Efeito das estações do ano no pico de fluxo expiratório de idosos institucionalizados e não institucionalizados / Efecto de las estaciones del año en el flujo espiratorio máximo de ancianos institucionalizados y no institucionalizados / Effect of the seasons on the peak expiratory flow in institutionalized and noninstitutionalized elderly

RESUMO As doenças respiratórias afetam milhões de pessoas, principalmente os idosos, e as mudanças climáticas estão entre os fatores predisponentes, interferindo na saúde dessa população. O objetivo deste estudo foi avaliar o pico de fluxo expiratório de idosos institucionalizados e não institucionalizados durante as quatro estações do ano. Estudo de coorte prospectivo com 67 idosos de ambos os sexos, residentes na cidade de Maringá (PR) e divididos em dois grupos: idosos institucionalizados (n=37) e idosos não institucionalizados (n=30). Os dados foram coletados durante um mês, uma vez por semana nas quatro estações do ano, totalizando 16 avaliações. O pico de fluxo expiratório foi avaliado com o equipamento peak flow meter. A comparação dos dois grupos de idosos foi feita por análise de variância de dois fatores utilizando o post-hoc de Bonferroni. A menor média de pico de fluxo expiratório para os idosos institucionalizados e não institucionalizados foi no verão (176,2±60,2 e 263,2±116,2), seguido pelo outono (193,4±59,5 e 287,5±118), inverno (215,3±82,5 e 291,5±08,4) e primavera (221,7±83,5 e 291,5±08,4). Conclui-se que o pico de fluxo expiratório de idosos varia de acordo com as estações do ano, porém os institucionalizados apresentam valores mais baixos. Os mais altos são encontrados na primavera, embora aquém do valor predito para os idosos de ambos os grupos.

RESUMEN Las enfermedades respiratorias afectan a millones de personas, especialmente a los ancianos, y el cambio climático es uno de los factores predisponentes que interfieren en la salud de esta población. El presente estudio tuvo como objetivo evaluar el flujo espiratorio máximo de ancianos institucionalizados y no institucionalizados durante las cuatro estaciones del año. Se realizó un estudio prospectivo de cohorte con 67 ancianos de ambos sexos que viven en la ciudad de Maringá (PR), los cuales se dividieron en dos grupos: ancianos institucionalizados (n=37) y ancianos no institucionalizados (n=30). Los datos se recolectaron durante un mes, una vez a la semana en las cuatro estaciones del año, y totalizó 16 evaluaciones. El flujo espiratorio máximo se evaluó con la herramienta peak flow meter. La comparación de los dos grupos de ancianos se realizó mediante el análisis de la varianza de dos factores utilizando el post hoc de Bonferroni. El promedio más bajo del flujo espiratorio máximo para los ancianos institucionalizados y no institucionalizados se registró en verano (176,2±60,2 y 263,2±116,2), seguido del otoño (193,4±59,5 y 287,5±118), invierno (215,3±82,5 y 291,5±08,4) y primavera (221,7±83,5 y 291,5±08,4). Se concluye que el flujo espiratorio máximo de los ancianos varía según las estaciones del año, sin embargo, los ancianos institucionalizados tienen los valores más bajos. Los más altos se encuentran en la primavera, aunque por debajo del valor previsto para los ancianos de ambos grupos.

ABSTRACT Respiratory diseases affect millions of people, especially the elderly, and climate change is among the predisposing factors interfering with the health of this population. This study aimed to evaluate the peak expiratory flow in institutionalized and noninstitutionalized elderly during the four seasons of the year. A prospective cohort study with 67 elderly men and women living in the city of Maringá, Paraná, Brazil, divided into two groups: institutionalized elderly (n=37) and noninstitutionalized elderly (n=30). The data were collected for one month, once a week in the four seasons of the year, totaling 16 evaluations. The peak expiratory flow was evaluated using the Peak-Flow Meter equipment. The two groups of elderly were compared by two-way analysis of variance using the Bonferroni post-hoc. The lowest mean peak expiratory flow for institutionalized and noninstitutionalized elderly was observed in the summer (176.2±60.2 and 263.2±116.2), followed by fall (193.4±59.5 and 287.5±118), winter (215.3±82.5 and 291.5±08.4), and spring (221.7±83.5 and 291.5±08.4). The conclusion was that the peak of expiratory flow of the elderly varies according to the seasons, but the institutionalized ones have lower values. The highest values are found in the spring, although below the value predicted for the elderly of both groups.

