Diagnosis Of Obstructive Lung Disease Research Articles

Clinical Manifestations of Subjects With the Non-Specific Pulmonary Function Test Pattern

IntroductionNon-specific pattern (NSP) is a subgroup of preserved ratio impaired spirometry (PRISm) that requires a normal total lung capacity measurement. NSP has been historically classified as being an obstructive lung disease pattern. There has been heightened interest and investigation into PRISm recently as it has been associated with an increased likelihood of developing chronic obstructive pulmonary disease (COPD). Given the inherent challenges of understanding the clinical significance of the NSP, the aim of this study was to further explore the clinical characteristics of patients with this pulmonary function test pattern. Material and methodsWe identified 111 and 79 subjects using pre-bronchodilator (pre-BD) and post-bronchodilator (post-BD) values, respectively, that met criteria for NSP. The outpatient medical records were retrospectively reviewed for associated diagnoses that were then clustered into ‘obstructive’ or ‘non-obstructive’ groups based on the treating physician's primary pulmonary clinical diagnosis. ResultsWithin this NSP cohort, cough, wheezing and sputum production were documented more frequently in those with an obstructive lung disease diagnosis. Whether identified using pre-BD or post-BD spirometric values, those with NSP and a positive BD response were more likely to carry an obstructive lung disease diagnosis. ConclusionApproximately one third of patients with NSP in this study were not given an obstructive lung disease diagnosis by their clinician, which supports the classification of NSP as not an exclusively obstructive lung disease pattern. However, the presence of supporting clinical symptoms, such as cough with sputum production and wheeze, and/or a positive BD response on PFT, support a diagnosis of obstruction in patients with NSP.

Abstract 15304: Apical Ballooning Syndrome in the Setting of Severe Chronic Obstructive Pulmonary Disease Exacerbation

Apical ballooning syndrome (ABS), also known as Takotsubo cardiomyopathy, is a form of acute dilated cardiomyopathy associated with excessive catecholamine release. A 74-year-old female, chronic smoker with previously diagnosis of obstructive lung disease presented in the emergency department with severe shortness of breath and increase sputum production for the last 24hr. The patient was diagnosed with severe COPD exacerbation and received multiple doses of albuterol, methylprednisolone, ipratropium bromide/albuterol, and azithromycin. Despite this, the patient remained tachypneic and tachycardic with signs of impending respiratory failure. She was transferred to the ICU and intubated. After intubation, the patient received a continuous albuterol nebulizer, methylprednisolone, and ceftriaxone. A few hours later, the patient complained of chest pain, and EKG was done showing T wave inversion in lateral leads, troponin levels were 1.08 ng/mL (ULN 0.12ng/mL), and 2D Echo showed EF 50-55%, apical ballooning with dyskinesia, and inferior wall hypokinesis. Left heart catheterization showed non-obstructive coronary artery disease with 50% stenosis on the left anterior descending artery and distal ostial artery. Based on the previously recommended criteria, the diagnosis of the ABS was made. The patient had resolution of symptoms and echocardiogram findings after follow up. Although albuterol acts mainly on beta-2 receptors, cross-activation of beta-1 receptors can potentially lead to tachycardia. Previous case reports also support that excessive albuterol use in cases of asthma and COPD exacerbation may lead to ABS. This case may raise awareness that the extensive use of albuterol could have dramatic effects. Early switch to beta-2 agonist with higher specificity such as levalbuterol could be a reasonable approach in patients with severe COPD exacerbation.

