Accuracy of spirometry for detection of asthma: a cross-sectional study

ABSTRACT BACKGROUND: Asthma is a chronic inflammatory disease with airway hyperresponsiveness. Spirometry is the most commonly used test among asthmatic patients. Another functional test used for diagnosing asthma is the bronchial challenge test. The aim of this study was to analyze the accuracy of spirometry for detecting asthma in the general population. DESIGN AND SETTING: Cross-sectional study with data analysis to evaluate the accuracy of spirometry through calculating sensitivity, specificity and predictive values and through the kappa agreement test. METHODS: Subjects who constituted a birth cohort were enrolled at the age of 23 to 25 years. Spirometric abnormality was defined as reduced forced expiratory volume in one second, i.e. lower than 80% of the predicted value. Measurement of bronchial responsiveness was performed by means of the bronchial challenge test with methacholine. The gold-standard diagnosis of asthma was defined as the presence of bronchial hyperresponsiveness in association with respiratory symptoms. RESULTS: Asthma was detected in 200 subjects (10.4%) out of the sample of 1922 individuals. Spirometric abnormality was detected in 208 subjects (10.9%) of the sample. The specificity of spirometric abnormality for detecting asthma was 90%, sensitivity was 23%, positive predictive value was 22%, and negative predictive value was 91%. The kappa test revealed weak agreement of 0.13 (95% confidence interval, CI: 0.07-0.19) between spirometry and the diagnosis of asthma. CONCLUSION: Spirometry, as a single test, has limitations for detecting asthma in the general population.

Reversion of methacholine induced bronchoconstriction with inhaled diazepam in patients with asthma / Bloqueo de la respuesta bronco constrictora a metacolina con diazepam inhalado en pacientes con asma

Background: Benzodiazepines have a direct bronchodilatory effect. Methacholine is a non-selective muscarinic receptor agonist causing bronchoconstriction. Aim: To examine the effects of inhaled benzodiazepines, modulating bronchoconstriction induced by methacholine in patients with asthma. Patients and Methods: Twelve patients with well controlled asthma were studied. On the first day, after determining the initial values of pulmonary function, a dose response curve was carried out with progressive doses of methacholine. After the last dose, when at least a 20% drop of the initial forced expiratory volume in the first second (FEV1) was achieved, vital capacity (VC) and FEV1 were measured at 7, 15 and 30 minutes after provocation. On the second day a diazepam aerosol was inhaled by the patients prior to the same protocol with methacholine. Results: In the first day of testing, methacholine inhalation (6 mg/mL) led to a significant drop in FEV1 from 2.98 to 1.69 L. On the second day of study, in the same patients, previous inhalation with diazepam reduced the changes of FEV1 after inhalation of methacholine. This parameter decreased from 2.48 to 2.21 L. Conclusions: Inhalation of benzodiazepines reduce bronchoconstriction after a methacholine challenge in patients with asthma.

Antecedentes: Las benzodiacepinas tienen un efecto broncodilatador directo. La metacolina es un agonista muscarínico que causa bronco constricción. Objetivo: Evaluar el efecto modulador de la inhalación de diazepam sobre la bronco constricción inducida por metacolina. Pacientes y Métodos: Se estudiaron 12 pacientes con asma bien controlada. En el primer día, se determinó la curva dosis respuesta de parámetros de función pulmonar a una dosis progresiva de metacolina. Después de la última dosis, cuando se consiguió un 20% de reducción en la capacidad vital forzada en el primer segundo (FEV1), se midió FEV1 y la capacidad vital (CV) a los 7, 15 y 30 min después de la provocación. En el segundo día los pacientes se inhalaron con diazepam antes de hacer la prueba con metacolina. Resultados: En el primer día, el FEV1 bajo de 2,98 a 1,69 l con 6 mg/ml de metacolina. En el segundo día, la inhalación de diazepam redujo la respuesta a metacolina con una reducción de FEV1 de 2,48 a 2,21 L. Conclusiones: La benzodiacepinas reducen la respuesta de vasoconstricción a metacolina.

Medicinas tradicionales andinas y su despenalización: entrevista con Walter Álvarez Quispe / Decriminalizing traditional Andean medicine: an interview with Walter Álvarez Quispe

Walter Álvarez Quispe, terapeuta kallawaya y biomédico especializado en cirugía general y ginecología, presenta la lucha de los terapeutas tradicionales y alternativos por la depenalización de estos sistemas médicos andinos realizada entre 1960 y 1990. Bolivia se torna el primer país en América Latina y el Caribe en despenalizar la medicina tradicional antes de los planteamientos de la Conferencia Internacional sobre Atención Primaria de Salud (Alma-Ata, 1978). Los datos aportados por el entrevistado aseguran que los logros alcanzados, principalmente por los kallawayas, responden a un proyecto propio y autónomo. Estas conquistas no se deben a las políticas oficiales de interculturalidad en salud, aunque busquen atribuirse para sí los logros alcanzados.

