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Background: Smokers manifest varied phenotypes of pulmonary impairment., Research Question: Which pulmonary phenotypes are associated with coronary artery disease (CAD) in smokers?, Study Design and Methods: We analyzed data from the University of Pittsburgh COPD Specialized Center for Clinically Oriented Research (SCCOR) cohort (n = 481) and the Genetic Epidemiology of COPD (COPDGene) cohort (n = 2,580). Participants were current and former smokers with > 10 pack-years of tobacco exposure. Data from the two cohorts were analyzed separately because of methodologic differences. Lung hyperinflation was assessed by plethysmography in the SCCOR cohort and by inspiratory and expiratory CT scan lung volumes in the COPDGene cohort. Subclinical CAD was assessed as the coronary artery calcium score, whereas clinical CAD was defined as a self-reported history of CAD or myocardial infarction (MI). Analyses were performed in all smokers and then repeated in those with airflow obstruction (FEV 1 to FVC ratio, < 0.70)., Results: Pulmonary phenotypes, including airflow limitation, emphysema, lung hyperinflation, diffusion capacity, and radiographic measures of airway remodeling, showed weak to moderate correlations (r < 0.7) with each other. In multivariate models adjusted for pulmonary phenotypes and CAD risk factors, lung hyperinflation was the only phenotype associated with calcium score, history of clinical CAD, or history of MI (per 0.2 higher expiratory and inspiratory CT scan lung volume; coronary calcium: OR, 1.2; 95% CI, 1.1-1.5; P = .02; clinical CAD: OR, 1.6; 95% CI, 1.1-2.3; P = .01; and MI in COPDGene: OR, 1.7; 95% CI, 1.0-2.8; P = .05). FEV 1 and emphysema were associated with increased risk of CAD (P < .05) in models adjusted for CAD risk factors; however, these associations were attenuated on adjusting for lung hyperinflation. Results were the same in those with airflow obstruction and were present in both cohorts., Interpretation: Lung hyperinflation is associated strongly with clinical and subclinical CAD in smokers, including those with airflow obstruction. After lung hyperinflation was accounted for, FEV 1 and emphysema no longer were associated with CAD. Subsequent studies should consider measuring lung hyperinflation and examining its mechanistic role in CAD in current and former smokers., (Copyright © 2021. Published by Elsevier Inc.)

Rationale: The prevalence of adults living with cystic fibrosis (CF) who have early-stage lung disease is increasing., Objectives: Describe the prevalence and evaluate spirometric risk factors associated with the subgroup of patients with early-stage lung disease and FEV 1 decline of ≥5% predicted/year., Methods: Retrospective cohort study of patients ≥18 years with FEV 1 % predicted ≥80% included in the US CF Foundation Patient Registry from 2010-2013. Regression models were developed to estimate FEV 1 rate of decline. Multivariable logistic analysis was used to assess if spirometric risk factors were associated with FEV 1 decline., Measurements and Main Results: 3,029 subjects were in the study cohort. Approximately 15% of the cohort had a substantial decline in lung function ≥5% predicted/year. In multivariable models adjusted for confounders, FEV 1 /FVC ratio <0.8 (Odds Ratio (OR) 1.63, 95% confidence interval (CI) 1.31 to 2.02) and history of FEV 1 % predicted variability (OR 2.35,95%CI 1.74 to 3.18) were associated with rapid lung function decline., Conclusions: Even among adults with early-stage lung disease, approximately 15% are shown to progress and experience a large decline in lung function. This reinforces the concept that lung function in early-stage CF is not normal or mild. Rather, lung function decline may be delayed, but not avoided, in these individuals. Variability in FEV 1 % predicted and airway obstruction as measured by FEV1/FVC ratio may identify individuals at increased risk of decline. Adults with early-stage lung disease should be followed in clinic to monitor for onset of decline., Competing Interests: Declaration of Competing Interest DJP and SJM are employees of ICON Clinical Research, which was paid by The Cystic Fibrosis Foundation for providing analytical services for this study. ECD has received honoraria from Gilead Sciences and Vertex Pharmaceuticals. DBS has received honoraria from Vertex Pharmaceuticals., (Copyright © 2019. Published by Elsevier B.V.)

