Cambios en Mecánica Respiratoria en Usuarios Pediátricos en Ventilación Mecánica Post Cirugía de Cardiopatía Congénita Sometidos a Kinesiología Respiratoria versus Succión Endotraqueal. Revisión Estructurada / Changes in Respiratory Mechanics in Pediatric Users on Mechanical Ventilation Post Congenital Heart Disease Surgery Undergoing Respiratory Kinesiology versus Endotracheal Suction. Structured Review

Introducción. Las cardiopatías congénitas (CC) en Chile corresponden a la segunda causa de muerte en menores de 1 año, requiriendo cirugías paliativas y/o correctivas el 65% de estas. En el post operatorio frecuentemente se utiliza ventilación mecánica invasiva (VM) y succión endotraqueal (SET) para remover secreciones. Sin embargo, la kinesiología respiratoria (KTR) ha mostrado mejoras significativas en la distensibilidad toracopulmonar (Cest) y resistencia de vía aérea (Rva) en otros grupos de usuarios pediátricos y adultos en VM. Objetivo. Comparar los cambios en la Cest y Rva en usuarios pediátricos en VM post cirugía de cardiopatía congénita (CCC) sometidos a KTR versus SET exclusiva. Métodos. Revisión sistemática de estudios publicados en bases de datos PUBMED, PeDro, Scielo y Google Scholar que comparan el uso de KTR ó SET sobre los cambios en mecánica ventilatoria en usuarios pediátricos en VM post cirugía de cardiopatía congénita, limitados a inglés, español y portugués, excluyendo a sujetos con traqueostomía o con oxigenación por membrana extracorpórea. Se utilizó guía PRISMA para la selección de artículos. Se revisaron 397 artículos y se seleccionó 1 artículo extra de los artículos sugeridos. Se eliminó 1 artículo por duplicidad. Por títulos y resúmenes se seleccionaron 2 artículos, los cuales al leer el texto completo fueron retirados debido a que la población no correspondía a cardiópatas. Resultados. El final de artículos seleccionados fue de 0 artículos, debido a lo cual se removió el operador Booleano "NOT", y se removió la población de cardiopatías. De este modo quedaron 2 artículos seleccionados para la revisión cualitativa final donde se compara KTR versus SET, y KTR en kinesiólogos especialistas y no especialistas, mostrando ambos aumento en la Cest y disminución de la Rva a favor de la KTR, hasta los 30 minutos post intervención. Conclusiones. No se encontraron artículos que demuestren cambios en Cest y Rva con el uso de KTR + SET versus SET exclusiva, en usuarios pediátricos ventilados posterior a CCC. Con la remoción de filtros seleccionamos 2 artículos que demuestran aumento de Cest y disminución de Rva en sujetos pediátricos en VM, uno comparando con SET, y por grupos de especialistas y no especialistas en respiratorio. Se sugieren estudios primarios para evaluar los efectos de esta intervención en esta población.

Introduction. Congenital heart diseases (CHD) are the second general cause for children death under 1 year. In Chile, approximately 65% CHD need surgery, could was palliative or corrective. In the postoperative period, invasive mechanical ventilation (MV) is frequently used as a life support method, but it is associated with complications. Tracheal suction (SET) is regularly used to remove secretions; however, respiratory chest physiotherapy (KTR) has shown significant improvements in thoraco-pulmonary compliance and airway resistance in other groups of pediatrics and adult's users in MV. Objetive. to compare changes in thoraco-pulmonary compliance and airway resistance in pediatric subjects under mechanical ventilation after congenital heart disease surgery comparing chest physiotherapy and exclusive tracheal suction. Methods. systematic review of studies published in PUBMED, PeDro, Scielo and Google Scholar databases who compares KTR or SET use on changes in ventilatory mechanics in pediatric users under MV after congenital heart disease surgery, limited to English, Spanish and Portuguese languages, excluding user with tracheostomy or extracorporeal membrane of oxygenation. It was use the PRISMA guide to articles selection. A search was carried out, with a total of 397 articles reviewed (English: PubMed = 3, PeDro = 8, Scholar = 383; Spanish: Scholar = 3, Scielo = 0; and Portuguese: Scielo = 0). One extra article was selected from the suggested articles, and 1 article was eliminated due to duplication. By titles and abstracts, 2 articles were selected, but the population did not correspond to heart disease. Results. the final selected articles were 0 articles. By this reason, it were removed: Boolean operator "NOT", and congenital heart disease population. Thus, 2 articles were selected for the final qualitative review where it was compares KTR versus SET, and KTR by specialist and non-specialist. Both articles shown improvement in compliance and resistance until 30 minutes post intervention. The CC population was in a 40 to 60% range in both studies. Conclusions. it was no found articles that demonstrate changes in compliance and resistance in the airway with the use of KTR + SET versus exclusive SET in pediatric users after CCC connected to MV. After filter remotion, we found 2 studies shown improves in increase compliance and reduce resistance in pediatric user in MV, ones comparing with SET, and the other one comparing between specialists in respiratory pediatric physiotherapy and not specialists. It suggests to made primary clinical studies about this intervention in CC population.

Real-time changes in rib cage expansion and use of abdominal mechanical stimulation in newborns: a quasi-experimental study / Mudanças na expansibilidade torácica com o uso de estímulo mecânico na região abdominal em recém-nascidos: um estudo quase-experimental

ABSTRACT Objective: To assess the rib cage expansion and respiratory rate in newborns using an abdominal stabilization band. Methods: The study included 32 newborns of both genders, with gestational age between 35 and 41 weeks. The abdominal stabilization band was used for 15 minutes between the xiphoid process and the anterosuperior iliac crest, with an abdominal contention 0.5cm smaller than the abdominal circumference. The rib cage expansion was evaluated by a breathing transducer (Pneumotrace II™) three minutes before using the band, during the use (15 minutes), and ten minutes after removing the band. The Shapiro-Wilk test verified data normality, and the Wilcoxon test compared the variables considering rib cage expansion and respiratory rate. Significance was set to p<0.05. Results: There was an increase in respiratory rate when comparing before and ten minutes after removing (p=0.008) the abdominal stabilization band, as well as when comparing during its use and ten minutes after its removal (p=0.001). There was also an increase in rib cage expansion when comparing before and during the use of the abdominal stabilization band (p=0.005). Conclusions: The use of the abdominal stabilization band promoted an increase in the rib cage expansion and respiratory rate in the assessed newborns and may be a viable option to improve the respiratory kinematics of this population.

RESUMO Objetivo: Avaliar a expansibilidade torácica e a frequência respiratória em recém-nascidos que fizeram uso de uma faixa de estabilização abdominal. Métodos: O estudo incluiu 32 recém-nascidos de ambos os sexos, com idade gestacional entre 35 e 41 semanas. A faixa de estabilização abdominal foi mantida por 15 minutos entre o processo xifoide e a espinha ilíaca anterossuperior, com contenção abdominal 0,5 cm menor do que a circunferência abdominal. A expansibilidade torácica foi avaliada por um transdutor piezoelétrico (Pneumotrace II™) 3 minutos antes do uso da faixa, durante 15 minutos, e 10 minutos após sua retirada. A normalidade das variáveis foi testada pelo teste de Shapiro-Wilk e a análise comparativa da expansibilidade torácica e da frequência respiratória foi realizada por meio do teste t pareado, considerando-se p<0,05. Resultados: Houve aumento da frequência respiratória quando comparados os tempos antes do uso da faixa e 10 minutos após a retirada (p=0,008), bem como quando comparados os tempos durante o uso e 10 minutos após a retirada da faixa (p=0,001). Houve aumento da expansibilidade torácica quando comparados os tempos antes e durante o uso da faixa (p=0,005). Conclusões: O uso da faixa de estabilização abdominal conferiu aumento da expansibilidade torácica e da frequência respiratória nos recém-nascidos estudados, podendo ser uma opção viável para a melhora da cinemática respiratória dessa população.

