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.

Analysis of the aerodynamic characteristics of the upper airway in obstructive sleep apnea patients.

Background/purpose: This study was designed to explore upper airway aerodynamic characteristics in individuals diagnosed with obstructive sleep apnea (OSA) and to evaluate correlations between these characteristics and other anatomical upper airway findings in these patients. Materials and methods: This was a retrospective study of 40 OSA patients (22 male, 18 female) who were stratified into groups with mild, moderate, and severe disease based upon overnight polysomnographic (PSG) recording results. Newtom5G cone-beam CT scans (CBCT) were conducted for all patients, and the resultant images were used to reconstruct three-dimensional images of the upper airways which were used to calculate aerodynamic characteristics. Differences in these characteristics between groups were evaluated with one-way ANOVAs, while relationships between anatomical and aerodynamic characteristics were assessed through Pearson correlation analyses. Results: The aerodynamic of the upper airway has typical characteristic in severe group. There was a significant negative correlation in severe group between resistance during inspiration (Rin) and volume (V) (r = -0.693, P = 0.013), minimum axial area (MMA) (r = -0.685, P = 0.014), and lateral dimension (LAT) (r = -0.724, P = 0.008), resistance during expiration (Rex) and LAT (r = -0.923, P < 0.001). Conclusion: This study showed that airway resistance during inspiration and expiration are most closely associated with upper airway collapse in OSA patients, with repetitive collapse occurring during both of these breathing processes. LAT may be an important anatomical factor associated with OSA pathogenesis and treatment.

Patência nasal em crianças respiradoras orais / Nasal patency in mouth breathing children

RESUMO Vários estudos mostram a importância da avaliação quantitativa na patência nasal e do estado funcional das vias aéreas superiores para fornecer informações clínicas e diagnósticas em indivíduos respiradores orais, as quais são de grande interesse para a fonoaudiologia. O objetivo deste estudo foi avaliar o efeito da irrigação de solução salina nasal nas vias aéreas superiores através da aeração nasal e rinomanometria anterior ativa em crianças respiradoras orais. Estudo de série de oito casos, realizado em crianças com idades entre 7 e 10 anos, com diagnóstico clínico otorrinolaringológico de respiração oral. O estudo consistiu em três etapas: avaliação inicial; intervenção e avaliação final. Foram aplicados os questionários do Índice de Identificação dos Sinais e Sintomas da Respiração Oral e qualidade de vida específica para doenças em pacientes pediátricos com queixas sinonasais. Realizaram-se as avaliações da aeração nasal e o exame da rinomanometria anterior ativa. A intervenção foi realizada por meio da irrigação de solução salina nasal com 10 ml. Em seguida, os pacientes foram reavaliados pela avaliação da aeração nasal e rinomanometria, para comparar os resultados. Em relação à avaliação da aeração nasal e rinomanometria, das 16 medidas comparativas entre pré e pós-irrigação nasal, constataram-se mudanças significativas na aeração nasal e na resistência nasal. A irrigação nasal resultou em melhora nas medidas da aeração nasal, enquanto para o fluxo nasal da rinomanometria, as medidas permaneceram inalteradas entre pré e pós-irrigação nasal.

ABSTRACT Several studies have shown the importance of quantitative assessment in nasal patency and functional status of the upper airways to provide clinical and diagnostic information in oral breather individuals, which are of great interest to speech therapy. The aim of the study was to evaluate the effect of nasal saline solution irrigation on the upper airways through nasal aeration and active anterior rhinomanometry in oral breathing children. This was an eight case series study, carried out in children aged 7 to 10 years with an otorhinolaryngological clinical diagnosis of mouth breathing. The study consisted of three stages: (I) initial evaluation; (II) intervention; and (III) final evaluation. The questionnaires of the Index for the Identification of Oral Breathing Signs and Symptoms and disease-specific quality of life in pediatric patients with sinonasal complaints were applied, nasal aeration assessments and the anterior active rhinomanometry exam were carried out. The intervention was performed by irrigating nasal saline solution with 10ml. Afterwards, they were re-evaluated by nasal aeration evaluation and rhinomanometry to compare the results. Regarding nasal aeration and rhinomanometry evaluation, from the 16 comparative measurements between pre and post nasal irrigation, we obtained significant changes in nasal aeration and nasal resistance. Nasal irrigation resulted in improvement in nasal aeration measurements while nasal flow measurements from rhinomanometry remained unchanged considering pre and post nasal irrigation.

Morphofunctional changes following adenotonsillectomy of obstructive sleep apnea children: a case series analysis.

