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Asian Pacific Journal of Allergy and... Dec 2021Small airways dysfunction (SAD) is not uncommon in asthma without fixed airflow obstruction (FAO).
BACKGROUND
Small airways dysfunction (SAD) is not uncommon in asthma without fixed airflow obstruction (FAO).
OBJECTIVE
We aimed to determine if SAD in non-FAO asthma is different from FAO-asthma and COPD.
METHODS
Cases of obstructive airway diseases who underwent spirometry, plethysmography, and impulse oscillometry [resistance at 5 Hz (R5) and at 20 Hz (R20), peripheral resistance (R5-R20), and reactance area (AX)] were reviewed, and classified as; 1) COPD, 2) FAO-asthma, and 3) non-FAO asthma. FAO was defined as post-bronchodilator (post-BD) FEV1/ FVC < 0.7. SAD was considered if 1) RV/TLC ≥ 40%, or 2) post-BD R5-R20 ≥ 0.075 kPa.L-1s.
RESULTS
A total of 73 patients (22 COPD, 24 FAO-asthma, and 27 non-FAO asthma) were analyzed. RV/TLC ratio was higher in FAO-asthma and COPD (45 ± 5% and 42 ± 8%) than in non-FAO asthma (32 ± 8%), p < 0.001. Post-BD values of R5-R20 and AX (median; range) were higher in FAO-asthma (0.17; 0.08, 0.47, 13.24; 6.52, 82.11) than in non-FAO asthma (0.11; 0.03, 0.23, 8.63; 2.40, 22.02), p = 0.007 and p = 0.017, respectively. The prevalence of SAD among diagnosis group by RV/TLC criterion was different (95%, 59%, and 15% in FAO-asthma, COPD, and non-FAO asthma, p < 0.001), but those were not observed by R5-R20 criterion (95%, 68%, and 77%, p = 0.052).
CONCLUSIONS
SAD in non-FAO asthma was less prevalent than FAO-asthma and COPD.
Topics: Asthma; Forced Expiratory Volume; Humans; Oscillometry; Prevalence; Pulmonary Disease, Chronic Obstructive
PubMed: 31175719
DOI: 10.12932/AP-310119-0485 -
Pediatric Research Aug 2020To determine normative data by forced oscillation technique (FOT) in non-sedated normal term neonates and test the hypothesis that infants with transient tachypnea of... (Observational Study)
Observational Study
BACKGROUND
To determine normative data by forced oscillation technique (FOT) in non-sedated normal term neonates and test the hypothesis that infants with transient tachypnea of the newborn (TTN) have higher resistance (R) and lower reactance (X) on day 1.
METHODS
Healthy term infants (n = 138) and infants with TTN (n = 17) were evaluated on postnatal days 1 through 3 (NCT03346343). FOT was measured with a mask using a TremoFlo C-100 Airwave System™. R, X, and area under the reactance curve (AX) were measured at prime frequencies 7-41 Hz for 8 s.
RESULTS
In all, 86% of control infants had adequate measurements (coherence >0.8, CV < 0.25) on day 1. Infants with TTN had higher resistance at 13 Hz (TTN 32.5 cm HO·s/L [95% CI 25.5-39.4]; controls 23.8 cm HO·s/L [95% CI 22.2 to 25.3], P = 0.007) and lower reactance from 17 to 37 Hz (TTN -35.1 to -10.5; controls -26.3 to -6.1, P < 0.05). In healthy controls, lung mechanics were unchanged from days 1 to 3. In TTN, lung mechanics normalized on days 2 and 3.
CONCLUSIONS
FOT is feasible in neonates and distinguishes normal control infants from those with TTN on postnatal day 1. Oscillometry offers a non-invasive, longitudinal technique to assess lung mechanics in newborns.
Topics: Airway Resistance; Asthma; Female; Forced Expiratory Volume; Humans; Infant, Newborn; Lung; Male; Oscillometry; Prospective Studies; Respiratory Function Tests; Respiratory Mechanics; Spirometry; Tachypnea; Vital Capacity
PubMed: 31935746
DOI: 10.1038/s41390-020-0751-7 -
Respiratory Medicine Oct 2021Increasing evidence shows that environmental factors in childhood play a role in development of irreversible airway obstruction. We evaluated early-life and...
BACKGROUND
Increasing evidence shows that environmental factors in childhood play a role in development of irreversible airway obstruction. We evaluated early-life and preschool-age risk factors for irreversible airway obstruction in adolescence after bronchiolitis in infancy.