Walter Álvarez Quispe, a Kallawaya healer and biomedical practitioner specializing in general surgery and gynecology, presents the struggle of traditional and alternative healers to get their Andean medical systems depenalized between 1960 and 1990. Bolivia was the first country in Latin America and the Caribbean to decriminalize traditional medicine before the proposals of the International Conference on Primary Health Care (Alma-Ata, 1978). The data provided by the interviewee show that the successes achieved, mainly by the Kallawayas, stem from their own independent initiative. These victories are not the result of official policies of interculturality in healthcare, although the successes achieved tend to be ascribed to them.

The preventive effects of natural adjuvants, G2 and G2F on tracheal responsiveness and serum IL-4 and IFN-? (th1/th2 balance) in sensitized guinea pigs

OBJECTIVE: The effects of natural adjuvants on lung inflammation and tracheal responsiveness were examined in sensitized guinea pigs. METHODS: The responses of guinea pig tracheal chains and the serum levels of interleukin-4 and interferon-gamma were examined in control pigs and three other groups of guinea pigs: the sensitized group and two other sensitized groups treated with either adjuvant G2 or adjuvant G2F (n = 7 for each group). Sensitization of the animals was achieved by injection and inhalation of ovalbumin. RESULTS: The results showed that sensitized animals had increased tracheal responsiveness and increased serum levels of interleukin-4 and interferon-gamma compared to controls (p<0.05 to p<0.001). Treatments with either G2 or G2F prevented the increase in tracheal responsiveness and serum interleukin-4 (p<0.01 to p<0.001). However, the serum levels of interferon-gamma and the interleukin-4-to-interferon-gamma ratio was increased in the treated groups (p<0.001 for all cases). CONCLUSIONS: These results indicate important preventive effects of two natural adjuvants, particularly G2, on the changes in tracheal responsiveness, serum cytokines and the interleukin-4-to-interferon-gamma ratio (T helper 1/T helper 2 balance) in sensitized guinea pigs. .

Capnografia volumétrica na identificação da não homogeneidade da ventilação em crianças e adolescentes com asma persistente controlada / Volumetric capnography to detect ventilation inhomogeneity in children and adolescents with controlled persistent asthma

OBJETIVOS: Estudar alterações nas variáveis de capnografia volumétrica em crianças e adolescentes asmáticos comparados com grupo-controle e investigar suas mudanças com o uso do broncodilatador e do teste de broncoprovocação com metacolina. MÉTODOS: Cento e três pacientes com asma persistente controlada e 40 voluntários saudáveis participaram do estudo. Todos realizaram exames de capnografia volumétrica e espirometria. Todos os asmáticos repetiram os exames após uso do broncodilatador. Dos 103 asmáticos, 33 realizaram teste de broncoprovocação com metacolina, e foram registradas as medidas em três momentos: antes e após metacolina e após broncodilatador. RESULTADOS: Comparados ao grupo-controle, os asmáticos apresentaram aumento do slope da fase III normalizado pelo volume corrente e diminuição do volume corrente, do volume expiratório forçado no primeiro segundo, da capacidade vital forçada, do índice de obstrução e do fluxo expiratório forçado entre 25 a 75 por cento da capacidade vital forçada. Após o broncodilatador, houve aumento das variáveis espirométricas, do volume espaço morto anatômico e diminuição do slope da fase II normalizado pelo volume corrente; porém não houve alteração do slope da fase III normalizado pelo volume corrente. Após a metacolina, houve aumento dessa variável, com diminuição após broncodilatador. CONCLUSÕES: O aumento do slope da fase III normalizado pelo volume corrente nos pacientes asmáticos sugere que eles apresentam uma não homogeneidade da ventilação nos espaços aéreos distais, podendo refletir tanto distúrbios estruturais crônicos de vias aéreas como alterações agudas reversíveis observadas no teste de broncoprovocação.

OBJECTIVES: To study changes in the variables of volumetric capnography in children and adolescents with asthma compared with a control group and to investigate their changes with the use of bronchodilators and bronchial provocation test with methacholine. METHODS: One hundred and three patients with controlled persistent asthma and 40 healthy volunteers participated in the study. All of them underwent volumetric capnography and spirometry. All asthmatics repeated the tests after bronchodilator use. Among 103 asthma patients, 33 underwent methacholine challenge test, and measures were recorded on three occasions: before and after methacholine and after bronchodilator use. RESULTS: Compared with the control group, asthmatics had an increase in the slope of phase III normalized by tidal volume and decreases in tidal volume, forced expiratory volume in one second, forced vital capacity, rate of obstruction and forced expiratory flow between 25 to 75 percent of forced vital capacity. After bronchodilator use, there was an increase in spirometric variables, volume of anatomic dead space, and decrease in the slope of phase II normalized by tidal volume, but the slope of phase III normalized by tidal volume did not change. After methacholine, there was an increase in this variable, which decreased after bronchodilator use. CONCLUSIONS: The increase in the slope of phase III normalized by tidal volume in asthma patients suggests that these patients have ventilation inhomogeneity in the distal air spaces, which may reflect chronic structural disorders or reversible acute changes seen on the bronchial provocation test.