Background: Obstructive lung disease occurs in 30% of children with early onset scoliosis (EOS); changes in degree of airway obstruction over time have not been reported., Methods: Longitudinal patterns of incidental, persistent, and progressive airway obstruction were retrospectively analyzed in a cohort of children with EOS with at least 1 forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) value <85% on serial spirometric assessments over a ≥3-year observation period. The prevalence of clinical features and the severity of coronal and sagittal spine deformities for each group at the beginning and end of the study period were compared., Results: Airway obstruction was incidental in 12 (24%) and persistent in 37 (76%) of 49 children with EOS. Twenty of 37 (54%) of those with persistent obstruction developed progressive airway obstruction. The decline in FEV1/FVC over 6±2 years was insignificant in the incidental group (4%±2%) and the persistent nonprogressive group (7%±4%) but significant in the progressive group (13%±4%, t test; P=0.002). In total, 29% of the 49 children at the onset and 57% at the end of the study had airway obstruction. The incidental, persistent nonprogressive, and progressive groups did not differ with regard to age, diagnosis distribution, or sex. The initial coronal curve size, apex, direction of the curve, and degree of kyphosis were statistically similar among the 3 groups. Coronal curve magnitude inversely correlated with FEV1/FVC at the end but not the beginning of the study (r=-0.19, P=0.002). Six of 19 responded to bronchodilator treatment, suggesting concurrent asthma. Airway obstruction did not relate to restrictive pulmonary abnormalities measured by FVC at first or last timepoints [slope=-0.076 (95% confidence interval, -0.99 to 0.038; P=0.19)]. Changes in degrees of airway obstruction and restrictive lung disease over time did not correlate [slope=-0.125 (95% confidence interval, -0.294 to 0.044; P=0.14)]., Conclusions: Children with EOS and progressive airway obstruction represent an important subgroup which may require new surgical and nonsurgical treatment strategies to prevent loss of lung function over time.

Objective: Identify risk factors associated with airway foreign bodies in children in the United States and report observed trends over time., Data Source: KID database (2000-2009)., Methods: ICD-9-CM codes for airway foreign bodies were used to identify patients. Risk factors were used for univariate analysis and a multivariate model to identify any increased risk of mortality. These factors were then also trended over time., Results: Children with airway foreign bodies demonstrate similar risk factors as previously reported, such as male gender, age less than five years and lack of private insurance. The weighted mortality rate for paediatric inpatients with airway foreign bodies was about 2.75%. Fortunately, the rate remained relatively unchanged from 2000 to 2009. Geographically, urban hospital settings appeared to be more affected. Increased risks of mortality were noted for older age, urban hospital setting and teaching hospital status., Conclusions: Our findings confirm previous findings and identified that the diagnosis of airway foreign bodies in children were associated with male gender, age <5 years, lack of private insurance and geographic location in an urban setting. Further investigation may be warranted to provide clarity on other factors found to have increased association with mortality for quality improvement., (© 2018 John Wiley & Sons Ltd.)

