Fisiología respiratoria mecánica de la respiración / Mechanics breathing

El trabajo respiratorio se ejerce en una estructura cerrada donde se encuentran los pulmones, estos son sometidos a cambios de presiones determinados por la musculatura pulmonar en las diferentes fases del ciclo respiratorio, lo que generará gradientes y permite la entrada y salida de aire. Se suman a ello el calibre de las vías aéreas, el tipo de flujo, las características de las vías aéreas y del surfactante pulmonar, que determinan un menor o mayor trabajo respiratorio según la condición fisiológica.

The work of breathing is exerted in a closed structure where the lungs are located. These are subjected to pressure changes determined by the pulmonary musculature in the different phases of the respiratory cycle, which will generate gradients and allow the entry and exit of air. In addition to the aforesaid, airway calibre, type of flow, airway characteristics and pulmonary surfactant determine less or more work of breathing depending on the physiological condition.

Genetic underpinnings of lung function and COPD

Spirometry based measurement of lung function is a global initiative for chronic obstructive lung disease (GOLD) standard to diagnose chronic obstructive pulmonary disease (COPD), one of the leading causes of mortality worldwide. Theenvironmental and behavioural risk factors for COPD includes tobacco smoking, air pollutants and biomass fuel exposure, which can induce one or more abnormal lung function patterns. While smoking remains the primary risk factor, only 15–20% smokers develop COPD, indicating that the genetic factors are also likely to play a role. According to the study of Global Burden of Disease 2015, ∼174 million people across the world have COPD. From a comprehensive literature search conducted using the ‘PubMed’ and ‘GWAS Catalogue’ databases, and reviewing the literature available, only a limited number of studies were identified which hadattempted to investigate the genetics of COPD and lung volumes, implying a huge research gap. With the advent of genomewide association studies several genetic variants linked to lung function and COPD, like HHIP, HTR4, ADAM19 and GSTCD etc., have been found and validated in different population groups, suggesting their potential role in determining lung volume and risk for COPD. This article aims at reviewing the present knowledge of the genetics of lung function and COPD

Laboratorio de función pulmonar / Lung function laboratory

El laboratorio de función pulmonar es esencial en el manejo de los pacientes con enfermedades respiratorias. El laboratorio de Clínica Las Condes realiza pruebas diagnósticas de uso habitual. El propósito de este artículo es revisar las indicaciones, limitaciones y la interpretación de éstas analizando también los aspectos técnicos, Estos exámenes son: Espirometría, volúmenes pulmonares, capacidad de difusión, test de metacolina, medición de la fracción exhalada de óxido nítrico y presión máximas inspiratorias y espiratorias, También se analizan los test de ejercicio realizados: test de marcha de seis minutos y test cardiopulmonar. Finalmente nos referimos a la oximetría nocturna como una forma de aproximarnos al diagnóstico de apnea del sueño.

Lung function tests are essential in the management of Respiratory patients. In Clinica Las Condes lab, we perform the most usual and important functional tests. The aim of this article is to review the indications, limitations and interpretation of them and also the technical aspects. This includes: Spirometry, lung volumes, DLCO, methacholine test, exhaled nitric oxide and maximum inspiratory and expiratory pressure. We also perform exercises tests like six minute walking and cardiopulmonary exercise test which we also describe. Finally, it is mention the nocturnal oximetry as an approximation to sleep apnea study.

O impacto dos valores previstos nos testes de função pulmonar / The impact of predicted values in pulmonary function tests

A interpretação dos testes de função pulmonar é resultado da comparação de valores obtidos com valores previstos para um determinado indivíduo. Os valores previstos são obtidos através de equações de referência, sendo estas determinadas por dados antropométricos e demográficos dos indivíduos. A presente revisão de literatura pretende identificar quais as equações referência mais utilizadas para os testes de função pulmonar, comparar estudos entre equações com ênfase nas publicações de equações de referência brasileiras.

Lung function test interpretation is based on the comparison between values measured according to the predicted values for each individual. The predicted values come from reference equations, which depend on anthropometric and demographic data of individuals. The present review aims to identify the most commonly used reference equations for pulmonary function tests, interpret comparative studies between equations and emphasizes publications with Brazilian reference equations.

