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

Dynamic hyperinflation on exercise and its relationship with lung mechanics at rest in adults with central obesity

This study aimed to evaluate the presence of dynamic hyperinflation (DH) during the Glittre-ADL test (TGlittre) coupled to the dynamic ventilation measurements in people with central obesity (pwCO) and to correlate it with lung mechanics at rest. Sixty-four pwCO underwent TGlittre and the following resting lung function tests: spirometry and impulse oscillometry system (IOS). On TGlittre, 22 participants presented DH at the end of the test (DH group), while 42 did not present DH (NDH group). Body mass index (BMI), waist circumference (WC), and hip circumference (HC) were higher in the DH group than in the NDH group. IOS abnormalities were more common in the DH group compared to the NDH group. TGlittre time significantly correlated with BMI, WC, waist-to-hip ratio (WHR), and neck circumference (NC). Delta inspiratory capacity correlated significantly with WC, HC, NC, and resonance frequency measured by IOS. Thus, pwCO perform worse on TGlittre, and DH is frequent in those with higher anthropometric indices and worse lung mechanics.

Performance of Impulse Oscillometry in Identifying Restrictive Lung Defects in a Veteran Cohort

Background

Impulse oscillometry (IOs) is a technique used to evaluate lung function that uses sound waves imposed over tidal breathing to characterize the airways and lung parenchyma. IOs has been particularly useful in the identification of obstructive lung defects. The present analysis seeks to explore the use of IOs in the identification of restrictive lung physiology among a group of Gulf War I veterans exposed to depleted uranium (DU).

Methods

A total of 36 out of a dynamic 85-veteran cohort attended in-person surveillance visits in 2019 and completed both IOs and PFTs. Performance on IOs was evaluated in a cross-sectional analysis of the group overall and in those identified as having restrictive lung defects defined by either spirometry (FEV1/FVC ≥ LLN and FVC < LLN) or lung volumes (TLC < LLN).

Results

A total of 6 individuals were identified as having restriction (4 based on spirometry alone and an additional 2 by lung volumes). When restriction was present, IOs values of both resistance and reactance were significantly more abnormal.

Conclusion

In the assessment of lung function, IOs may be advantageous over PFTs because it is faster to perform and effort-independent. Although little is known about the utility of IOs in identifying restrictive lung physiology, our results support its use.

Effects of pulmonary rehabilitation on ventilation dynamics measured during exertion in patients with post-acute COVID-19 syndrome: A cross-sectional observational study

BACKGROUND

Pulmonary rehabilitation (PR) is recommended in people with post-acute COVID-19 syndrome (PACS), although there is a lack of studies evaluating its benefits via the most commonly used primary endpoint: the six-minute walk test (6MWT). This study evaluated the effects of PR on the dynamics of ventilation measured during the 6MWT in patients with PACS and, secondarily, evaluated the association of these findings with measures of lung function and structure.

METHODS

This was an observational cross-sectional study of patients with PACS, in which 33 had undergone PR (PR-PACS group) and 32 had not undergone PR (NPR-PACS group). These patients underwent Spiropalm®-equipped 6MWT with measurement of inspiratory capacity (IC) to evaluate dynamic hyperinflation (DH). In addition, they performed spirometry, impulse oscillometry (IOS) and lung ultrasound (LUS).

RESULTS

Spirometry was abnormal in 21.2% and 31.3% of participants in the PR-PACS and NPR-PACS groups, respectively (p = 0.36). IOS was abnormal in 28.6% and 66.7% of participants in the PR-PACS and NPR-PACS groups, respectively (p = 0.003). LUS was altered in 39.4% and 43.8% of the participants in the PR-PACS and NPR-PACS groups, respectively (p = 0.72). The 6-min walk distance (6MWD) was greater in the PR-PACS group than in the NPR-PACS group (p = 0.001]. HD was observed in 6.1% and 37.5% of participants in the PR-PACS and NPR-PACS groups, respectively, with a significant difference in ΔIC (p<0.001). The 6MWD correlated significantly with several IOS parameters and with ΔIC.

CONCLUSIONS

Patients with PACS undergoing PR perform better in the 6MWT, with a higher 6MWD and less HD. In these patients, IOS is able to distinguish the effects of PR that are not differentiated by spirometry or LUS. Furthermore, the better the respiratory mechanics assessed by IOS and the less DH there was, the higher the performance in the 6MWT.

Impulse oscillometry indices in relation to respiratory symptoms and spirometry in the Swedish Cardiopulmonary Bioimage Study

Background

Impulse oscillometry (IOS) is sensitive in detecting lung function impairment. In small studies, impaired IOS relates better to respiratory symptoms than spirometry. We studied how IOS related to spirometry and respiratory symptoms in a large population of individuals (n=10 360) in a cross-sectional analysis.