Background: Patients with cystic fibrosis (CF) experience variable lung disease phenotypes. The R117H mutation is often associated with preserved lung function. Our objective was to compare the rate of lung function decline in patients with the R117H mutation and patients homozygous for the F508del mutation., Methods: Rate of decline in percentage-of-predicted FEV 1 (ppFEV 1 ) was analyzed using the 2006-2010 US CF Foundation Patient Registry., Results: 4-year rate of decline was slower in 156 R117H patients compared with 6251 F508del patients (-0.61 vs -2.03 ppFEV 1 /year, P<0.001). Rates of decline in children were slower in R117H vs F508del patients (6-12-year-olds: +0.73 vs -1.91 ppFEV 1 /year, P<0.001 and 13-17-year-olds: -1.55 vs -2.66 ppFEV 1 /year, P=0.046), whereas rates in adults were not significantly different (18-24-year-olds: -1.52 vs -2.12, P=0.26 and ≥25-year-olds: -1.17 vs -1.40, P=0.33)., Conclusions: These findings are consistent with a delayed onset, but ultimately similar progression, of lung disease in R117H compared with homozygous F508del patients., (Copyright © 2017 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Rationale: Rescue/recovery work at the World Trade Center disaster site (WTC) caused a proximate decline in lung function in Fire Department of the City of New York firefighters. A subset of this cohort experienced an accelerated rate of lung function decline over 15 years of post-September 11, 2001 (9/11) follow-up., Objectives: To determine if early postexposure blood leukocyte concentrations are biomarkers for subsequent FEV 1 decline and incident airflow limitation., Methods: Individual rates of forced expiratory volume in 1 second (FEV 1 ) change were calculated for 9,434 firefighters using 88,709 spirometric measurements taken between September 11, 2001, and September 10, 2016. We categorized FEV 1 change rates into three trajectories: accelerated FEV 1 decline (FEV 1 loss >64 ml/yr), expected FEV 1 decline (FEV 1 loss between 0 and 64 ml/yr), and improved FEV 1 (positive rate of change >0 ml/yr). Occurrence of FEV 1 /FVC less than 0.70 after 9/11 defined incident airflow limitation. Using regression models, we assessed associations of post-9/11 blood eosinophil and neutrophil concentrations with subsequent FEV 1 decline and airflow limitation, adjusted for age, race, smoking, height, WTC exposure level, weight change, and baseline lung function., Results: Accelerated FEV 1 decline occurred in 12.7% of participants (1,199 of 9,434), whereas post-9/11 FEV 1 improvement occurred in 8.3% (780 of 9,434). Higher blood eosinophil and neutrophil concentrations were each associated with accelerated FEV 1 decline after adjustment for covariates (odds ratio [OR], 1.10 per 100 eosinophils/μl; 95% confidence interval [CI], 1.05-1.15; and OR, 1.10 per 1,000 neutrophils/μl; 95% CI, 1.05-1.15, respectively). Multivariable-adjusted linear regression models showed that a higher blood neutrophil concentration was associated with a faster rate of FEV 1 decline (1.14 ml/yr decline per 1,000 neutrophils/μl; 95% CI, 0.69-1.60 ml/yr; P < 0.001). Higher blood eosinophil concentrations were associated with a faster rate of FEV 1 decline in ever-smokers (1.46 ml/yr decline per 100 eosinophils/μl; 95% CI, 0.65-2.26 ml/yr; P < 0.001) but not in never-smokers (P for interaction = 0.004). Higher eosinophil concentrations were also associated with incident airflow limitation (adjusted hazard ratio, 1.10 per 100 eosinophils/μl; 95% CI, 1.04-1.15). Compared with the expected FEV 1 decline group, individuals experiencing accelerated FEV 1 decline were more likely to have incident airflow limitation (adjusted OR, 4.12; 95% CI, 3.30-5.14)., Conclusions: Higher post-9/11 blood neutrophil and eosinophil concentrations were associated with subsequent accelerated FEV 1 decline in WTC-exposed firefighters. Both higher blood eosinophil concentrations and accelerated FEV 1 decline were associated with incident airflow limitation in WTC-exposed firefighters.

Background: Screening spirometry might help identify patients with chronic obstructive pulmonary disease (COPD) at an earlier stage. In this study, we evaluated the prevalence of airway obstruction in a cohort of asymptomatic smokers who underwent spirometry as part of a routine health maintenance examination., Methods: The study cohort consisted of a consecutive sample of 386 asymptomatic smokers (≥5 pack-years) without a history of COPD or asthma, who completed spirometry testing as part of a routine health maintenance examination., Results: Overall, 9 study subjects (2.3%, 95% confidence interval: 1.1-4.4%) had evidence of airway obstruction on spirometry. Univariate and multiple regression analyses showed that the risk of airway obstruction was not significantly associated with age, sex, race, smoking history or past history of respiratory symptoms., Discussion: Spirometry screening of asymptomatic smokers may help detect a small number of patients with airway obstruction who are at high risk for COPD.

