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.

Actualización de la bronquiolitis aguda / Acute bronchiolitis update

La bronquiolitis aguda es una condición respiratoria frecuente en los niños menores de 2 años. Representa la principal causa de hospitalización infantil y se caracteriza por la presencia de sibilancias asociada a signos de una infección respiratoria alta. El agente etiológico más común es el virus respiratorio sincicial. Existe una falta de consenso con respecto a su definición clínica; y por ello, su tratamiento varía en todo el mundo. El diagnóstico es clínico, sin necesidad de emplear laboratorio o imágenes en forma rutinaria. Diversas revisiones han demostrado que los broncodilatadores, adrenalina, corticoides y antibióticos, entre otros, carecen de eficacia por lo que no se sugiere su empleo. El tratamiento sigue siendo de soporte, mediante la administración de oxígeno y manteniendo una adecuada hidratación. Cuando no se logra disminuir el trabajo respiratorio o corregir la hipoxemia se puede utilizar la presión positiva en la vía aérea para prevenir y controlar la insuficiencia respiratoria. Este artículo desarrolla una breve revisión de las principales características clínicas, epidemiológicas, radiológicas, así como algunos de los diferentes tratamientos publicados en las últimas dos décadas.

Acute bronchiolitis is a common respiratory condition in children under 2 years old. It represents the main cause of childhood hospitalization characterized by the presence of wheezing associated with signs of an upper respiratory infection. The most common etiologic agent is respiratory syncytial virus. There is a lack of consensus regarding its clinical definition; and therefore, its treatment varies around the world. Diagnosis is clinical, without the need for routine laboratory or imaging. Various reviews have shown that bronchodilators, epinephrine, corticosteroids, and antibiotics, among others, lack efficacy, so their use is not suggested. Treatment continues to be supportive, by administering oxygen and maintaining adequate hydration. When it is not possible to reduce the work of breathing or correct the hypoxemia, positive airway pressure can be used to prevent and control respiratory failure. This article develops a brief review of the main clinical, epidemiological, and radiological characteristics, as well as some of the different treatments published in the last two decades.

Beta-2 agonistas para el tratamiento de bronquiolitis / Beta-2 agonists for the treatment of bronchiolitis

INTRODUCCIÓN La bronquiolitis es la inflamación aguda de las vías aéreas de pequeño calibre, teniendo como causa principal las infecciones virales. Es altamente frecuente en menores de dos años, sobretodo en menores de 12 meses. Existe gran controversia sobre el manejo de esta patología, siendo especialmente cuestionable el uso de beta-2 agonistas de corta acción tanto en el ámbito ambulatorio como hospitalario. MÉTODOS Para responder esta pregunta utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud a nivel mundial, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, reanalizamos los datos de los estudios primarios, realizamos un metanálisis, y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES Identificamos siete revisiones sistemáticas que en conjunto incluyen 47 estudios primarios, de los cuales 44 corresponden a ensayos aleatorizados. Concluimos que el uso de beta-2 agonistas podría no tener ningún beneficio en el manejo de la bronquiolitis, en términos de necesidad de hospitalización y/o duración de la misma. Por otra parte, podría aumentar efectos adversos como arritmias, sin embargo, la certeza de esta evidencia es baja

¿Tienen los corticoides inhalatorios un rol en la bronquiolitis? / Do inhaled corticosteroids have a role for bronchiolitis?

INTRODUCCIÓN: La bronquiolitis corresponde a una inflamación aguda de las vías aéreas pequeñas secundaria a infección viral y es una patología frecuente en menores de dos años. Se ha propuesto que el uso de corticoides inhalatorios durante una bronquiolitis podría reducir la recurrencia de sibilancias o el desarrollo de asma, sin embargo, existe controversia al respecto. MÉTODOS: Para responder a esta interrogante utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, reanalizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos tres revisiones sistemáticas que en conjunto incluyen 11 ensayos aleatorizados. Concluimos que el uso de corticoides inhalatorios no reduce la recurrencia de sibilancias o asma en pacientes con bronquiolitis.

