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International Journal of Chronic... 2021Bronchodilator responsiveness (BDR) is commonly used in the diagnosis of lung disease. Although small airways dysfunction is a feature of asthma and COPD, physiological...
BACKGROUND
Bronchodilator responsiveness (BDR) is commonly used in the diagnosis of lung disease. Although small airways dysfunction is a feature of asthma and COPD, physiological tests of small airways are not included in guidelines for BDR testing. This systematic review assessed the current evidence of BDR using small airways function in asthma and COPD.
METHODS
The systematic review used standard methodology with the protocol prospectively registered on PROSPERO (CRD42020164140). Electronic medical databases (EMBASE and Medline) were searched using related keywords. Abstracts and full texts were screened independently by two reviewers. Studies that reported the change of physiological small airways function and FEV were included in the review. The revised Cochrane risk of bias tool for RCT and NIH quality assessment tool for cohort and cross-sectional studies were used to evaluate the studies.
RESULTS
A total of 934 articles were identified, with 12 meeting the inclusion criteria. Ten studies included asthma patients, 1 study included COPD patients and 1 study included both asthma and COPD. A total of 1104 participants were included, of whom 941 were asthmatic, 64 had COPD and 109 were healthy controls. Studies were heterogeneous in design including the device, dose and time intervals for BDR assessment. A small airway BDR was seen for most tests in asthma and COPD, including oscillometry (R5-20, reactance (X5), area of reactance (AX) and resonant frequency (Fres)) and Maximal Mid Expiratory Flow.
CONCLUSION
There is a measurable BDR in the small airways. However, with no consensus on how to assess BDR, studies were heterogeneous. Further research is needed to inform how BDR should be assessed, its clinical impact and place in routine clinical practice.
Topics: Adult; Asthma; Bronchodilator Agents; Cross-Sectional Studies; Forced Expiratory Volume; Humans; Pulmonary Disease, Chronic Obstructive; Spirometry
PubMed: 34795479
DOI: 10.2147/COPD.S331995 -
Journal of Applied Physiology... May 2019Respiratory system reactance (Xrs) measured by the forced oscillation technique (FOT) is theoretically and experimentally related to lung volume. In chronic obstructive...
Respiratory system reactance (Xrs) measured by the forced oscillation technique (FOT) is theoretically and experimentally related to lung volume. In chronic obstructive pulmonary disease (COPD), the absolute volume measured by body plethysmography includes a proportion that is inaccessible to pressure oscillations applied via the mouth, that is, a "noncommunicating" lung volume. We hypothesized that in COPD the presence of noncommunicating lung would disrupt the expected Xrs-volume relationship compared with plethysmographic functional residual capacity (FRC). Instead, Xrs would relate to estimates of communicating volume, namely, expiratory reserve volume (ERV) and single-breath alveolar volume (Va). We examined FOT and lung function data from people with COPD ( = 51) and from healthy volunteers ( = 40). In healthy volunteers, we observed an expected inverse relationship between reactance at 5 Hz (X5) and FRC. In contrast, there was no such relationship between X5 and FRC in COPD subjects. However, there was an inverse relationship between X5 and both ERV and Va. Hence the theoretical Xrs-volume relationship is present in COPD but only when considering the communicating volume rather than the absolute lung volume. These findings confirm the role of reduced communicating lung volume as an important determinant of Xrs and therefore advance our understanding and interpretation of FOT measurements in COPD. To investigate the determinants of respiratory system reactance (Xrs) measured by the forced oscillation technique (FOT) in chronic obstructive pulmonary disease (COPD), we examine the relationship between Xrs and lung volume. We show that Xrs does not relate to absolute lung volume (functional residual capacity) in COPD but instead relates only to the volume of lung in communication with the airway opening. This communicating volume may therefore be fundamental to our interpretation of FOT measurements in COPD and other pulmonary diseases.
