t test or Mann-Whitney test was considered significant when P <0.05. Results: Of 128 patients evaluated 56.25% were men, the mean age was 60.05 ± 17.85 years and 40.62 % patients died, and they had higher APACHE II scores, mortality risk, time VM and IRRS GCS and the lower value (p<0.05). The age, initial and final maximal inspiratory pressure, time of weaning and duration of MV was similar between protocols. Conclusion: The study suggests that the GCS, APACHE II risk of mortality, length of MV and IRRS variables determined the evolution of MV patients in this sample. Not found differences in the variables studied when comparing the two methods of weaning.

Competences in the classroom in the perspectives of foreign language teachers

In this article we raise some considerations about teachers’ competences, from the perspective of teachers in the Brazilian public sector. The theoretical framework includes articles by Paulo Freire (2001), Philippe Perrenoud (2012), Edgar Morin (2003) and Maurice Tardif (2002) and, based on these authors, we reflect upon issues concerning teachers’ competences taking answers provided by the Brazilian language teachers as a departing point. In a teachers’ course, followed by the same teachers, we posed the main question in our study: Which competences are necessary for a teacher to be considered a good professional at present? From the answers given individually and group discussions we proceeded to a comparative analysis with the adopted framework, and other issues concerning teachers’ competences were considered as well. All the participants mentioned the same two competences, the use of technology and sound knowledge of the course content, and other competences were pointed out by the various teachers as well. Such procedure, besides providing data for our study, also helped as a self-reflexive activity for the teachers involved, about their own professional performance. Given the issues raised in the theoretical texts and the answers provided by the teachers, we expect to revisit the competences necessary for foreign language teacher efficient performance.

Comparison between noninvasive mechanical ventilation and standard oxygen therapy in children up to 3 years old with respiratory failure after extubation: a pilot prospective randomized clinical study

Objectives: The effectiveness of noninvasive positive-pressure ventilation in preventing reintubation due to respiratory failure in children remains uncertain. A pilot study was designed to evaluate the frequency of extubation failure, develop a randomization approach, and analyze the feasibility of a powered randomized trial to compare noninvasive positive-pressure ventilation and standard oxygen therapy post extubation for preventing reintubation within 48 hours in children with respiratory failure.Design: Prospective pilot study.Setting: PICU at a university-affiliated hospital.Patients: Children aged between 28 days and 3 years undergoing invasive mechanical ventilation for greater than or equal to 48 hours with respiratory failure after programmed extubation.Interventions: Patients were prospectively enrolled and randomly assigned into noninvasive positive-pressure ventilation group and inhaled oxygen group after programmed extubation from May 2012 to May 2013.Measurements and Main Results: Length of stay in PICU and hospital, oxygenation index, blood gas before and after tracheal extubation, failure and reason for tracheal extubation, complications, mechanical ventilation variables before tracheal extubation, arterial blood gas, and respiratory and heart rates before and 1 hour after tracheal extubation were analyzed. One hundred eight patients were included (noninvasive positive-pressure ventilation group, n = 55 and inhaled oxygen group, n = 53), with 66 exclusions. Groups did not significantly differ for gender, age, disease severity, Pediatric Risk of Mortality at admission, tracheal intubation, and mechanical ventilation indications. There was no statistically significant difference in reintubation rate (noninvasive positive-pressure ventilation group, 9.1%; inhaled oxygen group, 11.3%; p > 0.05) and length of stay (days) in PICU (noninvasive positive-pressure ventilation group, 3 [116]; inhaled oxygen group, 2 [1-25]; p > 0.05) or hospital (noninvasive positive-pressure ventilation group, 19 [7-141]; inhaled oxygen group, 17 [8-80]).Conclusions: The study indicates that a larger randomized trial comparing noninvasive positive-pressure ventilation and standard oxygen therapy in children with respiratory failure is feasible, providing a basis for a future trial in this setting. No differences were seen between groups. The number of excluded patients was high.

Assessing the influence of mechanical ventilation on blood gases and blood pressure in rattlesnakes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Prone positioning attenuates TNF-alpha production in rabbits with lung injury under protective conventional mechanical ventilation (CMV)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Association of student position in classroom and school performance

We analyzed whether the position of students in classroom is correlated with academic performance, and which factors might be involved. The sample consisted of 16 classrooms in a school year bimester, each one with around 30 students. Each student's position was registered in classroom maps and the reasons for the students' seat choice were gathered by a questionnaire. School performance and classroom absences of each student were collected directly from the teachers' register notebook. We found that better performances of students at school correlate with lower percentages of absence and choices of seating positions closer to the board. Moreover, the main reason to sit in a front position was motivation for learning. We suggest that school performance is associated to students’ position in the classroom because both are affected by the student motivation for learning. As a consequence, changing students' position in the classroom without increasing their motivation is not likely to improve school performance.