Factors associated with mortality in mechanically ventilated patients with severe acute respiratory syndrome due to COVID-19 evolution / Fatores associados à mortalidade em pacientes ventilados mecanicamente com síndrome respiratória aguda grave por evolução da COVID-19

ABSTRACT Objectives: To evaluate the factors associated with mortality in mechanically ventilated patients with acute respiratory distress syndrome due to COVID-19. Methods: This was a retrospective, multicenter cohort study that included 425 mechanically ventilated adult patients with COVID-19 admitted to 4 intensive care units. Clinical data comprising the SOFA score, laboratory data and mechanical characteristics of the respiratory system were collected in a standardized way immediately after the start of invasive mechanical ventilation. The risk factors for death were analyzed using Cox regression to estimate the risk ratios and their respective 95%CIs. Results: Body mass index (RR 1.17; 95%CI 1.11 - 1.20; p < 0.001), SOFA score (RR 1.39; 95%CI 1.31 - 1.49; p < 0.001) and driving pressure (RR 1.24; 95%CI 1.21 - 1.29; p < 0.001) were considered independent factors associated with mortality in mechanically ventilated patients with acute respiratory distress syndrome due to COVID-19. Respiratory system compliance (RR 0.92; 95%CI 0.90 - 0.93; p < 0.001) was associated with lower mortality. The comparative analysis of the survival curves indicated that patients with respiratory system compliance (< 30mL/cmH2O), a higher SOFA score (> 5 points) and higher driving pressure (> 14cmH2O) were more significantly associated with the outcome of death at 28 days and 60 days. Conclusion: Patients with a body mass index > 32kg/m2, respiratory system compliance < 30mL/cmH2O, driving pressure > 14cmH2O and SOFA score > 5.8 immediately after the initiation of invasive ventilatory support had worse outcomes, and independent risk factors were associated with higher mortality in this population.

RESUMO Objetivos: Avaliar os fatores associados à mortalidade em pacientes ventilados mecanicamente com síndrome o desconforto respiratório agudo por evolução da COVID-19. Métodos: Estudo de coorte retrospectiva, multicêntrica, que incluiu 425 pacientes adultos com COVID-19, ventilados mecanicamente, internados em 4 unidades de terapia intensiva. Foram coletados dados clínicos que compõem o escore SOFA, dados laboratoriais e características mecânicas do sistema respiratório, de forma padronizada, imediatamente após o início da ventilação mecânica invasiva. Os fatores de risco para óbito foram analisados por meio da regressão de Cox, para estimar as razões de risco, e seus respectivos IC95%. Resultados: Índice de massa corporal (RR de 1,17; IC95% 1,11 - 1,20; p < 0,001), escore SOFA (RR de 1,39; IC95% 1,31 - 1,49; p < 0,001) e driving pressure (RR de 1,24; IC95% 1,21 - 1,29; p < 0,001) foram considerados fatores independentes associados à mortalidade em pacientes ventilados mecanicamente com síndrome do desconforto respiratório agudo por COVID-19. Já a complacência do sistema respiratório (RR de 0,92; IC95% 0,90 - 0,93; p < 0,001) foi associada à menor mortalidade. A análise comparativa das curvas de sobrevida demonstra que pacientes com complacência do sistema respiratório (< 30mL/cmH2O), maior SOFA escore (> 5 pontos) e maior driving pressure (> 14cmH2O) apresentaram maior associação ao desfecho morte em 28 dias e 60 dias. Conclusão: Pacientes com índice de massa corporal > 32kg/m2, complacência do sistema respiratório < 30mL/cmH2O, driving pressure > 14cmH2O e SOFA escore > 5,8, imediatamente após o início da assistência ventilatória invasiva, apresentam piores desfechos no segmento, sendo fatores de risco independentes associados à maior mortalidade nessa população.

Effects of different ventilation modes on respiratory mechanics, hemodynamics and biochemical metabolism in patients undergoing laparoscopic colorectal cancer surgery / 中国医师进修杂志

Objective:To compare the effects of pressure controlled ventilation (PCV) and volume controlled ventilation (VCV) on respiratory mechanics, hemodynamics and biochemical metabolism in patients undergoing laparoscopic colorectal cancer surgery.Methods:The clinical data of 78 patients underwent laparoscopic colorectal cancer surgery from August 2019 to June 2020 in Inner Mongolia People′s Hospital were retrospectively analyzed. Among them, 39 patients were treated with PCV (PCV group), and 39 were treated with VCV (VCV group). The respiratory mechanics, hemodynamics and biochemical metabolism indexes 10 min after anesthesia induction (T 1), 10 min after pneumoperitoneum + low head and foot height (T 2), 60 min after pneumoperitoneum + low head and foot height (T 3) and 120 min after pneumoperitoneum + low head and foot height (T 4) were recorded. The respiratory mechanical indexes included mean airway pressure (P mean), airway peak pressure (P peak), pressure of end tidal carbon dioxide (P ETCO 2) and dynamic lung compliance (C Ldyn); hemodynamic indexes included mean arterial pressure (MAP) and heart rate; and biochemical metabolic indexes included base excess, serum natrium, serum potassium, negative logarithm of the hydrogen ion concentration (pH) and blood glucose. Results:The P mean, P peak and P ETCO 2 T 1 to T 4 in PCV group were significantly lower than those in VCV group, P mean: (7.12 ± 1.37) cmH 2O (1 cmH 2O = 0.098 kPa) vs. (8.54 ± 1.84) cmH 2O, (9.80 ± 2.26) cmH 2O vs. (11.63 ± 2.87) cmH 2O, (9.51 ± 2.17) cmH 2O vs. (11.72 ± 2.90) cmH 2O, (7.04 ± 1.34) cmH 2O vs. (8.65 ± 1.88) cmH 2O; P peak: (13.41 ± 2.68) cmH 2O vs. (15.06 ± 3.05) cmH 2O, (20.92 ± 3.11) cmH 2O vs. (23.45 ± 4.02) cmH 2O, (21.14 ± 3.50) cmH 2O vs. (23.69 ± 4.26) cmH 2O, (15.03 ± 2.74) cmH 2O vs. (16.45 ± 3.21) cmH 2O; P ETCO 2: (30.59 ± 1.57) mmHg (1 mmHg = 0.133 kPa) vs. (32.04 ± 2.11) mmHg, (35.02 ± 4.15) mmHg vs. (39.88 ± 4.76) mmHg, (35.90 ± 4.22) mmHg vs. (40.11 ± 4.87) mmHg, (34.33 ± 4.17) mmHg vs. (37.65 ± 2.69) mmHg; the C Ldyn was significantly higher than that in VCV group: (40.68 ± 3.98) ml/cmH 2O vs. (35.47 ± 2.56) ml/cmH 2O, (30.25 ± 3.21) ml/cmH 2O vs. (22.40 ± 2.75) ml/cmH 2O, (29.78 ± 3.06) ml/cmH 2O vs. (22.60 ± 2.81) ml/cmH 2O, (40.32 ± 4.25) ml/cmH 2O vs. (33.61 ± 2.81) ml/cmH 2O, and there were statistical differences ( P<0.01 or <0.05). The MAP and heart rate T 1 to T 4 in PCV group were significantly lower than those in VCV group, and there was statistical difference ( P<0.01 or <0.05). The base excess, serum natrium, serum potassium and pH T 1 to T 4 in PCV group were significantly higher than those in VCV group, while the blood glucose was significantly lower than that in VCV group, and there was statistical difference ( P<0.01 or <0.05). Conclusions:Compared with VCV, PCV can promote the recovery of respiratory mechanics index, stabilize hemodynamics and improve biochemical metabolism index in patients undergoing laparoscopic colorectal cancer surgery.