How to diagnose exercise induced asthma?

Exercise induced asthma [EIA] is a transient increase in airway resistance after intensive exercise and can be measured as a decline in forced expiratory volume in one second [FEV1]. The condition is due to increased training load and inhalation of cold and dry air. Several studies have shown that eucapnic voluntary hyperpnea challenge test [EVH test] is a very sensitive and specific diagnostic method. EVH test develops ELA by hyperventilation of dry gas and the test achieves the same airway obstruction as training in cold and dry air. The test is better than the previously used methacholine challenge test

Baixo grau de percepção da dispneia após teste de broncoprovocação induzida por metacolina em pacientes com asma / Poor perception of dyspnea following methacholine challenge test in patients with asthma

OBJETIVO: Determinar o percentual de asmáticos com má percepção da dispneia, correlacionando-a com gravidade da broncoconstrição aguda, hiper-responsividade brônquica, uso de medicação de manutenção e controle da asma. MÉTODOS: Ensaio clínico não controlado com pacientes asmáticos do Ambulatório de Pneumologia do Hospital São Lucas em Porto Alegre (RS). Foram realizados testes de broncoprovocação com metacolina com protocolo dosimetrado em cinco doses, e foi avaliada a percepção da dispneia após cada dose administrada, utilizando a escala de Borg. Dados sobre controle da asma, medicação em uso e uso de broncodilatador de curta ação de resgate foram coletados. RESULTADOS: Dos 65 pacientes incluídos, 53 completaram a avaliação. Desses, 32 (60,5 por cento) apresentaram percepção adequada da dispneia após o teste de broncoprovocação com metacolina, ao passo que 21 (39,5 por cento) não perceberam nenhuma alteração no grau de dispneia mesmo após uma queda de 20 por cento em VEF1. Não houve diferenças significativas entre os dois grupos em relação a VEF1 basal, percentagem de queda do VEF1 e dose de metacolina causadora de queda de 20 por cento do VEF1. Não houve correlação significativa entre percepção da dispneia e idade (p = 0,247), sexo (p = 0,329), uso de medicação de manutenção (p = 0,152), controle da asma (p = 0,562), hiper-responsividade brônquica (p = 0,082) e gravidade da broncoconstrição aguda (p = 0,749). CONCLUSÕES: Uma percentagem significativa dos asmáticos apresenta baixo grau de percepção da dispneia. Os fatores relacionados com a incapacidade de identificação da modificação da função pulmonar não estão bem definidos. A identificação e a orientação desse grupo de pacientes são fundamentais para a redução de morbidade e mortalidade por asma.

OBJECTIVE: To determine the proportion of asthma patients with a poor perception of dyspnea, correlating the level of that perception with the severity of acute bronchoconstriction, bronchial hyperresponsiveness, use of maintenance medication, and asthma control. METHODS: Uncontrolled clinical trial involving asthma patients treated at the Pulmonology Outpatient Clinic of the São Lucas Hospital, in Porto Alegre , Brazil. Methacholine challenge testing was performed using a five-breath dosimeter protocol. The perception of dyspnea after each breath was determined using the Borg scale. Data concerning asthma control, medication in use, and use of rescue short-acting bronchodilators were recorded. RESULTS: Of the 65 patients included in the study, 53 completed the evaluation. Of those, 32 (60.5 percent) showed adequate perception of dyspnea after the methacholine challenge test, whereas 21 (39.5 percent) did not perceive any changes in the degree of dyspnea even after a 20 percent fall in FEV1. There were no significant differences between the two groups regarding baseline FEV1, percentage fall in FEV1, and the dose of methacholine causing a 20 percent fall in FEV1. The perception of dyspnea was not significantly associated with age (p = 0.247); gender (p = 0.329); use of maintenance medication (p = 0.152); asthma control (p = 0.562), bronchial hyperresponsiveness (p = 0.082); or severity of acute bronchoconstriction (p = 0.749). CONCLUSIONS: A significant proportion of asthma patients have a poor perception of dyspnea. The factors related to the inability of these patients to identify changes in pulmonary function have not yet been well defined. In order to reduce asthma-related morbidity and mortality, it is essential that this group of patients be identified and counseled.

