Spirometric criteria for airway obstruction: Use percentage of FEV1/FVC ratio below the fifth percentile, not < 70%

BACKGROUND: Current authoritative spirometry guidelines use conflicting percentage of FEV1/FVC ratios (FEV1/FVC%) to define airway obstruction. The American Thoracic Society/European Respiratory Society Task Force characterizes obstruction as a FEV1/FVC% below the statistically defined fifth percentile of normal. However, many recent publications continue to use the Global Initiative for Chronic Obstructive Lung Disease (GOLD) primary criterion that defines obstruction as a FEV1/FVC% < 70%. Data from the Third National Health and Nutrition Examination Survey (NHANES-III) should identify and quantify differences, help resolve this conflict, and reduce inappropriate medical and public health decisions resulting from misidentification. METHODS: Using these two guidelines, individual values of FEV1/FVC% were compared by decades in 5,906 healthy never-smoking adults and 3,497 current-smokers of black (African American), Hispanic (Latin), or white ethnicities aged 20.0 to 79.9 years. RESULTS: In the never-smoking population, the lower limits of normal used in other reference equations fit reasonably well the NHANES-III statistically defined fifth percentile guidelines. But nearly one half of young adults with FEV1/FVC% below the NHANES-III fifth percentile of normal were misidentified as normal because their FEV1/FVC% was > 70% (abnormals misidentified as normal). Approximately one fifth of older adults with observed FEV1/FVC% above the NHANES-III fifth percentile had FEV1/FVC% ratios < 70% (normals misidentified as abnormal). CONCLUSIONS: The GOLD guidelines misidentify nearly one half of abnormal younger adults as normal and misidentify approximately one fifth of normal older adults as abnormal.     

Occult traumatic pneumothorax: diagnostic accuracy of lung ultrasonography in the emergency department

BACKGROUND: The role of chest ultrasonography (US) in the diagnosis of pneumothorax (PTX) has been established, but how it compares with lung CT scanning in the diagnosis of radiooccult PTX and in the determination of its topographic extension has not yet been completely evaluated. OBJECTIVE: To determine the diagnostic accuracy of chest US in the emergency department (ED) in the diagnosis of occult PTX in trauma patients and to define its ability to determine PTX extension. DESIGN: An 18-month prospective study. PATIENTS: A total of 109 conscious, spontaneously breathing patients who had been admitted to the ED for chest trauma or polytrauma. METHODS: All eligible patients underwent a standard anteroposterior supine chest radiograph (Rx) and a spiral CT lung scan within 1 h of ED admission. Lung US was carried out by an operator who was unaware of the other examination results, both for diagnosis and for the quantitative delimitation of the PTX. RESULTS: Twenty-five traumatic PTXs were detected in the 218 hemithoraxes (109 patients; 2 patients had a bilateral PTX) evaluated by spiral CT scan; of these, only 13 of 25 PTXs (52%) were revealed by chest Rx (sensitivity, 52%; specificity, 100%), while 23 of 25 PTXs (92%) were identified by lung US with one false-positive result (sensitivity, 92%; specificity, 99.4%). In 20 of 25 cases, there was agreement on the extension of the PTX between CT lung scan and lung US with a mean difference of 1.9 cm (range, 0 to 4.5 cm) in the localization of retroparietal air extension; chest Rx was not able to give quantitative results. CONCLUSIONS: Lung US scans carried out in the ED detect occult PTX and its extension with an accuracy that is almost as high as the reference standard (CT scanning).     

