Interpretando la función pulmonar. Una perspectiva para el siglo XXI desde la Neumología pediátrica / No disponible

Las pruebas de función pulmonar son básicas para el diagnóstico y seguimiento del paciente respiratorio. Su correcta interpretación es fundamental para distinguir lo normal de lo patológico. La aparición de las primeras ecuaciones globales para todas las edades (Global Lung Initiative [GLI]-2012) supone un reto para cualquier médico encargado de interpretar una espirometría, no solo por los cambios "numéricos" esperables al utilizar otros patrones de referencia, sino por la necesidad de expresar los resultados como desviaciones de la media (z-scores) y abandonar el clásico porcentaje sobre el valor predicho. La visión de los pediatras neumólogos, acostumbrados a trabajar con pacientes en constante cambio, puede ayudar a entender la necesidad de este tipo de ecuaciones. Este artículo pretende revisar el concepto de normalidad, los parámetros necesarios para interpretar una espirometría, las características ideales de una ecuación de referencia y las bondades y defectos de las nuevas ecuaciones GLI-2012

Pulmonary function tests are basic in the diagnosis and monitoring of respiratory patients. The proper interpretation of these tests is essential to distinguish normal from pathological. The first global equations for all ages (Global Lung Initiative [GLI]-2012) poses a challenge for any physician responsible for interpreting spirometry, not only due to the "numerical" changes expected when using a new reference equation, but also because of the need to express the results as deviations from the mean (z-scores) and leave the classical percentage of the predicted value. The view of the paediatric pulmonologists, who are used to working with patients in constant evolution, can help to understand the need for this type of equations. This article reviews the concept of normality, the parameters required to interpret a spirometry, the ideal characteristics of a reference equation and the virtues and defects of the new GLI-2012 equations

Methacholine challenge test by wheezing and oxygen saturation in preschool children with asthma

Methacholine challenge test (MCT) performed with spirometry is a commonly used test to evaluate bronchial hyperreactivity (BHR) in children. However, preschoolers do not usually collaborate. OBJECTIVES: To assess the usefulness of MCT through clinical evaluation (wheezing auscultation and decreased pulse arterial oxygen saturation [SpO2]) in recurrent wheezing preschoolers with asthma, in comparison to healthy controls. METHODS: We performed the MCT (modified Cockroft method) on healthy and on asthmatic preschoolers. The end point was determined by the presence of wheezing in the chest and/or tracheal auscultation (PCw) and/or a decrease in SpO2 of ≥5 from the baseline value (PCSpO2). Maximal methacholine concentration was 8 mg/ml. RESULTS: The study population comprised 65 children: 32 healthy and 33 asthmatic children. There were no differences in demographic characteristics between the groups. The median methacholine doses for PCw and for PCSpO2 were significantly lower among asthmatic than healthy children: 0.5 mg/ml (0.25-0.5 mg/ml) vs. 2 mg/ml (1-4 mg/ml), respectively, p < 0.001; and 0.25 mg/ml (0.25-0.5 mg/ml) and 2 mg/ml (0.5-4 mg/ml), respectively, p < 0.001. The best cut-off point of PCw was observed at a methacholine concentration of 0.5 mg/ml (AUC = 0.72 [95% CI = 0.66-0.77]), its sensitivity was 91%, specificity 43%, PPV 16% and NPV 98%. For PCSpO2 the best cut-off point was a methacholine concentration of 1 mg/ml (AUC = 0.85 [95% CI 0.81-0.89]), with sensitivity of 80%, specificity 74%, PPV 49%, and NPV 92%. There were no adverse reactions. CONCLUSION: MCT using clinical parameters such as wheezing auscultation and SpO2 measurement could be a useful and safe test to confirm BHR among preschoolers

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Lower limit of normal or FEV1/FVC < 0.70 in diagnosing COPD: an evidence-based review.

