Body mass index, obstruction of the airflow, dyspnea, and exercise capacity index as predictor of the severity of exacerbations and systemic involvement in patients with COPD

Background: Allocation of the limited resources to the needed patients and decision making regarding timely interventions demand development of a reliable, cost effective, simple assessment tool. Several studies propose body-mass index, airflow obstruction, dyspnea, and exercise (BODE) index for this purpose in patients with Chronic obstructive pulmonary disease (COPD). The objective of this study was to assess the utility of BODE index to predict the severity of exacerbations and systemic involvement in COPD.Methods: A Present hospital based cross sectional study was carried out among 100 COPD patients. BODE index was used to assess the patients and its association was studied with various variables. The data was analyzed using one-way analysis of variance (ANOVA) test.Results: As the body index class of severity increases, the number of hospitalizations required in the past also increases and this association is statistically significant. As the severity of the disease increased as indicated by the class the mean number of exacerbations in the past increased and this association was found out to be statistically significant. As the severity of the disease increased as indicated by the class level, the mean number of days of hospitalization increased. But this increase was of small difference and hence on one-way ANOVA test was not found out to be statistically significant. As the pack years increases, the BODE index increases significantly (p value <0.001). As the severity of the disease increased, the mean body mass index decreased. Haemoglobin level was found to decrease with increase in BODE index class of severity. This association was statistically significant.Conclusions: The BODE index has been found to be a very good tool to assess the prognosis of COPD as well as severity of acute exacerbations.

Association of metabolic syndrome with the severity of airflow obstruction in patients with chronic obstructive pulmonary disease / Journal of the ASEAN Federation of Endocrine Societies

@#<p><strong>BACKGROUND.</strong> Metabolic Syndrome (MetS) is common in Chronic Obstructive Pulmonary Disease (COPD) patients but their association is still an unsettled issue. The aim of this study was to determine the association of MetS with the severity of airflow obstruction.</p><p><strong>METHODOLOGY.</strong> This was a cross-sectional analytic study of 157 patients with COPD. They were classified using the Global Initiative for Chronic Obstructive Lung Diseases (GOLD). MetS was assessed using two well-recognized criteria. Demographics, clinical data, lifestyle-related characteristics, fasting blood sugar (FBS) and lipid profile were obtained. Multiple logistic regression was used to determine the association of MetS with the severity of airflow obstruction.</p><p><strong>RESULTS.</strong> 40.13% and 17.20% of patients had MetS using the NCEP/ATP III-AHA/NHBLI and IDF criteria, respectively. MetS was not associated with severity of airflow obstruction. Of the MetS components, only elevated blood pressure (BP) was significantly associated with severity of airflow obstruction (GOLD II: OR=3.28, p<0.001; GOLD III: OR=4.04, p=0.2; GOLD IV: OR=6.21, p=0.04). Elevated FBS was also associated with GOLD IV (OR=16.09, p=0.02). Significant factors associated with MetS in COPD patients were body mass index, inhaled steroid, number of pack-years, and GOLD II.</p><p><strong>CONCLUSION.</strong> MetS is not associated with severity of airflow obstruction. Only certain components of MetS showed significant associations such as elevated BP with GOLD II-IV and elevated FBS with GOLD IV.</p>

Associations between airflow obstruction and the risks of morbidity on major chronic diseases in Chinese adults: a prospective cohort study / 中华流行病学杂志