Spirometry reference values in the Brazilian population

The aim of the present study was to provide new spirometry reference equations in a sample of the Brazilian population for the following parameters: forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio, peak of expiratory flow (PEF), forced expiratory flow at 50% (FEF50%), 75% average vital capacity (FEF25-75%), and average forced expiratory flow time (FEFT). This was a prospective study using results from chest radiographs, electrocardiograms, and questionnaires to investigate the participants' respiratory symptoms, sedentarism, and comorbidities (Charlson comorbidity index). From December 2010 to July 2014, individuals were randomly selected from various locations in the state of Rio de Janeiro. All individuals were examined by a single technician in the morning at the laboratory, and performed the spirometry with the same spirometer. Spirometry values were tabulated for the creation of three equation models: linear regression, logarithmic regression, and logarithms through a method that incorporates the lambda, median, and coefficient of variation (LMS method). Initially, 7003 individuals from both genders were contacted, and 454 were recruited. The data from the new equations were compared with one Brazilian and eight international equations, resulting in a high correlation (r>0.9). The values derived from the LMS method and linear regression were very similar (P>0.5), and both could be used to acquire the reference values for Brazilian spirometry. Data derived from the equations of this study were different from the current Brazilian equation, which could be justified by the different method used.

The Prognostic Value of Residual Volume/Total Lung Capacity in Patients with Chronic Obstructive Pulmonary Disease

The prognostic role of resting pulmonary hyperinflation as measured by residual volume (RV)/total lung capacity (TLC) in chronic obstructive pulmonary disease (COPD) remains poorly understood. Therefore, this study aimed to identify the factors related to resting pulmonary hyperinflation in COPD and to determine whether resting pulmonary hyperinflation is a prognostic factor in COPD. In total, 353 patients with COPD in the Korean Obstructive Lung Disease cohort recruited from 16 hospitals were enrolled. Resting pulmonary hyperinflation was defined as RV/TLC > or = 40%. Multivariate logistic regression analysis demonstrated that older age (P = 0.001), lower forced expiratory volume in 1 second (FEV1) (P < 0.001), higher St. George Respiratory Questionnaire (SGRQ) score (P = 0.019), and higher emphysema index (P = 0.010) were associated independently with resting hyperinflation. Multivariate Cox regression model that included age, gender, dyspnea scale, SGRQ, RV/TLC, and 6-min walking distance revealed that an older age (HR = 1.07, P = 0.027), a higher RV/TLC (HR = 1.04, P = 0.025), and a shorter 6-min walking distance (HR = 0.99, P < 0.001) were independent predictors of all-cause mortality. Our data showed that older age, higher emphysema index, higher SGRQ score, and lower FEV1 were associated independently with resting pulmonary hyperinflation in COPD. RV/TLC is an independent risk factor for all-cause mortality in COPD.

Proposición de nuevas ecuaciones para calcular valores espirométricos de referencia en población chilena adulta: Sociedad Chilena de Enfermedades Respiratorias (SER) / New spirometric reference equations for healthy Chilean adults

Background: To correctly interpret spirometric results, reference values should come from the same population. Current spirometric reference equations have been under scrutiny due to deficiencies to fit adequately for Chilean population, specially, for those aged over 65 years old. Aim: To develop new spirometric reference values for Chilean adults, based on national studies in which spirometries were performed in healthy non-smoker adults. Material and Methods: A standardized database of spirometric values was developed combining spirometric data collected from five population-based studies, in which healthy nonsmoker adults participated. Spirometries from 448 males aged 19 to 84 years and from 726 females aged 19 to 94 years, obtained according to guidelines from the American Thoracic and European Respiratory Societies, were analyzed. Using multiple regression models, which included height, gender, and age, the theoretical value and inferior limits of normality were calculated for 1st second (FEV1), forced vital capacity (FVC), FEV1/FVC, and forced mid-expiratory flow rate (FEF25-75). Results: Reference values and lower limits of normality (LLN) were constructed for Chilean adults of both genders. The new proposed set of equations had a better fit, when compared with the current reference values used in Chile. Conclusions: The new spirometric references values derived from this study, fit better than currently used ones. Therefore, they should be used as new references values for Chilean adults.