AIM: To review the currently available literature comparing the FEV1/FVC 40 years. METHODS: A structured MEDLINE, EMBASE and Cochrane search of English-language literature was conducted. Studies comparing prevalence rates according to the LLN and a fixed value were included. Attention was paid to the choice of the reference test or gold standard used. RESULTS: Eighteen studies met the inclusion criteria. Sixteen studies compared the rates of subjects diagnosed with airflow obstruction by either definition of airflow obstruction without using a non-independent reference standard (level 4 studies). Using a fixed value of FEV1/FVC, an overall higher number of subjects were diagnosed with airflow obstruction that increased with age. Two studies included a follow-up phase comparing risks of either hospitalization or occurrence of respiratory symptoms and mortality (level 2b studies). Adjusted risks of hospitalization (HR 2.6) or mortality (HR 1.3) were significantly larger in subjects with an FEV1/FVC below 0.70 but above the LLN (in-between group) compared to subjects with normal lung function. CONCLUSION: The prevalence of spirometry-based COPD is greater when using the fixed value of FEV1/FVC in comparison to using the LLN. Based on one longitudinal study the in-between group appears to have a higher risk of hospitalization and mortality; therefore it seems that using the LLN of FEV1/FVC underestimates COPD. In absence of a gold standard of COPD longitudinal research will be necessary to determine which criterion is better and more clinically relevant.

Chronic obstructive pulmonary disease in older persons: A comparison of two spirometric definitions.

BACKGROUND: Among older persons, we previously endorsed a two-step spirometric definition of chronic obstructive pulmonary disease (COPD) that requires a ratio of forced expiratory volume in 1sec to forced vital capacity (FEV(1)/FVC) below .70, and an FEV(1) below the 5th or 10th standardized residual percentile ("SR-tile strategy"). OBJECTIVE: To evaluate the clinical validity of an SR-tile strategy, compared to a current definition of COPD, as published by the Global Initiative for Obstructive Lung Disease (GOLD-COPD), in older persons. METHODS: We assessed national data from 2480 persons aged 65-80 years. In separate analyses, we evaluated the association of an SR-tile strategy with mortality and respiratory symptoms, relative to GOLD-COPD. As per convention, GOLD-COPD was defined solely by an FEV(1)/FVC<.70, with severity staged according to FEV(1) cut-points at 80 and 50 percent predicted (%Pred). RESULTS: Among 831 participants with GOLD-COPD, the risk of death was elevated only in 179 (21.5%) of those who also had an FEV(1)<5th SR-tile; and the odds of having respiratory symptoms were elevated only in 310 (37.4%) of those who also had an FEV(1)<10th SR-tile. In contrast, GOLD-COPD staged at an FEV(1) 50-79%Pred led to misclassification (overestimation) in terms of 209 (66.4%) and 77 (24.6%) participants, respectively, not having an increased risk of death or likelihood of respiratory symptoms. CONCLUSION: Relative to an SR-tile strategy, the majority of older persons with GOLD-COPD had neither an increased risk of death nor an increased likelihood of respiratory symptoms. These results raise concerns about the clinical validity of GOLD guidelines in older persons.

Pico de fluxo expiratório em voluntários de 50 a 80 anos / Peak expiratory flow in 50 to 80 years old volunteers

Objetivo: Avaliar o valor de pico de fluxo expiratório (PFE) em voluntários idosos. Método: Foram incluídos 305 voluntários clinicamente estáveis, sendo 231 do sexo feminino com idade entre 50 e 80 anos. Foi registrada a altura, sexo e medido o PFE com o dispositivo ASSESS® Peak Flow Meter com esforços expiratórios máximos. Realizou-se 3 medidas, desde que a última não fosse a maior e que não houvesse diferenças superiores a 5 por cento. Utilizou-se nível de significância de 95 por cento. Resultados: O valor médio do PFE para os homens foi de 442 ± 122,9 l/min e para as mulheres foi 330 ± 71,8 l/min. A altura influenciou nos valores de PFE. Quanto maior a idade, menor é o PFE. Foi construída curva de regressão para o PFE, que estabelecem valores de normalidade para homens brasileiros com idade entre 50 e 80 anos: PFE (l/min) = - 140,438 - 2,351*idade + 409,689*altura. Para o sexo feminino não foi possível estabelecer uma equação, pois a variável altura não foi estatisticamente significante. Conclusão: Os homens apresentam valores de PFE mais elevados que as mulheres. Foi possível construir uma equação para predizer o PFE para homens, o mesmo não aconteceu para o sexo feminino.