Peripheral muscle alterations in non-COPD smokers

BACKGROUND: Although tobacco smoke is the main cause of COPD, relatively little attention has been paid to its potential damage to skeletal muscle. This article addresses the effect of smoking on skeletal muscle. METHODS: The vastus lateralis muscle was studied in 14 non-COPD smokers (FEV(1)/FVC, 78 +/- 5%) and 20 healthy control subjects (FEV(1)/FVC, 80 +/- 3%). Muscular structure, enzyme activity, constitutive and inducible nitric oxide (NO) synthases (endothelial NO oxide synthase [eNOS], neuronal NO synthase [nNOS] and inducible NO synthase [iNOS]), nitrites, nitrates, nitrotyrosine, and the presence of macrophages were analyzed. RESULTS: In smokers, type I muscle fibers cross-sectional area was decreased, and a similar trend was found in type IIa fibers. Lactate dehydrogenase levels and the percentage of fibers with low oxidative and high glycolytic capacity were increased in smokers. nNOS (96.9 +/- 11.7 vs 125.4 +/- 31.9 ng/mg protein; p < 0.01) and eNOS (38.9 +/- 11.0 vs 45.2 +/- 7.7 ng/mg protein [+/- SD]; p < 0.05) were lower in smokers, while fiber type distribution, capillarity measures, beta-hydroxy-acyl-CoA-dehydrogenase levels, iNOS, nitrite, nitrate, and nitrotyrosine levels, and macrophage number in the muscle tissue were similar to the nonsmoker subjects. CONCLUSIONS: Smokers presented some alterations of skeletal muscle such as oxidative fiber atrophy, increased glycolytic capacity, and reduced expression of the constitutive NO synthases (eNOS and nNOS). The findings support some muscular structural and metabolic damage but not the presence of local inflammation in the smokers. In addition, they suggest a possible effect of tobacco smoke impairing the normal process of NO generation.     

Factors related to diagnostic sensitivity using an ultrathin bronchoscope under CT guidance

BACKGROUND: We investigated factors related to the diagnostic sensitivity of CT-guided transbronchial biopsy (TBB) using an ultrathin bronchoscope and virtual bronchoscopy (VB) navigation for small peripheral pulmonary lesions. METHOD: We have performed this procedure on 83 patients with 85 small peripheral pulmonary lesions (< 20 mm in diameter). We analyzed the relationship between the diagnostic sensitivity and the location of the lesions, the bronchial generation to which an ultrathin bronchoscope was inserted, and the lesion-bronchial and lesion-pulmonary arterial relationships on high-resolution CT. RESULTS: Fifty-six of the 85 lesions (66%) were diagnosed following CT-guided TBB using an ultrathin bronchoscope with VB navigation. The lesions located in the left superior segment of the lower lobe (S6) had a significantly low diagnostic sensitivity compared to other locations (p < 0.01). When an ultrathin bronchoscope could be inserted to the fifth or greater bronchial generation, the yield was above the average diagnostic sensitivity of 66%. Moreover, not only the patients with the presence of a bronchus leading directly to a lesion (CT-bronchus sign), but also the patients with the presence of a pulmonary artery leading to a lesion (CT-artery sign), had high diagnostic sensitivity (p < 0.01). Multivariate analysis revealed that the location of lesion was an independent predictor of diagnostic sensitivity (p < 0.05). CONCLUSIONS: The location of the lesion, the bronchial generation to which an ultrathin bronchoscope was inserted, and the presence of a bronchus as well as a pulmonary artery leading to the lesion were valuable for predicting successful CT-guided TBB using an ultrathin bronchoscope with VB navigation.     