Topics: Adult; Aged; Airway Resistance; Female; Forced Expiratory Volume; Functional Residual Capacity; Humans; Lung; Male; Oscillometry; Pulmonary Disease, Chronic Obstructive; Spirometry; Tidal Volume; Vital Capacity
PubMed: 30763164
DOI: 10.1152/japplphysiol.00503.2018 -
The Clinical Respiratory Journal Feb 2022The literature provides some evidence of peripheral airways key role in the pathogenesis of asthma. However, the extent to which lung periphery including acinar zone...
OBJECTIVE
The literature provides some evidence of peripheral airways key role in the pathogenesis of asthma. However, the extent to which lung periphery including acinar zone contribute to asthma activity and control in pediatric population is unclear. Therefore, the aim of the study was to estimate peripheral airways involvement in children with asthma exacerbation and stable asthma simultaneously via different pulmonary function tests.
METHODS
Children with asthma exacerbation (n = 20) and stable asthma (n = 22) performed spirometry, body plethysmography, exhaled nitric oxide, impulse oscillometry (IOS), and multiple-breath washout (MBW).
RESULTS
Peripheral airway's function indexes were increased in children with asthma, particularly in group with asthma exacerbation when compared with stable asthma group. The prevalence of abnormal results was significantly higher in asthma exacerbation. All children with asthma exacerbation had conductive ventilation inhomogeneity; 76% had acinar ventilation inhomogeneity. According to IOS measurements, resistance and reactance were within normal range, but other IOS parameters were significantly higher in children with asthma exacerbation compared with stable asthma group. The 36% of children with acute asthma had air trapping.
CONCLUSION
Significant involvement of peripheral airways was observed in children with asthma, particularly in asthma exacerbation, which determine lung periphery as important additional target for therapy and provide new insights into pathophysiological process of pediatric asthma.
Topics: Asthma; Child; Exhalation; Humans; Lung; Respiratory Function Tests; Spirometry
PubMed: 34676678
DOI: 10.1111/crj.13456 -
Journal of Thoracic Disease Mar 2021Respiratory function declines after lung resection. However, perioperative changes in respiratory impedance and their clinical significance are unclear. The forced...
BACKGROUND
Respiratory function declines after lung resection. However, perioperative changes in respiratory impedance and their clinical significance are unclear. The forced oscillation technique can measure respiratory impedance during quiet breathing and possibly early after surgery. We investigated respiratory impedance changes before and after lung lobectomy and examined the correlation of impedance with clinical factors.
METHODS
We prospectively included patients who underwent lobectomy between February 2018 and March 2020 and measured respiratory impedance by forced oscillation preoperatively and postoperative days 1 and 7. We statistically analyzed changes in perioperative forced oscillation measurements and their correlation with clinical factors, including subjective symptoms. The modified British Medical Research Council scale and the chronic obstructive pulmonary disease (COPD) assessment test were used for scoring subjective symptoms.
RESULTS
Forty-four subjects were included, in whom respiratory impedance could be measured from postoperative day 1. The respective mean values for forced oscillation measurements preoperatively and at postoperative days 1 and 7 were as follows: respiratory resistance, 5 Hz: 2.28, 2.77, and 2.75; respiratory resistance, 20 Hz: 2.00, 2.36, and 2.32; difference in respiratory resistance at 5 and 20 Hz: 0.28, 0.40, and 0.43; respiratory reactance, 5 Hz: -0.31, -0.65, and -0.56; resonant frequency: 7.45, 10.41, and 9.81; and low-frequency reactance area: 1.33, 3.27, and 2.84. These changes were statistically significant (P<0.01). Besides the difference in respiratory resistance at 5 and 20 Hz, all other measurements on postoperative day 7 were relatively weakly correlated with the modified Medical Research Council scale score at this time point (all P<0.05). Respiratory complications correlated with the respiratory resistance difference, respiratory reactance, and resonant frequency on day 7 (R =0.415, -0.421, and 0.441), while the latter also correlated with postoperative hypoxemia on day 1 (R =0.433).