A incorporação das medidas de volumes pulmonares na interpretação dos testes de função pulmonar / The role of lung volumes measurement in interpretation of pulmonary function tests

Os volumes pulmonares estáticos, obtidos ao final do ciclo ventilatório corrente e ao final de manobras inspiratória e expiratória máximas, são chamados volumes pulmonares absolutos (VPA), e se estruturam na capacidade residual funcional (CRF), na capacidade pulmonar total (CPT) e no volume residual (VR). Os VPA não podem ser medidos diretamente pela espirometria, cuja mensuração aporta outros importantes parâmetros de volume, como a capacidade vital (CV) e suas subdivisões; a capacidade inspiratória (CI); e o volume de reserva expiratória (VRE). A CRF é determinada pelo equilíbrio entre o recolhimento elástico do pulmão e da parede torácica, considerando-se as constantes de tempo expiratório e atividade dos músculos inspiratórios durante a expiração; a CPTé determinada pela força dos músculos respiratórios e pela oposição entre os recolhimentos elásticos do pulmão eda parede torácica; o VR é determinado, em crianças, pela força dos músculos respiratórios e a complacência daparede torácica, em crianças e em adultos, pela oclusão de vias aéreas em adultos. A mensuração dos VPA é realizada pela pletismografia de corpo inteiro (padrão-ouro), pelos métodos de diluição de gases e exames de imagens.A indicação de mensuração dos VPA se baseia no significado de seus mecanismos determinantes, em paralelo ao avanço no conhecimento atual da fisiopatologia pulmonar. Os VPA qualificam e quantificam os distúrbios ventilatórios obstrutivos pela identificação funcional de hiperinsuflação e aprisionamento de ar e são essenciais para o diagnóstico de distúrbios ventilatórios restritivos e mistos, sendo que as informações deles advindas são úteis em muitas doenças e condições clínicas.

Static lung volumes obtained at the end of the current ventilatory cycle and the end of maximal inspiratory and expiratory maneuvers are called absolute lung volumes (VPA), and represent the functional residual capacity (FRC), total lung capacity (TLC) and volume residual (VR). The VPA cannot be directly measured by spirometry, which brings another important measurement parameters of volume as vital capacity (VC) and its subdivisions inspiratory capacity (IC) and expiratory reserve volume (ERV).The CRF is determined by the balance between the elastic recoil of the lung and the chest wall, the expiratory time-constants and the inspiratory muscle activity during expiration; CPT is determined by the strength ofrespiratory muscles and the opposition between the elastic recoil of the lung and the chest wall; VR is determinedby the strength of respiratory muscles, chest wall compliance in children and occlusion of airways in adults. Themeasurement of VPA is held by body plethysmography (gold standard), by the methods of dilution of gases andimaging tests. The indication for measurement of VPA is based on the meaning of its determinants mechanisms in parallel to advance the current understanding of pulmonary pathophysiology. OS VPA qualify and quantify the obstructive disorders with functional identification of hyperinflation and air trapping and are essential for the diagnosis of restrictive and mixed ventilatory disorders, and the resulting information of them are useful in many diseases and clinical conditions.

Evaluación de los músculos respiratorios en la parálisis diafragmática bilateral / Assessment of respiratory muscle strength in bilateral diaphragmatic paralysis

Measurement of respiratory muscle strength is useful in order to detect respiratory muscle weakness and to quantify its severity. Apropos of a patient with bilateral diaphragmatic paralysis, we review the clinical manifestations and methods for assessing the strength of the respiratory muscles. In patients with severe respiratory muscle weakness, vital capacity and total lung capacity are reduced but are a non-specific and relatively insensitive measure. Conventionally, inspiratory and expiratory muscle strength has been assessed by maximal inspiratory and expiratory mouth pressures sustained for one second (PIMax and PEMax). The sniffmanoeuvre is natural and probably easier to perform. Sniff pressures are more reproducible and useful measure of diaphragmatic strength. However, the PIMax-PEMax and sniff manoeuvres are volition dependent, and submaximal efforts are most likely to occur in patients who are ill or breathless. Non-volitional tests include measurements of twitch esophageal, gastric and transdiaphragmatic pressure during bilateral electrical and magnetic phrenic nerve stimulation. Electrical phrenic nerve stimulation is technically difficult and is also uncomfortable and painful. Magnetic phrenic nerve stimulation is less painful and transdiaphragmatic pressure is reproducible in normal subjects. Systematic clinical evaluation and additional laboratory tests allow the diagnosis in most patients with respiratory muscle weakness.