Fisiología respiratoria: fisiopatología de las enfermedades obstructivas / Pathophysiology of obstructive diseases

Las enfermedades obstructivas de la vía aérea pediátrica son muy frecuentes debido a los fenómenos mecánicos que están involucrados. En los niños más pequeños, la marcada resistencia de las vías aéreas pequeñas, determinada por la falta de tejido elástico y una caja torácica aún no bien desarrollada; tanto su estructura como la musculatura, facilitarán que cuadros infecciosos, mecánicos (cuerpo extraño) y compresivos, determinen que los flujos de aire se vean limitados y con ello la ventilación alveolar. La respuesta fisiológica con aumento del trabajo respiratorio es limitada y por lo tanto la fatiga muscular determinará hipoventilación con las consecuencias de hipoxemia e hipercapnia.

Obstructive diseases of the pediatric airway are very frequent due to the mechanical phenomena that are involved. The marked resistance of the small airways, such as the lack of elastic tissue and a thoracic cage that is not yet well developed, both in its structure and in the musculature, will make it easier for infectious, mechanical (foreign body), compressive and other conditions to determine that the flows of air are limited and with it the alveolar ventilation. The physiological response with increased work of breathing is limited and therefore muscle fatigue will determine hypoventilation, with the consequences of hypoxemia and hypercapnia.

Desfechos clínicos e características da mecânica pulmonar entre a síndrome do desconforto respiratório agudo associada à COVID-19 e a não associada à COVID-19: uma análise de escore de propensão de dois importantes ensaios randomizados / Clinical outcomes and lung mechanics characteristics between COVID-19 and non-COVID-19-associated acute respiratory distress syndrome: a propensity score analysis of two major randomized trials

RESUMO Objetivo: Comparar a mecânica pulmonar e os desfechos entre a síndrome do desconforto respiratório agudo associada à COVID-19 e a síndrome do desconforto respiratório agudo não associada à COVID-19. Métodos: Combinamos dados de dois ensaios randomizados sobre a síndrome do desconforto respiratório agudo, um incluindo apenas pacientes com COVID-19 e o outro incluindo apenas pacientes sem COVID-19, para determinar se a síndrome do desconforto respiratório agudo associada à COVID-19 está associada à maior mortalidade aos 28 dias do que a síndrome do desconforto respiratório agudo não associada à COVID-19 e também examinar as diferenças na mecânica pulmonar entre esses dois tipos de síndrome do desconforto respiratório agudo. Resultados: Foram incluídos na análise principal 299 pacientes com síndrome do desconforto respiratório agudo associada à COVID-19 e 1.010 pacientes com síndrome do desconforto respiratório agudo não associada à COVID-19. Os resultados mostraram que os pacientes sem COVID-19 utilizaram pressão positiva expiratória final mais alta (12,5cmH2O; DP 3,2 versus 11,7cmH2O; DP 2,8; p < 0,001), foram ventilados com volumes correntes mais baixos (5,8mL/kg; DP 1,0 versus 6,5mL/kg; DP 1,2; p < 0,001) e apresentaram menor complacência respiratória estática ajustada para o peso ideal (0,5mL/cmH2O/kg; DP 0,3 versus 0,6mL/cmH2O/kg; DP 0,3; p = 0,01). Não houve diferença entre os grupos quanto à mortalidade aos 28 dias (52,3% versus 58,9%; p = 0,52) ou à duração da ventilação mecânica nos primeiros 28 dias entre os sobreviventes (13 [IQ 5 - 22] dias versus 12 [IQ 6 - 26] dias; p = 0,46). Conclusão: Esta análise mostrou que os pacientes com síndrome do desconforto respiratório agudo não associada à COVID-19 têm mecânica pulmonar diferente, mas desfechos semelhantes aos dos pacientes com síndrome do desconforto respiratório agudo associada à COVID-19. Após pareamento por escore de propensão, não houve diferença na mecânica pulmonar e nem nos desfechos entre os grupos.

ABSTRACT Objective: To compare the lung mechanics and outcomes between COVID-19-associated acute respiratory distress syndrome and non-COVID-19-associated acute respiratory distress syndrome. Methods: We combined data from two randomized trials in acute respiratory distress syndrome, one including only COVID-19 patients and the other including only patients without COVID-19, to determine whether COVID-19-associated acute respiratory distress syndrome is associated with higher 28-day mortality than non-COVID-19 acute respiratory distress syndrome and to examine the differences in lung mechanics between these two types of acute respiratory distress syndrome. Results: A total of 299 patients with COVID-19-associated acute respiratory distress syndrome and 1,010 patients with non-COVID-19-associated acute respiratory distress syndrome were included in the main analysis. The results showed that non-COVID-19 patients used higher positive end-expiratory pressure (12.5cmH2O; SD 3.2 versus 11.7cmH2O SD 2.8; p < 0.001), were ventilated with lower tidal volumes (5.8mL/kg; SD 1.0 versus 6.5mL/kg; SD 1.2; p < 0.001) and had lower static respiratory compliance adjusted for ideal body weight (0.5mL/cmH2O/kg; SD 0.3 versus 0.6mL/cmH2O/kg; SD 0.3; p = 0.01). There was no difference between groups in 28-day mortality (52.3% versus 58.9%; p = 0.52) or mechanical ventilation duration in the first 28 days among survivors (13 [IQR 5 - 22] versus 12 [IQR 6 - 26], p = 0.46). Conclusion: This analysis showed that patients with non-COVID-19-associated acute respiratory distress syndrome have different lung mechanics but similar outcomes to COVID-19-associated acute respiratory distress syndrome patients. After propensity score matching, there was no difference in lung mechanics or outcomes between groups.

Influência da mechanical power e de seus componentes na ventilação mecânica em SARS-CoV-2 / Influence of mechanical power and its components on mechanical ventilation in SARS-CoV-2

RESUMO Objetivo: Analisar a influência da mechanical power e de seus componentes na ventilação mecânica em SARS-CoV-2; identificar os valores dos componentes da ventilação mecânica e verificar suas correlações entre si e com a mechanical power e efeitos sobre o resultado das fórmulas de Gattinoni-S e Giosa. Métodos: Estudo observacional, longitudinal, analítico e quantitativo dos parâmetros do respirador e da mechanical power no SARS-CoV-2. Resultados: A mechanical power média foi de 26,9J/minuto (Gattinoni-S) e 30,3J/minuto (Giosa). A driving pressure foi de 14,4cmH2O, a pressão de platô de 26,5cmH2O, a pressão expiratória positiva final 12,1cmH2O, a elastância de 40,6cmH2O/L, o volume corrente foi de 0,36L e a frequência respiratória de 32/minuto. A correlação entre as fórmulas de Gattinoni e de Giosa foi de 0,98, com viés de -3,4J/minuto e diferença na correlação da pressão de resistência de 0,39 (Gattinoni-S) e 0,24 (Giosa). Entre os componentes, destacaram-se as correlações da elastância com a driving pressure (0,88), pressão expiratória positiva final (-0,54) e volume corrente (-0,44). Conclusão: Na análise da ventilação mecânica da SARS-CoV-2, constatou-se que as correlações de seus componentes com a mechanical power influenciaram em seus valores momentâneos elevados, e que as correlações de seus componentes entre si influenciaram em seu comportamento ao longo do tempo. Por possuírem efeitos específicos sobre as fórmulas de Gatinnoni-S e Giosa, os componentes da ventilação mecânica tiveram influência em seus cálculos e causaram divergências nos valores da mechanical power.