Background and Purpose: It is not known how many stroke patients die from fatal pulmonary complications such as aspiration pneumonia (AP) and choking each year in the United States. This study aimed to determine the frequency of reporting of AP or choking as a cause of death on death certificates with mention of stroke in the United States as a proxy measure of the incidence of dying from AP or choking among patients with stroke., Methods: We used multiple-cause mortality data for the years 2001 to 2010 to identify death certificates with mention of stroke (International Classification of Diseases, Tenth Revision code I60-I69), AP (International Classification of Diseases, Tenth Revision code J69), and choking (International Classification of Diseases, Tenth Revision code W78-W80) for analysis., Results: Of 2 424 379 death certificates with mention of stroke in the United States between 2001 and 2010, 5.1% (n=124 503) reported AP as a cause of death, and 1.5% (n=36 997) reported choking as a cause of death. However, if we confined the analysis to autopsy-confirmed cases, the frequency decreased to 1.3% (555/42 732) and 1.3% (541/42 732), respectively. The adjusted odds ratios of reporting AP or choking as a cause of death were higher among men, increased with age, and were higher among decedents who died in a nursing home/long-term care., Conclusions: The estimated incidence of dying from AP and choking among patients who died with stroke was 5% (~12 000 deaths per year) and 1% (~3700 deaths per year) according to information reported on death certificates. Efforts are needed to reduce the number of deaths from these 2 preventable complications.

Objectives: To estimate the prevalence of operative ear disease in pediatric patients with tracheostomy tubes, as well as to identify risk factors predictive of operative otologic interventions in this patient cohort., Methods: We hypothesize that the prevalence of operative middle ear disease in patients with a tracheostomy tube is greater than that of the population at large. To validate our anecdotal observations, we queried the CHCA hospital database (PHIS) regarding the association between tympanostomy tube placements in children with tracheostomies. To further investigate, a retrospective chart review was undertaken at our regional tertiary care children's hospital to determine the frequency at which tympanostomy tubes were placed in children who have a tracheostomy. Risk factors were analyzed, applying independent samples t-tests and Pearson's Chi-square test. Univariate and multivariate logistic regression models were constructed to estimate odds ratios (OR) and 95% confidence intervals (CI) for predictors of operative ear disease. Institutional review board (IRB) approval was obtained., Results: Of a population of 181 patients with tracheostomies, 37 (or 20%, 95% CI 15-26%) have undergone placement of ventilation tubes in the past 3 years. No statistically significant difference was noted with regards to gender or race. The operative group had an average age of 23.0 months at the time of tracheostomy, compared to 52.5 months in the non-operative group (p=0.0022). In addition, home living situation, term birth, and craniofacial abnormalities were more frequently observed in the operative versus the non-operative group. Multivariate logistic regression models revealed the same factors as predictors of operative ear disease., Conclusion: The presence of a tracheostomy is associated with an increased risk of requiring ventilation tube placement over the population at large. Risk factors for operative middle ear disease among these children include age at time of the tracheostomy, craniofacial abnormalities, term birth, and home living situation., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Airflow obstruction is an independent risk factor for cardiovascular events in the general population. The affected vascular bed and contribution of emphysema to cardiovascular risk are unclear. We examined whether an obstructive pattern of spirometry and quantitatively defined emphysema were associated with subclinical atherosclerosis in the carotid, peripheral and coronary circulations. The Multi-Ethnic Study of Atherosclerosis recruited participants aged 45-84 yrs without clinical cardiovascular disease. Spirometry, carotid intima-media thickness (IMT), ankle-brachial index (ABI) and coronary artery calcium (CAC) were measured using standard protocols. Percentage of emphysema-like lung was measured in the lung windows of cardiac computed tomography scans among 3,642 participants. Multiple linear regression was used to adjust for cardiac risk factors, including C-reactive protein. Decrements in forced expiratory volume in 1 s (FEV(1)) and FEV(1)/forced vital capacity ratio were associated with greater internal carotid IMT, particularly among smokers (p=0.03 and p<0.001, respectively) whereas percentage emphysema was associated with reduced ABI regardless of smoking history (p=0.004). CAC was associated with neither lung function (prevalence ratio for the presence of CAC in severe airflow obstruction 0.99, 95% CI 0.91-1.07) nor percentage emphysema. An obstructive pattern of spirometry and emphysema were associated distinctly and independently with subclinical atherosclerosis in the carotid arteries and peripheral circulation, respectively, and were not independently related to CAC.