La evaluación de la fuerza de los músculos respiratorios permite diagnosticar y cuantificar la gravedad de la debilidad muscular en diferentes enfermedades. A propósito de un paciente con parálisis diafragmática bilateral, hemos revisado el cuadro clínico y los procedimientos diagnósticos para evaluar la fuerza de los músculos respiratorios. En los pacientes con debilidad muscular respiratoria severa, disminuye la capacidad vital y la capacidad pulmonar total, pero es una medida inespecífica y relativamente insensible. Tradicionalmente, la fuerza muscular respiratoria es evaluada midiendo la presión inspiratoria y espiratoria máximas en la boca sostenidas durante un segundo (PIMax y PEMax). La medición de la presión inspiratoria máxima en la nariz (SNIP) es una maniobra natural, más simple de medir y más reproducible, siendo útil en la evaluación de la fuerza diafragmática. Sin embargo, estas técnicas no invasivas son operador dependiente, por lo tanto, esfuerzos submáximos es más probable que ocurran en pacientes graves o con disnea. Las mediciones de las presiones esofágica, gástrica y transdiafragmática mediante estimulación eléctrica o magnética del nervio frénico no son dependientes de la voluntad y son más confiables. Sin embargo, la estimulación eléctrica del nervio frénico es técnicamente difícil y puede ser incómoda y dolorosa. La estimulación magnética del nervio frénico es menos dolorosa y la medición de la presión transdiafragmática es reproducible en sujetos normales. La evaluación clínica sistemática y los exámenes de laboratorio complementarios permiten establecer el diagnóstico en la mayoría de los pacientes con debilidad de los músculos respiratorios.

Pletismografia optoeletrônica: uma revisão da literatura / Optoelectronic plethysmography: a review of the literature

CONTEXTUALIZAÇÃO: A pletismografia optoeletrônica (POE) é um método inovador de mensuração indireta da ventilação pulmonar, capaz de avaliar ciclo a ciclo, de forma tridimensional e em tempo real, os volumes pulmonares absolutos e suas variações nos três compartimentos que compõem a parede torácica (caixa torácica pulmonar, caixa torácica abdominal e abdome). A POE permite mensurar variáveis do padrão respiratório, da assincronia respiratória, além da contribuição de cada compartimento da parede torácica e de cada hemitórax para o volume corrente. OBJETIVOS: Fazer uma revisão de literatura sobre os seguintes aspectos relacionados à POE: histórico, princípio de funcionamento, vantagens de utilização, propriedades psicométricas, variáveis mensuradas e método de análise do sistema, ressaltando informações sobre seu manuseio. Em uma segunda parte, abordar a aplicabilidade da pletismografia optoeletrônica em diferentes condições de saúde/situações, tais como: doença pulmonar obstrutiva crônica (DPOC; efeitos agudos do exercício, reabilitação pulmonar, exercício respiratório e transplante pulmonar), asma, pacientes em terapia intensiva, doenças neuromusculares e hemiplegia. MÉTODO: Foi realizada uma busca na base de dados MedLine, SciELO e Lilacs com o termo "optoelectronic plethysmography". Foram incluídos 43 estudos. CONCLUSÃO: Tendo por base a literatura revisada, a POE mostrou-se um instrumento de avaliação respiratória capaz de fornecer informações sobre parâmetros ventilatórios de indivíduos saudáveis e com disfunções em diferentes posições, situações e ambientes. Foram apresentados os principais resultados dos estudos em que a POE foi usada em indivíduos que apresentavam DPOC representando o maior corpo de conhecimento até o momento, assim como em alguma outra condição de saúde.

BACKGROUND: Optoelectronic plethysmography (OEP) is an innovative method of indirect measurement of pulmonary ventilation, capable of breath-by-breath, three-dimensional, real time assessment of absolute lung volumes and their variations in the three compartments of the chest wall (pulmonary rib cage, abdominal rib cage, and abdomen). OEP allows the measurement of variables of breathing pattern, breathing asynchrony, and contribution of each chest wall compartment and hemithorax to the tidal volume. OBJECTIVES: To review the literature on the following aspects related to OEP: history, operating principle, advantages, psychometric properties, variables, and method of system analysis, highlighting information about its handling. In a second part, the objective is to analyze the applicability of OEP in different health conditions/situations such as: chronic obstructive pulmonary disease (COPD; acute effects of exercise, pulmonary rehabilitation, breathing exercise, and lung transplantation), asthma, patients in intensive care, neuromuscular diseases, and stroke. METHOD: A search was performed in MedLine, SciELO and Lilacs with the term "optoelectronic plethysmography". Forty-three papers were included. CONCLUSION: Based on the literature reviewed, OEP has been shown to be an assessment tool that can provide information about ventilatory parameters in healthy subjects and subjects with various dysfunctions in different positions, situations, and settings. The main results of studies on OEP in COPD are shown, representing the largest body of knowledge to date. The results of studies on OEP in other health conditions are also shown.

Effect of flour dust on lung volumes and capacities in flour mill workers.

