Melatonin supplementation enhances pulmonary rehabilitation outcomes in COPD: a randomized, double-blind, placebo-controlled study.

Melatonin (MLT), the main product of the pineal gland, is involved in muscle tissue repair and regeneration, besides several other important physiologic functions. In COPD, MLT administration can improve lung oxidative stress and sleep quality, but its potential effects on the outcomes of pulmonary rehabilitation (PR) have not been previously investigated. A randomized controlled trial was undertaken to test the hypothesis that a combined approach of rehabilitative exercise training and MLT supplementation could maximize functional performance, health status and quality of life in patients with COPD. Thirty-nine individuals with COPD referred to a supervised PR program at the Federal University of Ceara, Brazil, were randomized to receive MLT (3 mg/day; n = 18) or placebo (n = 21). Exercise capacity (6-min walk test - 6MWT), health status (COPD assessment test), and quality of life (airways questionnaire 20) were investigated as primary outcomes. No differences were observed at baseline in demographic, anthropometric and clinical characteristics between MLT and placebo groups. At the end of PR, superiority of the MLT group was demonstrated in improvement in the distance covered in the 6MWT (71 ± 26 vs. 25 ± 36 m; p < 0.01), health status (-11 ± 6 vs. -3 ± 5; p < 0.01), and quality of life (-6.9 ± 3.0 vs. -1.9 ± 2.4; p < 0.01), compared to the placebo group. In conclusion, MLT supplementation during the course of 12 weeks of PR can improve functional capacity, health status and quality of life in patients with COPD. These findings may have significant implications for the management of this condition.

A New Full-Face Mask for Multifunctional Non-Invasive Ventilation.

Background: Noninvasive ventilation (NIV) provides positive pressure through different interfaces. A multifunctional full-face mask prototype was developed to provide NIV from three sources: ICU ventilators, portable ventilators, and high-flow medical gas pipeline systems. This study aimed to evaluate the usability of this prototype mask. Methods: This was a quantitative experimental study, conducted in two phases: the development of a full-face mask prototype NIV interface, and the evaluation of its usability by health professionals (evaluators) using a heuristic approach. The Wolf Mask prototype is a multifunctional full-face mask that makes it possible to deliver positive pressure from three different sources: microprocessor-controlled ICU ventilators, portable ventilators with single-limb circuits, and high-flow medical gas. The evaluation was conducted in three stages: presentation of the prototype to the evaluators; skills testing via simulation in a clinical environment; and a review of skills. Results: The prototype was developed by a multidisciplinary team and patented in Brazil. The evaluators were 10 health professionals specializing in NIV. Seven skills related to handling the prototype were evaluated. Three of the ten evaluators called for (non-urgent) changes to improve recognition of the components of the prototype. Only one evaluator called for (non-urgent) changes to improve recognition of the pieces, assembly, and checking the mask. Conclusions: The newly developed multifunctional full-face mask prototype demonstrated excellent usability for providing noninvasive ventilation from multiple sources. Minor modifications may further improve the design.

Influences of assisted breathing and mechanical ventilator settings on tidal volume and alveolar pressures in acute respiratory distress syndrome: a bench study. / Influência da ventilação assistida e dos ajustes do ventilador mecânico sobre o volume corrente e as pressões alveolares na síndrome do desconforto respiratório agudo: um estudo de bancada.

OBJECTIVE: To evaluate the influences of respiratory muscle efforts and respiratory rate setting in the ventilator on tidal volume and alveolar distending pressures at end inspiration and expiration in volume-controlled ventilation and pressure-controlled ventilation modes in acute respiratory distress syndrome. METHODS: An active test lung (ASL 5000™) connected to five intensive care unit ventilators was used in a model of acute respiratory distress syndrome. Respiratory muscle efforts (muscle pressure) were configured in three different ways: no effort (muscle pressure: 0cmH2O); inspiratory efforts only (muscle pressure:-5cmH2O, neural inspiratory time of 0.6s); and both inspiratory and expiratory muscle efforts (muscle pressure:-5/+5cmH2O). Volume-controlled and pressure-controlled ventilation modes were set to deliver a target tidal volume of 420mL and positive end-expiratory pressure of 10cmH2O. The tidal volume delivered to the lungs, alveolar pressures at the end of inspiration, and alveolar pressures at end expiration were evaluated. RESULTS: When triggered by the simulated patient, the median tidal volume was 27mL lower than the set tidal volume (range-63 to +79mL), and there was variation in alveolar pressures with a median of 25.4cmH2O (range 20.5 to 30cmH2O). In the simulated scenarios with both spontaneous inspiratory and expiratory muscle efforts and with a mandatory respiratory rate lower than the simulated patient's efforts, the median tidal volume was higher than controlled breathing. CONCLUSION: Adjusting respiratory muscle effort and pulmonary ventilator respiratory rate to a value above the patient's respiratory rate in assisted/controlled modes generated large variations in tidal volume and pulmonary pressures, while the controlled mode showed no variations in these outcomes.