Background: Pulmonary arterial hypertension (PAH) is a progressive and fatal disorder. Despite the emergence of effective therapy, PAH is commonly at an advanced stage when recognized. Factors associated with a prolonged symptomatic period before the recognition of PAH have not been fully evaluated., Methods: The Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL Registry) enrolled 2,967 US adult patients with PAH from March 2006 to September 2007. Patients were considered to have delayed disease recognition if > 2 years elapsed between symptom onset and the patient receiving a PAH diagnosis, starting on PAH-specific therapy, or receiving a diagnosis by right-sided heart catheterization., Results: In 21.1% of patients, symptoms were experienced for > 2 years before PAH was recognized. Patients with onset of PAH symptoms before age 36 years showed the highest likelihood of delayed disease recognition (OR, 3.07; 95% CI, 2.03-4.66). History of obstructive airways disease (OR, 1.93; 95% CI, 1.5-2.47) and sleep apnea (OR, 1.72; 95% CI, 1.33-2.22) were independently associated with delayed PAH recognition. Six-minute walk distance < 250 m (OR, 1.91; 95% CI, 1.16-3.13), right atrial pressure < 10 mm Hg (OR, 1.77; 95% CI, 1.26-2.48), and pulmonary vascular resistance < 10 Wood units (OR, 1.28; 95% CI, 1.02-1.60) were also associated with delayed disease recognition, but sex, race/ethnicity, and geographic region showed no association., Conclusions: One in five patients in the REVEAL Registry who were diagnosed with PAH reported symptoms for > 2 years before their disease was recognized. Younger individuals and patients with histories of common respiratory disorders were most likely to experience delayed PAH recognition., Trial Registry: ClinicalTrials.gov; No.: NCT00370214; URL: www.clinicaltrials.gov.

Normal lung development follows a series of orchestrated events. Premature birth interrupts normal in utero lung development, which results in significant alterations in lung function and physiology. Increasingly, there are reports documenting the broad range of complications experienced by infants aged 34 to 36 weeks' gestational age (GA). Our objective was to summarize the evidence demonstrating respiratory system vulnerability in infants aged 34 to 36 weeks' GA and to review the developmental and physiologic principles that underlie this vulnerability. A comprehensive search for studies that reported epidemiologic data and respiratory morbidity was conducted on the PubMed, Medline, Ovid Biosis, and Embase databases from 2000 to 2009 by using medical subject headings "morbidity in late preterm infants," "preterm infants and lung development," "prematurity and morbidity," and "prematurity and lung development." Because the number of studies exclusive to infants aged 34 to 36 weeks' GA was limited, selected studies also included infants aged 32 to 36 weeks' GA. Of the 24 studies identified, 16 were retrospective population-based cohort studies; 8 studies were observational. These studies consistently revealed that infants born at 32 to 36 weeks' GA, including infants of 34 to 36 weeks' GA, experience substantial respiratory morbidity compared with term infants. Levels of morbidity were, at times, comparable to those observed in very preterm infants. The developmental and physiologic mechanisms that underlie the increased morbidity rate and alterations in respiratory function are discussed. We also present evidence to demonstrate that the immaturity of the respiratory system of infants 34 to 36 weeks' GA at birth results in increased morbidity in infancy and leads to deficits in lung function that may persist into adulthood.

Objective: To review national trends in the management of pediatric airway foreign bodies (A-FBs) and esophageal foreign bodies (E-FBs) that obstruct the airway., Design: Retrospective review using a national pediatric data set (Kids' Inpatient Database)., Setting: Pediatric patients admitted across the United States during 2003., Patients: The Kids' Inpatient Database 2003 samples 2 984 129 pediatric discharges from 3438 hospitals in 36 states., Main Outcome Measures: The Kids' Inpatient Database 2003 was analyzed for A-FBs and E-FBs (International Classification of Diseases, Ninth Revision, Clinical Modification codes E911 and E912) in patients 20 years or younger, and weighted data are presented to facilitate national estimates., Results: A total of 2771 patients (59% male) were admitted for an A-FB or an E-FB that was obstructing the airway. The mean (SE) age of the patients was 3.5 (0.17) years; 55% were younger than 2 years. The foreign bodies were classified as food (42%; mean age, 2.5 years) or other (58%; mean age, 4.3 years). The average length of stay was 6.4 days (median [SE], 1.5 [0.6] days), and the average number of procedures was 2.4 (median [SE], 1.3 [0.1] procedures). Seventy-one percent of the patients were treated at teaching hospitals. The mean (SD) total charges were $34 652 ($3543), with regional variation (P < .001). Children's hospitals (28%) had higher mean total charges than nonchildren's hospitals (P = .03); 3.4% of admissions died in the hospital (mean [SE] age, 4.6 [0.9] years), with an average length of stay of 11.7 (SE, 2.7) days and an average of 6.2 (SE, 0.7) procedures. Bronchoscopy (52%), esophagoscopy (28%), and tracheotomy (1.7%) were the primary procedures performed. The rates of positive FB findings for bronchoscopy and esophagoscopy were 37% and 46%, respectively., Conclusions: Pediatric A-FBs and E-FBs that obstruct the airway occur infrequently. Most of the patients are referred to teaching institutions. Among patients who were admitted with a diagnosis of airway obstruction from an A-FB or an E-FB, the rates of positive findings at surgery were 37% and 46%, respectively. A surprisingly high mortality rate was noted. Alternative education measures should be considered to train physicians in the management of this infrequent, potentially lethal condition.

