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Advances in Respiratory Medicine 2019Pulmonary function testing involves a battery of tests from the simple pulse oximetry to the cardiopulmonary exercise testing. Impulse oscillometry (IOS) is one of the...
Pulmonary function testing involves a battery of tests from the simple pulse oximetry to the cardiopulmonary exercise testing. Impulse oscillometry (IOS) is one of the newly described pulmonary function tests. It is based on the old principle of forced oscillatory technique modified and refined as per research and advances. It involves the use of sound waves during normal tidal breathing, which gives information on oscillatory pressure-flow relationships and eventually resistance and reactance. The resistance at 20 Hz (R20) represents the resistance of the large airways. The resistance at 5 Hz (R5) means the total airway resistance. (R5-R20) reflects resistance in the small airways. The reactance at 5 Hz (X5) indicates the elastic recoil of the peripheral airways. Resonant frequency and area of reactance are also measured. IOS has major uses in diagnosis and control of asthma in children and the elderly, where spirometry is otherwise normal. IOS has been studied in other respiratory diseases like COPD, ILD and supraglottic stenosis.
Topics: Humans; Oscillometry; Pulmonary Disease, Chronic Obstructive; Reproducibility of Results; Respiratory Function Tests
PubMed: 31476011
DOI: 10.5603/ARM.a2019.0039 -
Lung Dec 2022The small airways dysfunction (SAD) asthma phenotype is characterised by narrowing of airways < 2 mm in diameter between generations 8 and 23 of the bronchial tree.... (Review)
Review
The small airways dysfunction (SAD) asthma phenotype is characterised by narrowing of airways < 2 mm in diameter between generations 8 and 23 of the bronchial tree. Recently, this has become particularly relevant as measurements of small airways using airway oscillometry for example, are strong determinants of asthma control and exacerbations in moderate-to-severe asthma. The small airways can be assessed using spirometry as forced expiratory flow rate between 25 and 75% of forced vital capacity (FEF) and has been deemed more accurate in detecting small airways dysfunction than forced expiratory volume in 1 s (FEV). Oscillometry as the heterogeneity in resistance between 5 and 20 Hz (R5-R20), low frequency reactance at 5 Hz (X5) or area under the reactance curve between 5 Hz and the resonant frequency can also be used to assess the small airways. The small airways can also be assessed using the multiple breath nitrogen washout (MBNW) test giving rise to values including functional residual capacity, lung clearance index and ventilation distribution heterogeneity in the conducting (Scond) and the acinar (Sacin) airways. The ATLANTIS group showed that the prevalence of small airways disease in asthma defined on FEF, oscillometry and MBNW all increased with progressive GINA asthma disease stages. As opposed to topical inhaler therapy that might not adequately penetrate the small airways, it is perhaps more intuitive that systemic anti-inflammatory therapy with biologics targeting downstream cytokines and upstream epithelial anti-alarmins may offer a promising solution to SAD. Here we therefore aim to appraise the available evidence for the effect of anti-IgE, anti-IL5 (Rα), anti-IL4Rα, anti-TSLP and anti-IL33 biologics on small airways disease in patients with severe asthma.
Topics: Humans; Asthma; Spirometry; Forced Expiratory Volume; Lung; Pulmonary Disease, Chronic Obstructive; Biological Therapy; Phenotype; Biological Products
PubMed: 36239786
DOI: 10.1007/s00408-022-00579-2 -
Tuberculosis and Respiratory Diseases Apr 2022Post-tuberculosis (TB) sequelae is a commonly encountered clinical entity, especially in high TB burden countries. This may represent chronic anatomic sequelae of...
BACKGROUND
Post-tuberculosis (TB) sequelae is a commonly encountered clinical entity, especially in high TB burden countries. This may represent chronic anatomic sequelae of previously treated TB, with frequent symptomatic presentation. This pilot study was aimed to investigate the pulmonary functions and systemic inflammatory markers in patients with post-TB sequelae (PTBS) and to compare them with post-TB without sequelae (PTBWS) participants and healthy controls.
METHODS
A total of 30 participants were enrolled, PTBS (n=10), PTBWS (n=10), and healthy controls (n=10). Pulmonary function tests included spirometry and measurement of airway impedance by impulse oscillometry. Serum levels of matrix metalloproteinase (MMP)-1, transforming growth factor-β, and interferon-γ were estimated.