OBJECTIVE: To perform a case series analysis of the changes in the pulmonary artery systolic pressure (PASP), nasal inspiratory flow (NIF), upper airway volume, obstructive apnea/hypopnea index (OAHI), and the maxillomandibular three-dimensional (3D) morphology after adenotonsillectomy (T&A) of obstructive sleep apnea children (OSA). MATERIALS AND METHODS: Retrospective assessment of files from 1002 children screened between 2012 and 2020 in a hospital-based mouth-breather referral center. From this universe, 15 obstructive sleep apnea children (7 females; 8 males), ages 4.1 to 8.9 years old (mean age of 5.4 years ± 1.3), who presented indications of tonsillectomy and/or adenoidectomy were selected. The complete baseline examination (T0) was carried out before T&A and a second complete examination (T1) was made 18.7-month follow-up after T&A (ranging from 12 to 30 months). Eleven patients were submitted to T&A, and four patients had indications but did not receive authorization for surgery from the public health system. According to the protocol of the outpatient clinic for OSA patients, Doppler echocardiography, polysomnography, rhinomanometry, and computed tomography imaging was performed at (T0) and (T1). RESULTS: PASP decreased 16.6% after T&A. NIF increased more in T&A children (40.3%) than in non-T&A children (16.8%). The upper airway volume increased in T&A and non-T&A children, but greater volumetric gain (45.6%) was found in the nasopharynx of T&A patients. OAHI did not change in six T&A children (55%) and three non-T&A children (75%). The maxilla displaced downward and backward relative to the cranial base in six T&A children (55%) and two untreated children (50%). Nine of the T&A children (85%) and three untreated children (75%) presented extensive condylar growth and increased mandibular length. The qualitative 3D assessment showed similar morphological 3D changes in T&A and non-T&A patients. CONCLUSION: Pulmonary artery systolic pressure decreased, nasal inspiratory flow increased, and nasopharynx volume increased following adenotonsillectomy, but obstructive apnea/hypopnea index and maxillomandibular morphology were similar in surgical and non-surgical patients.

Effectiveness of functional orthodontic appliances in obstructive sleep apnea treatment in children: literature review / Eficácia dos aparelhos ortodônticos funcionais no tratamento da apneia obstrutiva do sono em crianças: revisão da literatura

Abstract Introduction: Obstructive sleep apnea syndrome is a common condition in childhood and if left untreated can result in many health problems. An accurate diagnosis of the etiology is crucial for obstructive sleep apnea treatment success. Functional orthodontic appliances that stimulate mandibular growth by forward mandibular positioning are an alternative therapeutic option in growing patients. Objective: To perform a literature review about the effects of functional orthodontic appliances used to correct the mandibular deficiency in obstructive sleep apnea treatment. Methods: The literature search was conducted in June 2020 using Cochrane Library; PubMed, EBSCO (Dentistry & Oral Sciences Source), LILACS Ovid; SciELO Web of Science; EMBASE Bireme and BBO Bireme electronic databases. The search included papers published in English, until June 2020, whose methodology referred to the types and effects of functional orthopedic appliances on obstructive sleep apnea treatment in children. Results: The search strategy identified thirteen articles; only four articles were randomized clinical studies. All studies using the oral appliances or functional orthopedic appliances for obstructive sleep apnea in children resulted in improvements in the apnea-hypopnea index score. The cephalometric (2D) and tomographic (3D) evaluations revealed enlargement of the upper airway and increase in the upper airspace, improving the respiratory function in the short term. Conclusion: Functional appliances may bean alternative treatment for obstructive sleep apnea, but it cannot be concluded that they are effective in treating pediatric obstructive sleep apnea. There are significant deficiencies in the existing evidence, mainly due to absence of control groups, small sample sizes, lack of randomization and no long-term results.

Resumo Introdução: A síndrome da apneia obstrutiva do sono é uma condição comum na infância e, se não tratada, pode resultar em muitos problemas de saúde. Um diagnóstico preciso da etiologia é crucial para o sucesso do tratamento dessa condição clínica. Aparelhos ortodônticos funcionais que estimulam o crescimento mandibular através do anteroposicionamento mandibular são uma opção terapêutica para pacientes em crescimento. Objetivo: Fazer uma revisão da literatura sobre os efeitos do aparelho ortodôntico funcional usado para corrigir a deficiência mandibular no tratamento da apneia obstrutiva do sono. Método: A pesquisa bibliográfica foi feita em junho de 2020 nos os bancos de dados eletrônicos da Cochrane Library; PubMed, EBSCO (Dentistry & Oral Sciences Source), Lilacs Ovid; SciELO Web of Science; Embase Bireme e BBO Bireme. A busca incluiu artigos publicados em inglês, até junho de 2020, cuja metodologia referia-se aos tipos e efeitos dos aparelhos ortopédicos funcionais no tratamento da apneia obstrutiva do sono em crianças. Resultados: A estratégia de busca identificou 19 artigos; apenas quatro eram estudos clínicos randomizados. Todos os estudos que usaram aparelhos orais ou aparelhos ortopédicos funcionais para apneia obstrutiva do sono em crianças resultaram em melhorias no índice de apneia-hipopneia. As avaliações cefalométrica (2D) e tomográfica (3D) mostraram alargamento das vias aéreas superiores e aumento do espaço das vias aéreas superiores, que melhoraram a função respiratória em curto prazo. Conclusão: Os aparelhos funcionais podem ser um tratamento opcional para apneia obstrutiva do sono, mas não é possível concluir que sejam eficazes na população pediátrica. Existem deficiências significativas nas evidências existentes, principalmente devido à ausência de grupos de controle, tamanho pequeno das amostras, falta de randomização e ausência de resultados em longo prazo.