Objective: Spirometry is recognized as the gold standard assessment for the diagnosis of COPD. However, spirometry continues to be underused, perpetuating the underdiagnosis of COPD. The aim of this study was to evaluate the prevalence of COPD in a primary care setting in patients with a smoking history and self-reported chronic bronchitis symptoms., Research Design and Methods: This was a multi-center, cross-sectional study. The primary assessment was the percentage of patients with airway obstruction (post-bronchodilator FEV(1)/FVC ratio < or = 0.70) compared to those without obstruction (post-bronchodilator FEV(1)/FVC ratio > 0.70)., Results: Airflow obstruction consistent with COPD was confirmed in 26% of patients (mean age 52.9 years, FEV(1) 81.4% predicted and smoking history 39.8 pack-years) that reported chronic bronchitis symptoms. Airflow obstruction increased with age and smoking history. Slight or moderate dyspnea was reported by 68% of patients and the majority had not talked to their doctor about cough and continued to smoke., Limitations: Patients were evaluated at a single visit. The definition of airway obstruction used may have lead to overdiagnosis in patients aged 70 and older., Conclusion: This study confirms that many patients with COPD remain undiagnosed in the primary care setting. Evaluation of spirometry in patients with a smoking history and chronic bronchitis symptoms can aid in the diagnosis of COPD, allowing earlier treatment thereby reducing the burden of this debilitating disease., Clinical Trial Registration: Study code ADC109043; clinicaltrials.gov #NCT00442468.

Unlabelled: Sudden severe upper-airway obstruction occurring in a hospital setting can sometimes precipitate an episode of acute haemorrhagic pulmonary oedema. A review of 197 published case reports shows that the presenting feature is almost always the sudden appearance of blood stained fluid coming up through the larynx or out through the mouth and nose of an adult or child in obvious respiratory distress. Such overt features are seen in 10-15% of cases of sudden severe, but sub-lethal, upper-airway obstruction. Signs normally appear within minutes once the obstruction is relieved but are occasionally only recognized after 1-4 h. All signs and symptoms usually resolve within 12-24 h. Other causes of acute pulmonary haemorrhage are rare in young children., Conclusion: If what looks like blood is seen in, or coming from, the mouth or nose of a previously healthy young child who has suddenly become distressed and started to struggle for breath, that child has most probably suffered an episode of acute pulmonary oedema, and the commonest precipitating cause is sudden upper-airway obstruction.

Objectives: Asthma is frequently diagnosed in military personnel despite strict guidelines that disqualify persons with active disease or a recent history of asthma. It is generally considered incompatible with military service, because of the regular physical training, outdoor training exercises, and deployments to remote locations. The objective of this study was to determine the prevalence of airway hyperreactivity in asymptomatic military personnel, as an estimate of subclinical reactive airway disease., Methods: A prospective study of healthy, asymptomatic, military personnel with no previous history of asthma and <1 year on active duty status was conducted. After completion of a screening questionnaire, personnel underwent baseline spirometry with a portable spirometer. Personnel with obstructive indices (based on published guidelines) and matched control subjects participated in an exercise test (1.5-mile run), with pre- and postexercise spirometry., Results: A total of 222 asymptomatic military personnel completed baseline spirometry, and 31 (14%) were found have airway obstruction. A normal matched control group of 31 military personnel and 26 personnel with obstruction performed exercise spirometry. Twenty-three percent of the participants with obstruction demonstrated increased airway hyper-reactivity after exercise, based on a reduction in forced expiratory volume at 1 second, compared with 19% of control subjects., Conclusions: Asymptomatic airway obstruction has a prevalence of 14% in young military personnel. A significant percentage of individuals also have evidence of worsening obstruction during exercise. These data suggest that screening spirometry may identify early reactive airway disease in asymptomatic individuals and should be considered as a method to identify persons predisposed to developing symptomatic asthma.