Avaliação espirométrica e da hiper-responsividade brônquica de crianças e adolescentes com asma atópica persistente moderada submetidos a natação / Effects of swimming on spirometric parameters and bronchial hyperresponsiveness in children and adolescents with moderate persistent atopic asthma

OBJETIVO: Investigar os benefícios a médio prazo de um programa de natação em escolares e adolescentes com asma atópica persistente moderada (AAPM). MÉTODOS: Realizou-se um estudo randomizado e prospectivo com crianças e adolescentes (7-18 anos de idade) com AAPM no Hospital de Clínicas da Universidade Estadual de Campinas (UNICAMP), Campinas (SP). Após um período de run in de um mês, 61 pacientes (34 femininos) foram randomizados em dois grupos: grupo natação (GN) (n = 30) e grupo controle (GC) (n = 31) e foram acompanhados durante 3 meses. Os dois grupos receberam fluticasona (pó) inalada (250 mcg, 2 vezes ao dia) diariamente e salbutamol inalado, quando necessário. O programa de natação consistiu em um total de 24 aulas, duas vezes por semana, por 3 meses. O GN e o GC realizaram espirometria, teste de broncoprovocação com metacolina (provocative concentration of methacholine causing a 20 por cento fall in FEV1, PC20 de metacolina), antes e após os 3 meses de estudo. Pressão inspiratória máxima (PImax) e pressão expiratória máxima (PEmax) foram realizadas somente no GN. RESULTADOS: Observou-se que o GN apresentou aumento significativo da PC20 de metacolina (inicial 0,31±0,25 e final 0,63±0,78; p = 0,008), pressão inspiratória máxima (inicial 67,08±17,13 cm H2O e final 79,46±18,66; p < 0,001), pressão expiratória máxima (inicial 71,69±20,01 cm H2O e final 78,92±21,45 cm H2O; p < 0,001). CONCLUSÃO: Crianças e adolescentes com AAPM que se submeteram a um programa de natação apresentaram diminuição estatisticamente significativa da hiper-responsividade brônquica, com aumento dos valores da PC20 de metacolina, quando comparados aos com AAPM que não realizaram natação. O GN também apresentou melhora no componente da força elástica do tórax.

OBJECTIVE: To investigate the medium-term benefits of a swimming program in schoolchildren and adolescents with moderate persistent atopic asthma (MPAA). METHODS: A randomized, prospective study of children and adolescents (age 7-18 years) with MPAA was carried out at the Hospital de Clínicas of Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil. After a 1-month run-in period, 61 patients (34 female) were randomized into two groups, a swimming group (n = 30) and a control group (n = 31), and followed for 3 months. Both patient groups received inhaled fluticasone (dry powder, 250 mcg twice a day) and salbutamol as needed. The swim training program consisted of two weekly classes over a 3-month period for a total of 24 sessions. Both groups underwent spirometric assessment and methacholine challenge test - provocative concentration of methacholine causing a 20 percent fall in FEV1 (PC20) - before and after the study period. Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were measured only in the swimming group. RESULTS: Significant increases in PC20 (pre-training, 0.31±0.25; post-training, 0.63±0.78; p = 0.008), MIP (pre-training, 67.08±17.13 cm H2O; post-training 79.46±18.66; p < 0.001), and MEP (pre-training, 71.69±20.01 cm H2O; post-training, 78.92±21.45 cm H2O; p < 0.001) were found in the swimming group. CONCLUSION: Children and adolescents with MPAA subjected to a swim training program experienced a significant decrease in bronchial hyperresponsiveness, as determined by increased PC20 values, when compared with asthmatic controls who did not undergo swim training. Participants in the swimming group also showed improvement in elastic recoil of the chest wall.

Gender and perception of dyspnea: The role of the variation in the forced expiratory volume in one second / Género y percepción de disnea: el rol de la variación del volumen espiratorio forzado en un segundo

During bronchoconstriction women perceive more breathlessness than men. The aims of study were 1) to evaluate if quality of dyspnea in bronchoconstriction was different in women and men 2) to assess if gender difference in the perception of dyspnea could be related to the level of bronchoconstriction. 457 subjects (257 women) inhaled methacholine to a 20% decrease in FEV1, or 32 mg/ml. Dyspnea was evaluated using the modified Borg scale and a list of expressions of dyspnea. Borg scores were recorded immediately before the challenge test baseline and at the maximum FEV1 decrease. The prevalence of descriptors of dyspnea reported by women and men was similar. Dyspnea was related to the level of FEV1 (ΔFEV1: OR 1.05, 95%CI 1.01-1.09, p 0.0095), females (OR 2.90, 95%CI 1.33-6.33, p 0.0072), younger subjects (OR 0.93, 95%CI 0.89- 0.97, p 0.0013) and body mass index (BMI) (OR 1.11, 95%CI 1.01-1.23, p 0.023). As the FEV1 fell less than 20% from baseline, only the ΔFEV1 was significantly associated with dyspnea (ΔFEV1:OR 1.15, 95%CI 1.07- 1.24, p 0.0002). Instead, if the FEV1 fell higher ≥ 20%, the presence of dyspnea was related to the degree of bronchoconstriction (ΔFEV1: OR 1.04, 95%CI 1.01-1.09, p 0.0187), females (OR 3.02, 95%CI 1.36-6.72, p 0.0067), younger subjects (OR 0.92, 95%CI 0.88-0.96, p 0.0007) and BMI (OR 1.12, 95%CI 1.01-1.23, p 0.023). The quality of dyspnea during the bronchoconstriction was similar in women and men; women showed a higher perception of dyspnea than men only when the FEV1 fell more than 20% from baseline.