Spirometric surveillance of obstructive lung diseases

Obstructive Lung Disease (OLD) becomes global health issues that influencing the physical health and economic conditions of people. Chronic Respiratory Disease (CRD) is the disease of airways characterized by obstruction and influencing the structure of the lungs. It includes chronic bronchitis, COPD, emphysema and asthma. The most common disease is Chronic Obstructive Pulmonary Disease (COPD). The major causes of COPD involve exposure to an irritant that damage the lungs and airways that can cause such disease.1):Assess the prevalence of OLD among the patients admitted to general medical wards using spirometry; 2): Use a symptom questionnaire for screening patients with OLD and compare it with Spirometry; 3): Association of various medical co-morbidities with the diagnosis of OLD.The screening for OLDs and factors that are influencing it along with co morbidities were analyzed. This is a descriptive study conducted on patients admitted to general medical wards in hospital of South India for a period of 2 years. The study has involved the patients who are admitted in general wards and aged > 40 years.The physician diagnosis of OLD at admission was in 21 out of 144 patients. It was by symptom alone in 11% (16 of 144 patients) and based on spirometry in 3.48% (5 of 144) only. During the hospitalization the diagnosis of OLD increased by 2.08% (3 of 144) on the basis of symptom alone and 1.4% (2 of 144) by spirometry, cumulatively by 3.48% (5 of 144). Therefore, at admission about 14.48% were diagnosed to have OLD. An ROC curve was plotted and the area under the curve was 0.77 95% CI (0.688 — 0.865). By ROC coordinates a cut off of 15.5 for detecting OLDs showed a sensitivity and specificity of 71% and 78% respectively with a positive predictive value of 56% and negative predictive value of 87%.With the additional yield of Spirometry and association of medical comorbidities can help identify the conditions of patients earlier and pave way for offering appropriate holistic treatment.

Non-Invasive Early Diagnosis of Obstructive Lung Diseases Leveraging Machine Learning Algorithms

Lungs are a vital human body organ, and different Obstructive Lung Diseases (OLD) such as asthma, bronchitis, or lung cancer are caused by shortcomings within the lungs. Therefore, early diagnosis of OLD is crucial for such patients suffering from OLD since, after early diagnosis, breathing exercises and medical precautions can effectively improve their health state. A secure non-invasive early diagnosis of OLD is a primordial need, and in this context, digital image processing supported by Artificial Intelligence (AI) techniques is reliable and widely used in the medical field, especially for improving early disease diagnosis. Hence, this article presents an AI-based non-invasive and secured diagnosis for OLD using physiological and iris features. This research work implements different machine-learning-based techniques which classify various subjects, which are healthy and effective patients. The iris features include gray-level run-length matrix-based features, gray-level co-occurrence matrix, and statistical features. These features are extracted from iris images. Additionally, ten different classifiers and voting techniques, including hard and soft voting, are implemented and tested, and their performances are evaluated using several parameters, which are precision, accuracy, specificity, F-score, and sensitivity. Based on the statistical analysis, it is concluded that the proposed approach offers promising techniques for the non-invasive early diagnosis of OLD with an accuracy of 97.6%.

Underdiagnosis of obstructive lung disease: findings from the French CONSTANCES cohort

BackgroundThe burden of undiagnosed obstructive lung disease (OLD) (mainly asthma and chronic obstructive pulmonary disease) is not fully established, and targets for corrective action are yet to be identified. We assessed the underdiagnosis of OLD and its determinants in France.MethodsCONSTANCES is a French population-based cohort of adults aged 18–69 years at inception. We analysed data collected at inclusion in 2013–2014. Undiagnosed OLD was defined as spirometry-confirmed airflow limitation (FEV1/FVC < lower limit of normal) without prior diagnosis of asthma, chronic obstructive pulmonary disease, or bronchiectasis. Multivariate analysis was performed with weighted robust Poisson regression models to estimate the adjusted prevalence ratios (aPR) of undiagnosed OLD.ResultsSpirometry results were available for 19,398 participants. The prevalence of airflow limitation was 4.6%. Overall, 64.4% of adults with airflow limitation did not report a previous diagnosis of OLD. Individuals with high cumulative tobacco consumption (≥ 10 pack-years) (aPR: 1.72 [1.28–2.32]), without respiratory symptoms (aPR: 1.51 [1.28–1.78]), and with preserved lung function (aPR: 1.21 [1.04–1.41] for a 10-point increase in FEV1% predicted) had a higher risk of being undiagnosed. Half of symptomatic individuals with airflow limitation (45% of those with moderate to severe airflow limitation) were undiagnosed with OLD.ConclusionUnderdiagnosis of OLD is very common among French adults, even in patients with respiratory symptoms. Efforts should be made in France to raise awareness about OLD in the general population, improve the detection of respiratory symptoms, and increase the use of spirometry among primary care professionals.