Few disorders may manifest with predominantly sleep-related obstructive breathing. Obstructive sleep apnea (OSA) is a common disorder, varies in severity and is associated with significant cardiovascular and neurocognitive morbidity. It is estimated that between 8 and 18 million people in the United States have at least mild OSA. Although the exact mechanism of OSA is not well-delineated, multiple factors contribute to the development of upper airway obstruction and include anatomic, mechanical, neurologic, and inflammatory changes in the pharynx. OSA may occur concomitantly with asthma. Approximately 74% of asthmatics experience nocturnal symptoms of airflow obstruction secondary to reactive airways disease. Similar cytokine, chemokine, and histologic changes are seen in both disorders. Sleep deprivation, chronic upper airway edema, and inflammation associated with OSA may further exacerbate nocturnal asthma symptoms. Allergic rhinitis may contribute to both OSA and asthma. Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA. Treatment with CPAP therapy has also been shown to improve both daytime and nighttime peak expiratory flow rates in patients with concomitant OSA and asthma. It is important for allergists to be aware of how OSA may complicate diagnosis and treatment of asthma and allergic rhinitis. A thorough sleep history and high clinical suspicion for OSA is indicated, particularly in asthma patients who are refractory to standard medication treatments.

Objective: Quality control in the clinical pulmonary function laboratory has been well developed for spirometry and diffusing capacity but not for the measurement of TLC. The purpose of the present study was to test two approaches to this problem. First, we compared TLC by body plethysmography (TLCb) with a value predicted from TLC measured by multibreath helium dilution (TLCm). Concordance between the measured and predicted values would imply the validity of the measurements. Second, we measured the test-retest variability of TLCb, TLCm and TLC measured by single breath helium dilution (TLCs) to assess the consistency of the measurements., Methodology: We performed a prospective study of 815 veterans., Results: The prediction of TLCb from TLCm improved (r2 increased from 0.44 to 0.64) when FEV1/FVC and the difference between TLCm and TLCs were added to the model. The coefficient of variation for test-retest of TLCs, TLCm and TLCb were 8.9, 7.1 and 5.4%, respectively. Of all tests, 5.9% were inconsistent based on pathophysiology or measurement error and attributed mostly to TLCm., Conclusions: Prediction of TLCb from TLCm was not sufficiently accurate as to be useful for quality control. Comparison of TLCs, TLCm and TLCb may be useful for determining the internal data validity.

Lung disease is prevalent among workers. Occupational toxicant exposures have an important role in many cases of lung disease seen in workers. Most occupational lung diseases can be grouped into one of four categories that include asthma and the diffuse parenchymal lung diseases (also known as interstitial lung disease). Asthma is especially prevalent among workers, and occupational factors should be explored in all adults with asthma. A worker's visit to a primary care physician often represents the first opportunity to establish a link between lung disease and the workplace. Therefore, it is important to maintain a high level of suspicion about the potential etiologic role of workplace exposures, especially in new cases of lung disease among workers. Although accumulating absolute proof of work-relatedness may not be possible, a brief occupational history and physical evaluation can provide substantial evidence to effectively rule out, or begin to rule in, a link between work and lung disease.

Conditions associated with airflow obstruction are often over- and underdiagnosed. Prevalence estimates of undiagnosed airflow obstruction (UDAO) range from 3 to 12%. UDAO is a nonspecific physiologic abnormality that may be caused by a number of factors (eg, cigarette smoking) and can be the manifestation of many different disorders. The higher occurrence of UDAO among men, current or former smokers, and with advancing age provide preliminary evidence on probable causes and diagnoses (ie, chronic obstructive pulmonary disease). While cigarette smoking is associated with UDAO, a substantial proportion of persons have never smoked, particularly among women. Few studies suggest that this condition is associated with increased morbidity and mortality. While there is currently no evidence to support screening for UDAO, case-finding may have a role among persons with respiratory symptoms, who have ever smoked, with a family history of respiratory disease, or with occupational exposures to dusts or fumes.