Objective To examine the prospective associations between airflow obstruction (AFO) and risks of major chronic diseases morbidity in Chinese adults.Methods Samples of this study were from the China Kadoorie Biobank.A total of 486 996 participants aged 30 to 79 years (mean 51.5 years) at the baseline study,were included after excluding those who self-reported of having heart disease,stroke and cancer at baseline.AFO was defined under the Global Initiative on Obstructive Lung Disease (GOLD) criteria and forced expiratory volume per one second in percentage of the expected one (FEV1％P).Cox regression models were used to investigate the associations of AFO with incidence rates of ischemic heart disease,cerebrovascular disease and lung cancer after adjusted for potential confounders.Results Over a period of 7 years through the follow-up program,the incident cases of ischemic heart disease,cerebrovascular disease and lung cancer appeared as 24 644,36 336 and 3 218,respectively.Compared with people without AFO,the HR (95％CI) of GOLD-1 to GOLD-4 were 0.89 (0.78-1.01),1.05 (0.98-1.12),1.29 (1.18-1.40) and 1.65 (1.42-1.91) respectively for ischemic heart disease.The HR (95％ CI) of GOLD-1 to GOLD-4 were 0.96 (0.70-1.26),1.12 (0.96-1.31),1.38 (1.14-1.65) and 1.48 (1.05-2.02) respectively for lung cancer.No statistically significant differences in the associations between GOLD level and cerebrovascular disease morbidity were found.However,each 10％ decrease in FEV1％P was associated with 7.2％ (95％CI:6.4％-8.0％),3.6％ (95％CI:3.0％-4.3％) and 10.5％ (95％CI:8.4％-12.6％) increased the risks of ischemic heart disease,cerebrovascular disease and lung cancer respectively.The results were persistant when stratified by smoking status.Conclusion Higher degree of AFO seemed to be associated with the risks of ischemic heart disease,cerebrovascular disease and lung cancer morbidity among the Chinese adults.

Associations between airflow obstruction and the risks of morbidity on major chronic diseases in Chinese adults: a prospective cohort study / 中华流行病学杂志

Objective To examine the prospective associations between airflow obstruction (AFO) and risks of major chronic diseases morbidity in Chinese adults.Methods Samples of this study were from the China Kadoorie Biobank.A total of 486 996 participants aged 30 to 79 years (mean 51.5 years) at the baseline study,were included after excluding those who self-reported of having heart disease,stroke and cancer at baseline.AFO was defined under the Global Initiative on Obstructive Lung Disease (GOLD) criteria and forced expiratory volume per one second in percentage of the expected one (FEV1％P).Cox regression models were used to investigate the associations of AFO with incidence rates of ischemic heart disease,cerebrovascular disease and lung cancer after adjusted for potential confounders.Results Over a period of 7 years through the follow-up program,the incident cases of ischemic heart disease,cerebrovascular disease and lung cancer appeared as 24 644,36 336 and 3 218,respectively.Compared with people without AFO,the HR (95％CI) of GOLD-1 to GOLD-4 were 0.89 (0.78-1.01),1.05 (0.98-1.12),1.29 (1.18-1.40) and 1.65 (1.42-1.91) respectively for ischemic heart disease.The HR (95％ CI) of GOLD-1 to GOLD-4 were 0.96 (0.70-1.26),1.12 (0.96-1.31),1.38 (1.14-1.65) and 1.48 (1.05-2.02) respectively for lung cancer.No statistically significant differences in the associations between GOLD level and cerebrovascular disease morbidity were found.However,each 10％ decrease in FEV1％P was associated with 7.2％ (95％CI:6.4％-8.0％),3.6％ (95％CI:3.0％-4.3％) and 10.5％ (95％CI:8.4％-12.6％) increased the risks of ischemic heart disease,cerebrovascular disease and lung cancer respectively.The results were persistant when stratified by smoking status.Conclusion Higher degree of AFO seemed to be associated with the risks of ischemic heart disease,cerebrovascular disease and lung cancer morbidity among the Chinese adults.

The Airflow Obstruction and Subjective Health Status Among Stable Chronic Obstructive Pulmonary Disease Patients Residing in the Community

PURPOSE: This study was undertaken to examine the relationship between airflow obstruction and subjective health status reported by stable patients with chronic obstructive pulmonary disease (COPD) residing in the community. METHODS: A cross-sectional descriptive study was conducted with 78 stable COPD patients aged 69.7 years old on average and selected by a convenient sampling from an outpatient department of pulmonology in tertiary hospitals. They completed a constructed questionnaire including general characteristics, smoking history, dyspnea by modified medical research council (mMRC) scale, and health status by COPD assessment test (CAT). Anthropometric measurements were performed for body mass index (BMI) and pulse oxymetry for O₂ saturation (Sat O₂). Medical records were reviewed to obtain disease-related characteristics including duration of the disease, cardiovascular comorbidity, and forced expiratory volume in 1 second (FEV₁). Data were analyzed using PASW statistics 20.0. RESULTS: Mean FEV₁% and CAT scores were 55.11% and 17.73, respectively. Those in the lower stage of mMRC showed significantly higher FEV1 and lower CAT. FEV1 and CAT showed significant negative correlations; age and BMI with FEV₁, and Sat O₂ with CAT. CONCLUSION: The findings suggest that the less airway obstruction was, the better health status was, and provide the support for using subjective measures in clinical practices for COPD patients.