Design and Development of Smartphone-Enabled Spirometer With a Disease Classification System Using Convolutional Neural Network

Spirometry is one of the most basic of pulmonary function tests, and the measurements of this test, such as forced vital capacity, forced expiratory volume in the first second, and peak expiratory flow, play an important role in the diagnosis of obstructive lung diseases, such as chronic obstructive pulmonary disease and asthma. The lack of point-of-care, primary care, and personalized applications prohibits individuals from monitoring their own lung conditions beyond the hospital visit. This article presents the design and development of a low-cost, portable, smartphone-enabled spirometer with an automatic disease classification system based on the spirometric signal using the convolutional neural network. The classification model was trained using data, stored in the device, and the best model was extracted with an accuracy of 98.98%, which outperforms other classification models, such as long short-term memory network, deep belief network, and stacked autoencoder. The pretrained model has been imported in the smartphone device for real-time classification of spirometry.

Comparison of Forced and Slow Vital Capacity Maneuvers in Defining Airway Obstruction.

Obstructive lung disease is diagnosed by a decreased ratio of FEV1 to the vital capacity (VC). Although the most commonly used VC is FVC, American Thoracic Society guidelines suggest alternative VCs, for example, slow VC (SVC), may offer a more-accurate evaluation of breathing capacity. There is recent evidence that using only FEV1/FVC underrecognizes obstruction in subjects at high risk and who are symptomatic. Previous studies have indicated that healthy individuals show a minimum difference between FVC and SVC; however, testing of individuals with asthma and who are symptomatic indicates that SVC can be markedly larger than FVC. To evaluate the differences among SVC, FVC, and SVC-based measurements in the diagnosis of symptomatic obstructive lung disease. A retrospective analysis was performed of spirometry and plethysmography measurements from studies conducted between 2011 to 2015. We established a pulmonary function database that incorporated predictive equations from the National Health and Nutrition Examination Survey III (NHANES III). The SVC to FVC difference was calculated. FEV1/SVC was compared with FEV1/FVC by using NHANES III lower limit of normal values. A total of 2,710 studies with 2,244 subjects were reviewed. Spirometric obstruction, as defined by NHANES III, was identified in 26.1% of the studies (707/2,710). The mean (± SD) difference between SVC and FVC was 375.0 ± 623.0 mL and 258.8 ± 532.5 mL in those with and those without obstruction, respectively. Subgroup and multivariate analysis demonstrated age, body mass index, and FEV1 associated contributions to the difference between SVC and FVC. By using FEV1/SVC, the prevalence of obstruction increased from 26.1 to 45.0% (1,219/2,710) and identified 566 additional studies of subjects with obstruction. Fifty-four percent of the subjects with newly-identified obstructive lung disease (305/566) had smoking histories, and 67.4% (345/512) received medications for obstructive lung disease. The isolated use of FVC-based diagnostic algorithms did not recognize individuals with symptomatic obstructive lung disease. Recognizing the difference between SVC and FVC measurements in subjects will improve testing and diagnosis of obstructive lung disease.

Accuracy of diagnosis of COPD and factors associated with misdiagnosis in primary care setting. E-DIAL (Early DIAgnosis of obstructive lung disease) study group.

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide and results in both substantial and increasing socioeconomic burden. Guidelines on COPD encourage primary care physicians to detect the disease at an early stage. Our main aim was to evaluate the accuracy of the diagnosis of COPD at the primary health care. 6466 patients were randomly selected in 22 Italian primary care practices (46% males, mean age 56 ± 16 years) and were asked about respiratory symptoms and risk for any chronic respiratory disease including COPD. After a prior evaluation, 701 patients (51% males, mean age 59 ± 15 years) were sent by General Practitioners (GPs) to Pulmonary Units (PU) for confirming the diagnosis. The agreement in diagnosing COPD between GPs and pulmonary diseases specialists was assessed by using Cohen's kappa (k) statistic. Lack of precision in COPD diagnosis resulted in 13% of over-diagnosis and 59% of under-diagnosis. GPs were quite good in correctly excluding the patients who did not have COPD (specificity = 87%), but less good in diagnosing the patients with COPD (sensitivity = 41%). The risk of under-diagnosis was higher in people with age >62 years and in current/ex-smokers, when compared to no COPD, whereas it was higher in subject <62 years old and in those with no previous spirometry when compared to correctly diagnosed COPD. Our results confirm that COPD misdiagnosis is common in primary care and that under-diagnosis is a major problem. It is necessary to enhance COPD diagnosis and to reduce misdiagnosis in primary care settings.

