RESUMO Objetivo: Desenvolver e aplicar um teste baseado em competências para avaliar o aprendizado de residentes de clínica médica em estágio na UTI respiratória de um hospital universitário. Métodos: Desenvolvemos um teste com 19 questões de múltipla escolha sobre conhecimento em ventilação mecânica (VM) e 4 questões de autoavaliação sobre o nível de confiança no manejo da VM. Os testes foram aplicados no primeiro (pré-estágio) e no último dia (pós-estágio) do estágio de 30 dias na UTI respiratória. Durante o estágio, os residentes tiveram aulas teóricas, treinamento com simulador e visitas diárias à beira do leito focadas no ensino de VM. Resultados: Cinquenta residentes completaram o teste nos dois momentos. A média de pontuação (0-10 pontos) aumentou de 6,9 ± 1,2 no pré-estágio para 8,6 ± 0,8 no pós-estágio (p < 0,001). Observamos um aumento significativo no pós-estágio comparado com o pré-estágio em questões sobre abordagem da hipoxemia, reconhecimento da assincronia paciente-ventilador e reconhecimento de fatores de risco para falha de extubação. A confiança na abordagem de vias aéreas aumentou de 6% para 22% ao final do estágio (p = 0,02). A confiança no ajuste inicial da VM subiu de 31% para 96% (p < 0,001), e a confiança no ajuste dos modos ventilatórios aumentou de 23% para 77% (p < 0,001). Conclusões: Desenvolvemos um teste baseado em competências para avaliar o conhecimento sobre VM entre residentes antes e depois de um estágio em UTI respiratória. O desempenho dos residentes ao final do estágio aumentou significativamente, assim como sua confiança para cuidar de pacientes sob VM.

ABSTRACT Objective: To develop and apply a competency-based test to assess learning among internal medicine residents during a respiratory ICU rotation at a university hospital. Methods: We developed a test comprising 19 multiple-choice questions regarding knowledge of mechanical ventilation (MV) and 4 self-assessment questions regarding the degree of confidence in the management of MV. The test was applied on the first and last day of a 30-day respiratory ICU rotation (pre-rotation and post-rotation, respectively). During the rotation, the residents had lectures, underwent simulator training, and shadowed physicians on daily bedside rounds focused on teaching MV management. Results: Fifty residents completed the test at both time points. The mean score increased from 6.9 ± 1.2 (pre-rotation) to 8.6 ± 0.8 (post-rotation; p < 0.001). On questions regarding the approach to hypoxemia, the recognition of patient-ventilator asynchrony, and the recognition of risk factors for extubation failure, the post-rotation scores were significantly higher than the pre-rotation scores. Confidence in airway management increased from 6% before the rotation to 22% after the rotation (p = 0.02), whereas confidence in making the initial MV settings increased from 31% to 96% (p < 0.001) and confidence in adjusting the ventilator modes increased from 23% to 77% (p < 0.001). Conclusions: We developed a competency-based test to assess knowledge of MV among residents before and after an rotation in a respiratory ICU. Resident performance increased significantly after the rotation, as did their confidence in caring for patients on MV.

Resumo Neste estudo, compósitos de MnO2-levedura de pão, produzidos pela oxidação direta da levedura com KMnO4 sob condições ácidas, foram usados como biossorvente para remover o corante trifenilmetano verde Malaquita (VM) de solução aquosa. Os parâmetros que influenciam o processo de adsorção tais como pH, tempo de contato, temperatura, concentração inicial do corante e concentração do biossorvente foram avaliados em experimentos de bancada. As condições ótimas de descoloração foram observadas em pH 10 e concentração de biomassa igual a 1,0 g L-1. Os resultados de remoção do corante foram ajustados ao modelo cinético de pseudo segunda ordem. O processo de adsorção foi descrito pelo modelo isotérmico de Langmuir e a capacidade máxima de biossorção foi estimada em 243,9 mg g-1 (na temperatura de 25°C). Os valores negativos de ∆G° e valores positivos de ∆H° indicaram que a biossorção do VM pelo compósito MnO2-levedura é espontâneo e endotérmico. A técnica de espectroscopia no infravermelho com transformada de Fourier indicou que nanopartículas de MnO2 depositadas na superfície do compósito MnO2-levedura facilitaram a adsorção do VM. Concluiu-se que o compósito MnO2-levedura de pão possui potencial para ser usado como adsorvente na remoção de VM de solução aquosa.