INTRODUCTION: Bronchiolitis consists of an acute small airways inflammation secondary to a viral infection and is a frequent pathology among children under 2 years. The use of inhaled corticosteroids during bronchiolitis has been proposed to reduce recurrent wheeze or asthma, however there is controversy about it. METHODS: To answer this question we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified three systematic reviews including 11 randomized trials. We concluded that inhaled corticosteroids do not reduce recurrent wheeze or asthma in patients with bronchiolitis.

¿Deben utilizarse corticoides sistémicos en la bronquiolitis? / Should systemic corticosteroids be used for bronchiolitis?

INTRODUCCIÓN: La bronquiolitis es una inflamación aguda de las vías aéreas pequeñas debida principalmente a una infección viral. Es una patología frecuente en menores de dos años y en especial en menores de 12 meses. Se ha propuesto el uso de corticoides sistémicos en bronquiolitis, en especial en pacientes de mayor severidad, siendo controversial su utilidad. MÉTODOS: Para evaluarlo utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, reanalizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos cuatro revisiones sistemáticas que en conjunto incluyeron 20 ensayos aleatorizados. Concluimos que el uso de corticoides sistémicos no aporta ningún beneficio en el tratamiento de la bronquiolitis, aún en pacientes con ventilación mecánica.

INTRODUCTION: Bronchiolitis is an acute small airways inflammation mainly caused by a viral infection. It is frequent in children under two years of age, particularly under 12 months. The use of systemic corticosteroids has been proposed for bronchiolitis, especially for severely ill patients. However, its efficacy is still controversial. METHODS: To answer this question we gathered information using Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data from primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified four systematic reviews, including 20 randomized trials overall. We concluded the use of systemic corticosteroids has no benefit for the treatment of bronchiolitis, even for patients with mechanical ventilation.

Physical therapy for airway clearance improves cardiac autonomic modulation in children with acute bronchiolitis

BACKGROUND: The effects of physical therapy on heart rate variability (HRV), especially in children, are still inconclusive. OBJECTIVE: We investigated the effects of conventional physical therapy (CPT) for airway clearance and nasotracheal suction on the HRV of pediatric patients with acute bronchiolitis. METHOD: 24 children were divided into two groups: control group (CG, n=12) without respiratory diseases and acute bronchiolitis group (BG, n=12). The heart rate was recorded in the BG at four different moments: basal recording (30 minutes), 5 minutes after the CPT (10 minutes), 5 minutes after nasotracheal suction (10 minutes), and 40 minutes after nasotracheal suction (30 minutes). The CG was subjected to the same protocol, except for nasotracheal suction. To assess the HRV, we used spectrum analysis, which decomposes the heart rate oscillations into frequency bands: low frequency (LF=0.04-0.15Hz), which corresponds mainly to sympathetic modulation; and high frequency (HF=0.15-1.2Hz), corresponding to vagal modulation. RESULTS: Under baseline conditions, the BG showed higher values in LF oscillations, lower values in HF oscillations, and increased LF/HF ratio when compared to the CG. After CPT, the values for HRV in the BG were similar to those observed in the CG during basal recording. Five minutes after nasotracheal suction, the BG showed a decrease in LF and HF oscillations; however, after 40 minutes, the values were similar to those observed after application of CPT. CONCLUSIONS: The CPT and nasotracheal suction, both used for airway clearance, promote improvement in autonomic modulation of HRV in children with acute bronchiolitis. .

Clinical and Epidemiological Comparison of Human Metapneumovirus and Respiratory Syncytial Virus in Seoul, Korea, 2003-2008