Objective: To analyze the value of peak expiratory flow (PEF) in elderly volunteers. Methods: Were included 305 clinically stable volunteers, 231 females with age between 50 and 80 years old. It was registered the height, sex and measure the PEF with the device ASSESS® Peak Flow Meter with maximum expiratory efforts. Were performed 3 measures, since the latter was not the greatest and that there were no differences between the measures above 5 percent. It was used the significance level of 95 percent. Results: The average value of PEF for men was 442 ± 122.9 l/min and for women was 330 ± 71.8 l/min. The values of PEF are influenced for height of volunteers. How more the age less is the PEF. It was built for the regression curve of PEF, establishing values of normality for Brazilian men aged between 50 and 80 years: PFE (l/min) = (- 140.438 - 2.351*age + 409.689*height). For females they were not possible to establish an equation, because the variable height was not statistically significant. Conclusions: The men have higher values of PEF than women. It was possible to construct an equation to predict the PEF for men, the same has not happened for the women.

A comprehensive guide to buying a spirometer.

A guide to spirometers aimed at improving the knowledge of nurses looking to buy a spirometer for the first time or to replace existing equipment and giving details of some of the latest models available.

Manifestaciones pulmonares en pacientes con lupus eritomatoso generalizado / Pulmoray manifestations in patients with wide spread lupus erythematosus

El presente estudio fue realizado en el período comprendido de julio 1998 a enero del 2001. El objetivo general fue conocer la frecuenciade las manifestaciones pulmorares en pacientes con lupus eritematoso generalizado (LEG), desde el punto de vista clínico, radiolólgico, espirométrico y su correlación con otras manifestaciones de actividad de la enfermedad. Se diseño un estudio de casos y controles anidados en una cohorte, se estudiaron 20 casos y 31 controles. La recolección de la información se realizó a través del archivo clínico (expedientes) y registros de la Clínica de Reumatología y el propio paciente. La evaluación se realizó a través de una ficha de recolección de datos, espirometría y pletismografía, radiografía de toráx y el índice Mex-SLEDAI (indice deactividad de la enfermedad en el lupus erimatoso sistémico con modificación simplificada), para evaluar indice de actividad de la enfermedad. Dentro de los resultados más relevantes encontramos lo siguiente: El derrame pleural fue observadoen el 50 porciento de los casos, seguido del infiltrado insterticial con un 25 porciento. Con respecto a las manifestaciones clínicas se encontró artritis en el95 porciento de los casos y 87.1 porciento en el grupo control, estableciéndose asociación estadísticamente significativa (P= 0.001). Se observó anemia en el 70porciento de los casos y 67.7 porciento en el grupo control, acercándose a la significancuia estadística (P= 0.06). En conclusión el derrame pleural (clínico, radiológico) el patrón obstructivo (espirométrico) y la debilidad de los músculosinspiratorios fueron las manifestaciones observadas con mayor frecuencia. Hubo una asociación significativa entre artritis y anemia(actividad), neumonía (complicación) y la presenccia de manifestaciones pulmonares (derrame pleural)...

Instrumentation for spirometry.

In addition to improvements in spirometry instrumentation, the availability and quality of mechanical pump-testing equipment have also improved. These devices have largely relied on the ATS 24 standard waveforms and appear to simulate human FVC maneuvers reasonably well, at least with respect to testing using room air. Testing using mechanical pumps filled with heated and humidified air to better simulate the human FVC maneuver is still evolving. With the availability of these testing devices, many problems in both spirometric hardware and software can be identified and corrected. Perhaps the two most significant emerging advancements in spirometry instrumentation are the automated test acceptability and reproducibility assessments with immediate feedback to the technician and the development of small portable spirometers. At least two major studies (LHS8 and NHANES12) have described a second generation of comprehensive on-line assessment of test quality with immediate feedback to the spirometry technician. The use of quality assessment software appears to significantly improve the quality of the spirometry data through feedback to technicians. Spirometry hardware is also advancing as several hand-held devices are being developed to measure not only peak flow but also FEV1, FVC, and other parameters. These battery-powered portable spirometers will continue to decrease in size and cost and may eventually displace the hand-held peak flow meters in current use.