Prevalence of upper airway resistance syndrome in the São Paulo Epidemiologic Sleep Study.

OBJECTIVE: To establish the prevalence of upper airway resistance syndrome (UARS) according to different diagnostic criteria and evaluate its epidemiological characteristics in a representative sample of a large urban center. METHODS: This was a single-center evaluation involving volunteers from EPISONO, an epidemiological study focused on sleep disturbances and related factors in adults from São Paulo, Brazil in 2007. RESULTS: Considering the diagnostic criteria for UARS to be an apnea-hypopnea index of <5 events/h, minimum SpO2 ≥ 92%, the presence of airflow limitation during sleep for ≥5% of total sleep time, and daytime symptoms (sleepiness and/or fatigue), we observed a prevalence of the condition of 3.1% (4.4% in women and 1.5% in men). CONCLUSIONS: Although the diagnostic criteria for UARS, or even its existence as a syndrome, are still a subject of debate in the literature, the findings from this epidemiological study highlights UARS as a non-hypoxic sleep-disordered breathing condition with a significant prevalence in the general population, being more frequent among female young adults.

Effectiveness of functional orthodontic appliances in obstructive sleep apnea treatment in children: literature review.

INTRODUCTION: Obstructive sleep apnea syndrome is a common condition in childhood and if left untreated can result in many health problems. An accurate diagnosis of the etiology is crucial for obstructive sleep apnea treatment success. Functional orthodontic appliances that stimulate mandibular growth by forward mandibular positioning are an alternative therapeutic option in growing patients. OBJECTIVE: To perform a literature review about the effects of functional orthodontic appliances used to correct the mandibular deficiency in obstructive sleep apnea treatment. METHODS: The literature search was conducted in June 2020 using Cochrane Library; PubMed, EBSCO (Dentistry & Oral Sciences Source), LILACS Ovid; SciELO Web of Science; EMBASE Bireme and BBO Bireme electronic databases. The search included papers published in English, until June 2020, whose methodology referred to the types and effects of functional orthopedic appliances on obstructive sleep apnea treatment in children. RESULTS: The search strategy identified thirteen articles; only four articles were randomized clinical studies. All studies using the oral appliances or functional orthopedic appliances for obstructive sleep apnea in children resulted in improvements in the apnea-hypopnea index score. The cephalometric (2D) and tomographic (3D) evaluations revealed enlargement of the upper airway and increase in the upper airspace, improving the respiratory function in the short term. CONCLUSION: Functional appliances may be an alternative treatment for obstructive sleep apnea, but it cannot be concluded that they are effective in treating pediatric obstructive sleep apnea. There are significant deficiencies in the existing evidence, mainly due to absence of control groups, small sample sizes, lack of randomization and no long-term results.

Función pulmonar oscilometría de impulso en pediatría: procedimiento y aplicación clínica / Pulmonary function impulse oscillometry in pediatrics: procedure and clinical application

La Oscilometría de Impulso (IOS) es una técnica no invasiva que evalúa las propiedades mecánicas de todo el sistema respiratorio durante la respiración tranquila. Mide la impedancia total del sistema respiratorio, evaluando la resistencia total de la vía aérea, la resistencia de la vía aérea alta y las propiedades elásticas del pulmón. Detecta el compromiso de la vía aérea periférica en forma muy precoz, antes que la espirometría, y es útil en niños pequeños porque no requiere maniobras de espiración forzada. Permite evaluar la respuesta broncodilatadora y broncoconstrictora a través de pruebas de provocación bronquial para el diagnóstico de hiperreactividad bronquial. La IOS tiene un rol en la evaluación temprana y seguimiento de la función pulmonar en niños con enfermedades respiratorias crónicas, principalmente asma bronquial, displasia broncopulmonar y fibrosis quística. Este artículo revisa los aspectos fisiológicos, técnicos y aplicación clínica de la IOS, considerando las últimas recomendaciones para la estandarización del examen y las limitaciones que dificultan su interpretación .

Impulse Oscillometry (IOS) is a non-invasive technique that assesses the mechanical properties of the entire respiratory system during quiet breathing. It measures the total impedance of the respiratory system by evaluating total airway resistance, upper airway resistance, and elastic properties of the lung. It detects peripheral airway compromise very early, before spirometry, and is useful in young children because it does not require forced expiration maneuvers. It allows evaluating the bronchodilator and bronchoconstrictor response through bronchial provocation tests for the diagnosis of bronchial hyperreactivity. The IOS has a role in the early evaluation and monitoring of lung function in children with chronic respiratory diseases, mainly bronchial asthma, bronchopulmonary dysplasia and cystic fibrosis. This article reviews the physiological, technical, and clinical application aspects, considering the latest recommendations for the standardization of the test and the limitations that hinder its interpretation.

Open and Closed Endotracheal Suction Systems Divergently Affect Pulmonary Function in Mechanically Ventilated Subjects.

