Efeito do broncodilatador no tempo de apneia voluntária máxima em pacientes com distúrbios ventilatórios obstrutivos / Bronchodilator effect on maximal breath-hold time in patients with obstructive lung disease

OBJETIVO: Identificar o papel do broncodilatador no tempo de apneia voluntária máxima em pacientes com distúrbios ventilatórios obstrutivos (DVOs). MÉTODOS: Estudo caso-controle incluindo pacientes com DVOs e grupo controle. Foram realizadas espirometrias antes e após o uso de broncodilatador, assim como testes de apneia respiratória, utilizando-se um microprocessador eletrônico e um pneumotacógrafo como transdutor de fluxo. As curvas de fluxo respiratório foram exibidas em tempo real em um computador portátil, e os tempos de apneia voluntária inspiratória e expiratória máximos (TAVIM e TAVEM, respectivamente) foram determinados a partir do sinal adquirido. RESULTADOS: Um total de 35 pacientes com DVOs e 16 controles foram incluídos no estudo. O TAVIM sem o uso de broncodilatador foi significativamente menor no grupo DVO que no grupo controle (22,27 ± 11,81 s vs. 31,45 ± 15,73; p = 0,025), mas essa diferença não foi significativa após o uso de broncodilatador (24,94 ± 12,89 s vs. 31,67 ± 17,53 s). Os valores de TAVEM foram significativamente menores no grupo DVO que no grupo controle antes (16,88 ± 6,58 s vs. 22,09 ± 7,95 s; p = 0,017) e após o uso de broncodilatador (21,22 ± 9,37 s vs. 28,53 ± 12,46 s; p = 0,024). CONCLUSÕES: Estes resultados fornecem uma evidência adicional da utilidade clínica do teste de apneia na avaliação da função pulmonar e do papel do broncodilatador nesse teste.

OBJECTIVE: To identify the role of bronchodilators in the maximal breath-hold time in patients with obstructive lung disease (OLD). METHODS: We conducted a case-control study including patients with OLD and a control group. Spirometric tests were performed prior to and after the use of a bronchodilator, as were breath-hold tests, using an electronic microprocessor and a pneumotachograph as a flow transducer. Respiratory flow curves were displayed in real time on a portable computer. The maximal breath-hold times at end-inspiratory volume and at end-expiratory volume (BHTmaxV EI and BHTmaxV EE, respectively) were determined from the acquired signal. RESULTS: A total of 35 patients with OLD and 16 controls were included. Prior to the use of a bronchodilator, the BHTmaxV EI was significantly lower in the OLD group than in the control group (22.27 ± 11.81 s vs. 31.45 ± 15.73 s; p = 0.025), although there was no significant difference between the two groups in terms of the post-bronchodilator values (24.94 ± 12.89 s vs. 31.67 ± 17.53 s). In contrast, BHTmaxV EE values were significantly lower in the OLD group than in the control group, in the pre- and post-bronchodilator tests (16.88 ± 6.58 s vs. 22.09 ± 7.95 s; p = 0.017; and 21.22 ± 9.37 s vs. 28.53 ± 12.46 s; p = 0.024, respectively). CONCLUSIONS: Our results provide additional evidence of the clinical usefulness of the breath-hold test in the assessment of pulmonary function and add to the existing knowledge regarding the role of the bronchodilator in this test.

Effect of household exposure to environmental tobacco smoke on airflow mechanics in asymptomatic healthy women.

BACKGROUND & OBJECTIVES: Exposure to environmental tobacco smoke (ETS) can lead to airflow limitation, similar to that seen in smokers. However, the effects have not been conclusively proven. In the present study an attempt was made to characterize the effect of ETS exposure at home on airflow mechanics in asymptomatic healthy women. METHODS: Fifty women volunteers with no apparent health related problem, exposed to household ETS (group I), and 50 age-matched women not exposed (group II) were studied. Vital capacity (VC), forced expiratory flow in first second (FEV1), FEV1/VC ratio, peak expiratory flow (PEF), maximal midexpiratory flow (FEF(25-75%)), airway resistance (R(aw)) and specific airway conductance (sG(aw)) were measured, and compared between the two groups. Conditional logistic and linear regression analysis were done to assess contribution of household ETS exposure to decreased lung function. RESULTS: FEV1 and PEF values were marginally lower among women in group I (mean difference 0.13 l and 0.20 l/sec respectively). FEF(25-75%), R(aw) and sG(aw) were significantly impaired in this group. Ten (20.0%) women in group I and five (10.0%) in group II had abnormal R(aw) (adjusted odds ratio 6.72, 95% confidence limits 1.15-39.42), while eight (16.0%) women in group I and one (2.0%) in group II had abnormal sG(aw) (adjusted odds ratio 21.08, 95% confidence limits 1.30-341.05). Cumulative life time ETS exposure was, not significantly related to a reduction in FEV1, VC, PEF, FEF(25-75%), R(aw) or sG(aw) after adjustments for potential confounders. INTERPRETATION & CONCLUSION: Exposure to household ETS resulted in subtle impairment of airflow mechanics in asymptomatic women, possibly attributed to small airway narrowing. Further investigations are required to study the progression of this impairment with time.