Methods

Normal values for IOS and spirometry were defined in healthy, never-smoking individuals, aged 50-64 years, from the Swedish CArdioPulmonary bioImage Study (n=3664 for IOS and 3608 for spirometry). For IOS, abnormal values for resistance at 5 Hz (R5) and at 20 Hz and area of reactance were defined using the 95th percentile. Abnormal reactance at 5 Hz for IOS and abnormal conventional spirometry indices (forced expiratory volume in 1 s (FEV1), forced and slow vital capacity and their ratios) were defined using the 5th percentile.

Results

Abnormal IOS parameters were found in 16% of individuals and were associated with increased odds ratios for nearly all respiratory symptoms when adjusted for age, gender and smoking. In individuals with normal spirometry, abnormal IOS resistance was related to cough and dyspnoea, while abnormal reactance was related to wheeze. In these individuals, the combination of abnormal R5 with abnormal reactance resulted in approximately two-fold higher likelihood for having cough, chronic bronchitis and dyspnoea, even when further adjusting for FEV1, expressed as % predicted.

Conclusions

Abnormal IOS is related to increased respiratory burden in middle-aged individuals with normal spirometry, especially when resistance and reactance parameters are combined. The different relationships between respiratory symptoms and reactance and resistance warrant further research.

Ventilation dynamics using a portable device coupled to the six-minute walk test in people with long-COVID syndrome: a preliminary study

OBJECTIVE

To investigated the dynamic ventilatory responses and their influence on functional exercise capacity in patients with long-COVID-19 syndrome (LCS).

RESULTS

Sixteen LCS patients were subjected to resting lung function (spirometry and respiratory oscillometry-RO) and cardiopulmonary performance to exercise (Spiropalm®-equipped six-minute walk test-6MWT and cardiopulmonary exercise test-CPX). At rest, spirometry showed a normal, restrictive and obstructive pattern in 87.5%, 6.25% and 6.25% of participants, respectively. At rest, RO showed increased resonance frequency, increased integrated low-frequency reactance and increased difference between resistance at 4-20 Hz (R4-R20) in 43.7%, 50%, and 31.2% of participants, respectively. The median of six-minute walking distance (DTC6) was 434 (386-478) m, which corresponds to a value of 83% (78-97%) of predicted. Dynamic hyperinflation (DH) and reduced breathing reserve (BR) were detected in 62.5% and 12.5% of participants, respectively. At CPX, the median peak oxygen uptake (VO_2peak) was 19 (14-37) ml/kg/min. There was a significant correlation of 6MWD with both R4-R20 (r_s=-0.499, P = 0.039) and VO_2peak (r_s=0.628, P = 0.009). Our results indicate that DH and low BR are contributors to poor exercise performance, which is associated with peripheral airway disease. These are promising results considering that they were achieved with simple, portable ventilatory and metabolic systems.

Lung Function Reference Equations for Indian Ethnic Groups Based on a Handheld Forced Oscillation Device for Age 9-19 Years

OBJECTIVE

To develop regression equations to predict forced oscillation technique (FOT) parameters in Indian children and adolescents.

METHODS

Lung function was assessed in a multigeographic cohort of residential school children using a portable FOT-based device (PulmoScan) and spirometry. FOT measurements were performed in 1497 study participants, aged 9-19 y, from 8 Indian districts. Bland-Altman analysis was performed for additional 32 adult subjects to compare the results of PulmoScan to a standard IOS device in an outpatient setting. Reference equations were developed for R_rs and X_rs from the data of healthy subjects with normal spirometry using multivariate regression model for Indo-European, Dravidian, and mixed ethnic groups.

RESULTS

X5 (bias = 0.02) showed a better agreement than resistance parameters (R5 bias = 0.75, R20 bias =  -0.22) in IOS/PulmoScan comparison. Anthropometric variables (age, height, and weight) were positively correlated with reactance (X5) and negatively with resistance parameters (R5, R10, R15, and R20), with most associations being stronger in boys. Final regression model considered ethnicity as a key determinant along with anthropometry.

CONCLUSION

Multiethnic reference equations were developed for Indian children aged 9-19 y based on a novel handheld FOT device.

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 (DL_CO%) 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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02071-0.