BACKGROUND: In mechanically ventilated subjects, intra-tracheal secretions can be aspirated with either open suction systems (OSS) or closed suction systems (CSS). In contrast to CSS, conventional OSS require temporarily disconnecting the patient from the ventilator, which briefly diminishes PEEP and oxygen supply. On the other hand, CSS are more expensive and less effective at aspirating secretions. Thus, it was hypothesized that the 2 procedures differentially affect pulmonary and cardiovascular parameters after suction. METHODS: Subjects in the ICU (N = 66) were quasi-randomized for initial treatment with OSS or CSS in a crossover design. To compare the potential for these suction systems to compromise cardiorespiratory stability, changes in cardiopulmonary physiology were assessed from before to just after use of each suction system (three 10-s aspirations). RESULTS: For most pulmonary and cardiovascular parameters (ie, peak inspiratory pressure, airway resistance, pressure plateau, heart rate, and arterial pressures), the effects of aspiration inversely correlated with baseline values for that parameter, with a similar regression slope between suction systems. However, when controlling for baseline values, OSS caused significantly greater increases in airway resistance and peak inspiratory pressure (P < .001 and < .01 vs CSS, respectively). CONCLUSIONS: Elevated airway resistance prior to endotracheal suction may justify use of a CSS and contraindicate a conventional OSS in mechanically ventilated subjects. Adoption of this approach into clinical guidelines may prevent suction-induced pulmonary injury in subjects, especially for those with underlying diseases involving increased airway resistance or increased alveolar pressure. (ClinicalTrials.gov registration: NCT03256214.).

Airway Resistance and Respiratory Compliance in Children with Acute Viral Bronchiolitis Requiring Mechanical Ventilation Support.

BACKGROUND: Acute viral bronchiolitis (AVB) is a very frequent disease that affects the lower airways of young children increasing the inspiratory and expiratory resistance in variable degree as well as reducing the pulmonary compliance. It would be desirable to know whether these variables are associated with the outcome. OBJECTIVES: To evaluate the respiratory mechanics in infants with AVB requiring mechanical ventilation (MV) support and to evaluate if respiratory mechanics predict outcomes in children with AVB supported on MV. To evaluate the respiratory mechanics in infants with AVB submitted to MV. MATERIALS AND METHODS: A prospective observational study was conducted in two pediatric intensive care units (PICUs) between February 2016 and March 2017. Included were infants (1 month to 1 year old) admitted with AVB and requiring MV for >48 hours. Auto-PEEP, dynamic compliance (Cdyn), static compliance (Cstat), expiratory resistance (ExRes), and inspiratory resistance (InRes) were evaluated once daily on the second and third day of MV. RESULTS: A total of 64 infants (median age of 2.8 months and a mean weight of 4.8 ± 1.7 kg) were evaluated. A mean positive inspiratory pressure (PIP) of 31.5 ± 5.2 cmH2O, positive end-expiratory pressure (PEEP) of 5.5 ± 1.4 cmH2O, resulting in a mean airway pressure (MAP) of 12.5 ± 2.2 cmH2O and delta pressure of 22.5 ± 4.4 cmH2O without difference between the two hospitals. Measurements of respiratory mechanics showed high values of InRes and ExRes (median 142 [IQ25-75 106-180] cmH2O/L/s and 158 [IQ25-75 130-195.3] cmH2O/L/s, respectively), accompanied by decreased Cdyn and Cstat (0.46 ± 0.19 and 0.81 ± 0.25 mL/kg/cmH2O, respectively). None of the variables was associated with mortality, length of MV, or length of PICU stay. CONCLUSION: Infants with AVB requiring MV support present very high InRes and ExRes values. These findings might be the reason for the aggressive ventilatory parameters, especially PIP, required to ventilate this group of children with lower airway obstruction. CLINICAL SIGNIFICANCE: Monitoring respiratory mechanics could represent a useful tool to guide the ventilatory strategy to be adopted in patients with AVB. HOW TO CITE THIS ARTICLE: Andreolio C, Piva JP, Bruno F, da Rocha TS, Garcia PCR. Airway Resistance and Respiratory Compliance in Children with Acute Viral Bronchiolitis Requiring Mechanical Ventilation Support. Indian J Crit Care Med 2021;25(1):88-93.

Impulse oscillometry: pulmonary function assessment in preschool children.

OBJECTIVES: In contrast to spirometry, which requires active participation of the individual and is challenging for the preschool age group, the impulse oscillometry system comprises a test that minimizes the degree of coordination required. The study aimed to compare the results of Impulse Oscillometry System (IOS) in children with and without respiratory symptoms. METHODS: A cross-sectional study was conducted in children aged between 3 and 6 years. A short version of the ATS-DLD-78-C questionnaire validated for Brazilian children was applied to identify two groups: children with and without respiratory symptoms. The IOS analysis was carried out measuring the following parameters in triplicate: resistance at 5 Hz (R5Hz) and 20 Hz (R20Hz), respiratory reactance at 5 Hz (X5Hz), and R5-R20Hz before and after bronchodilator application. RESULTS: A total of 76 preschoolers were selected, 55 (72.4%) of whom had respiratory complaints. The coefficient of variability of R5Hz was ≤17% in 70/76 (92.1%) of the children. Resistances at R5Hz and R5-R20Hz in the children with respiratory complaints reached values higher than those of children without symptoms before bronchodilation. CONCLUSIONS: The results obtained for resistance using IOS in children with respiratory symptoms were higher in the pre-bronchodilator examination for R5Hz and R5-R20Hz compared to those of children without respiratory symptoms. EXPERT OPINION: Prospective investigations suggest that irreversible changes in lung function begin in infancy, before reaching school age. Pulmonary function follow-up in children with recurrent wheezing or asthma is important for confirmation of diagnosis and evaluation of the disease severity. The Impulse Oscillometry System (IOS) can be useful in assessing children's pulmonary function since it requires minimal patient cooperation and can be successfully applied to preschool children being an alternative to individuals who have difficulty performing spirometry.

