Consensus Statements on Deployment-Related Respiratory Disease, Inclusive of Constrictive Bronchiolitis: A Modified Delphi Study.

BACKGROUND: The diagnosis of constrictive bronchiolitis (CB) in previously deployed individuals, and evaluation of respiratory symptoms more broadly, presents considerable challenges, including using consistent histopathologic criteria and clinical assessments. RESEARCH QUESTION: What are the recommended diagnostic workup and associated terminology of respiratory symptoms in previously deployed individuals? STUDY DESIGN AND METHODS: Nineteen experts participated in a three-round modified Delphi study, ranking their level of agreement for each statement with an a priori definition of consensus. Additionally, rank-order voting on the recommended diagnostic approach and terminology was performed. RESULTS: Twenty-five of 28 statements reached consensus, including the definition of CB as a histologic pattern of lung injury that occurs in some previously deployed individuals while recognizing the importance of considering alternative diagnoses. Consensus statements also identified a diagnostic approach for the previously deployed individual with respiratory symptoms, distinguishing assessments best performed at a local or specialty referral center. Also, deployment-related respiratory disease (DRRD) was proposed as a broad term to subsume a wide range of potential syndromes and conditions identified through noninvasive evaluation or when surgical lung biopsy reveals evidence of multicompartmental lung injury that may include CB. INTERPRETATION: Using a modified Delphi technique, consensus statements provide a clinical approach to possible CB in previously deployed individuals. Use of DRRD provides a broad descriptor encompassing a range of postdeployment respiratory findings. Additional follow-up of individuals with DRRD is needed to assess disease progression and to define other features of its natural history, which could inform physicians better and lead to evolution in this nosology.

Postdeployment Respiratory Health: The Roles of the Airborne Hazards and Open Burn Pit Registry and the Post-Deployment Cardiopulmonary Evaluation Network.

Background: Following deployment to the Southwest Asia theater of operations and Afghanistan, many service members and veterans report respiratory symptoms and concerns about their military and environmental exposures. The US Department of Veterans Affairs (VA) established the national Airborne Hazards and Open Burn Pit Registry (AHOBPR) in 2014 to help better understand long-term health conditions that may be related to these exposures. Observations: The AHOBPR provides an online questionnaire and optional health evaluation performed by a primary care or environmental health clinician. The clinical evaluation provides an opportunity for the service member or veteran to talk with a health care professional about their symptoms, exposures, and potential treatment. Data derived from questionnaire responses and health evaluations facilitate medical surveillance and research. The VA also established a network of specialists, referred to as the Post-Deployment Cardiopulmonary Evaluation Network (PDCEN). The PDCEN identifies veterans within the AHOBPR who self-report certain conditions or have unexplained dyspnea and conducts comprehensive diagnostic evaluations. Primary objectives of PDCEN evaluations are to define respiratory and related conditions that are present, determine whether conditions are related to deployment, and work with the veteran's clinician to identify treatments and/or follow-up care to improve their health. We utilize a case example to illustrate the role of the primary care practitioner in connecting veterans to PDCEN clinical evaluations. Conclusions: AHOBPR clinical evaluations represent an initial step to better understand postdeployment health conditions. The PDCEN clinical evaluation extends the AHOBPR evaluation by providing specialty care for certain veterans requiring more comprehensive evaluation while systematically collecting and analyzing clinical data to advance the field.

Relationship between clinician documented blast exposure and pulmonary function: a retrospective chart review from a national specialty clinic.

BACKGROUND: Service member exposure to explosive blast overpressure waves is common with considerable attention to traumatic brain injury (TBI) and neuropsychological sequalae. Less is known about the impacts on the respiratory system, particularly long-term effects, despite vulnerability to overpressure. Using a national registry, we previously observed an independent relationship between self-reported blast exposure and respiratory symptoms; however, the impact on objective measures of pulmonary function is poorly understood. METHODS: 307 Veterans referred to our national specialty center for post-deployment health concerns underwent a comprehensive multi-day evaluation that included complete pulmonary function testing (PFT), occupational and environmental medicine history, neuropsychological or psychological evaluation. We developed an a priori chart abstraction process and template to classify Veterans into blast exposure groups: (1) none, (2) single-mild, or (3) multiple-mild. This template focused primarily on clinician documented notes of blast related TBI that were used as proxy for blast overpressure injury to thorax. PFT variables characterizing flow (FEV1%; %∆FEV1), volume (TLC%), diffusion (DLCO%) and respiratory mechanics (forced oscillometry) were selected for analysis. RESULTS: Veterans (40.5 ± 9.7 years; 16.3% female) were referred 8.6 ± 3.6 years after their last deployment and presented with considerable comorbid conditions and health problems (e.g., 62% post-traumatic stress, 55% dyspnea). After chart abstraction, Veterans were assigned to none (n = 208), single mild (n = 52) and multiple mild (n = 47) blast exposure groups. Among the blast exposed, clinicians documented 73.7% were < 50 m from the blast and 40.4% were physically moved by blast. PFT outcome measures were similar across all groups (p value range: 0.10-0.99). CONCLUSIONS: In this referred sample of deployed Veterans, PFT measures of flow, volume, diffusion, and respiratory mechanics were not associated with clinician documented blast exposure per the retrospective chart abstraction methodology applied. Yet, these clinical findings suggest future research should determine and assess distinction between Veteran recollections of perceived blast experiences versus overpressure wave exposure to the respiratory system.