Abstract In this study, baker’s yeast-MnO2 composites, produced by direct oxidation of yeast with KMnO4 under acidic conditions, were used as biosorbent to remove the triphenylmethane dye Malachite green (MG) from an aqueous solution. Parameters that influence the adsorption process, such as pH, contact time, temperature, initial dye concentration and biosorbent dosage, were evaluated in batch experiments. The optimum removal of MG was found to be 86.7 mg g-1 at pH 10, 1.0 g L-1 of biomass dosage and 45°C. The kinetic data of dye removal was better described by the pseudo-second-order model. The adsorption process followed the Langmuir isotherm model and the maximum biosorption capacity was estimated to be 243.9 mg g-1 (at 25°C). The negative values of ∆G° and the positive value of ∆H° indicated that the MG biosorption onto yeast-MnO2 composites is spontaneous and endothermic. Fourier transform infrared spectroscopy (FTIR) indicated that the nano-MnO2 particles deposited on yeast-MnO2 composites surface facilitated the MG adsorption. It was concluded that baker’s yeast-MnO2 composites have potential for application as adsorbent for removal of MG from aqueous solution.

Este estudo avaliou a eficiência do azul de metileno (AM) e do verde malaquita (VM) na inativação fotodinâmica (IFD) de Escherichia coli. Os fotossensibilizadores (FS) azul de metileno (1000 (mol L-1) e verde malaquita (250 (mol L-1) foram ativados com lâmpada de luz LED vermelha ((max = 636 nm). Suspensões bacterianas contendo 106 UFC mL-1 foram irradiadas por 5, 10 e 15 minutos (densidade de energia = 111,9 J cm-2, 223,9 J cm-2 e 335,8 J cm-2, respectivamente). As seguintes condições experimentais foram utilizadas para ambos os fotossensibilizadores: sem luz ou sem fotossensibilizador, somente luz, somente fotossensibilizador ou luz na presença do fotossensibilizador. Em seguida, diluições seriadas foram preparadas e semeadas em placas com meio PCA para determinação do número de UFC mL-1. Os resultados foram submetidos a análise de variância (ANOVA) e teste Tukey (P<0.05). A inativação fotodinâmica usando AM e VM foi efetiva na redução do crescimento de E. coli. A fotossensibilização do VM (250 µmol L-1) foi capaz de reduzir acima de 89% a contagem de células viáveis após 15 min de irradiação e o AM (1000 µmol L-1), no mesmo tempo de exposição, mostrou uma taxa de inibição de 94,6%. A lâmpada de LED vermelha utilizada se mostrou efetiva na fotossensibilização dos corantes e mostrou ser uma boa alternativa a fontes de luz convencional como o laser.

This study assessed the effectiveness of methylene blue (MB) and malachite green (MG) on photodynamic inactivation (PDI) of Escherichia coli. The photosensitizers methylene blue (1000 (mol L-1) and malachite green (250 (mol L-1) were activated with a red light-emitting diode (LED) lamp ((max = 636 nm). Bacterial suspensions containing 106 CFU mL-1 were irradiated for 5, 10 and 15 minutes (energy density = 119.9 J cm-2, 223.9 J cm-2 and 335.8 J cm-2, respectively). The following experimental conditions were performed for each photosensitizer: no light irradiation or photosensitizer, irradiation only, photosensitizer only or irradiation in the presence of a photosensitizer. Next, serial dilutions were prepared and seeded onto PCA medium for the determination of the number of colony-forming units per milliliter (CFU mL-1). The results were subjected to analysis of variance (ANOVA) and Tukey test (P<0.05). Photodynamic inactivation using MB and MG was effective in reducing the number of E. coli. Malachite green (250 µmol L-1) photosensitization was able to achieve reductions of over 89% in the viable counts after 15 min of irradiation and methylene blue (1000 µmol L-1), at the same conditions of irradiation, showed a rate growth inhibition of 94.6%. The red LED light used has proven to be effective in the photosensitizing dyes and proved a good alternative to conventional light sources such as laser.

Objective. We analyze the most suitable time to perform tracheostomy in neurocritically ill patients. We compare morbimortality and use of resources between those patients in which tracheostomy was done early (< 9 days) and those in which it was perform later (>9 days), in a selected group of patients. Material and methods. We made an observational prospective study involving a group of patients diagnosed as traumatic brain injury (TBI) or stroke, whose tracheostomy was performed during their stay at the Intensive Care Unit. We compared two groups: a) early tracheostomy (during first 9 days of ICU stay); b) late tracheostomy (made on 10th day or later). As variables, we studied: demographic data, severity of illness at admission, admittance department, diagnosis, length of intubation, length of mechanical ventilation (LMV), sedation and antibiotic treatment needs, ventilatorassociated pneumonia (VAP) events, ICU length of stay and mortality. We calculated relative risk of suffering from pneumonia and made a multivariate logistic regression to establish which factors were associated with an increased risk of developing pneumonia. Statistical signification p < 0.05. Results. We analyzed 118 patients, 60% with TBI. Mean length of intubation before tracheostomy was 12 days and mean LMV was 20 days. 94 VAP events were diagnosed in 81 patients (68.6%). Early tracheostomy group showed lower length of mechanical ventilation and ICU stay, lower length of sedation and antibiotic treatment, and less pneumonia events (p<0,001). The precocity of tracheostomy didn't have any influence either on hospital length of stay (p=0.844), ICU mortality (p=0.924) or in-hospital mortality (p=0.754). At the TBI group mean age was lower (p<0.001), tracheostomy was made later (p=0.026), and patients needed a longer sedation (p=0.001) and a longer antibiotic treatment (p=0.002). Length of intubation (p=0.034, OR 1.177) and ICU length of stay (p=0.003, OR 1.100) were factors independently associated with development of pneumonia. Relative risk of suffering from pneumonia when tracheostomy was made after 9 days of ICU stay was 1.55 (IC 95%: 1.10-2.16). The number needed to treat (NNT) for early tracheostomy avoiding one pneumonia event was 3.13. VAP was not associated with a higher ICU (p=0.558) or in-hospital mortality (p=0.370). Conclusions. Early tracheostomy (<9 days) provides significant advantages in neurocritically ill patients: it shortens length of mechanical ventilation and ICU stay and decreases antibiotic and sedatives requirements. Although later tracheostomy is not directly related with mortality, it increases considerably the risk of suffering from pneumonia, particularly in patients with TBI. These clinical circumstances should be evaluated individually in each patient, so the best time to perform tracheostomy in neurocritically ill patients could be established.