Oscillation mechanics of the respiratory system in never-smoking patients with silicosis: pathophysiological study and evaluation of diagnostic accuracy

OBJECTIVES: Silicosis is a chronic and incurable occupational disease that can progress even after the cessation of exposure. Recent studies suggest that the forced oscillation technique may help to clarify the changes in lung mechanics resulting from silicosis as well as the detection of these changes. We investigated the effects of airway obstruction in silicosis on respiratory impedance and evaluated the diagnostic efficacy of the forced oscillation technique in these patients. METHODS: Spirometry was used to classify the airway obstruction, which resulted in four subject categories: controls (n=21), patients with a normal exam (n=12), patients with mild obstruction (n=22), and patients with moderate-to-severe obstruction (n=12). Resistive data were interpreted using the zero-intercept resistance (R0), the resistance at 4 Hz (Rrs4), and the mean resistance. We also analyzed the mean reactance (Xm) and the dynamic compliance. The total mechanical load was evaluated using the absolute value of the respiratory impedance (Z4Hz). The diagnostic potential was evaluated by investigating the area under the receiver operating characteristic curve. ClinicalTrials.gov: NCT01725971. RESULTS: We observed significant (p<0.0002) increases in R0, Rrs4, Rm, and Z4Hz and significant reductions in Crs,dyn (p<0.0002) and Xm (p<0.0001). R0, Rrs4, Rm, and Z4Hz performed adequately in the diagnosis of mild obstruction (area under the curve>0.80) and highly accurately in the detection of moderate-to-severe obstruction (area under the curve>0.90). CONCLUSIONS: The forced oscillation technique may contribute to the study of the pathophysiology of silicosis and may improve the treatment offered to these patients, thus representing an alternative and/or complementary tool for evaluating respiratory mechanics. .

Teste de pressão negativa expiratória: um novo método simples para identificar pacientes com risco para apneia obstrutiva do sono / Negative expiratory pressure test: a new, simple method to identify patients at risk for obstructive sleep apnea

O objetivo deste artigo foi descrever um novo método para avaliar a limitação ao fluxo expiratório durante a respiração espontânea, possibilitando a identificação do risco para apneia obstrutiva do sono através do teste de pressão negativa expiratória. A colapsabilidade da via aérea superior é avaliada pela medida da queda de fluxo e de volume expirado a 0,2 segundos imediatamente após a aplicação de pressão negativa expiratória de 10 cmH2O. O teste de pressão negativa expiratória é de fácil aplicação e poderia ser utilizado na avaliação da limitação ao fluxo expiratório causada por obstrução da via aérea superior em sujeitos portadores de apneia obstrutiva do sono.

The objective of this article was to describe a new method for assessing expiratory flow limitation during spontaneous breathing, using the negative expiratory pressure test to identify patients at risk for obstructive sleep apnea. Upper airway collapsibility is evaluated by measuring decreases in flow and in expired volume in the first 0.2 seconds after negative expiratory pressure application at 10 cmH2O. The negative expiratory pressure test is easily applied and could be adopted for the evaluation of expiratory flow limitation caused by upper airway obstruction in patients with obstructive sleep apnea.

Función pulmonar y calidad de vida en niños y adolescentes con bronquiolitis obliterante por adenovirus / Pulmonary function and quality of life in children and adolescents with bronchiolitis obliterans post-adenoviral infection

Introduction: Adenovirus infection is an important cause of pneumonia in Chilean children. Postinfectious Bronchiolitis Obliterans (PIBO) is the most important complication. There are few studies assessing pulmonary function and quality of life in PIBO patients. Objective: The aim of this study is to assess the pulmonary function and the quality of life of patients with PIBO and the correlation between both variables. Methods: 14 children with PIBO in follow up at the pediatric pulmonology outpatient clinic of a public children hospital were included in this study. Study period: April 2009 - April 2010. Pulmonary function was assessed in a medical visit by spirometry, flow/volume curve and intrathoracic gas volume measurement. The following indices were analyzed FVC, FEV1, FEV25-75, FEV1/FVC, RV, TLC, RV and RV/TLC. A survey of a self-administered Quality of Life (PedsQL, version 4.0, Spanish for Chile) was applied at the visit to investigate their global, physical and psychosocial quality of life. The Pearson linear correlation between quality of life and the pulmonary function test parameters was assessed, in the statistical analysis ap value < 0.05 was considered significant. Results: The mean age of our patients was 12.4 (range: 9-19 years-old). The functional alterations were characteristics of an obstructive respiratory disorder in 64.3 percent of the patients. Average pulmonary function test indices showed decreases in FEV1 (75 percent), FEV25-75 (48.8 percent), FEV1/FVC (67.6 percent) with normal value of FVC (93,7 percent) as well as pronounced increases in RV (333.5 percent), TLC (156 percent) and RV/TLC (51.8 percent). Mean change of FEV1 and FEV25-75post-bronchodilator was 11.3 percent and 26.4 percent respectively. Only 14.3 percent of our patients showed normal pulmonary function. The quality of life parameters were in average 58.2 percent of overall quality of life, 58.6 percent of physical quality of life and 57.9 percent of psychosocial ...