CONCLUSIONS
Respiratory impedance was measurable even early after surgery and significantly changed postoperatively. As the sample size was small and appeared to be biased, assessing respiratory impedance and clinical factors in detail was difficult. Since respiratory impedance is suggested to be associated with clinical factors that affect the postoperative course, it is necessary to accumulate cases and observe them over longer periods.
PubMed: 33841928
DOI: 10.21037/jtd-20-3090 -
Wiener Klinische Wochenschrift May 2023After COVID-19 infection, persistent exercise intolerance, changes in lung function have been shown. Our aim is to investigate the correlation between impulse...
BACKGROUND
After COVID-19 infection, persistent exercise intolerance, changes in lung function have been shown. Our aim is to investigate the correlation between impulse oscillometry (IOS) parameters and exercise capacity by using incremental and endurance shuttle walk tests (ISWT, ESWT) and investigate the factors and parameters which might have an effect on both IOS parameters and exercise capacity tests.
METHOD
The patients who had a history of COVID-19 were enrolled into cross-sectional study according to inclusion criteria. The IOS parameters, ISWT, ESWT, smoking status, time since COVID-19 diagnosis, length of hospital stay, forced vital capacity (FVC), forced expiratory volume in one second (FEV1), body mass index (BMI), fat-free mass index (FFMI), dyspnea, hospital anxiety-depression and fatigue severity scores were recorded.
RESULTS
The study comprised 72 patients, 71% of whom were male, with a mean age of 54 ± 10 years. After COVID-19 diagnosis, the median duration was 3 (min: 1, max: 5) months and 51 (71%) of the patients were hospitalized. The FEV1 and FVC values were in normal range. The area of reactance (AX), resonance frequency (Fres), reactance at 20 Hz (X20) and the difference between resonance at 20 and 5 Hz (R5-20) correlated with both ISWT and ESWT. The FEV1 correlated with all IOS parameters (p < 0.05). Reactance correlated with FFMI (p = 024, r = 0.267), different according to hospitalization (p = 0.02).
CONCLUSION
In COVID-19 survivors, there could be correlations between IOS parameters and exercise capacity; and between these parameters and FEV and FVC. Furthermore, small airway disease with normal spirometric functions could be related to decreased exercise capacity in COVID-19 survivors regardless of concomitant diseases, BMI, smoking status and time since COVID-19 diagnosis.
Topics: Humans; Male; Adult; Middle Aged; Female; Oscillometry; Cross-Sectional Studies; COVID-19 Testing; Exercise Tolerance; Spirometry; COVID-19
PubMed: 36583749
DOI: 10.1007/s00508-022-02137-5 -
The European Respiratory Journal Aug 2021
Topics: Aged; Airway Obstruction; Asthma; Forced Expiratory Volume; Humans; Lung; Non-Smokers; Pulmonary Disease, Chronic Obstructive
PubMed: 33863745
DOI: 10.1183/13993003.04400-2020 -
Therapeutic Advances in Respiratory... 2023A few studies have reported the medium-sized and small airway morphological abnormalities of bronchiolitis. Whether spirometry or impulse oscillometry (IOS) is...
BACKGROUND
A few studies have reported the medium-sized and small airway morphological abnormalities of bronchiolitis. Whether spirometry or impulse oscillometry (IOS) is correlated with airway remodeling of bronchiolitis remains unclear.
OBJECTIVES
Aiming to demonstrate the airway morphological abnormalities of bronchiolitis obliterans (BO) and diffuse panbronchiolitis (DPB) assessed by endobronchial optical coherence tomography (EB-OCT), and elucidate whether spirometric and IOS parameters have correlation with the airway remodeling of bronchiolitis.
METHODS
We recruited 18 patients with bronchiolitis (BO, = 9; DPB, = 9) and 17 control subjects. Assessments of clinical features, St. George's respiratory questionnaire (SGRQ), chest computed tomography (CT), spirometry, IOS, and EB-OCT were performed in all enrolled subjects. The correlation between EB-OCT and lung function parameters was studied and analyzed.