Background And Objectives: Due to increase in industrialization, air pollution is increasing day by day. The workers working in these industries suffer from various types of air way diseases like Pneumoconiosis, Farmer’s Lung, Chronic bronchitis, pulmonary fibrosis and Asthma. So the present study was undertaken to study the effects of flour dust on the lung functions. Methods: Pulmonary function tests (PFT’s) of flour mill workers were compared with those of controls. We evaluated 100 subjects in the age group of 20-50 years consisting of 50 industrial workers from flour mills from the Amritsar Distt., and 50 healthy non-smoker, non-exposed subjects in the same age group served as controls. The PFT’s were carried out with a computerized spirometer “Med-Spiror”. The various data was collected, compiled, statistically analyzed and valid conclusions were drawn. Results And Interpretation: The present study results showed a significant decrease in the mean values of FVC, FEV1, PEFR, FEF25-75 and MVV and stratification of results showed a dose response of years of exposure in flour mills on lung functions. Conclusion: Flour dust causes chronic bronchial irritation which is responsible for the obstructive type of pulmonary impairment of lung functions.

Função pulmonar de obesos mórbidos submetidos à cirurgia bariátrica / Pulmonary function of morbidly obese submitted to bariatric surgery

OBJETIVO: Comparar a função pulmonar de indivíduos obesos mórbidos submetidos à gastroplastia. MÉTODOS: Participaram da pesquisa 25 indivíduos, divididos em grupo experimental com 15 sujeitos (feminino = 13 e masculino = 2) e grupo controle com 10 sujeitos (feminino = 8 e masculino = 2). Foram mensurados os valores espirométricos na fase pré-operatória e na fase pós-operatória, três meses após a cirurgia. RESULTADOS: Verificou-se diferença significante intragrupo na análise inicial e após os três meses de acompanhamento de peso, índice de massa corporal (IMC), Capacidade Vital forçada (CVF), Volume de Reserva Expiratório (VRE), Capacidade Inspiratória (CI) e do Fluxo Expiratório Forçado (FEF25-75 por cento), nos indivíduos que foram submetidos à cirurgia. Para os resultados obtidos da análise de diferença entre os grupos experimental e controle na análise de grupo e tempo, foram considerados significativos a CVF e o VRE. Verificou-se que aqueles que apresentavam distúrbios inespecíficos na fase pré-operatória passaram a ter função pulmonar normal na fase pós-operatória. Não foram verificadas diferenças significativas entre as características de proporções da espirometria entre os grupos e na avaliação intragrupo experimental. CONCLUSÃO: A cirurgia bariátrica influencia na melhora da função pulmonar, observando que um tempo maior de acompanhamento desses indivíduos pode nos mostrar resultados ainda mais confirmatórios sobre a importância da perda de peso para a função pulmonar.

OBJECTIVE: To compare the pulmonary function of individuals morbidly obese submitted to gastroplasty. METHODS: 25 individuals participated of this research, divided in experimental group with 15 subjects (female = 13 and male = 2) and control group with10 subjects (female = 8 and male = 2). Spirometric values were measured in the pre-operative and post-operative phase, three months after surgery. RESULTS: There was a significant difference intragroup in the initial analysis after three months follow-up weight, body mass index (BMI), Forced Vital Capacity (FVC), Expiratory Reserve Volume (ERV), Inspiratory Capacity (IC) and the Forced Expiratory Flow (FEF25-75 percent), in individuals who underwent surgery. For the results of the analysis of the differences between the experimental and control groups in the analysis of group and time, it were considered significant FVC and ERV. Verified that those nonspecific disturbances in the pre-operative and began to have normal lung function in the post-operative phase. There were not significant differences between the characteristics of the proportions of spirometry between groups and the intragroup experimental evaluation. CONCLUSION: Bariatric surgery influences in relation to improvement in lung function, observing that a longer follow-up of these individuals can show results in further confirming the importance of weight loss for lung function.

Relationship between smoking and pulmonary functions.

Background: Smoking is the most important factor contributing to the development of chronic obstructive pulmonary disease and is one of the major health risks in modern times. Aim: The purpose of the present study was to determine the relationship between cigarette smoking and pulmonary function tests between various groups of smokers and non-smokers. Methods: The study was carried out in 100 male subjects between 19-52 years of age. The subjects were drawn from the community such that they could be grouped as non-smokers (25), mild smokers (25), moderate smokers (25), and chronic smokers (25) according to their questionnaire response. Pulmonary Function Tests were carried out in each subject with a computerized spirometer. The various data was collected, compiled, statistically analyzed and valid conclusions were drawn Results: Results indicate that smoking is generally associated with lower levels of pulmonary functions. . It was established that pulmonary functions decreased with increasing number of pack years. The negative association was evident in most lung functions and capacities, but was largest and most progressive in FEV1, FEV1/FVC, FEF25-75% and PEFR. Conclusion: Pulmonary function data in smokers indicate narrowing of smaller airways, chiefly bronchioles. Rapidly declining pulmonary functions in smokers with increasing number of pack years is predictive of increased risk of development of chronic obstructive pulmonary disease (COPD). The study observed that spirometry was an effective and easy method for detection of COPD in risk group population like smokers and thus promotes smoking cessation efforts to reduce the burden of COPD in the community.