ABSTRACT Objective: To analyze the influence of mechanical power and its components on mechanical ventilation for patients infected with SARS-CoV-2; identify the values of the mechanical ventilation components and verify their correlations with each other and with the mechanical power and effects on the result of the Gattinoni-S and Giosa formulas. Methods: This was an observational, longitudinal, analytical and quantitative study of respirator and mechanical power parameters in patients with SARS-CoV-2. Results: The mean mechanical power was 26.9J/minute (Gattinoni-S) and 30.3 J/minute (Giosa). The driving pressure was 14.4cmH2O, the plateau pressure was 26.5cmH2O, the positive end-expiratory pressure was 12.1cmH2O, the elastance was 40.6cmH2O/L, the tidal volume was 0.36L, and the respiratory rate was 32 breaths/minute. The correlation between the Gattinoni and Giosa formulas was 0.98, with a bias of -3.4J/minute and a difference in the correlation of the resistance pressure of 0.39 (Gattinoni) and 0.24 (Giosa). Among the components, the correlations between elastance and driving pressure (0.88), positive end-expiratory pressure (-0.54) and tidal volume (-0.44) stood out. Conclusion: In the analysis of mechanical ventilation for patients with SARS-CoV-2, it was found that the correlations of its components with mechanical power influenced its high momentary values and and that the correlations of its components with each other influenced their behavior throughout the study period. Because they have specific effects on the Gatinnoni-S and Giosa formulas, the mechanical ventilation components influenced their calculations and caused divergence in the mechanical power values.

Espirometria e oscilometria de impulso durante internação por exacerbação pulmonar aguda em escolares com fibrose cística / Spirometry and impulse oscillometry during acute pulmonary exacerbation hospitalization in children with cystic fibrosis

Objetivo: avaliar o comportamento de parâmetros do sistema respiratório durante internação para antibioticoterapia intravenosa (AIV) como tratamento da exacerbação pulmonar aguda (EPA) em escolares com fibrose cística (FC). Métodos: estudo do tipo analítico observacional, before-after, realizado no Hospital Infantil Joana de Gusmão, Florianópolis ­ Santa Catarina. Foram incluídas crianças com diagnóstico de FC, entre seis e 15 anos, em internação para tratamento da exacerbação pulmonar aguda, no início (T1), durante (T2) e ao final (T3) da internação foi conduzida avaliação de escores específicos de EPA, dados antropométricos e realizada avaliação dos parâmetros do sistema respiratório pelo sistema de oscilometria de impulso (IOS) e espirometria. Foram obtidos, em prontuário, dados de colonização bacteriana, genótipo, gravidade da doença (Escore de Schwachman-Doershuk-ESD) e espirometria mais recente em estabilidade clínica. Aplicou-se o teste Shapiro-Wilk para análise da distribuição dos dados e os testes ANOVA de medidas repetidas, teste de Friedman, teste T pareado e Wilcoxon, com nível de significância de 5%. Resultados: participaram 16 crianças/adolescentes (68.8% meninas, 12.88±1.67anos). Houve aumento dos parâmetros da espirometria e dados antropométricos (p<0.005) no T3, bem como redução dos escores de EPA e do X5 (p<0.005) no T3. Conclusão: os dados apresentados nesse trabalho mostram melhora dos escores de EPA, dados antropométricos, parâmetros da espirometria e do parâmetro de recolhimento elástico do IOS (X5).RESUMODescritores: Fibrose cística, Exacerbação dos sintomas, Testes de função pulmonar, Mecânica respiratória (AU)

Objective: Evaluate the respiratory system parameters of children with cystic fibrosis (CF) during hospitalization for acute pulmonary exacerbation (APE) treatment. Methods: observational study before-after that occurred at the CF reference center. There were included children with cystic fibrosis (CF) between six to 15 years old hospitalized due to APE. The registration of the APE clinical scores, anthropometric data, and respiratory system (IOS and spirometry) evaluation occurred at the beginning (T1), during (T2), and at the end (T3) of the hospitalization. There were registered pathogens, genetic mutation, disease severity (Schwachman-Doershuk Score), and the most recent spirometry when they were clinically stable. The Shapiro-Wilk test was applied to analyze data distribution, and the repeated measure ANOVA, Friedman test, Tpaired test, and Wilcoxon test were performed to compare data, with a significance level set at 5%. Results: sixteen children/adolescents participated in the study (68.8% girls, 12.88±1.67 years old). The spirometric parameters, X5 parameter, and anthropometric data increased (p<0.005) and the APE scores decreased (p<0.005) at T3. Conclusion: APE scores, anthropometric data, spirometric parameters, and IOS elastic recoil parameter (X5) improved at the end of hospitalization (AU)

Espirometria e oscilometria de impulso durante internação por exacerbação pulmonar aguda em escolares com fibrose cística / Spirometry and impulse oscillometry during acute pulmonary exacerbation hospitalization in children with cystic fibrosis

RESUMO: Objetivo: avaliar o comportamento de parâmetros do sistema respiratório durante internação para antibioticoterapia intravenosa (AIV) como tratamento da exacerbação pulmonar aguda (EPA) em escolares com fibrose cística (FC). Métodos: estudo do tipo analítico observacional, before-after, realizado no Hospital Infantil Joana de Gusmão, Florianópolis ­ Santa Catarina. Foram incluídas crianças com diagnóstico de FC, entre seis e 15 anos, em internação para tratamento da exacerbação pulmonar aguda, no início (T1), durante (T2) e ao final (T3) da internação foi conduzida avaliação de escores específicos de EPA, dados antropométricos e realizada avaliação dos parâmetros do sistema respiratório pelo sistema de oscilometria de impulso (IOS) e espirometria. Foram obtidos, em prontuário, dados de colonização bacteriana, genótipo, gravidade da doença (Escore de Schwachman-Doershuk-ESD) e espirometria mais recente em estabilidade clínica. Aplicou-se o teste Shapiro-Wilk para análise da distribuição dos dados e os testes ANOVA de medidas repetidas, teste de Friedman, teste T pareado e Wilcoxon, com nível de significância de 5%. Resultados: participaram 16 crianças/adolescentes (68.8% meninas, 12.88±1.67anos). Houve aumento dos parâmetros da espirometria e dados antropométricos (p<0.005) no T3, bem como redução dos escores de EPA e do X5 (p<0.005) no T3. Conclusão: os dados apresentados nesse trabalho mostram melhora dos escores de EPA, dados antropométricos, parâmetros da espirometria e do parâmetro de recolhimento elástico do IOS (X5).RESUMODescritores: Fibrose cística, Exacerbação dos sintomas, Testes de função pulmonar, Mecânica respiratória. (AU)

ABSTRACT: Objective: Evaluate the respiratory system parameters of children with cystic fibrosis (CF) during hospitalization for acute pulmonary exacerbation (APE) treatment. Methods: observational study before-after that occurred at the CF reference center. There were included children with cystic fibrosis (CF) between six to 15 years old hospitalized due to APE. The registration of the APE clinical scores, anthropometric data, and respiratory system (IOS and spirometry) evaluation occurred at the beginning (T1), during (T2), and at the end (T3) of the hospitalization. There were registered pathogens, genetic mutation, disease severity (Schwachman-Doershuk Score), and the most recent spirometry when they were clinically stable. The Shapiro-Wilk test was applied to analyze data distribution, and the repeated measure ANOVA, Friedman test, Tpaired test, and Wilcoxon test were performed to compare data, with a significance level set at 5%. Results: sixteen children/adolescents participated in the study (68.8% girls, 12.88±1.67 years old). The spirometric parameters, X5 parameter, and anthropometric data increased (p<0.005) and the APE scores decreased (p<0.005) at T3. Conclusion: APE scores, anthropometric data, spirometric parameters, and IOS elastic recoil parameter (X5) improved at the end of hospitalization.ABSTRACTKeywords: Cystic fibrosis, Symptom flare up, Respiratory function tests, Respiratory mechanics.1. Universidade do Estado de Santa Catarina ­ UDESC ­ Florianópolis, (SC) ­ Brasil https://doi.org/10.11606/issn.2176-7262.rmrp.2022.183755Tayná Castilho1, Renata Maba Gonçalves Wamosy1, Camila Isabel Santos Schivinski1Este é um artigo publicado em acesso aberto (Open Access) sob a licença Creative Commons Attribution, que permite uso, distribuição e reprodução em qualquer meio, sem restrições, desde que o trabalho original seja corretamente citado. (AU)