Artificial intelligence in diagnosis of obstructive lung disease: current status and future potential.

The application of artificial intelligence in the diagnosis of obstructive lung diseases is an exciting phenomenon. Artificial intelligence algorithms work by finding patterns in data obtained from diagnostic tests, which can be used to predict clinical outcomes or to detect obstructive phenotypes. The purpose of this review is to describe the latest trends and to discuss the future potential of artificial intelligence in the diagnosis of obstructive lung diseases. Machine learning has been successfully used in automated interpretation of pulmonary function tests for differential diagnosis of obstructive lung diseases. Deep learning models such as convolutional neural network are state-of-the art for obstructive pattern recognition in computed tomography. Machine learning has also been applied in other diagnostic approaches such as forced oscillation test, breath analysis, lung sound analysis and telemedicine with promising results in small-scale studies. Overall, the application of artificial intelligence has produced encouraging results in the diagnosis of obstructive lung diseases. However, large-scale studies are still required to validate current findings and to boost its adoption by the medical community.

Preschool Multiple-Breath Washout Testing. An Official American Thoracic Society Technical Statement.

Obstructive airway disease is nonuniformly distributed throughout the bronchial tree, although the extent to which this occurs can vary among conditions. The multiple-breath washout (MBW) test offers important insights into pediatric lung disease, not available through spirometry or resistance measurements. The European Respiratory Society/American Thoracic Society inert gas washout consensus statement led to the emergence of validated commercial equipment for the age group 6 years and above; specific recommendations for preschool children were beyond the scope of the document. Subsequently, the focus has shifted to MBW applications within preschool subjects (aged 2-6 yr), where a "window of opportunity" exists for early diagnosis of obstructive lung disease and intervention. This preschool-specific technical standards document was developed by an international group of experts, with expertise in both custom-built and commercial MBW equipment. A comprehensive review of published evidence was performed. Recommendations were devised across areas that place specific age-related demands on MBW systems. Citing evidence where available in the literature, recommendations are made regarding procedures that should be used to achieve robust MBW results in the preschool age range. The present work also highlights the important unanswered questions that need to be addressed in future work. Consensus recommendations are outlined to direct interested groups of manufacturers, researchers, and clinicians in preschool device design, test performance, and data analysis for the MBW technique.

Multicenter study of the COPD-6 screening device: feasible for early detection of chronic obstructive pulmonary disease in primary care?

Background and aimEarly detection of COPD may reduce the future burden of the disease. We aimed to investigate whether prescreening with a COPD-6 screening device (measuring FEV1 and FEV6) facilitates early detection of COPD in primary care.MethodsIn primary care, individuals at high risk of COPD (ie, age ≥35 years, relevant exposure, and at least one respiratory symptom) and no previous diagnosis of obstructive lung disease were examined with a COPD-6 screening device. In prioritized order, the criteria for proceeding to confirmatory spirometry were FEV1/FEV6 <0.7, FEV1 <80%pred, or clinical suspicion of COPD regardless of test result (medical doctor’s [MD] decision). Based on spirometry, including bronchodilator (BD) reversibility test, individuals were classified as COPD (post-BD FEV1/FVC <0.70), asthma (ΔFEV1 ≥0.50 L), or no obstructive lung disease.ResultsA total of 2,990 subjects (54% men, mean age 59 years, and mean 28 pack-years) were enrolled, of whom 949 (32%) proceeded from COPD-6 screening to confirmative spirometry based on the following criteria: 510 (54%) FEV1/FEV6 <0.70, 382 (40%) FEV1 <80%pred, and 57 (6%) MD decision. Following confirmative spirometry, the 949 individuals were diagnosed as having COPD (51%), asthma (3%), and no obstructive lung disease (45%). COPD was diagnosed in 487 (16%) of the enrolled subjects in whom confirmative spirometry was performed in 69% based on FEV1/FEV6 <0.7 and in 29% based on FEV1 ≤80%pred.ConclusionPrescreening with the COPD-6 device showed acceptable specificity for the selection of subjects for diagnostic spirometry and is likely to be a useful alternative to current practice in primary care.

Lung Transplantation in Germany Since the Introduction of the Lung Allocation Score.