Employing the Forced Oscillation Technique for the Assessment of Respiratory Mechanics in Adults.

There is increasing interest in the use of the forced oscillation technique (FOT) or oscillometry to characterize respiratory mechanics in healthy and diseased individuals. FOT, a complementary method to traditional pulmonary function testing, utilizes a range of oscillatory frequencies superimposed on tidal breathing to measure the functional relationship between airway pressure and flow. This passive assessment provides an estimate of respiratory system resistance (Rrs) and reactance (Xrs) that reflect airway caliber and energy storage and dissipation, respectively. Despite the recent increase in popularity and updated Technical Standards, clinical adoption has been slow which relates, in part, to the lack of standardization regarding the acquisition and reporting of FOT data. The goal of this article is to address the lack of standardization across laboratories by providing a comprehensive written protocol for FOT and an accompanying video. To illustrate that this protocol can be utilized irrespective of a particular device, three separate FOT devices have been employed in the case examples and video demonstration. This effort is intended to standardize the use and interpretation of FOT, provide practical suggestions, as well as highlight future questions that need to be addressed.

Exercise-Induced Bronchoconstriction in Iraq and Afghanistan Veterans With Deployment-Related Exposures.

INTRODUCTION: Acute exposure to high-levels of ambient fine particulate matter while exercising results in airway narrowing, but the long-term effects of repeated exposure on exercise-induced bronchoconstriction (EIB) are not well known. The goal of this preliminary study is to determine the rate of EIB among a sample of non-treatment seeking veterans deployed to Iraq and Afghanistan. MATERIALS AND METHODS: Twenty-four veterans (median [interquartile range]: 35.0 [27.3, 45] years) without history of asthma volunteered for this study. Spirometry was assessed before and after a standardized exercise challenge. A positive EIB response was defined as an exercise-induced fall in forced expiatory volume in 1 second ≥10%. Secondary criteria (peak flow ≥10% or mid-expiratory flow ≥15%) were also considered as an estimate of probable EIB. RESULTS: A positive EIB response was observed in 16.7% and probable EIB response was observed in 41.7% of our sample. Median deployment length to Iraq or Afghanistan was 13.0 [10.3, 17.5] months and the median time since deployment was 4.2 [2.7, 7.7] years. At the time of testing, veterans reported persistent cough (58.3%), wheeze (37.5%), and shortness of breath (37.5%). During deployment, veterans reported exposure to dust and sand (70.8%), smoke from burn pits (66.7%), vehicle exhaust (83.3%), and regional air pollution (26.0%) on most days or daily. CONCLUSIONS: Approximately 17% of our sample of non-treatment seeking deployed Iraq and Afghanistan veterans demonstrated EIB, similar to the general population prevalence. However, persistent respiratory symptoms and alternative indices of probable EIB supports continued monitoring of this population.

Forced oscillation technique in veterans with preserved spirometry and chronic respiratory symptoms.

PURPOSE: To evaluate the utility of the forced oscillation technique (FOT) among military veterans with preserved spirometry and chronic unexplained respiratory symptoms. METHODS: 178 veterans referred for evaluation of unexplained respiratory symptoms completed pulmonary function testing and FOT. Preserved spirometry was defined as FEV1/FVC, FEV1 and FVC ≥ 5th percentile. Frequency dependence of resistance (R4-R20) and reactance area (AX) were assessed via FOT, and R4-R20 ≥ 20% and AX ≥ 95th percentile were considered abnormal. RESULTS: Spirometry was preserved in 71.3%, of whom 124 had acceptable FOT data. 93 of 124 (75.0%) veterans with preserved spirometry had one or more abnormal findings on FOT. Veterans with abnormal R4-R20 and/or AX had reduced FVC, FEV1, FEF25-75, and diffusing capacity (% predicted) in comparison to those with Normal FOT (p = 0.030 to p < 0.001). CONCLUSIONS: In our referral sample, distal airway dysfunction in the presence of preserved spirometry appears common and may represent an at-risk group requiring closer surveillance.

Effects of Exercise Training on Pulmonary Function in Adults With Chronic Lung Disease: A Meta-Analysis of Randomized Controlled Trials.