Long term oral appliance therapy decreases stress symptoms in patients with upper airway resistance syndrome.

STUDY OBJECTIVES: To evaluate the long-term effects of a mandibular advancement device (MAD) on stress symptoms and cognitive function in patients with upper airway resistance syndrome (UARS) compared with placebo. METHODS: This study was a randomized placebo-controlled clinical trial. Thirty UARS patients were randomized into 2 groups: placebo and MAD groups. UARS criteria were the presence of sleepiness (Epworth Sleepiness Scale ≥ 10) and/or fatigue (Modified Fatigue Impact Scale ≥ 38) associated with an apnea-hypopnea index ≤ 5 events/h and a respiratory disturbance index > 5 events/h of sleep, and/or flow limitation in more than 30% of total sleep time. All patients completed the Rey Auditory-Verbal Learning Test, the Logical Memory test, the Stroop Color Test, the Trail Making Test, the Digit Symbol Substitution Test, and Inventory of Stress Symptoms. Cognition protocol was defined based on the most used neuropsychological tests in the literature. Evaluations were performed before and after 1.5 years of treatment. RESULTS: Mean adherence to placebo and to MAD was 6.6 ± 2.6 and 6.1 ± 2.4 h/night, respectively. Side effects reported by MAD group were minor and short-term. There was no statistically significant difference in Rey Auditory-Verbal Learning Test, Logical Memory test, Stroop Color Test, Trail Making Test, and Digit Symbol Substitution Test before and after 1.5 years of treatment in both groups. Inventory of Stress Symptoms score decreased at the alert phase and the resistance phase after 1.5 years of MAD treatment compared to the placebo. CONCLUSIONS: Mandibular advancement devices were effective in decreasing stress symptoms in UARS patients after 1.5 years of treatment. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: Efficacy of Oral Appliance for Upper Airway Resistance Syndrome; URL: https://clinicaltrials.gov/ct2/show/record/NCT02636621; Identifier: NTC02636621.

A6 neurons simultaneously modulate active expiration and upper airway resistance in rats.

NEW FINDINGS: What is the central question of this study? Do A6 neurons modulate active expiratory and airway responses evoked by hypercapnia/acidosis? What is the main finding and its importance? Acute inhibition of A6 neurons reduced active expiratory, inspiratory and the associated oropharyngeal and laryngeal motor responses to hypercapnia/acidosis. A6 neurons provide excitatory synaptic drive contributing to the central generation of inspiratory and expiratory motor activity as well as the control of upper airway resistance. ABSTRACT: During rest, inspiration is an active phenomenon, whereas expiration is passive. Under conditions of high chemical drive, such as hypercapnia/acidosis, there is an increase in inspiratory activity, expiration becomes active and upper airway resistance is reduced. The locus coeruleus noradrenergic neurons (A6 neurons) are activated when exposed to elevated CO2 /[H+ ] levels and modulate respiratory brainstem neurons regulating ventilation. However, the role of A6 neurons in the control of upper airway resistance is not fully understood. We tested the hypothesis that A6 neurons contribute to the central generation of active inspiratory and expiratory responses and the associated changes in the motor nerves controlling upper airway resistance during hypercapnia/acidosis in rats. Using a perfused brainstem-spinal cord preparation, we inhibited A6 neurons using pharmacogenetics and evaluated the active expiratory (abdominal nerve), laryngeal (cervical vagus nerve), oropharyngeal (hypoglossal nerve) and inspiratory (phrenic nerve) motor nerve responses to hypercapnia/acidosis. Acute inhibition of A6 neurons did not produce significant changes in the respiratory pattern in normocapnia. However, the hypercapnia/acidosis-induced active expiratory response and the associated changes in the motor nerves responsible for control of oropharyngeal and laryngeal resistance, as well as the inspiratory response were all reduced after inhibition of A6 neurons. Our data demonstrate that A6 neurons exert an important excitatory synaptic drive to the central generation of both active inspiratory and expiratory activities and modulate the control of upper airway resistance during hypercapnia/acidosis.