Durante la broncoconstricción las mujeres perciben más disnea que los hombres. Los objetivos del estudio fueron evaluar: 1) si la calidad de la disnea durante la broncoconstricción fue diferente en mujeres y hombres, 2) si la diferencia entre sexos en la percepción de disnea podría relacionarse al nivel de broncoconstricción. 457 sujetos (257 mujeres) inhalaron metacolina hasta un descenso del FEV1 ≥ 20% o 32 mg/ml. La disnea fue evaluada mediante escala de Borg y una lista de expresiones de disnea. El Borg fue registrado en forma basal y con el máximo descenso del FEV1. La frecuencia de descriptores de disnea informados por mujeres y hombres fue similar. La disnea estuvo relacionada al grado de broncoconstricción (ΔFEV1: OR 1.05, 95%CI 1.01-1.09, p 0.0095), sexo femenino (OR 2.90, 95%CI 1.33-6.33, p 0.0072), edad (OR 0.93, 95%CI 0.89-0.97, p0.0013) e índice de masa corporal (IMC) (OR 1.11, 95%CI 1.01-1.23, p 0.023). Cuando el FEV1 cayó menos del 20%, solo el ΔFEV1 se asoció con disnea (ΔFEV1: OR 1.15, 95%CI 1.07-1.24, p 0.0002). En tanto que si el FEV1 cayó ≥ del 20%, la disnea estuvo relacionada al grado de broncoconstricción (ΔFEV1: OR 1.04, 95%CI 1.01-1.09, p 0.0187), sexo femenino (OR 3.02, 95%CI 1.36-6.72, p 0.0067), edad (OR 0.92, 95%CI 0.88-0.96, p 0.0007) e IMC (OR 1.12, 95%CI 1.01-1.23, p 0.023). La calidad de la disnea durante la broncoconstricción fue similar en hombres y mujeres; las mujeres tuvieron mayor percepción de disnea que los hombres solo cuando el FEV1 descendió más del 20%.

Protector mechanisms of the association between gastroesophageal reflux disease and asthma: experimental study in rats / Mecanismos protetores: doença do refluxo gastroesofágico e asma: estudo experimental em ratos

BACKGROUND: It is well known the association between gastroesophageal reflux disease and asthma. The hyperreactivity of the airways is a characteristic of an asthmatic. Many studies associate the increase of the airways reactivity with gastroesophageal reflux disease. AIM: In this study we have evaluated the effect of the intraluminal exposition to gastric juice of trachea on the reactivity to methacholine from rats submitted to a pulmonary allergic inflammation. METHODS: Group of rats were sensitized and challenged with ovalbumin. After 24 hours the animals were sacrificed, and their tracheae were removed to be cultured with gastric juice. The gastric juice was obtained from a donor rat. Subsequently the segments were placed into plastic plates with RPMI-1640 for incubation, under suitable atmosphere and time. After the period of incubation the segments were put into chambers for the analysis of the contractile response to methacholine. RESULTS: We observed reduction in the contractile response of trachea cultured with gastric juice from allergic rats. This result was confirmed by the pharmacological treatments with compound 48/80 and dissodium cromoglicate (mast cells blockade), L-NAME (nitric oxide inhibitor, NO), capsaicin (neuropeptides depletion) and indomethacin (ciclooxigenase inhibitor). CONCLUSIONS: Our results highlight to the existence of a complex interaction between pulmonary allergy and gastric juice in the airways. The involvement of the non-adrenergic non-cholinergic system, NO, prostanoids and mast cells are directly related to this interaction. We suggest that the reduced contractile response observed in vitro may represent a protector mechanism of the airways. Despite its presence in the human body it can not be observed due to the predominant effects of excitatory the non-adrenergic non-cholinergic system.

RACIONAL: É bem estabelecida a relação entre a doença do refluxo gastroesofágico e a asma. A hiperreatividade das vias aéreas é uma das características que o indivíduo asmático desenvolve e diversos estudos associam o aumento da reatividade das vias aéreas com o refluxo gastroesofágico. OBJETIVO: Avaliar a reatividade à metacolina de traquéia exposta intraluminalmente ao suco gástrico de ratos submetidos a inflamação alérgica pulmonar. MÉTODOS: Grupos de ratos foram sensibilizados e broncoprovocados com ovoalbumina. Após 24 horas, os animais foram sacrificados e a traquéia removida para preenchimento de seu lúmen com suco gástrico obtido de um animal doador. A seguir, os segmentos foram colocados em placas plásticas com RPMI-1640 e mantidos em estufa por 3 horas em condições ambientais adequadas. Após o tempo de incubação, os fragmentos foram montados em cubas de vidro para órgão isolado para registro isométrico de contração, através da construção de curvas concentração-efeito à metacolina. RESULTADOS: Observou-se redução da resposta contrátil em traquéia exposta ao suco gástrico proveniente de ratos alérgicos. Os tratamentos farmacológicos com composto 48/80 e cromoglicato de sódio (bloqueio de mastócitos), L-NAME (inibidor de óxido nítrico, NO), capsaicina (depleção de neuropeptídios) e indometacina (inibidor da ciclooxigenase) corroboraram esta observação. CONCLUSÕES: Os resultados apontam para a existência de complexa interação entre a alergia pulmonar e o suco gástrico nas vias aéreas, com o envolvimento do sistema não-adrenérgico não-colinérgico, NO, prostanóides e mastócitos. À luz das evidências in vivo sobre a hiperreatividade das vias aéreas na associação asma e refluxo gastroesofágico, sugere-se que a reduzida resposta contrátil detectada in vitro pode representar um mecanismo protetor das vias aéreas. A despeito de sua presença, esta redução pode não ser observada in vivo devido à proeminência dos efeitos do sistema não-adrenérgico ...