Effect of respiratory mechanics-guided sedation strategy on diaphragm function in mechanical ventilated patients with chronic obstructive pulmonary disease / 中华危重病急救医学

Objective:To investigate the effects of respiratory mechanics-guided sedation strategy on diaphragm function in chronic obstructive pulmonary disease (COPD) patients treated with mechanical ventilation (MV).Methods:A prospective study was conducted. Patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) received invasive MV who were admitted to the Affiliated Huxi Hospital of Jining Medical University from May 2020 to May 2021 were enrolled. The patients were divided into observational group and control group by random number table method. All patients were intubated for MV, and received bronchodilators, glucocorticoid, anti-infectives, expectorant, nutritional support, analgesia and sedation. The sedatives were dexmedetomidine combined with propofol, and the analgesics were sufentanil in both groups. Respiratory mechanics monitoring was performed every 6 hours in the observational group, and the depth of sedation was adjusted according to the parameters of respiratory mechanics: when airway resistance (Raw) > 20 cmH 2O·L -1·s -1, deep sedation was given to maintain Richmond agitation-sedation scale (RASS) ≤ -3; when the Raw was 10-20 cmH 2O·L -1·s -1, the initial depth of sedation maintained to reach the RASS score of -2-0; when Raw < 10 cmH 2O·L -1·s -1, withdrawn the sedation, or given light sedation, and maintained the RASS score of -2-0. While the control group received light sedation. The patients' diaphragmatic excursions (DE) was measured by bedside ultrasound, tidal volume (VT) and respiratory rate (RR) were recorded, and the diaphragmatic rapid shallow breathing index (D-RSBI, D-RSBI = RR/DE) and diaphragmatic excursion efficiency (DEE, DEE = VT/DE) were calculated. The differences in DE, D-RSBI, and DEE before and 3 days and 5 days of treatment between the two groups were compared. The difference in the RASS score within 3 days of sedation between the two groups was compared. The differences in the duration of MV and 28-day mortality between the two groups were compared. Results:A total of 96 patients were selected. Six patients were excluded due to delirium or the duration of MV shorter than 3 days. Finally, 90 patients were enrolled, with 46 in the observational group, and 44 in the control group. There were no statistically significant differences in DE, D-RSBI or DEE before treatment between the two groups. After treatment, D-RSBI in both groups was gradually decreased, and DEE was gradually increased with time. The D-RSBI at 3 days and 5 days of treatment in the observational group were significantly lower than those in the control group (times·min -1·mm -1: 1.73±0.48 vs. 1.96±0.35 at 3 days, 1.45±0.64 vs. 1.72±0.40 at 5 days, both P < 0.05), and DEE were significantly higher than those in the control group (mL/mm: 19.7±4.3 vs. 17.1±3.9 at 3 days, 25.8±5.6 vs. 22.9±5.4 at 5 days, both P < 0.05). There was no significant difference in DE at all time points between the two groups. The RASS scores within 2 hours of sedation in the observational group were significantly lower than those in the control group (1 day: -3.78±0.92 vs. -2.34±0.68, 2 days: -2.87±1.04 vs. -2.43±0.79, both P < 0.05), while no statistical difference at 3 days was found between the two groups. The duration of MV in the observational group was significantly shorter than that in the control group (days: 5.78±2.01 vs. 6.84±2.27, P < 0.05). One patient died in each of the control group and the observational group, and there was no significant difference in the 28-day mortality between the two groups (2.3% vs. 2.2%, P > 0.05). Conclusion:For AECOPD patients undergoing MV, respiratory mechanics-guided sedation strategy can reduce D-RSBI, increase DEE, shorten the duration of MV, and have a certain protective effect on the diaphragm.

Intra-breath oscillometry for the evaluation of lung function in children and adolescents with a history of preterm birth / Oscilometria intra-breath para avaliação da função pulmonar em crianças e adolescentes com história de prematuridade

ABSTRACT Objective: To assess respiratory system impedance (Zrs) and spirometric parameters in children and adolescents with and without a history of preterm birth. Methods: We evaluated a sample of 51 subjects between 11 and 14 years of age: 35 who had a history of preterm birth (preterm group) and 16 who had been born at term (full-term group). Lung function was measured by spirometry, spectral oscillometry, and intra-breath oscillometry. Results: Neither spirometry nor spectral oscillometry revealed any statistically significant differences between the preterm and full-term groups. However, intra-breath oscillometry demonstrated significant differences between the two groups in terms of the change in resistance, reactance at end-inspiration, and the change in reactance (p < 0.05 for all). Conclusions: Our findings suggest that abnormalities in Zrs persist in children and adolescents with a history of preterm birth and that intra-breath oscillometry is more sensitive than is spectral oscillometry. Larger studies are needed in order to validate these findings and to explore the impact that birth weight and gestational age at birth have on Zrs later in life.

RESUMO Objetivo: Avaliar a impedância do sistema respiratório (Zsr) e parâmetros espirométricos em crianças e adolescentes com e sem história de prematuridade. Métodos: Foi analisada uma amostra de 51 indivíduos entre 11 e 14 anos de idade: 35 com história de prematuridade (grupo pré-termo) e 16 nascidos a termo (grupo a termo). A função pulmonar foi medida por meio de espirometria, oscilometria espectral e oscilometria intra-breath. Resultados: A espirometria e a oscilometria espectral não revelaram diferenças estatisticamente significativas entre os grupos pré-termo e a termo. No entanto, a oscilometria intra-breath demonstrou diferenças significativas entre os dois grupos quanto à alteração da resistência, à reatância ao final da inspiração e à alteração da reatância (p < 0,05 para todas). Conclusões: Nossos achados sugerem que as anormalidades na Zsr persistem em crianças e adolescentes com história de prematuridade e que a oscilometria intra-breath é mais sensível do que a oscilometria espectral. São necessários estudos maiores para validar esses achados e para explorar o impacto do peso e idade gestacional ao nascer na Zsr mais tarde na vida.

Hiperinsuflação manual em crianças / Manual hyperinflation in children

RESUMO A hiperinsuflação manual é utilizada em unidades de terapia intensiva neonatal e pediátrica para promover um flow bias expiratório, porém não há consenso sobre os benefícios da técnica. Assim faz-se necessária uma revisão que apresente suas evidências. Este estudo objetiva revisar a literatura sobre a manobra de hiperinsuflação manual em unidades de terapia intensiva neonatal e pediátrica, para analisar as evidências dessa técnica em relação às formas de aplicação (associadas ou não a outras técnicas), sua segurança, o desempenho dos ressuscitadores manuais e a influência da experiência do fisioterapeuta, além de avaliar a qualidade metodológica dos artigos encontrados. Realizou-se uma busca nas bases de dados: Web of Science, ScienceDirect, PubMedⓇ, Scopus, CINAHL e SciELO. Dois pesquisadores selecionaram os artigos de forma independente. Verificaram-se os estudos duplicados, avaliados por títulos, resumos e, então, leitura na íntegra. Analisou-se a qualidade dos artigos pela escala PEDro. Foram incluídos seis artigos, sendo dois com alta qualidade metodológica. Os principais resultados trouxeram informações sobre a contribuição da válvula de pressão positiva expiratória final no aumento dos volumes pulmonares e a utilização das compressões torácicas para otimizar o flow bias expiratório, a influência negativa da experiência do operador no aumento do pico de fluxo inspiratório, o desempenho de diferentes ressuscitadores manuais durante a realização da técnica e a segurança na aplicação, com manutenção da estabilidade hemodinâmica e aumento da saturação periférica de oxigênio. Os estudos disponíveis apontam para um efeito positivo da manobra de hiperinsuflação manual realizada em crianças internadas em unidades de terapia intensiva. Registro PROSPERO: CRD42018108056.

