ERS International Congress 2022: highlights from the Respiratory Clinical Care and Physiology Assembly

It is a challenge to keep abreast of all the clinical and scientific advances in the field of respiratory medicine. This article contains an overview of the laboratory-based science, clinical trials and qualitative research that were presented during the 2022 European Respiratory Society International Congress within the sessions from the five groups of Assembly 1 (Respiratory Clinical Care and Physiology). Selected presentations are summarised from a wide range of topics: clinical problems, rehabilitation and chronic care, general practice and primary care, mobile/electronic health (m-health/e-health), clinical respiratory physiology, exercise and functional imaging

Adaptive Closed-Loop Neuromorphic Controller for Use in Respiratory Pacing

Respiratory pacing can treat ventilatory insufficiency through electrical stimulation of the respiratory muscles, or the respective innervating nerves, to induce ventilation. It avoids some of the adverse effects associated with mechanical ventilation such as risk of diaphragm atrophy and lung damage. However, current respiratory pacing systems provide stimulation in an open-loop manner. This often requires users to undergo frequent tuning sessions with trained clinicians if the specified stimulation parameters are unable to induce sufficient ventilation in the presence of time-varying changes in muscle properties, chest biomechanics, and metabolic demand. Lack of adaptation to these changes may lead to complications arising from hyperventilation or hypoventilation. A novel adaptive closed-loop neuromorphic controller for respiratory pacing has been developed to address the need for closed-loop control respiratory pacing capable of responding to changes in metabolic production of CO2, diaphragm muscle health, and biomechanics. A 3-stage processes was utilized to develop the controller. First, an adaptive controller that could follow a preset within-breath volume profile was developed in silico and evaluated in vivo in anesthetized rats with an intact spinal cord or with diaphragm hemiparesis induced by spinal cord hemisection. Second, a neuromorphic computational model was developed to generate a desired trajectory that reflects changes in breath volume and respiratory rate in response to arterial CO2 levels. An enhanced controller capable of generating and matching this model-based desired trajectory was evaluated in silico and in vivo on rats with depressed ventilation and diaphragm hemiparesis. Finally, the enhanced adaptive controller was modified for human-related biomechanics and CO2 dynamics and evaluated in silico under changes of metabolic demand, presence of muscle fatigue, and after randomization of model parameters to reproduce expected between-subject differences. Results showed that the adaptive controller could adapt and modulate stimulation parameters and respiratory rate to follow a desired model-generated breath volume trajectory in response to dynamic arterial CO2 levels. In silico studies aimed at assessing potential for clinical translation showed that an enhanced controller modified for human use could successfully control ventilation to achieve and maintain normocapnic arterial CO2 levels. Overall, these results suggest that use of an adaptive closed-loop controller could lead to improved ventilatory outcomes and quality of life for users of adaptive respiratory pacing

Emergency medicine physician and registrars knowledge of mechanical ventilation in Cape Town South Africa by Moosa Kalla.

Includes abstract.Includes bibliographical references.The aim of this study is: to determine whether Emergency Physicians have knowledge to optimally mechanically ventilate the intubated patient

Pico de fluxo da tosse como preditor de sucesso na extubação orotraqueal: revisão sistemática com metanálise

Uma porcentagem significativa de pacientes que obtêm sucesso no teste de respiração espontânea (TRE) é reintubada devido à incapacidade de proteger as vias aéreas. Esta revisão sistemática foi realizada para analisar a capacidade do pico de fluxo da tosse (PFT) em predizer o desfecho da extubação em pacientes que passaram no TRE. Métodos: A pesquisa abrangeu as bases de dados científicos MEDLINE, EMBASE, LILACS e IBECS, Scopus, Cochrane, Web of Science, CINAHL, SciELO e literatura cinzenta. O instrumento de avaliação Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) foi utilizado para avaliar a qualidade metodológica e o risco de viés do estudo. A heterogeneidade estatística através do likelihood e odds ratio foi avaliada usando gráfico de forest plot e através da estatística Q de Cochran, e calculou-se a curva SROC (summary receiver operating characteristic) utilizando múltiplos pontos de corte. Resultados: Muitos estudos apresentaram “risco incerto” de viés nos critérios de “seleção de pacientes” e “fluxo e tempo”. Dos 12 estudos incluídos, 7 apresentaram “alto risco” e 5 “risco incerto” no item “padrão de referência”, devido à falta de critérios clínicos objetivos para reintubação, uso de terapia de resgate e não exclusão de pacientes que reintubaram por laringoespasmo. A predição diagnóstica da PFT para o resultado da extubação foi baixa a moderada, considerando os resultados de todos os estudos incluídos. Uma análise de subgrupo incluindo apenas os estudos com ponto de corte entre 55-65 L/min mostrou um desempenho um pouco melhor, porém ainda moderado. Conclusão: A avaliação do PFT considerando um ponto de corte entre 55-65 L/min pode ser útil como uma medida complementar antes da extubação. São necessários mais estudos com protocolos bem estabelecidos para elucidar o melhor método e equipamento para registrar o PFT, bem como o melhor ponto de corte.A considerable proportion of patients who succeed in the spontaneous breathing trial (SBT) are reintubated because of the incapacity to protect their airways. This systematic review was designed to assess the cough peak flow CPF usefulness to predict the extubation outcome in patients who passed an SBT. Methods: The search covered the databases MEDLINE, EMBASE, LILACS and IBECS scientific databases, CINAHL, SciELO, Cochrane, Scopus, Web of Science, and gray literature. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) was used to assess the methodological quality and risk of study bias. The statistical heterogeneity of likelihood and diagnostic odds ratios was evaluated using forest plots and the Cochran’s Q statistic, and a crosshair summary receiver operator characteristic (SROC) plot using the multiple cutoffs model was calculated. Results: Many studies presented unclear risk of bias in the “patient selection”, and “flow and time” criteria. Of the 12 included studies, 7 presented “high risk” and 5 a “unclear risk” in the item “Reference Standard”, because of lack of objective clinical criteria for reintubation, use of rescue therapy and non-exclusion of patients who reintubated for laryngospasm. The diagnostic performance of CPF for extubation outcome was low to moderate when considering the results from all included studies. A subgroup analysis including only the studies with a cutoff between 55-65L/min showed a slightly better performance, however, still moderate. Conclusion: The CPF assessment considering a cutoff between 55-65L/min may be useful as a complementary measurement prior to the extubation. More well-designed studies are needed to elucidate the best method and equipment to record CPF, as well as the best cutoff.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Web applications for teaching the respiratory system: content validation