Impairment of left ventricular function in patients with mild-to-moderate chronic obstructive pulmonary disease / 中华全科医师杂志

Objective To determine whether the extent of airflow obstruction is associated with left ventricular function in mild-to-moderate chronic obstructive pulmonary disease (COPD) patients.Methods Left ventricle end diastolic volume ( LVEDV ),left ventricle end systolic volume ( LVESV ),left ventricle stroke volume( LVSV),left ventricle ejection fraction( LVEF),heart rate ( HR),cardiac output ( CO) and cardiac index (CI) were measured by ultrasonic cardiogram.Thirty-one patients with chronic bronchitis,42 mild-to-moderate COPD patients and 16 controls with normal lung function were recruited.The relations between the extent of airflow obstruction and the impairment of left ventricular function were analyzed.Results There were no significant differences of LVEDV,LVESV,LVSV,HR,CO or CI between the control and chronic bronchitis groups.LVEDV,LVESV,LVSV,CO and CI of chronic bronchitis group were significantly higher than those of mild-to-moderate COPD group while HR was lower.LVEDV,LVESV,LVSV,CO and CI had a positive correlation with forced expiratory volume in 1 second ( FEV1 ),forced vital capacity (FVC) and FEV1/FVC ratio.And HR had a negative correlation with FEV1 and FEV1/FVC.LVEF was positively correlated with FVC,but not with FEV1 and FEV1/FVC.LVEDV,LVESV,LVSV,HR,CO and CI were linearly related with FEV1.Conclusions Left ventricular function is maintained in chronic bronchitis patients. Left ventricular function,especially left ventricular end diastolic filling,deteriorates among the mild-to-moderate COPD patients.The extent of airflow obstruction may reflect the impairment of left ventricular function in COPD patients.

Manejo de la exacerbación aguda en la enfermedad pulmonar obstructiva crónica / Management of acute exacerbations of chronic pulmonary obstructive disease

La enfermedad pulmonar obstructiva crónica (EPOC), es una causa importante de muerte en países desarrollados (ocupa el cuarto lugar en EUA). Se ha determinado que es tan o más frecuente en los países en desarrollo, es causa de muchas hospitalizaciones y consultas por exacerbación aguda de la enfermedad (EABC). La definición de Anthonisen es la más usada y aceptada, pues señala la presencia de uno o más de los siguientes criterios: incremento en el volumen de la expectoración, cambio de color (purulencia) en el esputo y Empeoramiento de la disnea. El paciente con EPOC puede presentar de una a tres exacerbaciones agudas por año. El número de EABC es un marcador importante de severidad de la condición, pues determina la calidad de vida y mortalidad del paciente. Del 3 a 16% requiere hospitalizarse (más en casos severos). La mortalidad hospitalaria puede llegar a 10% en casos de EPOC severos y mayor si el paciente ingresa a una Unidad de Cuidado Intensivo. La etiología de la EABC es mayoritariamente infecciosa, (hasta el 80%), otras condiciones pueden explicarla, como la embolia pulmonar, neumotórax, insuficiencia cardiaca, fracturas en la caja torácica e infecciones no pulmonares, las cuales se consideran como "gatillos" y pueden coexistir más de uno por vez. A diferencia de la crisis asmática es importante que se realice una radiografía de tórax y una gasometría arterial, en todos los pacientes que acuden a la emergencia. Hasta el 20% de pacientes pueden presentar elevación del PCO2. al administrarles oxígeno, se recomienda usar de preferencia una máscara de venturi con la concentración necesaria para llevar la saturación de hemoglobina alrededor de 90% (86-92%). El uso de un broncodilatador es la elección en estos casos. Lo ideal es administrar un beta agonista de corta acción o un anticolinérgico, y si el paciente no mejora se pueden combinar. La elección...