METHODS
This study is a secondary analysis of data collected during prospective long-term follow-up of our post-bronchiolitis cohort. Risk factor data were collected during hospitalisation and on follow-up visits at 5-7 and 10-13 years of ages. Lung function was measured from 103 participants with impulse oscillometry at 5-7 years of age and from 89 participants with flow-volume spirometry at 10-13 years of age.
RESULTS
Asthma diagnosis at <12 months of age showed a significant association with irreversible airway obstruction at 10-13 years of age independently from current asthma. Irreversible airway obstruction was less frequent in children with variant than wild genotype of the Toll-like receptor 4(TLR4) rs4986790, but the significance was lost in logistic regression adjusted for current asthma and weight status. Higher post-bronchodilator respiratory system resistance at 5 Hz and lower baseline and post-bronchodilator reactance at 5 Hz by impulse oscillometry at 5-7 years of age were associated with irreversible airway obstruction at 10-13 years of age.
CONCLUSION
Asthma diagnosis during the first living year and worse lung function at preschool age increased the risk for irreversible airway obstruction at 10-13 years of age after bronchiolitis. TLR4 rs4986790 polymorphism may be protective for development of irreversible airway obstruction after bronchiolitis.
Topics: Adolescent; Age Factors; Airway Obstruction; Airway Resistance; Asthma; Bronchiolitis; Child; Child, Preschool; Female; Follow-Up Studies; Genotype; Humans; Male; Oscillometry; Polymorphism, Genetic; Prospective Studies; Risk Factors; Spirometry; Time Factors; Toll-Like Receptor 4
PubMed: 34332337
DOI: 10.1016/j.rmed.2021.106545 -
Transplant International : Official... 2023Peak spirometry after single lung transplantation (SLTx) for interstitial lung disease (ILD) is lower than after double lung transplantation (DLTx), however the...
Peak spirometry after single lung transplantation (SLTx) for interstitial lung disease (ILD) is lower than after double lung transplantation (DLTx), however the pathophysiologic mechanisms are unclear. We aim to assess respiratory mechanics in SLTx and DLTx for ILD using oscillometry. Spirometry and oscillometry (tremoflo C-100) were performed in stable SLTx and DLTx recipients in a multi-center study. Resistance (R, R) and reactance (X) were compared between LTx recipient groups, matched by age and gender. A model of respiratory impedance using ILD and DLTx data was performed. In total, 45 stable LTx recipients were recruited (SLTx = 23, DLTx = 22; males: 87.0% vs. 77.3%; median age 63.0 vs. 63.0 years). Spirometry was significantly lower after SLTx compared with DLTx: %-predicted mean (SD) FEV [70.0 (14.5) vs. 93.5 (26.0)%]; FVC [70.5 (16.8) vs. 90.7 (12.8)%], . R and R were similar between groups ( and , respectively) yet X was significantly worse after SLTx: median (IQR) X [-1.88 (-2.89 to -1.39) vs. -1.22 (-1.87 to -0.86)] cmHO.s/L], . R and X measurements from the model were congruent with measurements in SLTx recipients. The similarities in resistance, yet differences in spirometry and reactance between both transplant groups suggest the important contribution of elastic properties to the pathophysiology. Oscillometry may provide further insight into the physiological changes occurring post-LTx.
Topics: Male; Humans; Middle Aged; Oscillometry; Forced Expiratory Volume; Australia; Lung; Lung Diseases, Interstitial; Allografts
PubMed: 38116170
DOI: 10.3389/ti.2023.11758 -
Chest Jun 2020Persistent bronchodilator response (BDR) following diagnosis of asthma is an underrecognized treatable trait, associated with worse lung function and asthma control. The...
BACKGROUND
Persistent bronchodilator response (BDR) following diagnosis of asthma is an underrecognized treatable trait, associated with worse lung function and asthma control. The forced oscillation technique (FOT) measures respiratory system impedance, and BDR cutoffs have been proposed for healthy adults; however, the relevance in asthma is unknown. We compared BDR cutoffs, using FOT and spirometry, in asthma and the relationship with asthma control.
METHODS
Data from patients with asthma who withheld bronchodilator medication for at least 8 h before a tertiary airway clinic visit were reviewed. All subjects performed FOT and spirometry before and after salbutamol administration, and completed the Asthma Control Test. FOT parameters examined included respiratory system resistance (R5) and reactance (X5) at 5 Hz, and area under the reactance curve (AX). BDR was defined by standard recommendations for spirometry and based on the 95th percentile of BDR in healthy adults for FOT.