Introducción: La infección por adenovirus es una causa importante de neumonía en niños chilenos. La bronquiolitis obliterante (BOPI) es la complicación más importante. Existen pocos estudios donde evalúen la función pulmonar y la calidad de vida de los pacientes con BOPI. Objetivo: Evaluar la función pulmonar y la calidad de vida de los pacientes con BOPI y la correlación entre ambas variables. Métodos: Se incluyeron 14 niños con BOPI en el policlínico de la unidad de broncopulmonar de un hospital público de niños. Período de estudio: abril de 2009-abril de 2010. La función pulmonar se evaluó en una visita médica por espirometría, curva flujo / volumen y la determinación de volumen de gas intratorácico. Los índices analizados fueron los siguientes CVF, VEF1, FEV25-75, VEF1/CVF, VR,CPT, VR y VR / CPT. En la misma visita se realizó una encuesta auto-administrada de Calidad de Vida (PedsQL, versión 4.0, español de Chile) para investigar la calidad de vida global, física y psi-cosocial. Se aplicó la correlación lineal de Pearson entre calidad de vida y los parámetros de función pulmonar. Se consideró estadísticamente significativo unp <0,05. Resultados: La edad media de nuestros pacientes fue de 12,4 (rango: 9-19 años). La alteración funcional característica fue la obstructiva en el 64,3 por ciento de los pacientes. El promedio de los índices de pruebas de función pulmonar mostraron una disminución en VEF1 (75 por ciento), FEV25-75 (48,8 por ciento), VEF1/CVF (67,6 por ciento) con un valor normal de la CVF (93,7 por ciento), así como aumentos pronunciados en VR (333,5 por ciento), CPT (156 por ciento) y VR/CPT (51,8 por ciento). La media del cambio del VEF1 y FEV25-75post-broncodilatador fue 11,3 por ciento y 26,4 por ciento respectivamente. Sólo el 14,3 por ciento mostró una función pulmonar normal. Los parámetros de calidad de vida fueron en promedio 58,2 por ciento de calidad de vida general, 58,6 por ciento de calidad de vida física y el 57,9 por ciento...

Artificial External Glottic Device for Passive Lung Insufflation

PURPOSE: For patients with neuromuscular disease, air stacking, which inflates the lungs to deep volumes, is important for many reasons. However, neuromuscular patients with severe glottic dysfunction or indwelling tracheostomy tubes cannot air stack effectively. For these patients, we developed a device that permits deep lung insufflations substituting for glottic function. MATERIALS AND METHODS: Thirty-seven patients with bulbar-innervated muscle weakness and/or tracheostomies were recruited. Twenty-three had amyotrophic lateral sclerosis, and 14 were tetraplegic patients due to cervical spinal cord injury. An artificial external glottic device (AEGD) was used to permit passive deep lung insufflation. In order to confirm the utility of AEGD, vital capacity, maximum insufflation capacity (MIC), and lung insufflation capacity (LIC) with AEGD (LICA) were measured. RESULTS: For 30 patients, MICs were initially zero. However, with the use of the AEGD, LICA was measurable for all patients. The mean LICA was 1,622.7+/-526.8 mL. Although MIC was measurable for the remaining 7 patients without utilizing the AEGD, it was significantly less than LICA, which was 1,084.3+/-259.9 mL and 1,862.9+/-248 mL, respectively (p<0.05). CONCLUSION: The AEGD permits lung insufflation by providing deeper lung volumes than possible by air stacking.