Chronic obstructive pulmonary disease (COPD) is a common respiratory disorder that occurs in 10% to 15% of people who smoke, an estimated 16 million Americans. Asthma is also common. Spirometry is generally used to detect early COPD in smokers and to evaluate patients with respiratory symptoms. Although COPD and asthma account for most obstructive lung diseases, a broad spectrum of other disorders, including bronchiectasis, upper airway lesions, bronchiolar diseases, and some interstitial lung diseases, are associated with airflow obstruction. These less common forms of obstructive lung diseases are often misdiagnosed because of their uncommon occurrence and poor recognition. We describe the heterogeneous spectrum of disorders that can present with evidence of airflow obstruction and outline a diagnostic approach to obstructive lung disease.

Pulmonary flow loops display characteristic patterns and give clues to the underlying pathology of airway or parenchymal lung disease.

Study Objectives: To evaluate the distribution of airways obstruction in a general population sample., Methods: Cross-sectional epidemiologic survey of a general population sample living in Po Delta area (North Italy). Data on respiratory symptoms, diseases, and risk factors were collected through standardized interviewer-administered questionnaires. Lung function tests were performed, with criteria for defining airways obstruction based on the 1995 European Respiratory Society (ERS) statement (FEV(1)/vital capacity ratio < 88% predicted and < 89% predicted in men and women, respectively), "clinical" criteria (FEV(1)/FVC ratio < 70%), and the 1986 American Thoracic Society (ATS) statement (FEV(1)/FVC ratio < 75%)., Results: A total of 1,727 subjects aged > 25 years investigated from 1988 to 1991 were included. Prevalence rates of airways obstruction for subjects 25 to 45 years old and subjects >/= 46 years old were as follows: ERS, 10.8% and 12.2%; clinical, 9.9% and 28.8%; and ATS, 27% and 57%, respectively. When considering only moderate/severe obstruction, the rates were as follows: ERS, 0.4% and 3.6%; clinical, 0.3% and 4.4%; and ATS, 0.5% and 5.2%, respectively. The trend was confirmed after stratifying for smoking habit and the presence/absence of respiratory symptoms/diseases. The highest specificity and predictive value for any respiratory symptom/disease was shown by the ERS, and the lowest was shown by the ATS criterion, while the reverse was true for sensitivity; overall accuracy was slightly lower for the ATS criterion. Multiple logistic regression models indicated a higher number of significant associations with known risk factors for airways obstruction according to clinical and ATS criteria than ERS criterion., Conclusions: The prevalence of COPD in a general population depends very much on the criterion used for definition of airways obstruction. Further research is needed to reach a standardized and epidemiologically consistent criterion for airways obstruction.

COPD is easily detected in its preclinical phase using spirometry, and successful smoking cessation (a cost-effective intervention) prevents further disease progression. This consensus statement recommends the widespread use of office spirometry by primary-care providers for patients >/= 45 years old who smoke cigarettes. Discussion of the spirometry results with current smokers should be accompanied by strong advice to quit smoking and referral to local smoking cessation resources. Spirometry also is recommended for patients with respiratory symptoms such as chronic cough, episodic wheezing, and exertional dyspnea in order to detect airways obstruction due to asthma or COPD. Although diagnostic-quality spirometry may be used to detect COPD, we recommend the development, validation, and implementation of a new type of spirometry-office spirometry-for this purpose in the primary-care setting. In order to encourage the widespread use of office spirometers, their specifications differ somewhat from those for diagnostic spirometers, allowing lower instrument cost, smaller size, less effort to perform the test, improved ease of calibration checks, and an improved quality-assurance program.

Seizures are a frequent problem confronting EMS personnel. Most seizures will terminate by themselves in less than five minutes. Careful attention must be paid to the ABCs, including glucose. Seizures lasting more than five minutes should be treated with i.v. diazepam or lorazepam. Careful history-taking to look for possible causes of seizures, as well as a detailed description of the event, are invaluable to ED staff in the evaluation and treatment of a patient with a seizure. Patients with known epilepsy who have had a single typical seizure and are otherwise back to normal do not require transport to the hospital.