Swyer-james-macleod syndrome

This case report describes a patient with Swyer-James-MacLeod Syndrome [SJMS] in an adult male diagnosed on the basis of findings on X-ray chest, high resolution CT [HRCT] of chest and radionuclide perfusion lung scan. This rare syndrome is considered to be an acquired disease due to repeated pneumonias in early childhood

Airways are More Reactive to Histamine than to Methacholine in Patients with Mild Airway Hyperresponsiveness, Regardless of Atopy

BACKGROUND: The airway muscles from allergen-sensitized animals in vitro show a heightened response to histamine, but not to carbachol. This study investigated whether the airway responsiveness to histamine in vivo is comparable to that of methacholine in human subjects with varying degrees of atopy. METHODS: One-hundred-and-sixty-eight consecutive adult asthma patients or volunteers underwent bronchoprovocation tests to both histamine and methacholine after determining their blood eosinophil counts, serum total IgE levels and skin test reactivity to 10 common aeroallergens. RESULTS: The responsiveness to histamine was significantly related to that to methacholine (r=0.609, p<0.001), but many individuals with a negative methacholine test response showed a positive response to histamine. The histamine-bronchial reactivity index (BRindex) was significantly higher than the methacholine-BRindex in subjects with a positive response to none (n=69, p<0.01) or only one (n=42, p<0.001) of histamine and methacholine, while there was no significant difference in the subjects with positive responses to both of them (n=57). The histamine-BRindex was significantly higher than the methacholine-BRindex in the subjects with mild histamine hyperresponsiveness (n=58, 1.28+/-0.01 vs. 1.20+/-0.02, respectively, p<0.001). Both histamine and methacholine responsiveness was significantly related to the atopy markers. However, the histamine-BRindex/methacholine-BRindex ratio of the atopics was not significantly different from that of the non-atopics. CONCLUSIONS: The airway responsiveness to histamine is comparable to that of methacholine in the subjects with positive responses to both histamine and methacholine, but the airway responsiveness to histamine is greater than that to methacholine in those subjects with mild airway hyperresponsiveness, regardless of atopy.

Testes de broncoprovocação com metacolina e com exercício em bicicleta e corrida livre em crianças com asma intermitente / Bronchial provocation tests using methacholine, cycle ergometer exercise and free running in children with intermittent asthma

OBJETIVO: Comparar a responsividade de vias aéreas à metacolina e ao teste de exercício na bicicleta ergométrica e corrida livre em crianças com asma intermitente. MÉTODOS: Estudo randomizado. Trinta crianças de ambos os sexos com asma intermitente participaram do estudo. Cada teste foi realizado em 3 dias diferentes, através de randomização: a) broncoprovocação com metacolina, método do dosímetro; b) teste de exercício: corrida livre em um corredor de 50 m; c) teste de exercício: bicicleta ergométrica com ar seco. A freqüência cardíaca atingida foi 80 a 90 por cento da freqüência cardíaca máxima. A espirometria foi realizada aos 3, 6, 10, 15, 20 e 30 minutos após o exercício. Broncoespasmo induzido por exercício foi definido como a queda de volume expiratório forçado no primeiro segundo (VEF1) > 10 por cento em relação aos valores pré-teste. RESULTADOS: A média de idade foi 11±3 anos. O VEF1 e VEF1/CVF (capacidade vital forçada) foram normais e similares antes dos três testes de broncoprovocação. A freqüência cardíaca máxima foi de 178±7 bpm durante o exercício na bicicleta e 181±6 bpm na corrida livre (p > 0,05). Broncoespasmo significante foi visto em 23 crianças após o teste com metacolina, em 19 após a corrida livre e em 14 crianças após exercício em bicicleta (p < 0,05, metacolina versus testes de exercício). Levando-se em conta todas as medidas de VEF1 após o exercício, a corrida livre resultou em maior broncoespasmo em relação à bicicleta ergométrica (p = 0,003, chi2 = 8,948). Houve significante porém fraca correlação entre a queda máxima de VEF1 após a corrida livre e bicicleta (r = 0,46, p < 0,01). CONCLUSÕES: A broncoprovocação com metacolina identifica um maior número de asmáticos quando comparada aos testes de exercício. Quando a broncoprovocação com metacolina não estiver disponível, a corrida livre deve ser o teste de escolha, devido à sua simplicidade e maior capacidade de induzir broncoespasmo.