O papel da razão FEF50 por cento/0.5CVF no diagnóstico dos distúrbios ventilatórios obstrutivos / The role of the FEF50 percent/0.5FVC ratio in the diagnosis of obstructive lung diseases

OBJETIVO: Avaliar a contribuição de um novo coeficiente, a razão FEF50 por cento/0,5CVF, medida através da curva fluxo-volume máximo expiratório, no diagnóstico dos distúrbios ventilatórios obstrutivos (DVOs); testar esse coeficiente na diferenciação entre grupos de pacientes normais, com DVO e com distúrbio ventilatório restritivo (DVR); e estabelecer pontos de corte para cada um dos diagnósticos funcionais e a probabilidade para cada diagnóstico a partir de valores individuais. MÉTODOS: Estudo transversal, prospectivo, com a análise de testes de função pulmonar de 621 pacientes encaminhados ao Hospital de Clínicas de Porto Alegre entre janeiro a dezembro de 2003. Foram coletados dados demográficos e espirométricos. Os pacientes foram divididos conforme o diagnóstico funcional em três grupos: normal; DVO; e DVR. Foram calculadas as razões VEF1/CVF e FEF50 por cento/0,5CVF, e as médias de FEF50 por cento/0,5CVF foram comparadas entre os grupos. Para correlacionar FEF50 por cento/0,5CVF com VEF1/CVF, utilizou-se a correlação de Pearson. Os pacientes foram, então, divididos em dois grupos: com e sem DVO. Foram calculadas as razões de verossimilhança para diferentes pontos de corte. RESULTADOS: A média de idade dos pacientes foi de 55,8 ± 14,7 anos. Houve diferenças significativas nos valores médios de FEF50 por cento/0,5CVF entre os grupos (2,10 ± 0,82, 2,55 ± 1,47 e 0,56 ± 0,29, respectivamente, para normal, DVR e DVO; p < 0,001). Houve uma correlação positiva do FEF50 por cento/0,5CVF com VEF1/CVF no grupo DVO (r = 0,83). Valores de FEF50 por cento/0,5CVF < 0,79 mostraram-se fortes indicadores de DVO e valores > 1,33 praticamente afastam esse diagnóstico. CONCLUSÕES: A razão FEF50 por cento/0,5CVF é um parâmetro potencialmente útil para discriminar DVOs, correlacionando-se positivamente com o VEF1/CVF.

OBJECTIVE: To evaluate the contribution of a new coefficient, the FEF50 percent/0.5FVC ratio, obtained from the maximal expiratory flow-volume curve, to the diagnosis of obstructive lung disease (OLD); to test this coefficient in differentiating among patients considered normal, those with OLD and those with restrictive lung disease (RLD); and to determine cut-off points for each functional diagnosis, as well as the probability for each diagnosis based on individual values. METHODS: A prospective, cross-sectional study analyzing the pulmonary function of patients referred to the Porto Alegre Hospital de Clínicas, in Porto Alegre, Brazil, between January and December of 2003. We collected demographic and spirometric data. The patients were divided into three groups: normal; OLD; and RLD. We calculated the FEV1/FVC and FEF50 percent/0.5FVC ratios, and we compared the mean FEF50 percent/0.5FVC values among the groups. We used Pearson's correlation test in order to compare FEF50 percent/0.5FVC with FEV1/FVC. The patients were again divided into two groups: those with OLD and those without OLD. We calculated the likelihood ratio for different cut-off points. RESULTS: The mean age of the patients was 55.8 ± 14.7 years. There were significant differences among the groups in terms of the mean FEF50 percent/0.5FVC (2.10 ± 0.82, 2.55 ± 1.47 and 0.56 ± 0.29, respectively, for normal, RLD and OLD; p < 0.001). There was a positive correlation between FEF50 percent/0.5FVC and FEV1/FVC in the OLD group (r = 0.83). We found that an FEF50 percent/0.5FVC < 0.79 strongly suggests OLD, whereas an FEF50 percent/0.5FVC > 1.33 practically excludes this diagnosis. CONCLUSIONS: The FEF50 percent/0.5FVC ratio is a potentially useful parameter in the differential diagnosis of OLD and correlates positively with the FEV1/FVC ratio.

Transient expiratory flow interruptions (TEFI) increase expiratory flow in acute asthma exacerbation / Incremento del flujo espiratorio luego de interrupciones transitorias en la exacerbación aguda de asma

We have shown that expiratory flows increase when expirations are rapidly interrupted in stable asthmatic patients. We hypothesized that a similar increase could be obtained in patients with acute exacerbation of bronchial asthma treated in the Emergency Room. A total of 30 asthmatic patients were randomly allocated into two groups, the study and the control groups. Patients in the study group were connected to a device with an inspiratory line designed to administer pressurized aerosols. The expiratory line passed through a valve completely interrupting flow at 4 Hz, with an open/closed time ratio of 10/3. The control group patients were also connected to the device, but with the valve kept open. Mean expiratory flow at tidal volume (MEFTV) was measured under basal conditions and at 4, 8 and 12 minutes after connecting the patients to the device. All patients received standard treatment throughout the procedure. At all time points MEFTV increased more in the study than in the control group (p < 0.003 by two-way ANOVA). There was no residual effect after disconnection from the device. We conclude that TEFI can rapidly improve expiratory flows in patients with acute exacerbations of asthma, while pharmacologic interventions proceed.