The subject of respiratory mechanics has complex characteristics, functions, and interactions that can be difficult to understand in training and medical education contexts. As such, education strategies based on computational simulations comprise useful tools, but their application in the medical area requires stricter validation processes. This paper shows a statistical and a Delphi validation for two modules of a web application used for respiratory system learning: (I) “Anatomy and Physiology” and (II) “Work of Breathing Indexes”. For statistical validation, population and individual analyses were made using a database of healthy men to compare experimental and model-predicted data. For both modules, the predicted values followed the trend marked by the experimental data in the population analysis, while in the individual analysis, the predicted errors were 9.54% and 25.38% for maximal tidal volume and airflow, respectively, and 6.55%, 9.33%, and 11.77% for rapid shallow breathing index, work of breathing, and maximal inspiratory pressure, respectively. For the Delphi validation, an average higher than 4 was obtained after health professionals evaluated both modules from 1 to 5. In conclusion, both modules are good tools for respiratory system learning processes. The studied parameters behaved consistently with the expressions that describe ventilatory dynamics and were correlated with experimental data; furthermore, they had great acceptance by specialists.Peer ReviewedPostprint (published version

Modeling and Estimation of Cardiorespiratory Function, with Application to Mechanical Ventilation

Evidence-based medicine is at the heart of current medical practice where clinical decisions are driven by research data. However, most current therapy recommendations follow generalized protocols and guidelines that are based on epidemiological (population) studies and thus not suited for the individual patient's demands. Patient-tailored therapies are considered, hence, an unmet clinical need. We believe that mathematical models of the physiology can attend to such a clinical need, because they can be tuned to the individual patient. Such models provide a sound mathematical framework for personalized clinical decisions. In particular, physiological models in medicine can serve the following two purposes: 1) They can be an efficient tool to quantify cardiopulmonary dynamics, conduct virtual clinical/physiological experiments, and investigate the effects of specific treatments. 2) Model-based estimation techniques can assess physiological parameters or variables, which are otherwise impractical or dangerous to measure; they can effectively tune a generic model to become patient-specific, able to mimic the behavior of a particular patient. In this thesis, we propose a series of modifications to a previously developed cardiopulmonary model (CP Model) in order to better replicate heart-lung interaction phenomena that are typically observed under mechanical ventilation, hence allowing for a more accurate analysis of ventilation-induced changes in cardiac function. The response of this modified model is validated with experimental data collected during mechanical ventilation conditions. Further, as an industrial application of mathematical models, we present a patient emulator system that comprises the modified CP Model, a physical ventilator, and a piston-cylinder arrangement that serves as an electrical-to-hydraulic transducer. The modified CP Model then serves as the virtual patient that is being ventilated, where disease conditions can be instilled. Such a system is designed to offer a well-controlled experimental environment for ventilator manufacturers to efficaciously test and compare ventilation modalities and therapies, thereby enhancing their verification and validation manufacturing processes. Finally, we develop a model-based approach to estimate (noninvasively) the function of the cardiovascular system, in terms of cardiac performance (i.e., cardiac output) and the dynamics of the systemic arterial tree (i.e., time constant). With this technique, we envision to provide continuous and real-time bedside monitoring of changes in cardiovascular function, such as those induced by changes in ventilator settings

European Respiratory Society International Congress, Barcelona, 2022: Highlights from the Respiratory clinical care and physiology assembly

It is a challenge to keep abreast of all the clinical and scientific advances in the field of respiratory medicine. This article contains an overview of laboratory-based science, clinical trials and qualitative research that were presented during the 2022 European Respiratory Society International Congress within the sessions from the five groups of the Assembly 1 – Respiratory clinical care and physiology. Selected presentations are summarised from a wide range of topics: clinical problems, rehabilitation and chronic care, general practice and primary care, electronic/mobile health (e-health/m-health), clinical respiratory physiology, exercise and functional imaging