Human metapneumovirus (HMPV) shares clinical and epidemiological characteristics with well-known respiratory syncytial virus (RSV). The aim of this study was to investigate the clinical and epidemiological differences between HMPV- and RSV-induced wheezing illnesses. A total of 1,008 nasopharyngeal aspirate specimens was collected from 1,008 pediatric patients hospitalized with acute respiratory tract infection at Inje University Sanggye Paik Hospital from December 2003 to April 2008, and tested for seven common respiratory viruses. Conditions classified as wheezing illness were bronchiolitis, reactive airways disease, and bronchial asthma. HMPV caused a significantly lower proportion of wheezing illness when compared to RSV (48.1% vs. 82.2%, P<0.05). HMPV-induced wheezing illness occurred predominantly in older patients when compared to RSV patients (P<0.001). RSV infections peaked in the fall and winter followed by peaks of HMPV infection in winter and spring. Eosinophil counts were significantly higher (P<0.01) in RSV patients when compared to HMPV patients. These results show that human metapneumovirus patients exhibit several different clinical and epidemiological characteristics, such as higher proportion of wheezing illness, age and seasonal incidence, and eosinophil counts, when compared to RSV patients.

Comparação dos efeitos de duas técnicas fisioterapêuticas respiratórias em parâmetros cardiorrespiratórios de lactentes com bronquiolite viral aguda / Comparison of the effects that two different respiratory physical therapy techniques have on cardiorespiratory parameters in infants with acute viral bronchiolitis

OBJETIVO: Comparar os efeitos das técnicas de aumento do fluxo expiratório (AFE) e vibração associada à drenagem postural (DP) nos parâmetros cardiorrespiratórios de frequência cardíaca (FC), frequência respiratória (FR) e SpO2 de lactentes com bronquiolite viral aguda (BVA). MÉTODOS: Foram analisados lactentes com diagnóstico clínico e radiológico de BVA. A FC, FR e SpO2 foram registradas em quatro tempos: antes do procedimento e após 10, 30 e 60 min do término do procedimento. Os pacientes foram divididos em três grupos: submetido à AFE; submetido à vibração/DP; e controle. RESULTADOS: Foram incluídos no estudo 81 lactentes, 27 em cada grupo de estudo, com média de idade de 4,52 meses e peso médio de 6,56 kg. Na comparação por ANOVA, as médias da FR, FC e SpO2 nos grupos AFE e vibração/DP não apresentaram diferenças significantes em relação ao grupo controle (p > 0,05). Considerando somente os quatro tempos, houve queda significante dos valores médios de FR nos grupos AFE e vibração/DP em relação ao controle (p < 0,05). CONCLUSÕES: A aplicação de AFE e de vibração associada à DP não apresentou um benefício global na melhora dos parâmetros cardiorrespiratórios em lactentes com BVA. Quando analisados isoladamente no decorrer do tempo, a fisioterapia respiratória parece contribuir na diminuição da FR nesses pacientes.

OBJECTIVE: To compare the expiratory flow increase technique (EFIT) and vibration accompanied by postural drainage (PD) in terms of their effects on the heart rate (HR), respiratory rate (RR) and SpO2 of infants with acute viral bronchiolitis (AVB). METHODS: Infants with clinical and radiological diagnosis of AVB were analyzed. The HR, RR and SpO2 were registered at four time points: prior to the procedure; and at 10, 30 and 60 min after the procedure. The patients were divided into three groups: submitted to the EFIT; submitted to vibration/PD; and control. RESULTS: We included 81 infants, 27 per group, with a mean age of 4.52 years and a mean weight of 6.56 kg. Using ANOVA, we found that the EFIT and vibration/PD groups presented no significant differences in relation to the control group in terms of the mean values for HR, RR or SpO2 (p > 0.05). Considering only the four time points evaluated, the mean RR was significantly lower in the EFIT and vibration/PD groups than in the control group (p < 0.05). CONCLUSIONS: In terms of overall improvement of cardiorespiratory parameters, neither the EFIT nor vibration/PD provided any benefit to infants with BVA. However, over time, respiratory physical therapy seems to contribute to decreasing the RR in these patients.