Power spectral analysis of EEG activity during sleep in cigarette smokers

BACKGROUND: Research on the effects of cigarette smoking on sleep architecture is limited. The objective of this investigation was to examine differences in sleep EEG between smokers and nonsmokers. METHODS: Smokers and nonsmokers who were free of all medical comorbidities were matched on different factors, including age, gender, race, body mass index, and anthropometric measures. Home polysomnography was conducted using a standard recording montage. Sleep architecture was assessed using visual sleep-stage scoring. The discrete fast Fourier transform was used to calculate the EEG power spectrum for the entire night within contiguous 30-s epochs of sleep for the following frequency bandwidths: delta (0.8 to 4.0 Hz); theta (4.1 to 8.0 Hz); alpha (8.1 to 13.0 Hz); and beta (13.1 to 20.0 Hz). RESULTS: Conventional sleep stages were similar between the two groups. However, spectral analysis of the sleep EEG showed that, compared to nonsmokers, smokers had a lower percentage of EEG power in the delta-bandwidth (59.7% vs 62.6%, respectively; p < 0.04) and higher percentage of EEG power in alpha-bandwidth (15.6% vs 12.5%, respectively; p < 0.001). Differences in the EEG power spectrum between smokers and nonsmokers were greatest in the early part of the sleep period and decreased toward the end. Subjective complaints of lack of restful sleep were also more prevalent in smokers than in nonsmokers (22.5% vs 5.0%, respectively; p < 0.02) and were explained, in part, by the differences in EEG spectral power. CONCLUSIONS: Cigarette smokers manifest disturbances in the sleep EEG that are not evident in conventional measures of sleep architecture. Nicotine in cigarette smoke and withdrawal from it during sleep may contribute to these changes and the subjective experience of nonrestorative sleep.     

Intensive smoking cessation intervention reduces mortality in high-risk smokers with cardiovascular disease

PURPOSES: To compare an intensive smoking cessation intervention against usual care in hospitalized high-risk smokers with acute cardiovascular disease. METHODS: A total of 209 hospitalized smokers were randomized to the intensive intervention (n = 109) or to usual care (n = 100). Usual care consisted only of counseling and printed educational material provided prior to hospital discharge. Intensive treatment consisted of a minimum of 12 weeks of behavior modification counseling and individualized pharmacotherapy provided at no cost to the participant. Smoking status in all subjects was confirmed biochemically (ie, by measuring expired carbon monoxide) at 3, 6, 12, and 24 months after randomization. Outcomes included point prevalence and continuous abstinence smoking cessation rates, hospitalizations, and all-cause mortality. RESULTS: At each follow-up interval, point prevalence and continuous abstinence smoking cessation rates were significantly greater in the intensive-treatment group compared to the usual-care group. At 24 months, continuous abstinence smoking cessation rates were 33% in the intensive-treatment group and 9% in the usual-care group (p < 0.0001). Over the 2-year follow-up period, 41 patients in the usual-care group were hospitalized compared to 25 patients in the intensive-treatment group (relative risk reduction [RRR], 44%; 95% confidence interval [CI], 16 to 63%; p = 0.007). The all-cause mortality rate was 2.8% in the intensive-treatment group and 12.0% in the usual-care group (RRR, 77%; 95% CI, 27 to 93%; p = 0.014). The absolute risk reduction in mortality was 9.2% with a number needed to treat of 11. CONCLUSION: Hospitalized smokers, especially those with cardiovascular disease, should undergo treatment with a structured intensive cessation intervention. The duration of the initial treatment should be 3 months.     

Persistent airway obstruction after virus infection is not associated with airway inflammation

BACKGROUND: This study examined the contribution of airway inflammation to the delayed lung function recovery that occurs in some people following virus-induced asthma exacerbations. METHODS: Subjects (n = 40) were recruited at hospital admission for acute asthma exacerbation. Respiratory virus infection was diagnosed by viral nucleic acid detection and/or cell culture, using induced sputum, nasal, or throat swabs. Data collected included lung function, answers to common cold and asthma control questionnaires, and induced sputum cellular profiles. Subjects were reexamined 4 to 6 weeks postexacerbation and were compared with stable asthmatic subjects (n = 26) who had been recruited from ambulatory care clinics. RESULTS: Persistent airway obstruction, defined as lung function improvement at follow-up (ie, change in FEV1 percent predicted [Delta%FEV1]) of <15%, was observed in 10 subjects (25%). Airway recovery (Delta%FEV1, > or = 15%) was observed in the remaining subjects (30 subjects; 75%). During the acute episode, the airway-recovery group had increased total cell count (p = 0.019), increased number of neutrophils (p = 0.005), and increased percentage of neutrophils (p = 0.0043) compared to the group of stable subjects with asthma. Postexacerbation, the airway-recovery group had reduced numbers of neutrophils and an increased percentage of eosinophils. In contrast, during exacerbation, subjects with persistent airway obstruction showed no differences in inflammatory cell counts compared to stable subjects with asthma, nor did cell counts change postexacerbation. Symptoms improved in both groups postexacerbation. However, in the persistent-airway-obstruction group, asthma remained uncontrolled. CONCLUSION: Persistent airway obstruction and uncontrolled asthma are observed in some people after viral asthma exacerbations. These abnormalities are not associated with inflammatory cell influx into the airway lining fluid during the exacerbation and may reflect the involvement of noncellular elements. Further work should explore other mechanisms leading to incomplete airway recovery.     