Impact of particulate air pollutants on allergic diseases, allergic skin reactivity and lung function.

Elevated levels of particulate matter can exacerbate existing asthma and atopy, while evidence that it can promote the induction of atopy and asthma is limited. A cross sectional study was taken to compare the prevalence of eye, nose, ear and airway allergic symptoms, allergic skin sensitivity and lung function in 290 high school students with a history of high 24 hour average exposure to particulate matter less than 10 microm in diameter (PM10) = 170 microg/m3 versus low PM10 of 36 microg/m3 in central Bangkok. Multivariate analysis revealed an increased risk of eye and airway symptoms in groups exposed to higher PM10 levels (p = 0.003, and 0.05, respectively). Positive skin prick tests and a history of having a lawn at home were associated with nasal symptoms (p = 0.008 and 0.04, respectively). Mean FEF(25-75%) (forced expiratory flow that occurs during the middle 50% of the forced expiratory effort) was significantly lower in those who were exposed to higher PM10 levels (3.89 +/- 1 vs 4.42 +/- 0.9 l/sec, p < 0.001). A significant increase in days of school absence and medical expenses was associated with high PM10 exposure. It is concluded that chronic exposure to high PM 10 levels was significantly associated with increased prevalence of eye and airway symptoms and a decrement of FEF(25-75%) resulting in increase of school absence and medical expense.

Efecto broncodilatador de salbutamol más bromuro de ipratropio en niños asmáticos: relación dosis respuesta / Bronchodilator effect of ipratropium bromide plus salbutamol in asthmatic children: dose response relationship

El bromuro de ipratropio (BI) asociado con un agente beta 2 agonista en aerosol producido por inhalador de dosis medida (IDM) es frecuentemente empleado en lactantes y niños con obstrucción bronquial. En este estudio se evaluó el efecto broncodilatador de dos dosis diferentes (2 y 4 puffs) de una mezcla de BI más salbutamol (S) en IDM (Combivent) en 28 niños con asma leve a moderada. El estudio fue aleatorio, cruzado, controlado con placebo y simple ciego. La CVF, VEF1 y FEF25-75 se midieron en condiciones basales, antes y después de placebo y de cada una de las dosis empleadas. El análisis estadístico se realizó mediante pruebas no paramétricas para muestras pareadas. No hubo diferencias significativas en ninguno de los índices espirométricos descritos al usar 2 o 4 "puffs" de BI+S. Sin embargo, en los pacientes que tuvieron un aumento del VEF1 > o igual 15 por ciento con cualquiera de las 2 dosis de BI+S, el aumento del FEF25-75 fue significativamente mayor al usar 4 "puffs". Lo anterior sugiere que 2 "puffs" de BI+S serían igualmente efectivos para producir broncodilatación en niños asmáticos. Sin embargo, en aquellos pacientes que presentan un mayor grado de obstrucción bronquial, o como en este estudio, una reversibilidad bronquial más alta al broncodilatador, el empleo de 4 "puffs" de BI+S podría ser más eficiente para obtener una mejor broncodilatación

Evaluacion funcional de broncodilatadores beta 2 agonistas en pacientes asmaticos / Functional evaluation of Beta 2 agonists bronchodilators in asthmatic patients

Se estudio la funcion pulmonar de 80 pacientes asmaticos tratados con salmeterol, fenoterol, bitolterol y metaproterenol, indistintamente, por via inhalatoria. Se compararon los valores de algunos parametros funcionales respiratorios como FVC, FEV1 y FEF25-75 antes y a los 10 y 30 minutos de aplicado cada medicamento. Los resultaron evidenciaron la accion broncodilatadora de los 4 farmacos, demostrado por las variaciones de los valores espirometricos medidos antes y despues de la aplicacion del medicamento. No hubo diferencias enlas acciones entre los 4 farmacos; la cardioestimulacion fue mas notoria entre el fenoterol y el metaproterenol a los 10 minutos. A los 10 minutos no se encontraron diferencias significativas entre los 4 en cuanto a la cardioestimulacion. Concluimos que no existen diferencias en las acciones broncodilatadoras entre estos mediamentos. La cardioestimulacion detectada fue de corta duracion

Asma corticóideo resistente / Corticosteriod resistance in asthma

Desde hace años, los clínicos se han encontrado con pacientes asmáticos que no responden a corticoides. Estos comprenden pacientes con obstrucción irreversible de su vía aérea, pacientes con enfermedad severa que requieren altas dosis y un subgrupo menos frecuente, que se caracteriza por obstrucción bronquial reversible con ß2 agonistas, pero que no responden a corticoides, a dosis adecuadas. Diversos autores estudiaron la farmacocinética de los corticoides en estos pacientes, así como la presencia de anticuerpos antilipocortina, y los receptores esteróideos, no pudiendo aclarar el mecanismo de esta resistencia. La explicación a este fenómeno parece centrarse en la respuesta de los linfocitos, monocitos y eosinófilos de los pacientes a estas drogas, con disminución de efecto sobre varias funciones de las mismas, que nos acerca a la comprensión de la inflamación bronquial en asma