The allocation of donor lungs for transplantation in Germany was changed on 10 December 2011 to a system based on the Lung Allocation Score (LAS). The aim of the present study is to determine whether this change has prolonged the survival of patients on the transplant waiting list and of those who have undergone lung transplantation (LTx). We retrospectively compared data from the three-year periods before and after the change to an LAS-based allocation system (2009-2011 vs. 2012-2014). The number of patients on the active waiting list declined from 606 on 12/31/2011 to 432 on 12/31/2014, a 29% decrease. The number of patients who died while on the waiting list fell from 306 in 2009-2011 to 226 in 2012-2014 (-26%, p = 0.04). Waiting-list mortality declined across all disease groups. Meanwhile, the number of lung transplantation procedures per year increased by 21% over the period of observation, from 865 to 1045. During the period in which the LAS was used, the proportion of transplant recipients with restrictive lung disease (46% vs. 31%; p<0.001) surpassed the proportion of those with a diagnosis of obstructive lung disease (33% vs. 40%; p = 0.003). The percentage of transplantations in patients treated with mechanical ventilation or extracorporeal respiratory support before transplantation rose from 9% to 13%. The one-year survival rate after lung transplantation was 76% in 2009-2011 and 81% in 2012-2014. The introduction of the LAS in Germany was associated with a decrease in the number of patients on the waiting list, and also in the number of deaths among patients on the waiting list. The distribution of primary diagnoses among transplant recipients shifted away from obstructive and toward restrictive lung diseases. In the future, additional parameters of patients on the waiting list should be considered to enable further improvement of the allocation model.

Identifying possible asthma\u2013COPD overlap syndrome in patients with a new diagnosis of COPD in primary care

The asthma–chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) remains poorly characterised. Our aim was to describe an algorithm for identifying possible ACOS in adults with newly diagnosed COPD in primary care. General practitioners (n=241) consecutively recruited subjects ⩾35 years, with tobacco exposure, at least one respiratory symptom and no previous diagnosis of obstructive lung disease. Possible ACOS was defined as chronic airflow obstruction, i.e., post-bronchodilator (BD) forced expiratory volume 1/forced vital capacity (FEV1/FVC) ratio<0.70, combined with wheeze (ACOS wheeze) and/or significant BD reversibility (ACOS BD reversibility). Of 3,875 (50% females, mean age 57 years) subjects screened, 700 (18.1%) were diagnosed with COPD, i.e., symptom(s), tobacco exposure and chronic airflow obstruction. Indications for ACOS were found in 264 (38%) of the COPD patients. The prevalence of ACOS wheeze and ACOS BD reversibility was 27% (n=190) and 16% (n=113), respectively (P<0.001), and only 6% (n=39) of the COPD patients fulfilled both criteria for ACOS. Patients with any ACOS were younger (P=0.04), had more dyspnoea (P<0.001), lower FEV1%pred (67% vs. 74%; P<0.001) and lower FEV1/FVC ratio (P=0.001) compared with COPD-only patients. Comparing subjects fulfilling both criteria for ACOS with those fulfilling criteria for ACOS wheeze only (n=151) and those fulfilling criteria for ACOS BD reversibility only (n=74) revealed no significant differences. Irrespective of the applied ACOS definition, no significant difference in life-time tobacco exposure was found between ACOS- and COPD-only patients. In subjects with a new diagnosis of COPD, the prevalence of ACOS is high. When screening for COPD in general practice among patients with no previous diagnosis of obstructive lung disease, patients with possible ACOS may be identified by self-reported wheeze and/or BD reversibility.

A new diagnosis of asthma or COPD is linked to smoking cessation - the Tromsø study.