Comparação entre os volumes pulmonares irradiados com técnica bidimensional e tridimensional conformada na radioterapia de pacientes com tumores de pulmão localmente avançados / Comparison between irradiated lung volumes with two-dimensional and three-dimensional conformal radiotherapy techniques for locally advanced lung cancer

OBJETIVO: Comparar e quantificar os volumes pulmonares irradiados utilizando planejamentos bidimensional (2D) e tridimensional (3D) conformado na radioterapia de tumores de pulmão. MATERIAIS E MÉTODOS: Em 27 pacientes portadores de câncer de pulmão foi feito planejamento 3D e outro correspondente em 2D. As doses prescritas variaram de 45 a 66 Gy. Foram avaliadas as doses no volume alvo planejado (PTV), volume tumoral macroscópico (GTV) e pulmões (volume de pulmão que recebe 20 Gy ou 30 Gy - V20 e V30, respectivamente, e dose média). Os órgãos de risco adjacentes (medula espinhal, esôfago e coração) receberam doses abaixo dos limites de tolerância. RESULTADOS: O GTV variou de 10,5 a 1.290,0 cm³ (média de 189,65 cm³). Nos planejamentos 2D foi utilizado, em média, um total de 59,33 campos, e nos planejamentos 3D, 75,65 campos. Em todas as situações analisadas houve significante (p < 0,05) preservação dos volumes pulmonares com o planejamento 3D, com diminuição de cerca de 15 por cento dos volumes irradiados. O pulmão sem tumor foi mais beneficiado. CONCLUSÃO: A radioterapia 3D permitiu maior preservação dos pulmões, tanto para tumores iniciais quanto avançados. A radioterapia 3D deve ser utilizada nos pacientes com tumores de pulmão, mesmo que volumosos.

OBJECTIVE: To compare and quantify irradiated lung volumes using two-dimensional (2D) and three-dimensional (3D) conformal planning for radiotherapy in the treatment of lung cancer. MATERIALS AND METHODS: 2D and 3D conformal radiotherapy plannings were performed for 27 patients with lung cancer. Prescribed doses ranged from 45 to 66 Gy. The analysis covered the doses to planning target volume (PTV), gross tumor volume (GTV) and lungs (lung volume receiving 20 Gy or 30 Gy - V20 and V30, respectively, and mean dose). The doses to adjacent organs at risk (spinal cord, esophagus and heart) were maintained below the tolerance limits. RESULTS: GTV ranged from 10.5 to 1,290.0 cm³ (mean, 189.65 cm³). On average, a total of 59.33 fields were utilized in the 2D planning and 75.65 fields in the 3D planning. Lung volumes were significantly preserved (P < 0.05) with the 3D conformal planning in all the evaluated cases, with about 15 percent decrease in the irradiated lung volumes. Lungs without tumor were most benefited from this technique. CONCLUSION: 3D radiotherapy allowed a better sparing of the lungs, both in cases of early and advanced tumors. 3D radiotherapy should be used in the treatment of patients with lung cancer, even in cases of large tumors.

Relationship between waist to hip ratio and static lung volumes in adults / 中国病理生理杂志

AIM: The study is designed to probe for the relationship between waist to hip ratio(WHR)and static lung volumes of adults. METHODS: In July-October 2008, 1 307 healthy adults(372 males and 935 females)were selected in Heilongjiang province by means of questionnaire and physical examination. The height, weight, WHR, fat mass, percentage body fat and lung function were measured, and then grouped according to the standard of classification of WHR(central obesity male WHR ≥ 0.86, female ≥ 0.82)for analysis of the relationship between WHR and static lung volume. RESULTS: WHR was found, regardless of sex, to tend to go up with the increase in age and BMI(P<0.01), and both the fat mass and percentage body fat of the central obesity group were higher than those in the group with normal WHR(P<0.01). An independent negative correlation was found(P<0.05), also regardless of sex, between the WHR with expiratory reserve volume(ERV)in all these adults. ERV in central obesity group was lower than that in the group with normal WHR(P<0.05). Compared to the normal group, ERV in the central obesity group decreased by 11% for males and 8% for females(P<0.05). However, with regard to the relationship between WHR and VT, IC, MV, and VC, gender differences were found. For the males, a significant independent positive correlation was observed between WHR and IC(P<0.05), with IC of the central obesity group 6% higher than that in the group with normal WHR(P<0.05). For the females, significant independent positive correlation was found between WHR and MV(P<0.05), with the VT and MV of the central obesity group 7% and 6% higher(P<0.05), respectively, than that in the group with normal WHR. CONCLUSION: WHR is in an independent negative correlation with ERV. The elevation of WHR may play a role in the impairment of respiratory function. Its occurrence is accompanied by a rise of IC for the male and a rise of MV for the female. These changes in the two genders could be associated with the decrease in arterial oxygen tension caused by the decrease of ERV.