OBJETIVO: Avaliar a influência dos esforços musculares respiratórios e do ajuste da frequência respiratória no ventilador sobre o volume corrente e as pressões de distensão alveolar ao final da inspiração e expiração com ventilação sob os modos controle por volume e controle por pressão na síndrome do desconforto respiratório agudo. MÉTODOS: Utilizou-se um simulador mecânico de pulmão (ASL 5000™) conectado a cinco tipos de ventiladores utilizados em unidade de terapia intensiva, em um modelo de síndrome do desconforto respiratório agudo. Os esforços musculares respiratórios (pressão muscular) foram configurados de três formas distintas: sem esforço (pressão muscular: 0cmH2O), apenas esforços inspiratórios (pressão muscular: - 5cmH2O, tempo inspiratório neural de 0,6 segundos) e esforços musculares inspiratórios e expiratórios (pressão muscular:-5/+5cmH2O). Foram configuradas ventilação sob os modos controle por volume e ventilação com controle por pressão para oferecer um volume corrente de 420mL e pressão positiva expiratória final de 10cmH2O. Avaliaram-se o volume corrente fornecido aos pulmões, as pressões alveolares no final da inspiração e as pressões alveolares no final da expiração. RESULTADOS: Quando disparado pelo paciente simulado, o volume corrente mediano foi 27mL menor do que o volume corrente ajustado (variação-63 a +79mL), e ocorreu uma variação nas pressões alveolares com mediana de 25,4cmH2O (faixa de 20,5 a 30cmH2O). Nos cenários simulados com esforço muscular tanto inspiratório quanto expiratório e com frequência respiratória mandatória inferior à dos esforços do paciente simulado, o volume corrente mediano foi maior com ventilação controlada. CONCLUSÃO: O ajuste do esforço muscular respiratório e da frequência respiratória no ventilador em um valor acima da frequência respiratória do paciente nos modos de ventilação assistida/controlada gerou maiores variações no volume corrente e nas pressões pulmonares, enquanto o modo controlado não mostrou variações nesses desfechos.

Influência da ventilação assistida e dos ajustes do ventilador mecânico sobre o volume corrente e as pressões alveolares na síndrome do desconforto respiratório agudo: um estudo de bancada / Influences of assisted breathing and mechanical ventilator settings on tidal volume and alveolar pressures in acute respiratory distress syndrome: a bench study

RESUMO Objetivo: Avaliar a influência dos esforços musculares respiratórios e do ajuste da frequência respiratória no ventilador sobre o volume corrente e as pressões de distensão alveolar ao final da inspiração e expiração com ventilação sob os modos controle por volume e controle por pressão na síndrome do desconforto respiratório agudo. Métodos: Utilizou-se um simulador mecânico de pulmão (ASL 5000™) conectado a cinco tipos de ventiladores utilizados em unidade de terapia intensiva, em um modelo de síndrome do desconforto respiratório agudo. Os esforços musculares respiratórios (pressão muscular) foram configurados de três formas distintas: sem esforço (pressão muscular: 0cmH2O), apenas esforços inspiratórios (pressão muscular: - 5cmH2O, tempo inspiratório neural de 0,6 segundos) e esforços musculares inspiratórios e expiratórios (pressão muscular:-5/+5cmH2O). Foram configuradas ventilação sob os modos controle por volume e ventilação com controle por pressão para oferecer um volume corrente de 420mL e pressão positiva expiratória final de 10cmH2O. Avaliaram-se o volume corrente fornecido aos pulmões, as pressões alveolares no final da inspiração e as pressões alveolares no final da expiração. Resultados: Quando disparado pelo paciente simulado, o volume corrente mediano foi 27mL menor do que o volume corrente ajustado (variação-63 a +79mL), e ocorreu uma variação nas pressões alveolares com mediana de 25,4cmH2O (faixa de 20,5 a 30cmH2O). Nos cenários simulados com esforço muscular tanto inspiratório quanto expiratório e com frequência respiratória mandatória inferior à dos esforços do paciente simulado, o volume corrente mediano foi maior com ventilação controlada. Conclusão: O ajuste do esforço muscular respiratório e da frequência respiratória no ventilador em um valor acima da frequência respiratória do paciente nos modos de ventilação assistida/controlada gerou maiores variações no volume corrente e nas pressões pulmonares, enquanto o modo controlado não mostrou variações nesses desfechos.

ABSTRACT Objective: To evaluate the influences of respiratory muscle efforts and respiratory rate setting in the ventilator on tidal volume and alveolar distending pressures at end inspiration and expiration in volume-controlled ventilation and pressure-controlled ventilation modes in acute respiratory distress syndrome. Methods: An active test lung (ASL 5000™) connected to five intensive care unit ventilators was used in a model of acute respiratory distress syndrome. Respiratory muscle efforts (muscle pressure) were configured in three different ways: no effort (muscle pressure: 0cmH2O); inspiratory efforts only (muscle pressure:-5cmH2O, neural inspiratory time of 0.6s); and both inspiratory and expiratory muscle efforts (muscle pressure:-5/+5cmH2O). Volume-controlled and pressure-controlled ventilation modes were set to deliver a target tidal volume of 420mL and positive end-expiratory pressure of 10cmH2O. The tidal volume delivered to the lungs, alveolar pressures at the end of inspiration, and alveolar pressures at end expiration were evaluated. Results: When triggered by the simulated patient, the median tidal volume was 27mL lower than the set tidal volume (range-63 to +79mL), and there was variation in alveolar pressures with a median of 25.4cmH2O (range 20.5 to 30cmH2O). In the simulated scenarios with both spontaneous inspiratory and expiratory muscle efforts and with a mandatory respiratory rate lower than the simulated patient's efforts, the median tidal volume was higher than controlled breathing. Conclusion: Adjusting respiratory muscle effort and pulmonary ventilator respiratory rate to a value above the patient's respiratory rate in assisted/controlled modes generated large variations in tidal volume and pulmonary pressures, while the controlled mode showed no variations in these outcomes.