BackgroundPatients with COPD have had a lower tendency to quit smoking compared to patients with coronary heart disease (CHD). We wanted to investigate if this is still true in a Norwegian population.MethodsOur data came from the fifth and sixth Tromsø surveys, which took place in 2001–2002 and 2007–2008. The predictors of smoking cessation were evaluated in a cohort of 4,497 participants who had stated their smoking status in both surveys.ResultsOf the 4,497 subjects in the cohort, 1,150 (25.6%) reported daily smoking in Tromsø 5. In Tromsø 6, 428 had quit (37.2%). A new diagnosis of obstructive lung disease (asthma or COPD) and CHD were both associated with increased quitting rates, 50.6% (P=0.01) and 52.1% (P=0.02), respectively. In multivariable logistic regression analysis with smoking cessation as outcome, the odds ratios (ORs) of a new diagnosis of obstructive lung disease and of CHD were 1.7 (1.1–2.7) and 1.7 (1.0–2.9), respectively. Male sex had an OR of 1.4 (1.1–1.8) compared to women in the multivariable model, whereas the ORs of an educational length of 13–16 years and ≥17 years compared to shorter education were 1.6 (1.1–2.2) and 2.5 (1.5–4.1), respectively.ConclusionThe general trend of smoking cessation in the population was confirmed. Increased rates of smoking cessation were associated with a new diagnosis of heart or lung disease, and obstructive lung disease was just as strongly linked to smoking cessation as was CHD. This should encourage the pursuit of early diagnosis of COPD.

Trends in hospital admissions for obstructive lung disease from 2000 to 2010 in Portugal

The burden of hospitalisations for obstructive lung diseases (OLD) has not been sufficiently studied. We aimed to characterise the hospitalisations for OLD from 2000 to 2010 in all Portuguese public hospitals. We analysed hospital discharges with a diagnosis of OLD regarding the patients’ gender, age, residence and comorbidities. Of the 120 399 hospital admissions with a principal diagnosis of OLD, COPD (ICD-9-CM 491.x, 492.x, 496) was responsible for 81%. The change in patients discharged with OLD as a principal diagnosis was only 1% from 2000 to 2010 and did not change for COPD. Hospital admissions and deaths for COPD and other OLD increased with age and were more common in men than women. In-hospital mortality for COPD decreased 34.1% from 2000 to 2010, while the median length of stay was fairly constant at 8 days. Respiratory failure, insufficiency and/or arrest, and pneumonia, are the principal diagnoses often associated with COPD. When both pneumonia and COPD were diagnosed there was an increasing trend to classify pneumonia as the principal diagnosis (64.4%–72.9%), a sign that may lead to underestimation of COPD hospitalisations. In summary, a considerable decrease in in-hospital COPD mortality was observed while hospital admissions and the length of stay did not change substantially. These results suggest that better healthcare or other factors may be counteracting the expected increase of the burden of COPD.

Pulmonary Function Testing and Role of Pulmonary Rehabilitation in the Elderly Population with Pulmonary Diseases

With an aging population worldwide, the incidence and prevalence of certain pulmonary conditions such as chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) are increasing. Pulmonary function tests (PFTs) are helpful tools to confirm pulmonary disorders. However, in the elderly population, age-associated changes in PFTs increase the risk for over diagnosis of obstructive lung disease. Therefore, an individualized approach to diagnosis of pulmonary disorders is essential for optimal management. For patients with established pulmonary disorders, pulmonary rehabilitation is a valuable but underutilized therapeutic intervention which has been shown to improve patient’s quality of life, exercise tolerance, and overall prognosis. Recent evidence confirms that benefits of pulmonary rehabilitation are similar between the elderly and younger populations.

Clinical Utility of Additional Measurement of Total Lung Capacity in Diagnosing Obstructive Lung Disease in Subjects With Restrictive Pattern of Spirometry.

Total lung capacity (TLC), forced expiratory flow between 25 and 75% (FEF25-75%), peak expiratory flow (PEF), or post-bronchodilator volume response is recommended to detect obstructive abnormalities in the lung. The present study was performed to evaluate the usefulness of these pulmonary function test (PFT) parameters to diagnose obstructive lung disease in subjects with a restrictive pattern of spirometry. A retrospective study was conducted in 64 subjects with a restrictive pattern of spirometry (normal FEV1/FVC and low FVC) out of 3,030 patients who underwent all pre- and post-bronchodilator spirometry and lung volume measurement between April 2008 and December 2010. After subjects were clinically classified into those with obstructive lung disease, restrictive lung disease, and mixed lung disease, the agreements between the clinical diagnosis and PFT classification according to TLC, FEF(25-75%), PEF, and post-bronchodilator response criteria were compared. Of 64 subjects, 18 (28.1%) were classified with obstructive lung disease, 39 (60.9%) had restrictive lung disease, 1 (1.6%) had mixed lung disease, and 6 (9.4%) had no clinical lung disease. Among the 58 subjects with clinical lung disease, 22 (37.9%), 37 (63.8%), 33 (56.9%), and 3 (5.2%) were classified as having obstructive pattern based on TLC, FEF25-75%, PEF, and post-bronchodilator response criteria, respectively. The kappa coefficients for the agreement between the clinical classification and PFT classification using TLC, FEF25-75%, PEF, and post-bronchodilator response criteria in 58 subjects were 0.59, 0.18, 0.17, and < 0.01, respectively. The additional measurement of TLC is more useful than FEF25-75%, PEF, and post-bronchodilator response for diagnosis of obstructive lung disease in subjects with a restrictive pattern of spirometry, when obstructive lung disease is clinically suspected.