Bronquiolite constritiva: aspectos tomográficos e correlação anatomopatológica / Constrictive bronchiolitis: tomographic aspects and pathologic correlation

Os autores relatam os principais aspectos da bronquiolite constritiva na tomografia computadorizada de alta resolução (TCAR) do tórax em ins e expiração, e os comparam aos achados anatomopatológicos, mediante estudo de três casos da doença em mulheres com idade entre 29 e 46 anos que apresentavam dispnéia incaracterística, de caráter progressivo, encaminhadas para realização de espirometria, TCAR do tórax e biópsia pulmonar. A TCAR do tórax em ins e expiração demonstrou, em dois casos, padrão de atenuação em mosaico difuso, acentuado na expiração. No terceiro caso foram observados nódulos centrolobulares, não sendo realizado estudo em expiração. O material histopatológico demonstrou estenose importante de luzes bronquiolares por espessamento fibroso da lâmina própria e atrofia do epitélio bronquiolar, alterações diagnósticas da bronquiolite constritiva. A realização de TCAR do tórax em ins e expiração mostrou-se de fundamental importância na suspeição de doenças relacionadas à obstrução de pequenas vias aéreas, sendo o aspecto de atenuação em mosaico na expiração característico da topografia periférica das lesões. O diagnóstico de bronquiolite constritiva deve ser confirmado por biópsia pulmonar por meio de toracotomia

We report the main findings of inspiratory and expiratory high-resolution computed tomography (HRCT) of the thorax in three women aged between 29 and 46 years with constrictive bronchiolitis and compare these results with the anatomopathological findings. The three women presented with progressive noncharacteristic dyspnea and were submitted to pulmonary function tests, HRCT of the thorax and lung biopsy. In two of the patients, inspiratory and expiratory HRCT of the thorax demonstrated a mosaic attenuation pattern that was accentuated during expiration. The expiratory phase was not performed in the third patient who presented centrilobular nodules. The pathology studies revealed significant bronchiolar stenosis due to fibrous thickening of the lamina propria and atrophy of the bronchiolar epithelium, which are diagnostic findings of constrictive bronchiolitis. Inspiratory and expiratory HRCT demonstrated to be of fundamental importance in the assessment of patients with diseases that cause obstruction of small airways. The mosaic attenuation pattern in the expiratory phase is characteristic of the peripheral topography of the lesions. The diagnosis of constrictive bronchiolitis should be confirmed by lung biopsy.

Modalidades terapéuticas en bronquiolitis a través de cinco años / Modalities therapeutics in broncholities during fith years

La Bronquiolitis es una patología ampliamente distribuida en todo el mundo. Afecta predominantemente a lactantes menores, especialmente a menores de 6 meses. Los criterios de terapéutica son muy controvertidos y cambiantes. Con la finalidad de analizar las modalidades y resultados de las terapéuticas utilizadas en los últimos 5 años (1986-1991) en un Hospital de tercer nivel, sé realizó un estudio retrospectivo de 337 casos (10 por ciento del universo) con diagnóstico de egreso de Bronquiolitis de un total de 3596 casos

Hiperreactividad bronquial en pacientes con bronquiolitis / Bronchial hyperreactivity secondary to bronchiolitis

La hiperreactividad bronquial (HRB) se caracteriza por un incremento de la respuesta de la vía aérea a diversos estímulos químicos, físicos y/o biológicos. De estos últimos las infecciones virales que ocasionan bronquiolitis (Br) pueden dejar como secuela una HRB tardía. En este estudio nuestro objetivo fue la detección de HRB en niños que tuvieron Br. Se eligieron pacientes de 7 a 13 años asintomáticos (clínicamente y espirométricamente) sin asma. Se formaron dos grupos, uno de los cuales cursó con Br. siendo lactante y el otro de control, de las mismas características sin este antecedente. Todos fueron sometidos a la inhalación de concentraciones crecientes de metacolina. Las respuestas fueron evaluadas clínicamente y espirométricamente. En el grupo de estudio los restos con metacolina fueron positivos en 40 por ciento, con manifestaciones clínicas (tos, opresión torácica) y/o disminución de los parámetros ventilatorios. En contraste en los controles sólo en dos fue positivo con las concentraciones máximas permisibles. Concluimos que los médicos y los padres deben estar alerta de la posibilidad de HRB tardía en los niños que padecieron

Lower airway obstruction in the PICU.

Lower airway obstruction is one of the most frequent causes of admission to pediatric intensive care unit. A thorough understanding of the pathophysiology underlying the disease will lead to effective management and decreased mortality and morbidity.