Chronic obstructive lung disease (COPD) is an important cause of death in industrialized countries (it is the 4th cause of death in the U.S.). This condition is also prevalent in developing countries, in some its frequency may be higher, and it is an important cause of hospitalizations and consultations because of acute exacerbations. The Anthonisen definition is the most widely and accepted instrument for diagnosing COPD exacerbations, pointing out at the presence of one or more of the following: increased sputum volume, change of color of the sputum, and worsening dyspnea. Patients with COPD may develop one to three acute exacerbation episodes per year. The number of these episodes is an important marker for the severity of COPD, since it determines quality of life and the mortality risk. Three to sixteen per cent of affected patients may require hospitalization (this rate may be higher in more severe cases). In-hospital mortality may reach 10% in severe COPD cases, and it becomes increased if the patient is admitted to an intensive care unit. The etiology of acute exacerbations of COPD is mainly because of infections (up to 80%), but other conditions may also account for such exacerbations, such as pulmonary embolism, pneumothorax, heart failure, thoracic trauma (including rib fracture), and extrapulmonary infections, being considered as triggering factors, and they may also coexist. Differently from asthma crisis, it is important to have a chest X-ray film taken and arterial blood gases determinations in every patient presenting to the emergency department with an acute exacerbation of COPD. Up to 20% of patients may present with elevated PCO2. When administering oxygen, it is preferable to use a Venturi mask with an oxygen concentration able to maintain hemoglobin saturation around 90% (86-92%)...

Rehabilitación pulmonar en la enfermedad pulmonar obstructiva crónica / Lung rehabilitation in stable chronic pulmonary obstructive disease

El proceso de rehabilitación pulmonar en la enfermedad pulmonar obstructiva crónica, es un hecho tangible que se encuentra respaldado en las evidencias científicas. Hoy se reconoce claramente que existe reducción de la disnea, incremento de la capacidad para el ejercicio, mejor calidad de vida, menos días de hospitalización y menor uso de los servicios de salud en los pacientes con EPOC que siguen programas de rehabilitación pulmonar.

Lung rehabilitation in chronic obstructive pulmonary disease (COPD) is a tangible fact supported by scientific evidence. Nowadays it is clearly recognized that there is dyspnea reduction, an increase in exercise capacity, better quality of life, and less use of healthcare services in COPD patients undergoing lung rehabilitation programs.

Tracheal collapsibility measured using end-expiratory chest CT in chronic airway disease / 대한내과학회지

BACKGROUND/AIMS: Partial tracheal narrowing can occur during expiration in the normal population. It is not certain whether the trachea collapses more readily in chronic airway disease. We evaluated the tracheal narrowing at end-expiration using computed tomography (CT). METHODS: We investigated 45 patients and 22 normal subjects who underwent high-resolution CT and pulmonary function tests. In each subject, two CT images at the same level of the aortic arch were compared: one at end-inspiration and the other at end-expiration. The cross-sectional area and sagittal diameter of the trachea were measured using a hand-tracing method, using the in-program measuring tools of Medical Image Viewer, and the percentage changes of each value were calculated. RESULTS: Of the 45 patients with chronic airway disease, 21 had chronic obstructive pulmonary disease, 16 had bronchial asthma, and 8 had bronchiectasis. The mean change in the cross-sectional area was 13.3% in the patients and 9.0% in the normal subjects (p0.05). The decrease in tracheal cross-sectional area was greatest in bronchiectasis, while the greatest decrease in sagittal diameter was in bronchial asthma. There was no significant difference in tracheal collapsibility among the disease groups. The percent change in the tracheal cross-sectional area was correlated with the % predicted FVC (r=-0.033, p<0.05) and FEV1 (r= 0.277, p<0.05) in both the patients and normal controls. CONCLUSIONS: The decrease in tracheal cross-sectional area at end-expiration measured using chest CT was greater in chronic airway disease than in normal subjects, and was associated with ventilatory function.