RESULTS
The magnitude of abnormalities of spirometric and IOS parameters was significantly greater in patients with bronchiolitis than that in control subjects ( < 0.05). Patients with BO had notably lower forced expiratory volume in 1 s (FEV), forced vital capacity (FVC), FEV/FVC, maximal mid-expiratory flow (MMEF)% pred and higher resonant frequency (Fres), and area of reactance (AX) than those with DPB ( < 0.05). The EB-OCT measurement among patients with bronchiolitis and between the bronchus in the left and the right lung demonstrated a heterogeneous distribution of airway calibers, presenting a high intra- and inter-individual variability. Patients with bronchiolitis had notably greater airway wall area ( < 0.05) compared with control, while BO presented greater magnitude of airway abnormalities than DPB. Fres and the difference in airway resistance at 5 and 20 Hz (R-R) correlated negatively with medium-sized and small airway inner area, and correlated positively with airway wall area ( < 0.05), whose correlation coefficients were higher than those of spirometric parameters.
CONCLUSION
Bronchiolitis, BO and DPB, manifested a heterogeneous distribution of airway calibers with significant intra- and inter-individual variability. IOS parameters, rather than spirometry, correlated better with medium-sized and small airway remodeling in bronchiolitis assessed by EB-OCT measurement.
Topics: Humans; Tomography, Optical Coherence; Airway Remodeling; Lung; Respiratory Function Tests; Spirometry; Forced Expiratory Volume; Bronchiolitis
PubMed: 37073792
DOI: 10.1177/17534666231167351 -
Comparative evaluation of expiratory airflow limitation between patients with COPD and BE using IOS.Scientific Reports Feb 2021Impulse oscillometry (IOS) allows evaluation of the compartmentalized resistance and reactance of the respiratory system, distinguishing central and peripheral... (Comparative Study)
Comparative Study
Impulse oscillometry (IOS) allows evaluation of the compartmentalized resistance and reactance of the respiratory system, distinguishing central and peripheral obstruction. The IOS measurements are getting attention in the diagnosis and differentiation of chronic respiratory diseases. However, no data are available in the literature to differentiate between COPD and BE using IOS parameters. We aimed to evaluate the feasibility of IOS in the diagnosis of bronchiectasis non-cystic fibrosis (BE) in comparison to COPD. Whole breath, inspiration, expiration, and inspiratory-expiratory difference (Δ) were evaluated based on the IOS parameters: total resistance (R5), central airway resistance (R20), peripheral airway resistance (R5-R20), reactance (X5), reactance area (AX), and resonance frequency (Fres). Fifty-nine subjects (21 Healthy, 19 BE, and 19 COPD) participated in this study. It was observed a significant difference in the comparison of healthy and pulmonary disease groups (BE and COPD) for total breathing (R5-R20, X5, AX, and Fres), inspiratory phase (R5 and R5-R5), and expiratory phase (R5-R20 and X5). The comparison between BE and COPD groups showed significant difference in the expiratory phase for resistance at 5 and 20 Hz and, ΔR5 and ΔR20. The IOS evidenced an increase of R5, R20 and R5-R20 in patients with BE and COPD when compared to healthy subjects. Expiratory measures of IOS revealed increased airway resistance in COPD compared to BE patients who had similar FEV1 measured by spirometry, however, further studies are needed to confirm these differences.
Topics: Aged; Airway Resistance; Bronchiectasis; Case-Control Studies; Disease Management; Female; Forced Expiratory Volume; Humans; Male; Middle Aged; Oscillometry; Pulmonary Disease, Chronic Obstructive; Pulmonary Ventilation; Respiratory Function Tests; Spirometry
PubMed: 33633234
DOI: 10.1038/s41598-021-84028-9 -
Respiratory Care May 2018Impulse oscillometry is a method of airway assessment and diagnosis that provides data on lung mechanics. In the literature, studies have used different types of...
BACKGROUND
Impulse oscillometry is a method of airway assessment and diagnosis that provides data on lung mechanics. In the literature, studies have used different types of mouthpieces or did not describe the model used for the tests. We sought to compare the 3 most commonly described mouthpieces in terms of test results, comfort, and subject preference.