Etiology of community-acquired pneumonia in hospitalized patients in chile: the increasing prevalence of respiratory viruses among classic pathogens

BACKGROUND AND STUDY OBJECTIVES: The range and relative impact of microbial pathogens, particularly viral pathogens, as a cause of community-acquired pneumonia (CAP) in hospitalized adults has not received much attention. The aim of this study was to determine the microbial etiology of CAP in adults and to identify the risk factors for various specific pathogens. METHODS: We prospectively studied 176 patients (mean [+/- SD] age, 65.8 +/- 18.5 years) who had hospitalized for CAP to identify the microbial etiology. For each patient, sputum and blood cultures were obtained as well as serology testing for Mycoplasma pneumoniae and Chlamydophila pneumoniae, urinary antigen testing for Legionella pneumophila and Streptococcus pneumoniae, and a nasopharyngeal swab for seven respiratory viruses. RESULTS: Microbial etiology was determined in 98 patients (55%). S pneumoniae (49 of 98 patients; 50%) and respiratory viruses (32%) were the most frequently isolated pathogen groups. Pneumococcal pneumonia was associated with tobacco smoking of > 10 pack-years (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.2 to 5.4; p = 0.01). Respiratory viruses were isolated more often in fall or winter (28%; p = 0.011), and as an exclusive etiology tended to be isolated in patients >/= 65 years of age (20%; p = 0.07). Viral CAP was associated with antimicrobial therapy prior to hospital admission (OR, 4.5; 95% CI, 1.4 to 14.6). CONCLUSIONS: S pneumoniae remains the most frequent pathogen in adults with CAP and should be covered with empirical antimicrobial treatment. Viruses were the second most common etiologic agent and should be tested for, especially in fall or winter, both in young and elderly patients who are hospitalized with CAP.     

Chronic and acute effects of smoking on left and right ventricular relaxation in young healthy smokers

BACKGROUND: Left ventricular (LV) diastolic dysfunction has been observed in cigarette smokers with coronary artery disease. The aim of the study was to assess LV and right ventricular (RV) diastolic function in healthy, young, and slim smokers before and after smoking one cigarette. MATERIAL AND METHODS: The participants were 66 healthy volunteers (age < 40 years; body mass index < 25 kg/m(2)): 33 smokers (study group [HS]) and 33 nonsmokers (control group). Echocardiographic examination was done in the HS before smoking one cigarette (HS-1) and after smoking one cigarette (HS-2). To assess diastolic function of LV and RV mitral valve flow (MVF), pulmonary venous flow (PVF) and tricuspid valve flow (TVF) were evaluated. RESULTS: MVF early to late phase ratio (E/A) was significantly lower in HS-1 and HS-2 than in the control group. The PVF systolic to diastolic phase ratio (S/D) was significantly higher in HS-1 and HS-2 than in the control group. These changes suggest LV diastolic function impairment in the HS, but the MVF pattern remained within the normal range. PVF S/D showed systolic dominance (S/D > 1) typical for impaired LV relaxation and abnormal for this age group. TVF E/A was significantly lower in HS-2 than in HS-1 and control subjects and suggests RV diastolic dysfunction. CONCLUSIONS: The following conclusion are made: (1) MVF and PVF demonstrate LV relaxation impairment in healthy smokers before and after smoking one cigarette; (2) the assessment of PVF is a good method reflecting LV diastolic function changes, even when MVF remains normal; and (3) TVF shows RV relaxation impairment after smoking one cigarette in healthy smokers.     