OBJECTIVE: To quantify the effect of exercise training on indices of pulmonary function in adults with chronic lung disease using meta-analytic techniques. DATA SOURCES: Eligible trials were identified using a systematic search of MEDLINE, Web of Science, Physiotherapy Evidence Database, and GoogleScholar databases. STUDY SELECTION: Randomized controlled trials that evaluated pulmonary function before and after whole-body exercise training among adult patients (aged ≥19y) with chronic lung disease were included. DATA EXTRACTION: Data were independently extracted from each study by 3 authors. Random-effects models were used to aggregate a mean effect size (Hedges' d; Δ) and 95% confidence interval (CI), and multilevel linear regression with robust maximum likelihood estimation was used to adjust for potential nesting effects. DATA SYNTHESIS: Among 2923 citations, a total of 105 weighted effects from 21 randomized controlled trials were included. After adjusting for nesting effects, exercise training resulted in a small (Δ=.18; 95% CI, .07-.30) and significant (P=.002) improvement in a composite measure of pulmonary function. Tests of heterogeneity of the mean effect size were nonsignificant. CONCLUSIONS: Contrary to prior assumptions, whole-body exercise training is effective for improving pulmonary function in adults with chronic lung disease, particularly spirometric indices. Subsequent studies are necessary to determine the optimal exercise training characteristics to maximize functional improvement.

Isolated diffusing capacity reduction is a common clinical presentation in deployed Iraq and Afghanistan veterans with deployment-related environmental exposures.

Following deployment to Iraq and Afghanistan ("post-9/11"), a spectrum of respiratory conditions has been reported; however, there are few published reports of objective physiologic data or later experience of symptoms and function. To better understand the post-deployment clinical presentation, we conducted a retrospective review of pulmonary function testing in 143 veterans referred to our tertiary care clinic for post-deployment health concerns. More than 75% of our sample had normal lung volumes and spirometry on pulmonary function testing; however, an isolated reduction in lung diffusing capacity (DLCO) was observed in 30% of our sample of post-9/11 veterans. An isolated reduction in DLCO is a rare pattern in primary-care seeking dyspneic patients, but is commonly associated with underlying pulmonary disease. Post-9/11 veterans with respiratory complaints and an isolated reduction in DLCO should undergo further evaluation.

Bronchodilator Responsiveness and Airflow Limitation Are Associated With Deployment Length in Iraq and Afghanistan Veterans.

OBJECTIVE: The aim of this study was to determine the relationship between deployment length and indices of airflow obstruction in Iraq and Afghanistan veterans with airborne hazards exposure. METHODS: One hundred twenty-four post-9/11 veterans completed pulmonary function testing and questionnaires. We examined the association of airflow limitation [forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC)] and bronchodilator responsiveness (ΔFEV1 and ΔFVC) with deployment length, adjusting for smoking. RESULTS: Longer deployment length was associated with lower FEV1/FVC [ß = -0.19; 95% confidence interval (95% CI), -0.39 to 0.01], greater ΔFEV1 (ß = 0.27; 95% CI, 0.09 to 0.45) and ΔFVC (ß = 0.19; 95% CI, 0.05 to 0.33). In our model adjusted for smoking history, longer deployment length remained associated with greater ΔFEV1 and ΔFVC (P < 0.01), but not with FEV1/FVC (P = 0.059). CONCLUSION: In our sample of post-9/11 veterans, longer deployment lengths were associated with significant bronchodilator responsiveness and a trend toward airflow limitation independent of tobacco use.

Airborne hazards exposure and respiratory health of Iraq and Afghanistan veterans.

More than 2.6 million military personnel have been deployed to recent conflicts in Iraq and Afghanistan and were likely exposed to a variety of airborne hazards during deployment. Despite several epidemiologic reports of increased respiratory symptoms, whether or not these respiratory illnesses lead to reductions in lung function and/or specific pulmonary disease is unclear. We reviewed data published from 2001 to 2014 pertaining to respiratory health in military personnel deployed to Iraq and Afghanistan and found 19 unique studies. Study designs were primarily retrospective and observational in nature with patient symptom reporting and medical encounter data as primary outcome measures. Two case series reported on rare respiratory diseases, and one performed a standardized evaluation of new-onset respiratory symptoms. Respiratory outcomes in relation to proximity to a specific air pollution source (i.e., smoke from burning trash and sulfur mine fire) were described in 2 separate studies. Only 2 longitudinal investigations were identified comparing pre- and postdeployment measurement of exercise capacity. In summary, published data based on case reports and retrospective cohort studies suggest a higher prevalence of respiratory symptoms and respiratory illness consistent with airway obstruction. However, the association between chronic lung disease and airborne hazards exposure requires further longitudinal research studies with objective pulmonary assessments.