Demostramos que el flujo espiratorio máximo, en pacientes asmáticos en estado estable, se incrementaba cuando se generaban rápidas y transitorias interrupciones del flujo. Formulamos la hipótesis de que un incremento similar podría ser observado en pacientes con exacerbación aguda de asma tratados en la sala de emergencias. Un total de 30 pacientes asmáticos fueron distribuidos al azar en dos grupos. Los pacientes del grupo en estudio fueron conectados a un aparato con una vía inspiratoria diseñada para la administración de aerosoles. La vía espiratoria pasaba por una válvula que interrumpía el flujo completamente a 4 hz, con una relación tiempo abierta/tiempo cerrada de 10/3. Los pacientes del grupo control también fueron conectados al aparato pero con la válvula siempre abierta. Se midió el flujo medio de la espiración a volumen circulante en condiciones basales y a los 4, 8 y 12 minutos después de conectado el paciente al equipo. Todos los pacientes recibieron el tratamiento farmacológico estándar a lo largo del ensayo. Se observó un incremento significativamente mayor del flujo espiratorio medio a volumen circulante en el grupo en estudio en comparación al grupo control (p < 0.003 ANOVA de dos vías) durante todo el ensayo. No hubo efecto residual después de la desconexión del equipo. Concluimos que las interrupciones transitorias del flujo espiratorio pueden incrementar rápidamente el flujo espiratorio en pacientes con exacerbaciones agudas de asma dando tiempo a que el tratamiento farmacológico comience a actuar.

Novos valores de referência para espirometria forçada em brasileiros adultos de raça branca / New reference values for forced spirometry in white adults in Brazil

OBJETIVO: Descrever novas equações de referência para a espirometria em adultos brasileiros saudáveis que nunca fumaram, e comparar os valores previstos atuais com os valores derivados em 1992. MÉTODOS: Equações e limites de referência foram derivados em 270 homens e 373 mulheres, habitantes de oito cidades brasileiras, por espirômetro. A idade variou de 20 a 85 anos nas mulheres e 26 a 86 anos nos homens. Os exames seguiram as normas recomendadas pela Sociedade Brasileira de Pneumologia e Tisiologia. Os limites inferiores foram derivados pela análise do 5º percentil dos resíduos. RESULTADOS: Os valores previstos para capacidade vital forçada (CVF), volume expiratório forçado no primeiro segundo (VEF1) e para as relações VEF1/CVF e VEF1/volume expiratório forçado nos primeiros seis segundos (VEF6) se ajustaram melhor em regressões lineares. Os fluxos ajustaram-se melhor em equações logarítmicas. Em ambos os sexos, maiores estaturas resultaram em menores valores para as relações VEF1/CVF, VEF1/VEF6 e fluxos/CVF. Os valores de referência do VEF1 e da CVF, no presente estudo, foram maiores do que aqueles derivados para adultos brasileiros em 1992. CONCLUSÃO: Novos valores previstos para a espirometria forçada foram obtidos em uma amostra da população brasileira de raça branca. Os valores são maiores do que os obtidos em 1992, provavelmente em decorrência de fatores técnicos.

OBJECTIVE: To describe spirometric reference equations for healthy Brazilian adults who have never smoked and to compare the predicted values with those derived in 1992. METHODS: Reference equations for spirometry were derived in 270 men and 373 women living in eight cities in Brazil. Ages ranged from 20 to 85 years in women and from 26 to 86 years in men. Spirometry examinations followed the recommendations of the Brazilian Thoracic Society. Lower limits were derived by the analysis of the fifth percentiles of the residuals. RESULTS: Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC and FEV1/forced expiratory volume in six seconds (FEV6) were best fitted by linear regression. Flows were best fitted using log equations. For both genders, greater height resulted in lower values for FEV1/FVC, FEV1/FEV6 and flow/FVC ratios. The reference values for FEV1 and FVC in the present study were higher than those derived for Brazilian adults in 1992. CONCLUSION: New predicted values for forced spirometry were obtained in a sample of white Brazilians. The values are greater than those obtained in 1992, probably due to technical factors.