Objetivos. Analizar el momento más adecuado para la realización de la traqueotomía en enfermos neurocríticos, comparando en una población seleccionada de pacientes las diferencias de morbimortalidad y consumo de recursos entre el grupo en que se realizó la traqueotomía precozmente (<9 días) y aquéllos en los que fue más tardía (>9 días). Material y métodos. Estudio prospectivo y observacional en una población de pacientes con diagnóstico de traumatismo craneoencefálico (TCE) o accidente cerebrovascular (ACVA) que precisaron traqueotomía durante su ingreso en UCI. Se compararon los datos en dos grupos de pacientes: a) traqueotomía precoz (TP) en los primeros 9 días; b) traqueotomía tardía (TT) a partir del 10º día. Variables estudiadas: datos demográficos, gravedad al ingreso, procedencia, diagnóstico, duración de la intubación orotraqueal (IOT) y de la ventilación mecánica (VM), necesidades de sedación y de antibioterapia, frecuencia de neumonía asociada a ventilación mecánica (NAV), duración de la estancia y mortalidad. Se calculó el riesgo relativo de padecer neumonía y un modelo de regresión logística multivariante para determinar los factores asociados al desarrollo de neumonía. Significación estadística para una p<0.05. Resultados. Se estudiaron 118 pacientes, 60% con TCE. La media de IOT previa a la traqueotomía (TRQ) fue de 12 días y la duración de la VM de 20 días. Se diagnosticaron 94 episodios de NAV en 81 pacientes (68.6%). El grupo de TP muestra menor duración de la VM, de la sedación, de la antibioterapia y de la estancia en UCI, con menor incidencia de neumonía (p<0.001). La precocidad de la TRQ no influyó en la duración de la estancia hospitalaria (p=0.844), ni en la mortalidad en UCI (p=0.924), ni en la hospitalaria (p=0.754). La media de edad fue menor en el grupo con TCE (p<0.001), además la TRQ se realiza más tarde (p=0.026) y requieren más días de sedación (p=0.001) y de tratamiento antibiótico (p=0.002). Los factores independientemente asociados con el desarrollo de neumonía fueron los días de IOT (p=0.034, OR 1.177) y los días de estancia en UCI (p=0.003, OR 1.100). El riesgo relativo de padecer neumonía si la TRQ se realiza después de 9 días es 1.55 mayor (IC 95%: 1.10-2.16). Número necesario de pacientes a tratar (NNT) para que la TRQ precoz evite un episodio de neumonía: 3.13. La presencia de NAV no se asocia con una mayor mortalidad en UCI (p=0.558) ni hospitalaria (p=0.370). Conclusiones. La traqueotomía precoz (<9 días) en los enfermos neurocríticos aporta ventajas apreciables, acortando los días de ventilación mecánica y de estancia en UCI, con menores requerimientos de sedación y de antibioterapia. Aunque la TRQ más tardía no se relaciona directamente con la mortalidad, se eleva considerablemente el riesgo de padecer neumonía, de manera especial en pacientes con TCE. Estas circunstancias clínicas deben valorarse individualmente en cada caso a fin de establecer el momento más adecuado para practicar la TRQ en los pacientes neurocríticos.

Antivenoms have been widely used for more than a century for treating snakebites and other accidents with poisonous animals. Despite their efficacy, the use of heterologous antivenoms involves the possibility of adverse reactions due to activation of the immune system. In this paper, alternatives for antivenom production already in use were evaluated in light of their ability to minimize the occurrence of adverse reactions. These effects were classified according to their molecular mechanism as: anaphylactic reactions mediated by IgE, anaphylactoid reactions caused by complement system activation, and pyrogenic reactions produced mainly by the presence of endotoxins in the final product. In the future, antivenoms may be replaced by humanized antibodies, specific neutralizing compounds or vaccination. Meanwhile, improvements in antivenom quality will be focused on the obtainment of a more purified and specific product in compliance with good manufacturing practices and at an affordable cost.