The expressions of matrix metalloproteinase and their inhibitor,and ICAM-1,VCAM-1 in lung tissue associated with COPD / 中国实用内科杂志

Objective To investigate the change of MMP-9,TIMP-1,ICAM-1 and VCAM-1 expression in serum from patients with COPD,as well as the correlation between the expressions of these factors and lung function.Methods Enzyme-linked Immunosorbent Assay(ELISA)was used to determine the levels of MMP-9,TIMP-1,ICAM-1 and VCAM-1 in serum from 58 patients with COPD and 30 samples from healthy donors in order to better understand the correlation between the expression of these factors and airflow obstruction.Results The serum levels of MMP-9,TIMP-1,ICAM-1 and VCAM-1[(128.89?115.84),(228.28?107.13),(203.98?70.37) and (352.98?117.73)?g/L]from patients with COPD were statistically and significantly higher than the control group[(30.65?18.43),(133.69?41.41),(148.35?23.77) and (233.57?36.65)?g/L],P

Levels of interleukin-6 and CRP in patients with chronic obstructive pulmonary disease and its significance / 中国实用内科杂志

Objective To investigate IL-6 and CRP levels,and their relationship with airflow obstruction、frequency of exacerbation in patients with COPD.Methods From Feb.2004 to Jul.2004,sputum and serum specimens were obtained from 54 patients with stable COPD and 10 age-matched healthy controls.The concentrations of sputum IL-6 and serum IL-6 were measured by ELISA.The concentrations of sputum CRP and serum CRP were measured by transmissive heterometric titration.Results (1)Sputum IL-6 levels in COPD patients of all stages were higher than those in controls(P

The Time Responses of Spirometric Values in Response to Single Doses of Inhaled Salbutamol / 결핵

BACKGROUND: An assessment of the presence and the degree of reversibility of airflow obstruction is clinically important in patients with asthma or chronic obstructive pulmonary disease. However, the time responses of spirometric parameters in response to bronchodilator have not been well investigated. METHODS: We studied 15 patients with asthma. Spirometric and mini-Wright peak expiratory flow measurements were performed at 15, 30, 45, and 60 minutes after using single dose(200 micro gram) of inhaled bronchodilator, salbutamol. RESULTS: The mean values of forced expiratory volume in one second(FEV1) and forced vital capicaty(FVC) were significantly increased at 60 minutes after using bronchodilator in comparison to 15 minutes. And peak expiratory flow rate measured by either mass flow sensor or mini-Wright peak flow meter were significantly increased at 45 minutes after using bronchodilator in comparison to 15 minutes. CONCLUSIONS: To appropriate evaluation of the bronchodilator response in patients with reversible airflow limitation, it would be useful measuring either FEV1 or PEF at the later time point 60 or 45 minutes in comparison to 15 minutes after using bronchodilator.

Validity of peak expiratory flow for assessing the presence of airflow obstruction / 대한내과학회지

BACKGROUND: Since there has been strong correlation between peak expiratory flow (PEF) and forced expiratory volume in one second (FEV1), assessing the presence of airflow obstruction by PEF measurements would be useful in general practice, but its usefulness has not been well investigated. We hypothesize that PEF would be practicable for assessing the presence of airflow obstruction. METHODS: PEF measurements were performed mini-Wright peak flow meter in 106 patients (aged 19-82) with a history of asthma or chronic obstructive lung disease. The change in PEF (% predicted value) was compared with the change in FEV1 and forced expiratory volume in one second to forced vital capacity ratio (FEV1/FVC). Airflow obstruction was analyzed according to European Community for Coal and Steel criteria. When defined as an FEV1 and FEV1/FVC ratio both below the 90% confidence interval of predicted values before bronchodilator. RESULTS: Airflow obstruction was observed in 76.4% (81) of patients. Relative operating characteristic analysis showed that an below in PEF of 60% of predicted value gave optimal discrimination between patients with no airflow obstruction and airflow obstruction (the sensitivity and specificity of below 60% of predicted value in detecting FEV1 and FEV1/FVC ratio both below the 90% confidence interval of predicted values were 86.4% and 83.0% respectively, with a positive predictive value of 94.5%) CONCLUSION: Percentage of predicted value in PEF could be used to diagnose airflow obstruction.