ABSTRACT Manual hyperinflation is used in neonatal and pediatric intensive care units to promote expiratory flow bias, but there is no consensus on the benefits of the technique. Thus, a review that presents supporting evidence is necessary. This study aims to review the literature on the manual hyperinflation maneuver in neonatal and pediatric intensive care units to analyze the evidence for this technique in terms of the forms of application (associated with other techniques or not), its safety, the performance of manual resuscitators and the influence of the physical therapist's experience, in addition to evaluating the methodological quality of the identified articles. A search was performed in the following databases: Web of Science, ScienceDirect, PubMedⓇ, Scopus, CINAHL and SciELO. Two researchers independently selected the articles. Duplicate studies were assessed, evaluated by title and abstract and then read in full. The quality of the articles was analyzed using the PEDro scale. Six articles were included, two of which had high methodological quality. The main results provided information on the contribution of the positive end-expiratory pressure valve to increasing lung volumes and the use of chest compressions to optimize expiratory flow bias, the negative influence of operator experience on the increase in peak inspiratory flow, the performance of different manual resuscitators when used with the technique and the safety of application in terms of maintaining hemodynamic stability and increasing peripheral oxygen saturation. The available studies point to a positive effect of the manual hyperinflation maneuver in children who are admitted to intensive care units. Registration PROSPERO: CRD42018108056.

Impacto de alvos de saturação liberais versus conservadores sobre os índices de troca gasosa na síndrome do desconforto respiratório agudo relacionada à COVID-19: um estudo fisiológico / Impact of liberal versus conservative saturation targets on gas exchange indices in COVID-19 related acute respiratory distress syndrome: a physiological study

RESUMO Objetivo: Comparar o comportamento dos índices de troca gasosa conforme o uso de alvos de oxigenação liberais em comparação a conservadores em pacientes com síndrome do desconforto respiratório agudo moderada a grave secundária à COVID-19 e em uso de ventilação mecânica; avaliar a influência da FiO2 elevada na mecânica do sistema respiratório. Métodos: Foram incluídos prospectivamente pacientes consecutivos com idades acima de 18 anos, diagnóstico de COVID-19 e síndrome do desconforto respiratório agudo moderada e grave. Para cada paciente, aplicou-se aleatoriamente dois protocolos de FiO2 para obter SpO2 de 88% a 92% ou 96%. Avaliaram-se os índices de oxigenação e a mecânica do sistema respiratório. Resultados: Foram incluídos 15 pacientes. Todos seus índices foram significantemente afetados pela estratégia de FiO2 (p < 0,05). A proporção PaO2/FiO2 deteriorou, o PA-aO2 aumentou e o Pa/AO2 diminuiu significantemente com a utilização de FiO2 para obter SpO2 96%. Opostamente, a fração de shunt funcional foi reduzida. A mecânica respiratória não foi afetada pela estratégia de FiO2. Conclusão: Uma estratégia com alvos liberais de oxigenação deteriorou significantemente os índices de troca gasosa, com exceção do shunt funcional, em pacientes com síndrome do desconforto respiratório agudo relacionada à COVID-19. A mecânica do sistema respiratório não foi alterada pela estratégia de FiO2. Registro Clinical Trials: NCT04486729.

ABSTRACT Objective: To compare gas exchange indices behavior by using liberal versus conservative oxygenation targets in patients with moderate to severe acute respiratory distress syndrome secondary to COVID-19 under invasive mechanical ventilation. We also assessed the influence of high FiO2 on respiratory system mechanics. Methods: We prospectively included consecutive patients aged over 18 years old with a diagnosis of COVID-19 and moderate-severe acute respiratory distress syndrome. For each patient, we randomly applied two FiO2 protocols to achieve SpO2 88% - 92% or 96%. We assessed oxygenation indices and respiratory system mechanics. Results: We enrolled 15 patients. All the oxygenation indices were significantly affected by the FiO2 strategy (p < 0.05) selected. The PaO2/FiO2 deteriorated, PA-aO2 increased and Pa/AO2 decreased significantly when using FiO2 to achieve SpO2 96%. Conversely, the functional shunt fraction was reduced. Respiratory mechanics were not affected by the FiO2 strategy. Conclusion: A strategy aimed at liberal oxygenation targets significantly deteriorated gas exchange indices, except for functional shunt, in COVID-19-related acute respiratory distress syndrome. The respiratory system mechanics were not altered by the FiO2 strategy. Clinical Trials Register: NCT04486729.

Driving pressure e mortalidade no trauma sem síndrome do desconforto respiratório agudo: estudo observacional prospectivo / Driving pressure and mortality in trauma without acute respiratory distress syndrome: a prospective observational study

RESUMO Objetivo: Identificar a existência de associação entre os valores de driving pressure e mechanical power e do índice de oxigenação no primeiro dia de ventilação mecânica com a mortalidade de pacientes vítimas de trauma sem diagnóstico de síndrome do desconforto respiratório agudo. Métodos: Foram incluídos pacientes ventilados em modo de pressão ou volume controlado, com coleta de dados 24 horas após sua intubação orotraqueal. O acompanhamento do paciente foi realizado por 30 dias para obter o desfecho clínico. Os pacientes estiveram internados em duas unidades de terapia intensiva do Hospital de Pronto Socorro de Porto Alegre, no período de junho a setembro de 2019. Resultados: Foram avaliados 24 pacientes. Os valores de driving pressure, mechanical power e do índice de oxigenação foram similares entre os pacientes que sobreviveram e os que tiveram desfecho de óbito, sem diferença estatisticamente significativa entre os grupos. Conclusão: Os valores de driving pressure, mechanical power e índice de oxigenação obtidos no primeiro dia de ventilação mecânica não demonstraram ter associação com a mortalidade de pacientes vítimas de trauma sem síndrome do desconforto respiratório agudo.

ABSTRACT Objective: To identify the possible association between driving pressure and mechanical power values and oxygenation index on the first day of mechanical ventilation with the mortality of trauma patients without a diagnosis of acute respiratory distress syndrome. Methods: Patients under pressure-controlled or volume-controlled ventilation were included, with data collection 24 hours after orotracheal intubation. Patient follow-up was performed for 30 days to obtain the clinical outcome. The patients were admitted to two intensive care units of the Hospital de Pronto Socorro de Porto Alegre from June to September 2019. Results: A total of 24 patients were evaluated. Driving pressure, mechanical power and oxygenation index were similar among patients who survived and those who died, with no statistically significant difference between groups. Conclusion: Driving pressure, mechanical power and oxygenation index values obtained on the first day of mechanical ventilation were not associated with mortality of trauma patients without acute respiratory distress syndrome.