Large and medium-sized pulmonary artery obstruction does not play a role of primary importance in the etiology of sickle-cell disease-associated pulmonary hypertension

BACKGROUND: Pulmonary hypertension (PHT) occurs in approximately 30% of adult patients with sickle-cell disease (SCD) and is a risk factor for early death. The potential role of pulmonary artery obstruction, whether due to emboli or in situ thrombosis, in the etiology of SCD-related PHT is unknown. METHODS: Consecutive SCD patients were screened for PHT (defined as a tricuspid regurgitant jet flow velocity > or = 2.5 m/s) employing echocardiography and were evaluated for pulmonary artery obstruction with ventilation-perfusion (VQ) scintigraphy. RESULTS: Fifty-three HbSS, 6 HbSbeta(0)-thalassemia, 20 HbSC, and 6 HbSbeta(+)-thalassemia patients were included. The overall prevalence of PHT was 41% in HbSS/HbSbeta(0)-thalassemia patients and 13% in HbSC/HbSbeta(+)-thalassemia patients. High-probability VQ defects (Prospective Investigation of Pulmonary Embolism Diagnosis criteria) were detected in two patients, one of whom had PHT. In HbSS/HbSbeta(0)-thalassemia patients with PHT, 19 patients (86%), 2 patients (9%), and 1 patient (5%) had low-, intermediate-, or high-probability scan results as compared to 30 patients (97%), 1 patient (3%), and 0 patients (0%) in HbSS/HbSbeta(0)-thalassemia patients without PHT (p = 0.31). In HbSC/HbSbeta(+)-thalassemia patients with PHT, 3 patients (100%), 0 patients (0%), and 0 patients (0%) had low-, intermediate-, and a high-probability scan as compared to 19 patients (90%), 1 patient (5%), and 1 patient (5%) in HbSC/HbSbeta(+)-thalassemia patients without PHT (p = 0.86). There were no statistical differences in irregular distribution of the radiopharmaceutical or nonspecific signs associated with PHT between patients with and without PHT. CONCLUSIONS: Although small pulmonary artery obstruction cannot be excluded, large to medium-sized pulmonary artery obstruction is an unlikely primary causative factor in SCD-related PHT.     

Bronchial hyperresponsiveness, airway inflammation, and airflow limitation in endurance athletes

BACKGROUND: Whereas a high prevalence of bronchial abnormalities has been reported in endurance athletes, its underlying mechanisms and consequences during exercise are still unclear. STUDY OBJECTIVES: The purpose of this study was to assess the following: (1) bronchial responsiveness to methacholine and to exercise; (2) airway inflammation; and (3) airflow limitation during intense exercise in endurance athletes with respiratory symptoms. DESIGN: Cross-sectional observational study. SETTING: Lung function and exercise laboratory at a university hospital. PATIENTS AND MEASUREMENTS: Thirty-nine endurance athletes and 13 sedentary control subjects were explored for the following: (1) self-reported respiratory symptoms; (2) bronchial hyperresponsiveness (BHR) to methacholine and exercise; (3) airflow limitation during intense exercise; and (4) bronchial inflammation using induced sputum and nitric oxide (NO) exhalation. RESULTS: Fifteen athletes (38%) showed BHR to methacholine and/or exercise in association with bronchial eosinophilia (mean [+/- SD] eosinophil count, 4.1 +/- 8.5% vs 0.3 +/- 0.9% vs 0%, respectively), higher NO concentrations (19 +/- 10 vs 14 +/- 4 vs 13 +/- 4 parts per billion, respectively), a higher prevalence of atopy, and more exercise-induced symptoms compared with non-hyperresponsive athletes and control subjects (p < 0.05). Furthermore, airflow limitation during intense exercise was observed in eight athletes, among whom five had BHR. Athletes with airflow limitation reported more symptoms and had FEV1, FEV1/FVC ratio, and forced expiratory flow at midexpiratory phase values of 14%, 9%, and 29%, respectively, lower compared with those of nonlimited athletes (p < 0.05). CONCLUSION: BHR in endurance athletes was associated with the criteria of eosinophilic airway inflammation and atopy, whereas airflow limitation during exercise was primarily a consequence of decreased resting spirometric values. Both BHR and bronchial obstruction at rest with subsequent expiratory flow limitation during exercise may promote respiratory symptoms during exercise in athletes.     