Analysis of tidal breathing flow-volume curves in stable COPD patients / 中国实用内科杂志

Objective To investigate the severity of airflow obstruction in stable COPD patients and to assess the effects of salbutamol by analysis of tidal breathing flow-volume curves(TBFV).Methods 61 moderate-to-severve COPD patients and 68 normal controls were performed pulmonary function test and TBFV loops in seated position.Measurements of TBFV loops and spirometry were performed at rest after salbutamol 400 ?g inhalation in 26 COPD patients.Results COPD patients exhibited a significant decrease in FEV_1%、FEV_1/FVC、FEF50% and FEF75%.The fraction of exhaled volume to achieve PTEF to V_(TE)(V_(PTEF)/V_(TE))and the fraction of exhaled time to achieve PTEF to T_(E)(T_(PTEF)/T_(E))were lower than 18%[(12.8?2.7)% and(11.6?2.4)%],and much lower than normals(25.0?3.1)% and(29.5?3.7)%.But peak tidal expiratory flow(PTEF)and peak tidal inspiratory flow(PTIF)were decreased slightly.After salbutamol administration,26 COPD patients exhibited a significant increase in TEF50%(21.5?6.8)% versus(15.6?4.2)%,P

Validity of Peak Expiratory Flow for Assessing Reversible Airflow Obstruction / 결핵

BACKGROUNDS: Assessment of the presence and degree of reversibility of airflow obstruction is clinically important in patients with asthma or chronic obstructive pulmonary disease. The measurement of peak expiratory flow(PEF) is a simple, fast, and cheap method to assess the severity of obstruction and its degree of reversibility. Assessing the reversibility of airflow obstruction by peak expiratory flow(PEF) measurements would be is practicable in general practice, but its usefulness has not been well investigated. We compared PEF and FEV1 in assessing reversibility of airflow obstruction in patients with chronic obstructive pulmonary disease or asthma and developed a practical criterion for assessing the presence of reversibility in general practice. METHODS: PEF measurements were performed (Spirometry) in 80 patients(aged 24-78) with a history of asthma or chronic obstructive lung disease before and after the inhalation of 200 mg salbutamol. The change in PEF was compared with the change in forced expiratory volume in one second(FEV1). Reversible airflow obstruction was analysed analyzed according to American Thoracic Society(ATS) criteria. RESULTS: When defined as a 12% A 12% increase above the prebronchodilator value and a 200ml increase in either FVC or FEV1 reversibility was were observed in 45%(36) of the patients. Relative operating characteristic(ROC) analysis showed that an absolute improvement in PEF of 30l/min gave optimal discrimination between patients with reversible and irreversible airflow obstruction(the sensitivity and specificity of an increase of 30l/min in detecting a 12% increase above the prebronchodilator value and a 200ml increase in either FVC or FEV1 were 72.2% and 72.7% respectively, with a positive predictive value of 68.4%) CONCLUSIONS: Absolute changes in PEF can be used to diagnose reversible airflow obstruction.

Atopy as predictable index of reversibility in chronic airflow obstruction / 천식및알레르기

BACKGROUND: Smoking-related chronic obstructive pulmonary disease and chronic asthmatic bronchitis, which are the most important causes of chronic airflow obstruction (CAO), can occur together in a pat,ient and the prognoses of these two diseases are different each other. OBJECTIVE AND METHOD: To estimate the extent of asthmatic component in patients with CAO and to evaluate the role of atopy as a predictable index for reversibility of airflow obstruction, 89 CAO patients who were older than 40 years were examined retrospectively. RESULT: Only 15 patients (16.8%) showed an increase of >15% in FEV20 to inhaled salbutamol (short-term responder). However, 18 out of 32 patients (56.3%), who were not responded significantly to inhaled bronchodilator and performed a follow-up lung function study, showed an increase of ) 15% in FEV20 to anti-asthmatic therapy including corticosteroid for 3-4 weeks (long-term responder). Peripheral blood eosinophil count only was different between short-term responder and short-term nonresponder, and there was no difference in all of the measurements between short-term responder and long-term responder. However, there were significant differences in smoking, wheezing on auscultation, peripheral blood eosinophil counts, serum total IgE levels, and MAST atopy score between long-term responder and long-term nonresponder. The increase in FEV, following shortor long-term therapy was related to peripheral blood eosinophil counts and MAST atopy score, and it was significantly great,er in patients with high eosinophil counts or high atopy score. CONCLUSION: About 2/3 of patients with CAO who were older than 40 years had an asthmatic component ap atopy may be useful to predict good bronchodilator response to anti-asthmatic therapy.