Model of single-sized endotracheal tube for adults / Modelo de tubo endotraqueal de tamanho único para adultos

ABSTRACT Objective To simulate different diameters of endotracheal tubes and to verify the fluid dynamics aspects by means of flow and resistance measurements. Methods Fluid dynamics software was used to calculate mean flow and airway resistance in endotracheal tube with a diameter of 6.0, 7.0, 7.5, 8.0, 9.0 and 10.0mm at normal body temperature and under constant pressure. The same measurements were taken in the fusion of the first 22cm of a 9.0mm endotracheal tube with 10.0mm diameter, and with the end part in 12cm of a 6.0mm endotracheal tube with 7.0mm diameter. Results The fusion of the first 22cm of an endotracheal tube of 10.0mm diameter with the terminal part in 12cm of an endotracheal tube of 6.0mm diameter, preserving the total length of 34cm, generated average flow and airway resistance similar to that of a conventional 7.5mm endotracheal tube. Conclusion This simulation study demonstrates that a single-sized endotracheal tube may facilitate endotracheal intubation without causing increased airway resistance.

RESUMO Objetivo Simular diferentes diâmetros de tubos endotraqueais e verificar os aspectos fluidinâmicos, considerando medições de fluxo e resistência. Métodos Foi utilizado um software de fluidinâmica para calcular o fluxo médio e a resistência das vias aéreas nos tubos endotraqueais com diâmetro de 6,0, 7,0, 7,5, 8,0, 9,0 e 10,0mm, em temperatura corporal normal e pressão constante. As mesmas medidas foram realizadas na fusão dos primeiros 22cm de um tubo endotraqueal de 9,0 e 10,0mm de diâmetro, com a parte terminal em 12cm de um tubo endotraqueal de 6,0 e 7,0mm de diâmetro. Resultados A fusão dos primeiros 22cm de um tubo endotraqueal de diâmetro 10,0 mm com a parte terminal em 12cm de um tubo endotraqueal de 6,0mm de diâmetro, preservando o comprimento total de 34cm, gerou fluxo médio e resistência de vias aéreas semelhantes aos de um tubo endotraqueal convencional de 7,5mm. Conclusão Um tubo endotraqueal de tamanho único pode facilitar a intubação endotraqueal, sem causar aumento de resistência na via aérea.

Insuflador-exsuflador mecânico versus manobra PEEP-ZEEP em pacientes em ventilação mecânica prolongada / Mechanical insufflator-exsufflator versus PEEP-ZEEP maneuver in patients on prolonged mechanical ventilation

Introdução: A presença da via aérea artificial, associada com a imobilidade no leito, resulta em um déficit na desobstrução das vias aéreas em pacientes sob ventilação mecânica (VM). Tal condição contribui para o desenvolvimento de quadros de hipoxemia e/ou infecções respiratórias, aumentando o trabalho respiratório e também as falhas de extubação. Objetivo: Comparar os efeitos da utilização do insuflador-exsuflador mecânico e da manobra PEEP-ZEEP em relação à mecânica respiratória em pacientes ventilados mecanicamente por tempo prolongado. Métodos: Ensaio clínico randomizado cruzado, incluindo pacientes em ventilação mecânica por mais de 10 dias. Os pacientes foram randomizados para receber a aplicação do insuflador-exsuflador mecânico e da manobra PEEP-ZEEP. Foram mensuradas complacência pulmonar, estática e dinâmica, e resistência pulmonar antes e após a aplicação de cada técnica. Resultados: Foram incluídos 22 pacientes. Na análise intragrupos observa-se aumento significativo na complacência dinâmica e complacência estática após a aplicação de ambas as técnicas. A resistência pulmonar variou significativamente apenas após a aplicação do insuflador-exsuflador mecânico. Não foram observadas diferenças significativas na análise intergrupos. Conclusão: O insuflador-exsuflador mecânico e a manobra de PEEP-ZEEP demonstraram ter efeito positivo tanto sobre a complacência estática quanto a dinâmica. Entretanto, a resistência pulmonar aumentou após a aplicação do insuflador-exsuflador mecânico. (AU)

Introduction: The presence of the artificial airway associated with immobility in the bed results in a deficit in the clearance of the airways in patients under mechanical ventilation (MV). This condition contributes to the development of hypoxemia and/or respiratory infections, increasing respiratory work and also extubation failures. Objective: To compare the effects of the use of mechanical insufflation-exsufflation and PEEP-ZEEP maneuver in relation to respiratory mechanics in patients on prolonged mechanical ventilation. Methods: Randomized cross-over trial, including patients on mechanical ventilation for more than 10 days. The patients were randomized to receive the application of mechanical insufflator-exsuflator and PEEP-ZEEP maneuver. Pulmonary compliance, static and dynamic, and pulmonary resistance were measured before and after the application of each technique. Results: 22 patients were included. In the intragroup analysis we observed a significant increase in the dynamic compliance and static compliance after the application of both techniques. Pulmonary resistance varied significantly only after application of the mechanical insufflation-exsufflation. No significant differences were observed in the inter-group analysis. Conclusion: The mechanical insufflator-exsuflator and the PEEP-ZEEP maneuver were shown to have a positive effect on both static and dynamic complacency. However, pulmonary resistance increased after the application of the mechanical insufflation-exsufflation.(AU)

Tidal Flow-Volume Loop Enveloping at Rest in Advanced COPD.