METHODS
Thirty-nine healthy volunteers were evaluated with spirometry and impulse oscillometry, assessing the resistance at 5 Hz and 20 Hz (R5 and R20, respectively), reactance at 5 Hz (X5), reactance area, and resonant frequency. A filter heat exchanger with a circular mouthpiece (B1), a filter heat exchanger with an oval mouthpiece (B2), and a filter heat exchanger with a circular mouthpiece coupled with a free-flow piece (B3) were compared using an acceptability and tolerance scale, and subjects noted their preference.
RESULTS
Statistical analysis showed differences between all the mouthpieces and the predicted values for R5, R20, and X5. The mouthpiece comparison showed differences in R5 between a filter heat exchanger with an oval mouthpiece (B2) and a circular mouthpiece coupled with a free-flow piece (B3) ( = .007); resonant frequency between a filter heat exchanger with a circular mouthpiece (B1) and a filter heat exchanger with an oval mouthpiece (B2) ( = .004) and between a filter heat exchanger with a circular mouthpiece (B1) and a circular mouthpiece coupled with a free-flow piece (B3) ( = .003); and reactance area between a filter heat exchanger with a circular mouthpiece (B1) and a circular mouthpiece coupled with a free-flow piece (B3) ( = .01). In the subjective evaluation, acceptability and tolerance differences were found in the ease of carrying out the evaluation, and no difference was found with regard to the degree of discomfort. Ten subjects preferred a filter heat exchanger with a circular mouthpiece (B1), 15 preferred a filter heat exchanger with an oval mouthpiece (B2), and 14 preferred a circular mouthpiece coupled with a free-flow piece (B3).
CONCLUSIONS
A circular mouthpiece coupled with a free-flow piece (B3) appeared to be the most suitable mouthpiece for the impulse oscillometry tests. It assured smaller impedance values for the respiratory system, and subjects expressed the most confidence in using this mouthpiece.
Topics: Adult; Airway Resistance; Equipment Design; Female; Healthy Volunteers; Humans; Lung; Male; Oscillometry; Respiratory Function Tests; Respiratory Mechanics
PubMed: 29487095
DOI: 10.4187/respcare.05471 -
European Clinical Respiratory Journal 2015Interstitial lung disease often occurs as an early complication of systemic sclerosis (SSc). The aim was to investigate whether impulse oscillometry (IOS) could be used...
BACKGROUND
Interstitial lung disease often occurs as an early complication of systemic sclerosis (SSc). The aim was to investigate whether impulse oscillometry (IOS) could be used to evaluate lung impairment in SSc.
METHODS
Seventy-eight SSc patients, of which 65 had limited cutaneous SSc (lcSSc) and 13 had diffuse cutaneous SSc (dcSSc), were subjected to high-resolution computed tomography (HRCT) and pulmonary function tests (spirometry, IOS, and single breath CO diffusion capacity test). Twenty-six healthy individuals served as controls.
RESULTS
Patients with lcSSc had higher levels of peripheral airway resistance, that is, R5-R20 (difference between resistance at 5 Hz and resistance at 20 Hz) showed a median (and interquartile range) of 0.05 (0.02-0.09) in lcSSc, 0.01 (0.00-0.04) in dcSSc and 0.04 (0.01-0.06) in healthy controls. They also had higher levels of reactance: reactance area was 0.26 (0.15-0.56) in lcSSc, 0.20 (0.11-0.29) in dcSSc and 0.18 (0.08-0.30) in healthy controls, and resonant frequency was 10.9 (8.8-14.8) in lcSSc, 9.0 (8.3-11.6) in dcSSc and 9.1 (8.0-13.1) in healthy controls. Airway reactance correlated to fibrotic findings on HRCT, such as ground glass opacities and reticulations.
DISCUSSION
This implies that IOS parameters to some extent are related to fibrosis in patients with SSc.
PubMed: 26672963
DOI: 10.3402/ecrj.v2.28667