Volúmenes pulmonares normales en pacientes con fibrosis pulmonar idiopática y enfisema / Normal lung volumes in patients with idiopathic pulmonary fibrosis and emphysema

La fibrosis pulmonar idiopática (FPI) es una enfermedad que se caracteriza por presentar un compromiso pulmonar de tipo restrictivo, resultante de una reducción en la complacencia pulmonar secundaria a fibrosis difusa. En el enfisema, la pérdida de elasticidad pulmonar y el colapso de las vías aéreas periféricas generan obstrucción e hiperinflación. El efecto simultáneo que ambas enfermedades producen sobre la fisiología pulmonar no es del todo claro y se han descripto volúmenes pulmonares normales o casi normales. Presentamos 4 pacientes de sexo masculino de 64, 60, 73 y 70 años, con antecedentes de tabaquismo e historia de disnea progresiva, tres de ellos con grave limitación en su calidad de vida al momento de la consulta. En la tomografía de tórax de alta resolución todos los pacientes presentaban signos de enfermedad intersticial pulmonar avanzada, con cambios de tipo fibrótico con predominio basal y subpleural, que coexistían con enfisema centroacinar con predominio en lóbulos superiores. Uno de ellos tuvo confirmación diagnóstica de ambas condicioes por biopsia pulmonar a cielo abierto. En los cuatro pacientes la espirometría y volúmenes pulmonares fueron normales, pero tenían importante compromiso del intercambio gaseoso evaluado mediante el test de caminata de 6 minutos. Tres de los pacientes tenían hipertensión pulmonar grave diagnosticado por ecocardiograma. La presencia de volúmenes pulmonares normales no excluye un diagnóstico de fibrosis pulmonar idiopática en pacientes fumadores si coexisten evidencias tomográficas de enfisema. En estos pacientes el grado de compromiso funcional, determinado por la reducción de los volúmenes pulmonares, no debería ser considerado en la evaluación de la gravedad.

Pulmonary function tests in idiopathic pulmonary fibrosis characteristically show a restrictive pattern, resulting from reduction of pulmonary compliance due to diffuse fibrosis. Conversely, an obstructive pattern with hyperinflation results in emphysema by loss of elastic recoil, expiratory collapse of the peripheral airways and air trapping. Previous reports suggest that when both diseases coexist, pulmonary volumes are compensated and a smaller than expected reduction or even normal lung volumes can be found. We report 4 male patients of 64, 60, 73 and 70 years, all with heavy cigarette smoking history and progressive breathlessness. Three of them had severe limitation in their quality of life. All four showed advanced lung interstitial involvement, at high resolution CT scan, fibrotic changes predominantly in the subpleural areas of lower lung fields and concomitant emphysema in the upper lobes. Emphysema and pulmonary fibrosis was confirmed by open lung biopsy in one patient. The four patients showed normal spirometry and lung volumes with severe compromise of gas exchange and poor exercise tolerance evaluated by 6 minute walk test. Severe pulmonary arterial hypertension was also confirmed in three patients. Normal lung volumes does not exclude diagnosis of idiopathic pulmonary fibrosis in patients with concomitant emphysema. The relatively preserved lung volumes may underestimate the severity of idiopathic pulmonary fibrosis and attenuate its effects on lung function parameters.