BACKGROUND: Expiratory flow limitation (EFL) is a key physiological abnormality in COPD. Comparing tidal-to-maximum flow-volume (F-V) loops is a simple and widely available method to assess EFL in patients with COPD. We aimed to investigate whether subjects with COPD showing significant resting tidal F-V enveloping (ie, > 50% tidal volume) would present with higher exertional operating lung volumes, which would lead to greater burden of dyspnea and poorer exercise tolerance compared to their counterparts. METHODS: 37 subjects with COPD (21 males; 63.1 ± 9.2 years old; FEV1 = 37 ± 12% predicted) and 9 paired controls (3 males; 55.9 ± 11.7 y old) performed an incremental cardiopulmonary exercise testing on a cycle ergometer. Dyspnea perception, inspiratory capacity maneuvers after 3-4 sequential tidal F-V loops, and esophageal and gastric pressures were measured during exercise. RESULTS: Most subjects (31 of 37, 84%) presented with significant tidal F-V enveloping. Critical inspiratory constraints and upward dyspnea inflection points (as a function of both work rate and ventilation) were reached earlier in these subjects, thereby leading to poorer exercise tolerance compared to their counterparts (P = .01). Abdominal muscle recruitment (ie, increase in gastric pressure ≥ 15%) during tidal expiration was significantly higher in the EFL+ group. However, this did not bear an influence on the operating lung volumes, inspiratory constraints, dyspnea, cardiocirculatory responses, or exercise tolerance (P > .05). CONCLUSIONS: Tidal F-V loop enveloping at rest should be valued as it is related to relevant clinical outcomes, such as dyspnea burden and exercise tolerance in subjects with COPD.

Influencia de la obesidad sobre la resistencia y conductancia específica de la vía aérea en niños escolares / The impact of obesity on specific airway resistance and conductance among schoolchildren

Introducción. La obesidad infantojuvenil es un problema epidemiológico en los países en vías de desarrollo. Su prevalencia entre los niños en edad preescolar y escolar supera el 30%. Esta se asocia a una amplia variedad de complicaciones de salud, entre ellas, una acelerada pérdida de la función pulmonar, que provoca cambios en la fisiología y mecánica ventilatoria. El objetivo de este estudio fue estudiar la asociación entre obesidad y aumento de la resistencia específica de las vías aéreas (specific resistance airway; sRaw, por sus siglas en inglés) en una muestra infantojuvenil obesa de la comuna de Talca. Material y método. En una muestra de 36 sujetos con un promedio de edad de 9,38 ± 1,99 años, dividida en dos grupos, peso normal y obesos, se midieron los pliegues tricipital, subescapular, abdominal y volúmenes pulmonares. Para el análisis estadístico, se determinó la normalidad de los datos y, posteriormente, se utilizaron los test t de Student o U de Mann-Whitney y Pearson o Spearman según correspondiera. Se consideró un nivel de significancia estadística de p < 0,05. Resultados. Al comparar sujetos de peso normal con obesos, se observó un aumento significativo de la sRaw y una disminución significativa de la conductancia específica de la vía aérea en sujetos obesos. Además, se observó una correlación buena y significativa entre sRaw y porcentaje de grasa. Conclusiones. Los sujetos obesos mostraron un aumento de la sRaw y disminución de la conductancia específica de la vía aérea.

Introduction. Child and adolescent obesity is an epidemiological problem in developing countries. Its prevalence among preschoolers and schoolchildren is over 30%. It has been associated with a wide range of health complications, including rapid loss of lung function leading to changes in physiology and ventilatory mechanics. The objective of this study was to analyze the association between obesity and the increase in specific airway resistance (sRaw) in a sample of obese children and adolescents from the district of Talca. Material and method. In a sample of 36 subjects with an average age of 9.38 ± 1.99 years, divided into 2 groups (normal weight and obese), the tricipital, subscapular, and abdominal skinfolds and lung volumes were measured. For the statistical analysis, data normality was determined and then the Student's t test or the Mann-Whitney U test and Pearson's or Spearman's correlations were used, as applicable. A value of p < 0.05 was considered statistically significant. Results. When comparing normal weight and obese subjects, a significant increase in sRaw and a significant reduction in specific airway conductance (sGaw) were observed in obese subjects. In addition, an adequate and significant correlation was observed between sRaw and fat percentage. Conclusions. Obese subjects showed an increased sRaw and a reduced sGaw.

The impact of obesity on specific airway resistance and conductance among schoolchildren. / Influencia de la obesidad sobre la resistencia y conductancia específica de la vía aérea en niños escolares.