Teste de broncoprovocação com metacolina / Methacholine bronchoprovocation test

Os testes de broncoprovocação têm como finalidade a demonstração da presença de resposta brônquica (bronco constricção) avários estímulos. Descrevemos a técnica do volume corrente com metacolina e com débito de fluxo constante, com concentrações crescentes e sucessivas de metacolina, de 0,125 a 16mg/ml com determinação subseqüente do VEF1 decorridos 30 e 90 segundos após cada etapa. O exame é interrompido quando há queda maior ou igual a 20% do VEF1 ou após atingirmos a última concentração. Os valores são expressos como a concentração de metacolina necessária para causar uma queda do VEF1 (CP20).

Airway Hyperresponsiveness to Hypertonic Saline as a Predictive Index of Exercise-Induced Bronchoconstriction

BACKGROUND: Changes in airway mucosal osmolarity are an underlying mechanism of bronchoconstrictive responses to exercise and hypertonic saline (HS). The purpose of this study was to examine whether an osmotic challenge test using HS can predict exercise-induced bronchospasm (EIB) in asthma patients. METHODS: Thirty-six young male asthmatic patients underwent bronchial challenge tests based on 4.5% HS, exercise (> 24h later), and methacholine (MCh) at the Chonnam National University Hospital. The relationships between responses to HS and exercise, and between MCh and exercise were evaluated. RESULTS: The maximal fall in forced expiratory volume in one second following exercise was significantly higher in the HS-responders (n=19) than in the HS-nonresponders (n=17, 35.9+/-4.1% vs. 17.9+/-2.7%, p< 0.001), and there was a significant correlation between the severity of EIB and HS-airway hyperresponsiveness (AHR). When compared with the MCh-AHR test in terms of predicting EIB, the HS-AHR test showed higher specificity (71.4% vs. 42.9%), but a lower sensitivity (58.6% vs. 89.7%) and negative predictive value (29.4% vs. 50.0%). At the moderate AHR cutoff value, the MCh-AHR test had a specificity that was comparable with and predictive values that were higher than those of the HS-AHR test. CONCLUSIONS: The HS-AHR test was more specific than the MCh-AHR test, but was less sensitive and had a poorer negative predictive value, which in combination preclude the use of the HS-AHR test as a screening tool for EIB. The MCh-AHR test had a cutoff value for moderate AHR that may be more useful for predicting EIB in asthmatic patients.

Asthmatic Airway Inflammation is More Closely Related to Airway Hyperresponsiveness to Hypertonic Saline than to Methacholine

BACKGROUND: Airway hyperresponsiveness (AHR) to direct stimuli, such as methacholine (MCh), is observed not only in asthma but other diseases. AHR to indirect stimuli is suggested to be more specific for asthma. The purpose of this study was to determine whether asthmatic airway inflammation is more closely related to AHR to hypertonic saline (HS), an indirect stimulus, than to MCh. METHODS: Sixty-four consecutive adult patients with suspected asthma (45 asthma and 19 non-asthma) performed a combined bronchial challenge and sputum induction with 4.5% saline, and MCh challenge on the next day. RESULTS: Both HS-PD15 and MCh-PC20 were significantly lower in asthma patients than in non-asthma patients. However, the sensitivity/ specificity for asthma was 48.9%/100%, respectively, in the HS test and 82.2%/ 84.2%, respectively, in the MCh test. There was a significant relationship between HS-PD15 and MCh-PC20 and only 52.9% of patients with MCh-PC20 4 mg/mL. There were significant correlations between both HS-PD15 and MCh-PC20 and FEV1, or sputum eosinophils, but FEV1 was more closely related to MCh-PC20 (r=0.478, p < 0.01) than to HS-PD15 (r=0.278, p < 0.05), and sputum eosinophils were more closely related to HS-PD15 (r=-0.324, p < 0.01) than to MCh-PC20 (r=-0.317, p < 0.05). Moreover, the IL-5 level (r=-0.285, p < 0.05) and IFN-gamma/IL-5 ratio (r=0.293, p < 0.05) in sputum were significantly related to HS-PD15, but not to MCh-PC20. CONCLUSION: HS-AHR may reflect allergic asthmatic airway inflammation more closely than MCh-AHR.