RESULTS
Fifty-two subjects (18 men; mean age, 53 ± 18 years) were included. BDR was identified more frequently by FOT than spirometry (54% vs 27% of subjects). BDR assessed by X5 and AX, but not R5, was associated with spirometric BDR (χ, P < .01) and correlated with asthma control (X5: r = -0.36, P < .01; AX: r = 0.34, P = .01). BDR measured by reactance parameters identified more subjects with poor asthma control than did spirometry (AX, 69% vs spirometry, 41%).
CONCLUSIONS
BDR assessed by FOT can identify poor asthma control. Reactance parameters were more sensitive in identifying poor asthma control than spirometry, supporting the use of FOT to complement spirometry in the clinical management of asthma.
Topics: Airway Resistance; Asthma; Bronchodilator Agents; Female; Follow-Up Studies; Forced Expiratory Volume; Humans; Lung; Male; Middle Aged; Oscillometry; Retrospective Studies; Spirometry
PubMed: 31982392
DOI: 10.1016/j.chest.2019.12.035 -
Journal of Thoracic Disease May 2022The ethnicity is significantly under-reported and this may limit the applicability of current impulse oscillometry (IOS) equations to heterogeneous patient populations....
BACKGROUND
The ethnicity is significantly under-reported and this may limit the applicability of current impulse oscillometry (IOS) equations to heterogeneous patient populations. Establishing predictive equations for the IOS in the Thai adult population is still required. Therefore, this study aimed to establish reference equations for the IOS in the Thai adult population.
METHODS
This retrospective cross-sectional study of IOS parameters in healthy adults aged greater than 20 years old with normal spirometry and who had no chronic respiratory diseases. Pre-bronchodilator (BD) IOS was performed in all subjects. Reference equations were calculated separately for men and women using multivariable linear regression analysis.
RESULTS
A total of 127 subjects (87 men and 40 women) with a mean age of 48.7±17.2 (range, 22-92) years were included. The resistance at 5 Hz (R5), resistance at 20 Hz (R20), and area under reactance curve between 5 Hz and resonant frequency (AX) were significantly higher in women compared to men. The reference equations of the IOS parameters were established for men and women. Age, height, and bodyweight were shown to be the influential predictor as they contributed to the most of IOS indices except for the R5-R20 in men equations. Bodyweight was shown to be the influential predictor as it contributed to the most IOS indices except for the X5 in women's equations.
CONCLUSIONS
We provided the reference equations for the IOS indices in Thai adults. IOS indices including R5, R20, and AX were significantly higher in women compared to men.
PubMed: 35693627
DOI: 10.21037/jtd-21-1989 -
European Review For Medical and... Apr 2023Small airway dysfunction is a pathological component of chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), and impulse oscillometry is...
OBJECTIVE
Small airway dysfunction is a pathological component of chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), and impulse oscillometry is an easy-to-administer, effort-independent non-invasive test reflecting small airway dysfunction. We aimed to compare the impulse oscillometry (IOS) measurements between COPD and IPF patients and investigate their correlation with severity of both diseases and other conventional parameters.
PATIENTS AND METHODS
This was a prospective, longitudinal study. We longitudinally evaluated the baseline demographic characteristics, COPD Assessment Test (CAT) and modified Medical Research Council (mMRC) dyspnea scale, Pulmonary Function Test (PFT), Carbon Monoxide Diffusing Capacity (DLCO), Hemogram and Impulse Oscillometry measurements of the patients diagnosed with COPD and IPF.
RESULTS
The study included 60 IPF patients and 48 COPD patients. The CAT and mMRC scores were higher in COPD patients. The majority of COPD patients were classified into Category B (46%), while 68% of IPF patients had Stage 1 GAP. The mean FEF 25-75%, which is typically considered to reflect small airway disease, was 93% in IPF patients, while it was significantly lower in COPD patients (29%). Impulse oscillometry measurements were consistent with spirometry parameters. IOS resistance and reactance values were significantly higher in COPD patients than in IPF patients.
CONCLUSIONS
IOS is advantageous in COPD and IPF patients who cannot exhale due to severe dyspnea, as it is easy to administer and reflects small airway resistance better. Diagnosis of small airway dysfunction may be beneficial in the management of patients with IPF and COPD.