The Changes of Breathing Pattern Observed During Maximal Exercise Testing in the Patients with Chronic Airflow Obstruction: the Correlation Between the Change of Inspiratory Duty Cycle and the Degree of Airflow Obstruction / 결핵

BACKGROUND: Normal humans meet the increased ventilatory need during exercise initially by the increase of tidal volume (TV) and later by the increase of respiratory frequency (Rf). And the inspiratory duty cycle (Ti/Ttot) is also increased more than 50% for the compensation of the decrease of respiratory cycle provoked by the increase of respiratory frequency. The patients with chronic airflow obstruction show rapid and shallow breathing pattern during exorcise because of the degreased ventilatory capacity and the increased dead space ventilation. However, the studies about the change of inspiratory duty cycle are only a few and there is no literature about the relationship between the change of inspiratory duty cycle and the degree of airflow obstruction. METHODS: The subjects were the twelve patients with chronic airflow obstruction (CAO) and ten normal people. The incremental exercise test was done. The increase of work load was 10 Win CAO group and 25 Win normal control group. The analysis of the results was done by the comparison of the parameters such as minute ventilation (VE), TV, Rf, physiologic dead space (Vd/vt), and inspiratory duty cycle between the two groups. Each parameters were compared after transformation into % control duration base that means dividing the total exercise time into five fractons and % control duration data were obtained at rest, 20%, 40%, 60%, 80%, and max. Statistical analysis was done by repeated measure ANOVA using SAS program. RESULTS: The changes of VE and TV were significantly different between two groups while the change of Rf was not significant. The decrease of Vd/vt was significantly low in CAO group. Ti/Ttot was markedly increased from 38.4+3.0% at rest to 48.6+4.5% at max in normal control group while Ti/Ttot showed little change from 40.5+2.2% at rest to 42.6+3.5% at max. And the change of inspiratory duty cycle showed highly good correlation with the degree of airflow obstruction (FEVl%). (r=0.8151, p<0.05) CONCLUSIONS: The increase of Ti/Ttot during exercise observed in normal humans is absent in the patients with CAO and the change of Ti/TtDt is well correlated with the degree of airflow obstruction.

The role of the pulmonary function test and the exercise test for assessing impairment/disability in patients with chronic airflow obstruction / 결핵

BACKGROUND: In 1980, WHO made a definition in which the term "impairment" as applied to the respiratory system is used to describe loss of lung function, "disability" the resulting diminution in exercise capacity. The measurement of pulmonary function during exercise would give us information about overall functional capacity and respiratory performance that would be lacking in tests performed at rest. We conducted this study to investigate the role of resting pulmonary function test and exercise test for assessing impairment/disability in patients with chronic airflow obstruction(CAO). METHOD: We studied 19 patients with CAO. The spirometry and body plethysmograph were performed in stable condition. And then patients performed a progressive incremental exercise test to a symptom-limited maximum using cycle ergometer. Patients were divided in two groups, severe and non-severe impairment, according to the resting PFTs and compaired each other. A patient was considered to be severely impaired if FVC < 50%, FEV1 < 40% or FEV1/FVC < 40%. RESULTS: 1) The airway obstruction and hypoxemia of severe impairment group were more severe and exercise performance was markedly reduced compairing to non-severe impairment group. 2) The severe impairment group showed ventilatory limitation during exercise test and the limiting symptomes ware dyspnea in 9/10 patients. 3) The impairment and disability of the patients with tuberculous destructed lung were most marked in patients with CAO. 4) The FEV1 was the most prevalent criterion for the determination of severe impairment based on resting PFTs and was the varuable best correlated to VO2max(r=0.8l, p < 0.001). 5) The sensitivity of exercise limits for predicting severe disability according to resting PFTs was 80% and specificity 89%. CONCLUSION: In patients with severe CAO, FEV1 is a good predictive of exercise performance and impairment measured by resting PFTs can predict a disability by exercise test.