INTRODUCTION: Child and adolescent obesity is an epidemiological problem in developing countries. Its prevalence among preschoolers and schoolchildren is over 30%. It has been associated with a wide range of health complications, including rapid loss of lung function leading to changes in physiology and ventilatory mechanics. The objective of this study was to analyze the association between obesity and the increase in specific airway resistance (sRaw) in a sample of obese children and adolescents from the district of Talca. MATERIAL AND METHOD: In a sample of 36 subjects with an average age of 9.38 ± 1.99 years, divided into 2 groups (normal weight and obese), the tricipital, subscapular, and abdominal skinfolds and lung volumes were measured. For the statistical analysis, data normality was determined and then the Student's t test or the Mann-Whitney U test and Pearson's or Spearman's correlations were used, as applicable. A value of p < 0.05 was considered statistically significant. RESULTS: When comparing normal weight and obese subjects, a significant increase in sRaw and a significant reduction in specific airway conductance (sGaw) were observed in obese subjects. In addition, an adequate and significant correlation was observed between sRaw and fat percentage. CONCLUSIONS: Obese subjects showed an increased sRaw and a reduced sGaw.

INTRODUCCIÓN: La obesidad infantojuvenil es un problema epidemiológico en los países en vías de desarrollo. Su prevalencia entre los niños en edad preescolar y escolar supera el 30%. Esta se asocia a una amplia variedad de complicaciones de salud, entre ellas, una acelerada pérdida de la función pulmonar, que provoca cambios en la fisiología y mecánica ventilatoria. El objetivo de este estudio fue estudiar la asociación entre obesidad y aumento de la resistencia específica de las vías aéreas (specific resistance airway; sRaw, por sus siglas en inglés) en una muestra infantojuvenil obesa de la comuna de Talca. MATERIAL Y MÉTODO: En una muestra de 36 sujetos con un promedio de edad de 9,38 ± 1,99 años, dividida en dos grupos, peso normal y obesos, se midieron los pliegues tricipital, subescapular, abdominal y volúmenes pulmonares. Para el análisis estadístico, se determinó la normalidad de los datos y, posteriormente, se utilizaron los test t de Student o U de Mann-Whitney y Pearson o Spearman según correspondiera. Se consideró un nivel de significancia estadística de p < 0,05. RESULTADOS: Al comparar sujetos de peso normal con obesos, se observó un aumento significativo de la sRaw y una disminución significativa de la conductancia específica de la vía aérea en sujetos obesos. Además, se observó una correlación buena y significativa entre sRaw y porcentaje de grasa. CONCLUSIONES: Los sujetos obesos mostraron un aumento de la sRaw y disminución de la conductancia específica de la vía aérea.

Metformin influences on respiratory system in obese mice induced by postnatal overnutrition.

Many studies have confirmed the merits of metformin to treat type 2 diabetes, but few studies have addressed its effect on the respiratory system. Moreover, vascular endothelial growth factor (VEGF) is critical to many lung functions. In this way, we evaluated the metformin impact on the lung in treated obese Swiss mice, induced by postnatal overnutrition. Glucose and insulin were detected and the insulin resistance index (HOMA) was calculated; inflammatory cells and nitrite/nitrate concentration (NOx) was quantified from bronchoalveolar lavage, collagen and lung VEGF-a was analysed in the lung tissue and lung mechanics were evaluated by methacholine-induced bronchoconstriction. Values of glucose, insulin, HOMA; VEGF-a and collagen demonstrate the partial ability of metformin to improve the effects of obesity. However, metformin is ineffective in re-establishing the inflammation, shows no effects on NOx and does not restore bronchoconstriction in obese mice. In conclusion, metformins beneficial effects on lung are questionable in the postnatal overnutrition model of obesity.

Long-Term Oral Appliance Therapy Improves Daytime Function and Mood in Upper Airway Resistance Syndrome Patients.

Objectives: To evaluate the long-term effects of an oral appliance on clinical symptoms, respiratory sleep parameters, sleep quality, and sustained attention in patients with upper airway resistance syndrome (UARS) were compared with placebo. Methods: This study was a randomized placebo-controlled clinical trial. Thirty UARS patients were randomized in two groups: placebo and mandibular advancement device (MAD) groups. UARS criteria were presence of sleepiness (Epworth Sleepiness Scale ≥ 10) and/or fatigue (Modified Fatigue Impact Scale ≥ 38) associated with an apnea/hypopnea index ≤ 5 and a respiratory disturbance index (RDI) > 5 events/hour of sleep, and/or flow limitation in more than 30% of total sleep time. All patients completed the Pittsburgh Sleep Quality Index (PSQI), the Functional Outcomes of Sleep Questionnaire, the Beck Anxiety and Depression Inventories, underwent full-night polysomnography, multiple sleep latency test, and Psychomotor Vigilance Test (PVT). Evaluations were performed before and after 1.5 years of treatment. Results: RDI, number of respiratory effort-related arousal, percentage of total sleep time with flow limitation, and arousal index significantly decreased after 1.5 years of MAD treatment. PSQI total score improved, severity of depression symptoms decreased, and mean reaction time in the PVT, based on the first measurement taken at 8:00 am, significantly decreased (p = .03) at the end of the protocol. Conclusions: The MAD was effective in decreasing respiratory events in UARS patients. For UARS, 1.5 years of oral appliance therapy also improved sleep quality and sustained attention, and decreased the severity of depression symptoms. Clinical Trial: Efficacy of Oral Appliance for Upper Airway Resistance Syndrome: Randomized, Parallel, Placebo-Controlled Study, NCT02636621.