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

Comparison of the effects between low-level assisted ventilation and T-piece method on respiratory mechanics during weaning of mechanically ventilated patients / 中华危重病急救医学

Objective:To compare the difference of low-level assisted ventilation and T-piece method on respiratory mechanics of patients with invasive mechanical ventilation during spontaneous breathing trial (SBT) within 3 days before extubation.Methods:A retrospective observational study was conducted. Twenty-five patients with difficulty in weaning or delayed weaning from invasive mechanical ventilation who were admitted to department of critical care medicine of the First Affiliated Hospital of Guangzhou Medical University from December 2018 to June 2020, and were in stable condition and entered the weaning stage after more than 72 hours of invasive mechanical ventilation were studied. A total of 119 cases of respiratory mechanical indexes were collected, which were divided into the low-level assisted ventilation group and the T-piece group according to the ventilator method and parameters used during the data collection. The different ventilation modes related respiratory mechanics indexes such as the esophageal pressure (Pes), the gastric pressure (Pga), the transdiaphragmatic pressure (Pdi), the maximum Pdi (Pdimax), Pdi/Pdimax ratio, the esophageal pressure-time product (PTPes), the gastric pressure-time product (PTPga), the transdiaphragmatic pressure-time product (PTPdi), the diaphragmatic electromyography (EMGdi), the maximum diaphragmatic electromyography (EMGdimax), PTPdi/PTPes ratio, Pes/Pdi ratio, the inspiratory time (Ti), the expiratory time (Te) and the total time respiratory cycle (Ttot) at the end of monitoring were recorded and compared between the two groups.Results:Compared with the T-piece group, Pes, PTPes, PTPdi/PTPes ratio, Pes/Pdi ratio and Te were higher in low-level assisted ventilation group [Pes (cmH 2O, 1 cmH 2O = 0.098 kPa): 2.84 (-1.80, 5.83) vs. -0.94 (-8.50, 2.06), PTPes (cmH 2O·s·min -1): 1.87 (-2.50, 5.93) vs. -0.95 (-9.71, 2.56), PTPdi/PTPes ratio: 0.07 (-1.74, 1.65) vs. -1.82 (-4.15, -1.25), Pes/Pdi ratio: 0.17 (-0.43, 0.64) vs. -0.47 (-0.65, -0.11), Te (s): 1.65 (1.36, 2.18) vs. 1.33 (1.05, 1.75), all P < 0.05], there were no significant differences in Pga, Pdi, Pdimax, Pdi/Pdimax ratio, PTPga, PTPdi, EMGdi, EMGdimax, Ti and Ttot between the T-piece group and the low-level assisted pressure ventilation group [Pga (cmH 2O): 6.96 (3.54,7.60) vs. 7.74 (4.37, 11.30), Pdi (cmH 2O): 9.24 (4.58, 17.31) vs. 6.18 (2.98, 11.96), Pdimax (cmH 2O): 47.20 (20.60, 52.30) vs. 29.95 (21.50, 47.20), Pdi/Pdimax ratio: 0.25 (0.01, 0.34) vs. 0.25 (0.12, 0.41), PTPga (cmH 2O·s·min -1): 7.20 (2.54, 9.97) vs. 7.97 (5.74, 13.07), PTPdi (cmH 2O·s·min -1): 12.15 (2.95, 19.86) vs. 6.87 (2.50, 12.63), EMGdi (μV): 0.05 (0.03, 0.07) vs. 0.04 (0.02, 0.06), EMGdimax (μV): 0.07 (0.05, 0.09) vs. 0.07 (0.04, 0.09), Ti (s): 1.20 (0.95, 1.33) vs. 1.07 (0.95, 1.33), Ttot (s): 2.59 (2.22, 3.09) vs. 2.77 (2.35, 3.24), all P > 0.05]. Conclusions:When mechanically ventilated patients undergo SBT, the use of T-piece method increases the work of breathing compared with low-level assisted ventilation method. Therefore, long-term use of T-piece should be avoided during SBT.

A theoretical analysis of respiratory mechanics in mechanical ventilation / 中华危重病急救医学

As a non-physiological way of ventilation, mechanical ventilation has a great effect on the respiratory mechanics. The biggest problem of artificial airway is that it brings extra airway resistance to the respiratory tract. For different parts of the lung, positive pressure ventilation could cause different mechanic states. We can find the formation and influencing factors of transpulmonary pressure, transchest wall pressure, trans-lung-chest pressure, trans-diaphragmatic pressure, trans-pulmonary-diaphragmatic pressure, intrapleural pressure, plateau pressure and driving pressure, by analyzing the mechanic state in a unit area of the chest or diaphragm position in the way of basic mechanics. It is obviously different in the pulmonary pressure gradient caused by inspiratory driving between in spontaneous breathing and in mechanical ventilation. The pressure is transmitted from the periphery to the center in spontaneous breathing in physiological state, playing a traction role for lung tissue. The pressure is transmitted from the center to the periphery in positive pressure ventilation without spontaneous breathing, playing a pushing role for lung tissue. It can be divided into two stages in positive pressure ventilation with spontaneous breathing. The first stage is from inspiratory trigger effort to trigger sensitivity. It is similar to spontaneous inspiration in physiological state. The pressure gradient in this stage is from the peripheral to center. But the period is very short. The second stage is the positive pressure ventilation progress after the trigger sensitivity. The pressure gradient is caused by the pulling of the patient's spontaneous inhalation and the pushing of the positive pressure ventilation of the ventilator. There is a certain complementarity in the distribution and transmission of pressure, especially for non-physiological positive pressure ventilation. Therefore, through these basic mechanical analysis, clinical medical staff can better understand the impact of mechanical ventilation on respiratory mechanics.

Reprodutibilidade das mensurações da mecânica respiratória em pacientes sob ventilação mecânica invasiva / Reproducibility of respiratory mechanics measurements in patients on invasive mechanical ventilation

RESUMO Objetivo: Avaliar a reprodutibilidade intra e interexaminador das mensurações da resistência e das complacências estática e dinâmica do sistema respiratório em pacientes sob ventilação mecânica. Métodos: Trata-se de estudo analítico realizado com indivíduos com idade ≥ 18 anos, em ventilação mecânica invasiva, que não tinham diagnóstico clínico de doença do aparelho respiratório e/ou anormalidade de caixa torácica. Foram realizadas três aferições da mecânica respiratória com intervalo de 1 minuto entre elas. A primeira e a terceira aferições foram realizadas pelo avaliador A e a segunda aferição, pelo avaliador B. A comparação dos valores de resistência e complacências estática e dinâmica do sistema respiratório foi calculada por meio do coeficiente de correlação intraclasse. Resultados: Foram realizadas 198 aferições da mecânica respiratória em 66 pacientes sob ventilação mecânica, com idade média de 52,6 ± 18,6 anos, índice de massa corporal médio de 21,6 ± 2,1kg/m2, predomínio do perfil cirúrgico (61,5%) e sexo feminino (53,8%). Foram obtidos valores médios das três aferições para resistência do sistema respiratório (A1: 15,7 ± 6,8cmH2O/L/s; B1: 15,7 ± 6,4cmH2O/L/s e A2: 15,9 ± 6,2cmH2O/L/s), para complacência estática do sistema respiratório (A1: 42,1 ± 13,7mL/cmH2O; B1: 42,4 ± 14,6mL/cmH2O e A2: 42,2 ± 14,5mL/cmH2O) e para complacência dinâmica do sistema respiratório (A1: 21,3 ± 7,3mL/cmH2O; B1: 21,4 ± 7,5mL/cmH2O e A2: 21,3 ± 6,2mL/cmH2O). Também foram encontrados valores do coeficiente de correlação intraclasse para resistência do sistema respiratório (R = 0,882 e p = 0,001; R = 0,949 e p = 0,001 - interexaminadores A1 versus B e B versus A2, respectivamente; R = 0,932 e p = 0,001 - intraexaminador); complacência estática do sistema respiratório (R = 0,951 e p = 0,001; R = 0,958 e p = 0,001 - interexaminadores A1 versus B e B versus A2, respectivamente; R = 0,965 e p = 0,001 - intraexaminador) e complacência dinâmica do sistema respiratório (R = 0,957 e p = 0,001; R = 0,946 e p = 0,001 - interexaminadores A1 versus B e B versus A2 respectivamente; R = 0,926 e p = 0,001 - intraexaminador). Conclusão: A mensuração de mecânica respiratória apresenta boa reprodutibilidade intra e interexaminador para as aferições de resistência e complacências estática e dinâmica do sistema respiratório em pacientes ventilados.