Efecto del Bromuro de ipratropio sobre la broncoconstriccion por histamina en sujetos con obstruccion cronica al flujo aereo / Effect of ipratropium bromide on histamine-induced bronchoconstriction in subjects with chronic airway obstruction

El bromuro de ipratropio (B I) es un agente anticolinérgico muy recomendado para el tratamiento de la obstrucción crónica al flujo aéreo (EPOC). No obstante, no hay definición respecto a la existencia de efectos preventivos (no broncodilatadores) del BI. Con el fin de evaluar la acción del BI (80 µg en aerosol) ante una prueba de histamina se estudiaron 9 sujetos (hombres) con EPOC moderada, mediante un diseño doble ciego, aleatorio, controlado y cruzado entre placebo y BI. Tenían una edad promedio (ñ error standard de media) = 57,9 ñ 2,4 años con antecedentes de tabaquismo de 54,6 ñ 5,1 paquete-años y un FEV1 basal = 1,36 ñ 0,08 litros (47,2 ñ 3,8 percent del teórico).La hiperreactividad bronquial a la histamina en el día control fue logPC20 =-0,54 ñ 0,24 mg/ml (media geométrica: 0,27 mg/ml). El BI produjo un aumento significativo en el FEV1 basal; aunque no hubo correlación entre la obstrucción basal (FEV1, FEV1/FVC percent) y la broncodilatación con la hiperreactividad (logPC20). El BI redujo la broncoconstricción por histamina (logPC20 BI = -0,15 ñ 0,17 mg/ml; media geométrica [MG] = 0,70 mg/ml) en comparación con placebo (logPC20 post placebo = -0,76 ñ 0,22 mg/ml [MG = 0,17 mg/ml]; P = 0,018) y la dosis doble fue para BI = 2,02 ñ 0,68 vs placebo = -0,62 ñ 0,79; p: 0,024. Tanto el fenoterol como el BI revirtieron totalmente la caída del FEV1 al final de la prueba de histamina. Se concluye que el BI mostró un efecto protector ante la histamina en estos sujetos con diagnóstico de EPOC moderada

Clinical application of urinary leukotriene E4 in bronchial asthma / 천식및알레르기

BACKGROUND: Cysteinyl leukotrienes are important inflammatory mediators in bronchial asthma because they enhance microvascular permeability, increase nonspecific bronchial hyperresponsiveness, and are potent bronchoconstrictor agents. Leukotriene E4 is a major metabolite of cysteinyl leukotriene excreted in urine and its concentration of urine can be a reliable marker of the overall leukotriene production in the body. OBJECTIVE: To determine whether clinical parameters of bronchial asthma are associated with production of cysteinyl leukotrienes, expressed by urinary leukotriene E4. METHOD: We measured the urinary concentration of leukotriene E4 in bronchial asthma(127 patients) and normal control(15 persons) group by ELISA method. Pulmonary function test, allergic skin test, measurement of peripheral eosinophil count and eosinophil cationic protein were undertaken in bronchial asthma patients. RESULTS: The concentrations of urinary leukotriene E4 were significantly higher in bronchial asthma patients than normal controls (p<0.05). The increased concentrations of leukotriene E4 had a significant correlation with FEV1/FVC or methacholine PC20(p<0.05). However, the concentration of leukotriene E4 did not have any correlation with the presence of atopy, peripheral blood eosinophil count, and eosinophil cationic protein level. CONCLUSION: The concentration of urinary leukotriene E4 that represents the overall leukotriene production in the body is correlated with the degree of airway obstruction and airway hyperresponsiveness. So, the concentration of urinary leukotriene E4 may be used as an adjunctive parameter of airway obstruction and hyperresponsiveness in bronchial asthma.

Airway Reactivity to Bronchoconstrictor and Bronchodilator: Assessment Using Thin-Section and Volumetric Three-Dimensional CT

OBJECTIVE: To determine the extent to which thin-section and volumetric three-dimensional CT can depict airway reactivity to bronchostimulator, and to assess the effect of different airway sizes on the degree of reactivity. MATERIALS AND METHODS: In eight dogs, thin-section CT scans were obtained before and after the administration of methacholine and ventolin. Cross-sectional areas of bronchi at multiple levels, as shown by axial CT, proximal airway volume as revealed by three-dimensional imaging, and peak airway pressure were mea-sured. The significance of airway change induced by methacholine and ventolin, expressed by percentage changes in cross-sectional area, proximal airway volume, and peak airway pressure was statistically evaluated, as was correlation between the degree of airway reactivity and the area of airways. RESULTS: Cross-sectional areas of the bronchi decreased significantly after the administration of methacholine, and scans obtained after a delay of 5 minutes showed that normalization was insufficient. Ventolin induced a significant increase in cross-sectional areas and an increase in proximal airway volume, while the effect of methacholine on the latter was the opposite. Peak airway pres-sure increased after the administration of methacholine, and after a 5-minute delay its level was near that of the control state. Ventolin, however, induced no significant decrease. The degree of airway reactivity did not correlate with airway size. CONCLUSION: Thin-section and volumetric spiral CT with three-dimensional reconstruction can demonstrate airway reactivity to bronchostimulator. The degree of reactivity did not correlate with airway size.