Obstructive Lung Disease in Mexican Americans and Non-Hispanic Whites: An Analysis of Diagnosis and Survival in the National Health and Nutritional Examination Survey III Follow-up Study

Although obstructive lung disease (OLD), which includes COPD, affects all the populations, Hispanics seem to be protected against COPD development and progression. Whether this advantage translates into a survival benefit for this population is unknown. We aimed to determine the risk for OLD in Mexican Americans, the largest US Hispanic subgroup, compared with non-Hispanic whites and to assess all-cause mortality in subjects with OLD. We assessed the relationships between Mexican American ethnicity and spirometric OLD and risk of death among 6,456 US adults aged ≥ 40 years who participated in the Third National Health and Nutritional Examination Survey Follow-up Study. We used logistic and Cox regression analyses to estimate the OR for OLD among Mexican Americans and the hazard ratio (HR) for all-cause mortality among Mexican Americans with OLD, respectively. After adjustment for demographic factors, socioeconomic status, and COPD risk factors, Mexican Americans had decreased odds of OLD diagnosis compared with whites (OR, 0.72 [95% CI, 0.54-0.95]). Among the 1,734 participants with OLD, 1,054 (60.8%) died during median follow-up of 12 years. In an adjusted model, Mexican Americans had no advantage in mortality from all causes (HR, 0.88 [95% CI, 0.69-1.13]). After accounting for the fact that some Mexican Americans may have moved back to Mexico and died there (thus, had no US death certificate), there was still no difference in mortality between these groups. Although Mexican Americans appear to have lower risk for OLD, subjects of this ethnicity with OLD do not seem to have a survival advantage.

A method for quantification of lung resistive and compliant properties for spirometry interpretation support—Tests on a virtual patient

The forced expiratory volume in one second (FEV1), the fundamental index in obstructive lung disease diagnosis, depends on both resistive (RP) and compliant (CP) properties of the respiratory system (RS). The study aim was to test initially a method that could differentiate their influence to aid spirometry interpretation during screening examinations. Tests were done on a virtual RS elaborated previously. After respiratory muscle relaxation, a part of air was exhaled passively to an added compliance (Cad) or through an added resistance (Rad). The CP and RP were estimated from mouth pressure changes under different conditions of RS and measurement (different obstruction severities, various Cad and Rad values, etc.). Measurements had to be performed after maximal inspiration to avoid dependence of results on the lung volume. The Cad maneuver enabled to estimate the CP properly. Inertances and bronchi collapse caused pressure fluctuations, whereas bronchi reopening modified pressure rise after airflow interruption. Rad>0.8kPas/L eliminated these problems and made the RP estimation independent from the Rad value and the CP. The calculated value of resistance depended on both airway resistance and parenchyma viscosity (like FEV1) and viscosity of other tissues. Since collapse instantaneous observation in real patients is impossible, initial but extensive tests illustrating influence of the collapse on measurement could be done only on a virtual RS.

Reversibility of Airway Obstruction vs Bronchodilatation: Do We Speak the Same Language?

Airway reversibility test (or bronchodilatation test) is performed routinely in the diagnosis of obstructive lung diseases. The results of this test may be helpful in the diagnosis and differential diagnosis of asthma and chronic obstructive pulmonary disease (COPD), but sometimes bring confusion. Unfortunately, the nomenclature used for test result is not uniform, which also leads to confusion. Next the reader will find an attempt to order the state of affairs and the introduction of a uniform nomenclature, which would be consistent with the logic and allow for unambiguous classification of reversibility test results to facilitate future decisions based on the differential diagnosis.