Valor de la espirometría para el diagnostico de restricción pulmonar / Accuracy of spirometry in the diagnosis of pulmonary restriction

Un defecto ventilatorio restrictivo está caracterizado por una reducción en la capacidad pulmonar total. El objetivo de este estudio fue evaluar la utilidad de la espirometría para determinar la presencia de restricción en pacientes con y sin obstrucción bronquial. Fueron incluídos 520 pacientes. Se definieron los valores normales mediante el intervalo de confianza del 95% (IC) utilizando la ecuación de Morris para la espirometría, y la de la European Respiratory Society (ERS) para capacidad pulmonar. Las espirometrías fueron clasificadas como obstructivas cuando mostraban relación volumen espiratorio forzado en 1 segundo (VEF1)/capacidad vital forzada (CVF) < 70% + VEF1 menor al límite inferior por IC. En los pacientes sin obstrucción espirométrica (n = 357) la sensibilidad y especificidad fueron 42.2% y 94.3% respectivamente, el valor predictivo negativo (VPN) fue 86.6% y el VP positivo (VPP) 65.2%. En el grupo de pacientes con obstrucción espirométrica (n = 66) la sensibilidad aumentó al 75.8% con una especificidad de 65.9%. El VPP disminuyó a sólo 57.8% y el VPN fue del 81.5%. Los pacientes con obstrucción y falsos positivos de CVF disminuida (n = 22) tuvieron los mismos valores de CVF (57.36 ± 13.45 vs. 58.82 ± 8.71%, p = 0.6451), de VEF1 (44.73 ± 19.24 vs. 44.0 ± 13.08%, p = 0.8745) y de difusión de monóxido de carbono (DLCO) (67.50 ± 27.23 vs. 77.00 ± 16.00%, p = 0.1299) que los pacientes verdaderos positivos. En conclusión, nuestros datos dan soporte experimental a la recomendación de no interpretar una CV o una CVF disminuida como evidencia de restricción en presencia de una relación VEF1/ CVF disminuida. La definición de defectos "mixtos" en la espirometría es inexacta e inaceptable.

A restrictive ventilatory defect is characterized by a decreased total lung capacity (TLC). The objective of this study was to determine the accuracy of spirometry to detect pulmonary restriction in patients with or without airflow obstruction in the spirometry. Five hundred and twenty patients were included. Normal values for lung function were determined by using the 95% confidence interval (CI) with Morris reference equation for spirometry and European Respiratory Society equation for lung volume. Spirometries were considered obstructive when FEV1/FVC ratio was <70% and FEV1 was below 95%CI. In patients without obstruction in the spirometry (n = 357) sensitivity and specificity were 42.2% and 94.3% respectively, negative predictive value (NPP) was 86.6% and positive PV (PPV) was 65.2%. In patients with an obstructive spirometry (n = 66) sensitivity increased to 75.8% but specificity decreased to 65.9%. PPV was only 57.8% and NPV 81.5%. Patients showing obstruction in the spirometry and false positives of a low FVC (n = 22) had similar values of FVC (57.36 ± 13.45 vs. 58.82 ± 8.71%, p = 0.6451), FEV1 (44.73 ± 19.24 vs. 44.0 ± 13.08%, p = 0.8745) and DLCO (67.50 ±27.23 vs. 77.00 ±16.00%, p = 0.1299) than true positives. Residual volume (RV) (125.72 ± 64. vs. 77.96 ± 29.98%, p = 0.0011) and RV/ TLC ratio (56.89 ± 12.82 vs. 38.43 ± 13.07%, p = <0.0001) were significantly higher. We conclude that a decreased FVC or VC cannot be considered evidence of ventilatory restriction in the presence of airflow obstruction on spirometry. Diagnosis of "mixed defects" by spirometry is inaccurate and should be avoided without the measurement of lung volumes.

Lung Volumes and Diffusing Capacity in Bronchiectasis : Correlation with the Findings of High Resolutional CT / 결핵

BACKGROUND: The patient with bronchiectasis may have obstructive ventilatory impairment combined with mild restrictive ventilatory impairment due to fibrosis of surrounding lung parenchyme and pleural adhesions caused by chronic recurrent pulmonary infections. Since hyperinflation or emphysematous change can be occured in bronchiectasis, pulmonary functions such as lung volumes and diffusing capacity may also vary with associated emphysema. METHODS: For the evaluation of lung volumes and diffusing capacity in bronchiectasis with respect to the anatomic types and severity of bronchiectasis, a total of 40 cases comprising 24 cases of tubular, and 16 cystic type of bronchiectasis were analyzed retrospectively. Correlation between lung functions and extent of bronchiectasis or associated emphysema detected in HRCT were also evaluated. RESULTS: Vital capacity(VC) tended to decrease in cystic type than in tubular type. As the severity of bronchiectasis became serious, the VC were significantly reduced, whereas the total lung capacity(TLC), residual volume(RV) and its ratio to the total lung capacity(RV/TLC) had no significant difference. Lung clearance index(LCI) was significantly increased in cystic type than in tubular type, whereas the slope of phase III in single breath nitrogen curve(deltaN2/L) was not significantly changed regard to the type and severity of bronchiectasis. DLCO and DLCO/VA reflecting diffusing capacity were significantly decreased in cystic type and also as the severity of bronchiectasis became serious. The correlation coefficient of VC, DLCO and LCI with the extent of bronchiectasis were -0.322, -0.339 and 0.487, respectively, whereas other parameters were not significantly correlated with the extent of bronchiectasis. VC and DLCO correlated negatively with the extent of emphysema while RV, RV/TLC, LCI and deltaN2/L correlated positively. CONCLUSION: These findings suggest that the reduction of VC and diffusing capacity or uneven distribution of inspired gas in bronchiectasis are related to both the extent of bronchiectasis and associated emphysema while increased residual volume be related to the extent of associated emphysema alone.