ABSTRACT Objective: To evaluate the intra- and interexaminer reproducibility of measurements of the resistance and static and dynamic compliance of the respiratory system in patients on mechanical ventilation. Methods: This was an analytical study conducted with individuals aged ≥ 18 years who were on invasive mechanical ventilation and had no clinical diagnosis of respiratory system disease and/or chest abnormality. Three measurements of respiratory mechanics were performed with a 1-minute interval between them. The first and third measurements were performed by examiner A, the second by examiner B. The values for the resistance and static and dynamic compliance of the respiratory system were compared using the intraclass correlation coefficient. Results: A total of 198 measurements of respiratory mechanics were performed for 66 patients on mechanical ventilation. The patients had a mean age of 52.6 ± 18.6 years and a mean body mass index of 21.6 ± 2.1kg/m2; a surgical profile (61.5%) and female sex (53.8%) were predominant. Mean values were obtained for the three measurements of respiratory system resistance (A1: 15.7 ± 6.8cmH2O/L/s; B1: 15.7 ± 6.4cmH2O/L/s and A2: 15.9 ± 6.2cmH2O/L/s), respiratory system static compliance (A1: 42.1 ± 13.7mL/cmH2O; B1: 42.4 ± 14.6mL/cmH2O and A2: 42.2 ± 14.5mL/cmH2O) and respiratory system dynamic compliance (A1: 21.3 ± 7.3mL/cmH2O; B1: 21.4 ± 7.5mL/cmH2O and A2: 21.3 ± 6.2mL/cmH2O). The intraclass correlation coefficient was also calculated for respiratory system resistance (R = 0.882 and p = 0.001; R = 0.949 and p = 0.001 - interexaminer A1 versus B and B versus A2, respectively; R = 0.932 and p = 0.001 - intraexaminer); respiratory system static compliance (R = 0.951 and p = 0.001; R = 0.958 and p = 0.001 - interexaminer A1 versus B and B versus A2, respectively; R = 0.965 and p = 0.001 - intraexaminer) and respiratory system dynamic compliance (R = 0.957 and p = 0.001; R = 0.946 and p = 0.001 - interexaminer A1 versus B and B versus A2, respectively; R = 0.926 and p = 0.001 - intraexaminer). Conclusion: The measurements of resistance and static and dynamic compliance of the respiratory system show good intra- and interexaminer reproducibility for ventilated patients.

Interação toracoabdominal e sua relação com os fatores de risco biológico em recém-nascidos prematuros / Interacción toracoabdominal y su relación con los factores de riesgo biológico en recién nacidos prematuros / Thoracoabdominal interaction and its relationship with biological risk factors in premature newborns

RESUMO O objetivo do estudo foi avaliar a participação toracoabdominal durante a respiração e sua relação com os fatores de risco clínicos em recém-nascidos prematuros (RNPT). Trata-se de um estudo multicêntrico, transversal, realizado em duas unidades de cuidado intermediário neonatal com RNPT entre 26-35 semanas, estáveis hemodinamicamente, que fizeram uso de oxigênio ou suporte ventilatório durante a fase da internação. O movimento lateral do tronco foi filmado por 2 minutos e os vídeos foram avaliados no software MATLAB® para interpretação quantitativa da participação toracoabdominal, por um pesquisador cego sobre os dados da amostra. Os dados foram expressos graficamente em cm2 representando os valores máximos, mínimos e médios da participação de tórax e abdômen. O coeficiente de Pearson foi usado para avaliar a correlação entre as variáveis neonatais com a mobilidade. Foram avaliados 2.080 frames de 26 RNPT com idade gestacional média de 31 semanas ±2,34. Quanto maior a idade e o peso, maior a participação do tórax na respiração (r=0,55; p=0,001); e quanto maior o tempo de internação, menor é a sua participação (r=-0,40; p=0,04). A participação do abdômen aumenta de acordo com o aumento do número de dias em uso de oxigênio (r=0,33; p=0,001) e diminui com o aumento da idade e do peso (r=-0,41; p=0,001). A participação toracoabdominal tem relação direta com a idade gestacional e o peso. Como fatores externos, o uso prolongado de oxigênio e o tempo de internação interferem negativamente no padrão respiratório, uma vez que o aumento da participação abdominal durante a biomecânica respiratória pode representar um gasto energético.

RESUMEN El presente estudio tuvo como objetivo evaluar la participación toracoabdominal durante la respiración y su relación con los factores de riesgo clínico en recién nacidos prematuros (RNPT). Este es un estudio transversal, multicéntrico, realizado en dos unidades de cuidados intermedios neonatales con RNPT entre 26-35 semanas, hemodinámicamente estables, que utilizaron oxígeno o soporte ventilatorio durante la hospitalización. El movimiento lateral del tronco se filmó durante 2 minutos, y un investigador a ciegas sobre los datos de la muestra evaluó los videos por medio del software MATLAB® para la interpretación cuantitativa de la participación toracoabdominal. Los datos se reprodujeron gráficamente en cm2 representando los valores máximos, mínimos y promedio de la participación del tórax y el abdomen. El coeficiente de Pearson se utilizó para evaluar la correlación entre las variables neonatales con la movilidad. Se evaluaron 2.080 frames de 26 RNPT con una edad gestacional promedio de 31 semanas ±2,34. Cuanto mayor es la edad y el peso, mayor es la participación del tórax en la respiración (r=0,55; p=0,001), y cuanto más largo es el tiempo de hospitalización, menor será su participación (r=-0,40; p=0,04). La participación del abdomen aumenta conforme aumenta la cantidad de días utilizando oxígeno (r=0,33; p=0,001) y disminuye con el aumento de la edad y el peso (r=-0,41; p=0,001). La participación toracoabdominal está directamente relacionada con la edad gestacional y el peso. Como factores externos, el uso prolongado de oxígeno y el tiempo de hospitalización afectan negativamente al patrón de respiración, ya que el aumento de la participación abdominal durante la biomecánica respiratoria puede representar un gasto de energía.

ABSTRACT The objective of this study was to assess the participation of thoracoabdominal muscles in breathing and its relationship with clinical risk factors in preterm newborns (PTNBs). This is a multicenter, cross-sectional study conducted in two neonatal intermediate care units with PTNBs between 26 and 35 weeks of age, hemodynamically stable, who used oxygen or ventilatory support during hospital stay. The lateral movements of the thorax were filmed for 2 minutes and the videos were quantitatively evaluated by a researcher blinded to sample data using the MATLAB Software for assessing thoracoabdominal participation patterns. Data for the maximum, minimum and mean values of the participation of the thorax and abdomen were expressed graphically in cm2. The Pearson correlation coefficient was used to assess the correlation between neonatal variables and mobility. We evaluated 2,080 frames of 26 newborns with an average gestational age of 31 weeks ±2.34. The greater the age and weight, the greater the participation of the thorax in breathing (r=0.55, p=0.001); and the longer the hospital stay, the lower the thoracic participation (r=-0.40, p=0.04). The participation of the abdomen increases according to the increase in the number of days of oxygen use (r=0.33, p=0.001) and decreases with higher age and weight (r=-0.41, p=0.001). The thoracoabdominal participation pattern is directly related to gestational age and weight. Prolonged use of oxygen and the length of hospital stay adversely affect the respiratory pattern, since increasing abdominal participation in respiratory biomechanics may increase energy expenditure.