Topics: Humans; Oscillometry; Longitudinal Studies; Prospective Studies; Forced Expiratory Volume; Pulmonary Disease, Chronic Obstructive; Respiratory Function Tests; Lung; Spirometry; Idiopathic Pulmonary Fibrosis; Dyspnea
PubMed: 37070906
DOI: 10.26355/eurrev_202304_31937 -
ERJ Open Research Sep 2023Impulse oscillometry (IOS) is sensitive in detecting lung function impairment. In small studies, impaired IOS relates better to respiratory symptoms than spirometry. We...
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 () 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 (FEV), 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 with abnormal reactance resulted in approximately two-fold higher likelihood for having cough, chronic bronchitis and dyspnoea, even when further adjusting for FEV, 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.
PubMed: 37753278
DOI: 10.1183/23120541.00736-2022 -
Respiratory Research Sep 2022While optimizing spirometry is a challenge for lung function labs, long-term variability if any between IOS (impulse oscillometry) parameters and spirometry is not...
BACKGROUND
While optimizing spirometry is a challenge for lung function labs, long-term variability if any between IOS (impulse oscillometry) parameters and spirometry is not clearly known in stable COPD (chronic obstructive pulmonary disease) and chronic asthma. The forced oscillation technique is increasingly employed in routine lung function testing. Our aim in this study was to determine the variability in oscillometric parameters between clinic visits over weeks or months in two patient groups during a period of clinical stability. Moreover, the research assessed relationships between IOS parameters long-term variability and COPD severity.
METHODS
We used data from 73 patients with stable COPD and 119 patients with stable asthma at the Shanghai Pulmonary Hospital Affiliated to Tongji University. Patients were included if they had three or more clinic visits where spirometry and IOS were performed during a clinically stable period. Data recorded from the first three visits were used. The standard deviation (SDbv), the coefficient of variation (COV), intraclass correlation coefficient (ICC) and the coefficient of repeatability (COR) were calculated, Wilcoxon Mann-Whitney test was used for data that did not conform to normality of distributions, Kruskal Wallis test was used to compare with multiple groups, post hoc comparison was analyzed by Bonferroni, Spearman correlation coefficients for non-parametric data, the multiple regression analyses to determine the relationship between long-term variability and airflow obstruction.
RESULTS
(1) The repeatability of IOS resistance parameters with ICC values > 0.8 was high in COPD and asthma. ICC values of IOS resistance parameters were higher than IOS reactance parameters; (2) the repeatability of spirometry parameters with ICC values < 0.8 was lower than IOS resistance parameters in different GOLD (the Global Initiative for Chronic Obstructive Lung Disease) stages, the higher the stage the worse the repeatability; (3) the severity of airflow obstruction was correlated with long-term variability of R5 (R at 5 Hz) (P < 0.05) in GOLD4, not with long-term variability of R20 (R at 20 Hz) (P > 0.05) and R5-R20 (P > 0.05).
CONCLUSION
IOS resistance parameters have good long-term repeatability in asthma and COPD. Additionally, repeatability of spirometry parameters is lower than IOS resistance parameters in different GOLD stages.
Topics: Asthma; China; Forced Expiratory Volume; Humans; Oscillometry; Pulmonary Disease, Chronic Obstructive; Spirometry
PubMed: 36131305
DOI: 10.1186/s12931-022-02185-5 -
Jornal Brasileiro de Pneumologia :... 2022To assess respiratory system impedance (Zrs) and spirometric parameters in children and adolescents with and without a history of preterm birth.
OBJECTIVE
To assess respiratory system impedance (Zrs) and spirometric parameters in children and adolescents with and without a history of preterm birth.
METHODS
We evaluated a sample of 51 subjects between 11 and 14 years of age: 35 who had a history of preterm birth (preterm group) and 16 who had been born at term (full-term group). Lung function was measured by spirometry, spectral oscillometry, and intra-breath oscillometry.
RESULTS
Neither spirometry nor spectral oscillometry revealed any statistically significant differences between the preterm and full-term groups. However, intra-breath oscillometry demonstrated significant differences between the two groups in terms of the change in resistance, reactance at end-inspiration, and the change in reactance (p < 0.05 for all).
CONCLUSIONS
Our findings suggest that abnormalities in Zrs persist in children and adolescents with a history of preterm birth and that intra-breath oscillometry is more sensitive than is spectral oscillometry. Larger studies are needed in order to validate these findings and to explore the impact that birth weight and gestational age at birth have on Zrs later in life.
Topics: Adolescent; Adult; Child; Female; Forced Expiratory Volume; Humans; Infant, Newborn; Lung; Oscillometry; Pregnancy; Premature Birth; Spirometry
PubMed: 35137869
DOI: 10.36416/1806-3756/e20210290