Lung Volumes and Diffusing Capacity in Bronchiectasis : Correlation with the Findings of High Resolutional CT / 결핵

BACKGROUND: The patient with bronchiectasis may have obstructive ventilatory impairment combined with mild restrictive ventilatory impairment due to fibrosis of surrounding lung parenchyme and pleural adhesions caused by chronic recurrent pulmonary infections. Since hyperinflation or emphysematous change can be occured in bronchiectasis, pulmonary functions such as lung volumes and diffusing capacity may also vary with associated emphysema. METHODS: For the evaluation of lung volumes and diffusing capacity in bronchiectasis with respect to the anatomic types and severity of bronchiectasis, a total of 40 cases comprising 24 cases of tubular, and 16 cystic type of bronchiectasis were analyzed retrospectively. Correlation between lung functions and extent of bronchiectasis or associated emphysema detected in HRCT were also evaluated. RESULTS: Vital capacity(VC) tended to decrease in cystic type than in tubular type. As the severity of bronchiectasis became serious, the VC were significantly reduced, whereas the total lung capacity(TLC), residual volume(RV) and its ratio to the total lung capacity(RV/TLC) had no significant difference. Lung clearance index(LCI) was significantly increased in cystic type than in tubular type, whereas the slope of phase III in single breath nitrogen curve(deltaN2/L) was not significantly changed regard to the type and severity of bronchiectasis. DLCO and DLCO/VA reflecting diffusing capacity were significantly decreased in cystic type and also as the severity of bronchiectasis became serious. The correlation coefficient of VC, DLCO and LCI with the extent of bronchiectasis were -0.322, -0.339 and 0.487, respectively, whereas other parameters were not significantly correlated with the extent of bronchiectasis. VC and DLCO correlated negatively with the extent of emphysema while RV, RV/TLC, LCI and deltaN2/L correlated positively. CONCLUSION: These findings suggest that the reduction of VC and diffusing capacity or uneven distribution of inspired gas in bronchiectasis are related to both the extent of bronchiectasis and associated emphysema while increased residual volume be related to the extent of associated emphysema alone.

The effects of water Immersion on dynamic and static pulmonary function at both neck and diaphragm levels in normal subjects / 体力科学

A study was conducted to clarify the influence of water immersion at different levels on pulmonary response. The subjects, ten healthy men (mean age, 26.2±7.9 years), subjected to measurement of static lung volumes and maximum expiratory flow-volume curves while sitting immersed in water at the level of both the neck and diaphragm. TLC, VC, ERV and FRC for water immersion at the diaphragm level were significantly decreased in comparison with those measured in air. These lung volumes were further decreased upon water immersion to neck level. However, RV did not change significantly upon immersion at either water level. Significant decreases of FEV<SUB>1⋅0</SUB>, FEV<SUB>1⋅0</SUB>%, V<SUB>50</SUB> and V<SUB>25</SUB> were observed upon water immersion at the diaphragm level as compared with those obtained in air. Water immersion to neck level produced further decreases in pulmonary functional parameters. Although peak flow and V<SUB>75</SUB> did not change significantly upon water immersion at either level, V<SUB>50</SUB> and V<SUB>25</SUB> were decreased markedly in comparison with the values obtained in air. A tendency for a marked decrease in pulmonary function parameters was observed upon water immersion to neck level. The changes observed upon water immersion to diaphragm level may have resulted from compression of small airways induced by both an increase of blood volume in the thorax and hydrostatic pressure against the abdomen. The changes induced by water immersion to neck level may have been exacerbated by the two mechanisms described above, in addition to hydrostatic pressure on the chest wall. The present results suggest that the significant reduction of pulmonary functional parameters caused by water immersion may be due to compression of small airways induced by an increase of blood volume in the thorax and hydrostatic pressure on the chest wall and abdomen.