Can home rehabilitation impact impulse oscillometry and lung ultrasound findings in patients with scleroderma-associated interstitial lung disease? A pilot study

Objective

Exercise has been demonstrated to be beneficial for improving physical capacity and quality of life in people with scleroderma, although knowledge of its impact on the respiratory system is limited. This study evaluated the impact of therapist-oriented home rehabilitation (TOHR) on impulse oscillometry (IOS) and lung ultrasound (LUS) findings in patients with scleroderma-associated interstitial lung disease (ILD).

Results

Twelve women with scleroderma underwent spirometry, IOS, and LUS before and after performing TOHR. Regarding spirometry, a normal pattern and restrictive damage were observed in five (41.7%) and seven (58.3%) participants pre-TOHR and post-TOHR, respectively. For IOS, an abnormal result was detected in nine (75%) pre-TOHR participants and six (50%) post-TOHR participants. Heterogeneity of resistance between 4–20 Hz (R4-R20) > 20% of the predicted value was observed in eight (66.7%) pre-TOHR participants and three (25%) post-TOHR participants (P = 0.031). An abnormal LUS result was observed in nine (75%) participants both pre-TOHR and post-TOHR. The main change observed was B-lines > 2, which was noted in nine (75%) participants both pre-TOHR and post-TOHR. Our findings suggest that TOHR for women with scleroderma-associated ILD improves the resistance and reactance measured by IOS, including small airway disease.

Trial Registration ClinicalTrials.gov ID: NCT05041868 Registered on: 13th September 2021.

Small airway dysfunction on impulse oscillometry and pathological signs on lung ultrasound are frequent in post-COVID-19 patients with persistent respiratory symptoms

Background

Thousands of people worldwide are suffering the consequences of coronavirus disease-2019 (COVID-19), and impulse oscillometry (IOS) and lung ultrasound (LUS) might be important tools for the follow-up of this population. Our objective was to prospectively evaluate abnormalities detected using these two methods in a cohort of COVID-19 survivors with respiratory symptoms.

Methods

In this follow-up study, 59 patients underwent clinical evaluations, spirometry, IOS and LUS in the 2nd (M1) and 5th (M2) months after diagnostic confirmation of COVID-19 by real-time reverse transcriptase–polymerase chain reaction. Aeration scores were obtained from the LUS exams based on the following findings: B-lines >2, coalescent B-lines, and subpleural consolidations.

Results

Fifty-nine (100%) participants had cough and/or dyspnea at M1, which decreased to 38 (64.4%) at M2 (p = 0.0001). Spirometry was abnormal in 26 (44.1%) and 20 (33.9%) participants at M1 and M2, respectively, although without statistical significance (p = 0.10). Normal examination, restrictive patterns, and obstructive patterns were observed in 33 (55.9%), 18 (30.5%), and 8 (13.6%) participants, respectively, at M1 and in 39 (66.1%), 13 (22%), and 7 (11.9%) participants at M2 (p = 0.14). Regarding IOS, considering changes in resistive and reactive parameters, abnormal exams were detected in 52 (88.1%) and 42 (71.2%) participants at M1 and M2, respectively (p = 0.002). Heterogeneity of resistance between 4 and 20 Hz >20% was observed in 38 (64.4%) and 33 (55.9%) participants at M1 and M2, respectively (p = 0.30). Abnormal LUS was observed in 46 (78%) and 36 (61%) participants at M1 and M2, respectively (p = 0.002), with a reduction in aeration scores between M1 and M2 [5 (2–8) vs. 3 (0–6) points, p<0.0001].

Conclusions

IOS and LUS abnormalities are frequent in the first 5 months post-COVID-19 infection; however, when prospectively evaluated, significant improvement is evident in the parameters measured by these two methods.

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.

The pragmatic role of FEF25-75 in asymptomatic subjects, allergic rhinitis, asthma, and in military setting

Introduction: The forced expiratory flow between 25% and 75% of forced vital capacity (FEF_25-75) is a spirometry parameter that may be useful in many clinical settings. Values <65% of predicted have been defined as abnormal.Areas covered: The current report discusses the clinical value of FEF_25-75 in different settingv, namely military medicine, primary care, and specialized clinic. Moreover, the predictive role of FEF_25-75 was discussed considering different patients' populations, including patients suffering from allergic rhinitis and/or asthma, as well as normal subjects. The most recent literature concerning the assessment of FEF_25-75 in these covered areas was searched.Expert opinion: In clinical practice, impaired values have been defined as a reliable surrogate marker for bronchial airflow limitation associated with early onset of asthma, bronchial hyperresponsiveness, lower airway inflammation, reversibility to bronchodilation testing, allergic sensitization, and uncontrolled asthma. In the military medicine setting, simple spirometry, including FEF_25-75, may suggest a series of fruitful information.