Comparação entre valores espirométricos de referência obtidos a partir das equações de Knudson e de Pereira Adultos / Comparing reference spirometric values obtained from Knudson and Pereira equations - Adults

Em revisão de 1991, a American Thoracic Society (ATS) recomenda que cada região defina equações próprias para obtenção dos valores teóricos (VTs) dos parâmetros espirométricos, que traduzam a realidade funcional para a população local. Quando dessa recomendação, os EUA já dispunham de diversos sistemas de equações próprios, bem como a Comunidade Européia e a Polônia em particular. Em 1992, Pereira et al., analisando 4.200 espirogramas de brasileiros normais, encontraram VT para capacidade vital forçada (CVF), volume expiratório forçado de 1 seg. (VEF1) e de fluxo expiratório médio (FEF25-75) diferentes dos descritos pelos autores americanos e europeus. Este estudo foi realizado para comparar as equações de Pereira et al., desenvolvida a partir de amostra de população brasileira, e as americanas de Knudson et al., bastante utilizadas em nosso meio. Foi também investigada a conseqüente influência nos laudos espirométricos, quando uma ou outra é empregada. Foram analisados 1.070 espirogramas de pacientes de ambos os sexos (389 homens e 681 mulheres) que vieram ao serviço para avaliação funcional de rotina. Não foi excluída qualquer patologia nem levada em conta a situação tabágica do paciente. Para cada paciente foi feito o cálculo do VT para CVF, VEF1 e FEF25-75 segundo as equações de Pereira (VT-P) e de Knudson 1983 (VT-K) e comparados as médias, desvios padrões e os laudos obtidos por um e por outro. Os VT-K para a CVF foram de 4,01 por cento [p < 0,005] maiores entre as mulheres, levando a sobrevalorização das restrições respiratórias, mas entre os homens não houve diferença relevante. Quanto à VEF1, os VT-P foram superiores tanto em homens (4,76 por cento [p < 0,005]) como em mulheres (5,04 por cento [p < 0,05]), levando a maior sensibilidade na identificação de obstruções respiratórias. Não se observou diferença relevante entre os VT-P e VT-K para o FEF25-75 em nenhum dos sexos.

Cough and asthma.

Cough is a common symptom in office practice. Though troublesome, it serves to maintain normal function of respiratory tract. Chronic or recurrent cough may be caused by variety of diseases, asthma being the most common amongst them. Cough, wheeze and breathlessness are classical features of asthma syndrome. Many diseases may lead to this syndrome. Asthmatic children present with cough of variable intensities and patterns. At times, wheeze and breathlessness may not be clinically apparent. It was well known that all that wheezes is not asthma but now it is well understood that every asthmatic child does not wheeze. In an acute attack of asthma, cough often starts at the end of wheezing episode. It leads to expulsion of thick, stringy mucus often in the form of casts. Though cough is a minor symptom during acute attack, it ensures removal of secretions and avoid complications. Cough is a prominent symptom in persistent asthma especially between acute exacerbations. Episodic nocturnal cough may be the only symptom of chronic asthma. Children with cough variant asthma do not wheeze. It is postulated that they have milder degree of airway hyperresponsiveness and higher wheezing threshold. However, they show all the characteristics of asthma on laboratory tests. Cough represents bronchial hyperresponsiveness and is not a measure of asthma. Hence it may be caused by many diverse etiologies such as gastroesophageal reflux, enlarged adenoids, sinusitis or tropical eosinophilia. Cough in such conditions mimicks asthma and relevant tests may be necessary for proper diagnosis.

Respiratory pressures in normal Indian subjects.

Regression equations for the prediction of maximum inspiratory pressures (MIP) in North Indian adults are reported, based on observations in 120 females and 153 males. Age and sex were the only significant predictor variables. MIP was significantly related to vital capacity, FEV1 and peak flow rate. The MIP observed in the present study are similar to those reported earlier in Caucasians and Chinese. The lower lung volumes and flow rates in Indians are not explained by differences in MIP.