Cardiac involvement in patients with sarcoidosis: diagnostic and prognostic value of outpatient testing

BACKGROUND: Cardiac sarcoidosis (CS) causes substantial morbidity and sudden death. Early diagnosis and risk stratification are warranted. METHODS: Ambulatory patients with sarcoidosis were interviewed to determine whether they experienced palpitations, syncope, or presyncope, and were evaluated with ECG, Holter monitoring, and echocardiography (transthoracic echocardiogram [TTE]). Those with symptoms or abnormal results were studied with cardiac MRI (CMRI) or positron emission tomography (PET) scanning. The diagnosis of CS was based on abnormalities detected by these imaging studies. Patients with CS were referred for risk stratification by electrophysiology study (EPS). RESULTS: Among the 62 patients evaluated, the prevalence of CS was 39%. Patients with CS had more cardiac symptoms than those without CS (46% vs 5%, respectively; p < 0.001), and were more likely to have abnormal Holter monitoring findings (50% vs 3%, respectively; p < 0.001) and TTE findings (25% vs 5%, respectively; p = 0.02). The degree of pulmonary impairment did not predict CS. Two of the 17 patients who underwent EPS had abnormal test findings and received implantable cardioverter-defibrillators. No patients died, had ventricular arrhythmias that triggered defibrillator therapy, or had heart failure develop during almost 2 years of follow-up. This diagnostic approach was more sensitive than the established criteria for identifying CS. CONCLUSION: CS is common among patients with sarcoidosis. A structured clinical assessment incorporating advanced cardiac imaging with PET scanning or CMRI is more sensitive than the established criteria for the identification of CS. Sarcoidal lesions seen on CMRI or PET scanning do not predict arrhythmias in ambulatory patients with preserved cardiac function, who appear to be at low risk for short-term mortality.     

High prevalence of proximal and distal gastroesophageal reflux disease in advanced COPD

BACKGROUND: Gastroesophageal reflux disease (GERD) is common in a variety of chronic respiratory diseases, but little is known about GERD in the setting of COPD. The aims of this study were to determine the prevalence, presentation, and predictors of GERD based on proximal and distal esophageal pH monitoring in patients with severe COPD. METHODS: Forty-one COPD patients with a mean FEV1 of 24% of predicted underwent dual-probe 24-h esophageal pH monitoring, and 1 patient underwent esophagogastroduodenoscopy. RESULTS: The prevalence of GERD was 57%. Elevated distal and proximal reflux were present in 41% and 46% of patients undergoing esophageal pH studies, respectively. Fifteen percent of these patients had abnormal proximal reflux despite having normal distal probe results. Most patients with GERD were not receiving acid blockers at the time of their referral, and only one third reported heartburn and/or acid regurgitation during the pH study. Only higher body mass index was predictive of reflux on regression analysis (odds ratio, 1.2; 95% confidence interval, 1.0 to 1.5; p = 0.05). CONCLUSIONS: GERD is common in advanced COPD. Patients are often asymptomatic and have a relatively high prevalence of isolated abnormal proximal reflux. Dual-probe monitoring is therefore well suited for detecting GERD in patients with advanced COPD.     