Valores espirometricos normales para la ciudad de Buenos Aires / Normograms of spirometric values for the city of Buenos Aires

Debido a la diferencia existente entre las distintas tablas de valores teóricos espirométricos de la literatura, decidimos realizar la de la Ciudad de Buenos Aires y Gran Buenos Aires. Se realizó espirometría forzada, siguiendo las recomendaciones de la American Thoracic Society, a 237 personas (105 de sexo femenino y 132 de sexo masculino) de entre 18 y 86 años, y entre 144 y 194 centímetros de altura. Se les midió Capacidad Vital Forzada (FVC), Volumen Espiratorio Forzado en el primer segundo (FEV1), y Flujo Espiratorio Forzado entre el 25 y el 75 por ciento de la FVC(FEF25-75) en espirómetros previamente calibrados mediante el Simulador de Espirometría por Descompresión Explosiva. Se realizó Regresión Múltiple de los valores obtenidos de Función Pulmonar (FP) con la edad y la altura para cada sexo. Considerando la FP de distribución normal, se determinó el Límite Inferior Normal (LIN) calculando el intervalo de confianza a una cola con un nivel de confianza del 95 por ciento, y se consideró como LIN un porcentaje variable para cada parámetro, a cada edad, y a cada altura, eliminando así el concepto de valor porcentual fijo, utilizado ampliamente en nuestro medio.

Determinación de valores espirométricos en una población chilena normal mayor de 5 años, a nivel del mar / Reference spirometric values for a standard chilean population older than 5 years, at sea level

Maximal expiratory flow-volume curves were obtained from a randomly selected population of 850 healthy non-smoking subjects living at sea level, in cities without atmospheric pollution. Equipment and techniques were used according to the recommendations of the American Thoracic Society. Linear regression equations were obtained, using age and height as independent variables and spirometric values as dependent variables, for both sexes and ages from 6 to 70 years old. Our values for forced vital capacity and forced expiratory volume were 9 to 18 percent and 10 to 15 percent higher than those reported by Knudson et al. In conclusion, chilean spirometric reference values differ from those used abroad, emphazing the need to use local standards to interpret spirometric results

Espirometría / Spirometry

La espirometría es una prueba de función respiratoria que permite diferenciar las alteraciones ventilatorias restrictivas de las obstructivas y determinar aproximadamente su severidad y su reversibilidad. Se utiliza también para evaluar los resultados de las medidas terapéuticas utilizadas, así como la respuesta frente a tests de provocación (histamina, metacolina, etc.) empleados para estudiar la reactividad bronquial

Curva normal de pico respiratorio forzado en niños de Lima, Perú / Normal curve of forced expiratory peak in children from Lima, Peru

Se realizó un estudio observacional transversal con el objeto de diseñar una curva normal de Pico Espiratorio Forzado (PEF) en niños sanos de ambos sexos, de la ciudad de Lima. Se incluyeron a 425 niños entre 100 y 177 centimetros de estatura, y entre 3 y 16 años de edad, a los cuales se les practicó la flujometría, registrándose elmejor de 5 intentos, con un Mini-Wright Peak Flow Meter. Fueron evaluados 199 varones y226 mujeres. Se obtuvieron las siguientes curvas de rgresión para el cálculo del PEF. Varones: PEF (lt/min) = -433.893 + 5.501 x (talla en cm.), y para las mujeres: PEF (lt/min) = -369.562 + 4.915 x (talla en cm.). Se observó que no existe diferencia significativa entre las asociaciones PEF vs talla entre hombres y mujeres de este estudio, ni tampoco al compararlas con las descritas en el estudio de Godfrey, de Inglaterra. Se recomienda el uso de estas ecuaciones para el diagnóstico y segumiento de niños con broncoespasmo de la ciudad de Lima, Perú

Exercise induced bronchial lability in normal men and women--a comparison.

Normal male (n = 29) and female (n = 39) medical students with a mean age of 19.2 years who were nonsmokers, with no personal history of allergy were studied. The bronchial lability was assessed from peak expiratory flows and forced expiratory spirograms taken before, during and upto 45 minutes after a standard exercise using the Harvard steps. Women had a significantly lower (P < .001) resting FVC, FEV1, FEF 25-75% and PEF as compared to men. Although the exercise lability index was not significantly different in men and women, the latter showed a greater percent increase (P < .02) and a lesser percent decrease (P < .02) of PEF during and after the exercise respectively. They also showed a significantly (P < .005) faster recovery to normal. These results suggest that airway dynamics may be better in women than in men. This could account for the lower incidence and morbidity from respiratory allergic disease seen in women as compared to men.