Silent upper airway resistance syndrome: prevalence in a mixed military population

STUDY OBJECTIVES: The upper airway resistance syndrome (UARS) is a recently described form of sleep-disordered breathing in which transient increases in upper airway resistance result in repetitive EEG arousals. UARS is not associated with apnea or diminished airflow, although snoring and excessive daytime somnolence (EDS) are common. This report describes a subset of patients with UARS diagnosed by polysomnography who do not manifest snoring, which we define as silent upper airway resistance syndrome (SUARS). DESIGN: A retrospective review of all polysomnographies performed at our sleep disorders center during 2000. SETTING: Sleep disorders center of a large, academic, military hospital. PATIENTS: Our center serves military personnel, military retirees, and their dependent families. INTERVENTIONS: Esophageal manometry during polysomnography was routinely performed on patients with hypersomnolence (Epworth sleepiness scale > 10) who demonstrated a total arousal index >or= 10/h and a respiratory disturbance index of < 5/h on prior polysomnography. UARS was definitely diagnosed in patients who demonstrated repetitive increased upper airway resistance (IUAR) associated with brief EEG arousals followed by normalization of esophageal pressure (Pes). IUAR was defined by a pattern of crescendo negative inspiratory Pes of 相似文献   

Prevalence and risks of chronic airway obstruction: a population cohort study in taiwan

BACKGROUND: This study investigated the prevalence, incidence, and hospitalization for chronic airway obstruction (CAO) in a population cohort. METHODS: Medical reimbursement claims from 1996 to 2002 based on a 1996 insured cohort of 167,372 persons from National Health Insurance, Taiwan, were used. We presented the chronological trends of CAO (International Classification of Diseases, Ninth Revision code 496) and the relationships between the CAO severity and age, sex, urbanization, and hospitalization and comorbidity for the population >/= 40 years old. RESULTS: The overall average annual prevalence and incidence rates were 2.48/100 and 0.66/100, respectively, for the population, among 4,568 patients with CAO cared during the study period. For the population aged >/= 70 years, the prevalence rates had a peak of 8.83/100 in 1998 and afterward remained a plateau until 2002. The corresponding incidence decreased from 2.48/100 to 1.62/100, and the hospitalization rate for them had a peak of 2.22/100 in 1999. The multivariate logistic regression analysis showed that the risk of hospitalization for CAO was higher for patients with the comorbidity of renal failure, coronary artery disease, and pneumonia and influenza, but lower with skin and joint disorders. CONCLUSIONS: The national insurance program promotes patient care and provides a proper pathway for surveillance and identification of CAO.     

The association between small airway obstruction and emphysema phenotypes in COPD

BACKGROUND: Airflow limitation in COPD is due to a variable combination of small airway obstruction and centrilobular emphysema (CLE) and/or panlobular emphysema (PLE), but the relationship between these three different phenotypes is poorly understood. This study compares the severity of small airway obstruction in both forms of emphysema and determines its relationship with FEV(1). METHODS: We compared the lung histology of nonsmoking control subjects without emphysema (n = 10) to that of patients with CLE (n = 30) and PLE with (n = 8) and without alpha(1)-antitrypsin (AAT) deficiency (n = 11). The degree of airspace enlargement was measured using the mean interalveolar wall distance (IAWD) [mean linear intercept, Lm], and the evenness of airspace destruction was assessed by the coefficient of variation (CV) of the IAWD. The severity of small airway obstruction was determined by dividing total wall area by the length of the basement membrane to obtain wall thickness. RESULTS: Lm was greater in all three subgroups of emphysema than in control subjects, and in AAT deficiency than in PLE or CLE. The CV of IAWD was greater in AAT deficiency and CLE than in control subjects and in CLE than in AAT deficiency or PLE. Although small airway wall thickness was greater in CLE and PLE with AAT deficiency than in control subjects, the association between wall thickness and both Lm and FEV(1) was observed only in CLE. CONCLUSIONS: Small airway wall thickening occurs in CLE and PLE with AAT deficiency but is more closely associated with degree of emphysema and airflow limitation in CLE.