RESULTS
Slow vital capacity (SVC), forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC, and peak expiratory flow were significantly lower in PTBS as compared to controls. SVC and FEV1 were significantly less in PTBS as compared to PTBWS. Total airway impedance (Z5), total airway resistance (R5), central airway resistance (R20), area of reactance (Ax), and resonant frequency (Fres) were significantly higher and respiratory reactance at 5 and 20 Hz (X5, X20) were significantly lower in PTBS as compared to PTBWS. Spirometry parameters correlated with impulse oscillometry parameters in PTBS. Serum MMP-1 level was significantly higher in PTBS as compared to other groups.
CONCLUSION
Significant pulmonary function impairment was observed in PTBS, and raised serum MMP-1 levels compared with PTBWS and healthy controls. Follow-up pulmonary function testing is recommended after treatment of TB for early diagnosis and treatment of PTBS.
PubMed: 35232004
DOI: 10.4046/trd.2021.0127 -
Internal Medicine (Tokyo, Japan) 2016The forced oscillation technique (FOT) is a noninvasive method with which to measure respiratory system resistance and reactance during tidal breathing. Recently, its... (Review)
Review
The forced oscillation technique (FOT) is a noninvasive method with which to measure respiratory system resistance and reactance during tidal breathing. Recently, its clinical application has spread worldwide with the expansion of commercially available broadband frequency FOT devices, including MostGraph and Impulse Oscillometry. An increasing number of reports have supported the usefulness of the FOT in the management of asthma and chronic obstructive pulmonary disease (COPD). However, the FOT is not a surrogate test for spirometry, but should be used complementarily. Furthermore, reference values are not necessarily available and the interpretation of some measured data is controversial. There is a need to update the international statement for not only technical aspects but also the clinical use of the FOT. In this review, we summarize the previously published studies and discuss how to use the FOT in a clinical setting.
Topics: Asthma; Chest Wall Oscillation; Disease Management; Humans; Oscillometry; Practice Guidelines as Topic; Pulmonary Disease, Chronic Obstructive; Reference Values; Respiratory Mechanics; Spirometry
PubMed: 26984069
DOI: 10.2169/internalmedicine.55.5876 -
Respiratory Medicine Oct 2023Bronchial thermoplasty is an effective intervention to improve respiratory symptoms and to reduce the rate of exacerbations in uncontrolled severe asthma. A reduction in...
INTRODUCTION
Bronchial thermoplasty is an effective intervention to improve respiratory symptoms and to reduce the rate of exacerbations in uncontrolled severe asthma. A reduction in airway smooth muscle is arguably the most widely discussed mechanisms accounting for these clinical benefits. Yet, this smooth muscle reduction should also translate into an impaired response to bronchodilator drugs. This study was designed to address this question.
METHODS
Eight patients with clinical indication for thermoplasty were studied. They were uncontrolled severe asthmatics despite optimal environmental control, treatment of comorbidities, and the use of high-dose inhaled corticosteroids and long-acting β-agonists. Lung function measured by spirometry and respiratory mechanics measured by oscillometry were examined pre- and post-bronchodilator (salbutamol, 400 μg), both before and at least 1 year after thermoplasty.
RESULTS
Consistent with previous studies, thermoplasty yielded no benefits in terms of baseline lung function and respiratory mechanics, despite improving symptoms based on two asthma questionnaires (ACQ-5 and ACT-5). The response to salbutamol was also not affected by thermoplasty based on spirometric readouts, including forced expiratory volume in 1 s (FEV), forced vital capacity (FVC), and FEV/FVC ratio. However, a significant interaction was observed between thermoplasty and salbutamol for two oscillometric readouts, namely reactance at 5 Hz (X) and reactance area (Ax), showing an attenuated response to salbutamol after thermoplasty.
CONCLUSIONS
Thermoplasty attenuates the response to a bronchodilator. We argue that this result is a physiological proof of therapeutic efficacy, consistent with the well-described effect of thermoplasty in reducing the amount of airway smooth muscle.
Topics: Humans; Bronchodilator Agents; Bronchial Thermoplasty; Asthma; Albuterol; Adrenal Cortex Hormones; Forced Expiratory Volume
PubMed: 37422022
DOI: 10.1016/j.rmed.2023.107340 -
Frontiers in Pediatrics 2018Lung function is an important tool in the diagnosis and monitoring of patients with asthma at all ages. Airway obstruction is a typical feature of asthma and it can be... (Review)
Review
Lung function is an important tool in the diagnosis and monitoring of patients with asthma at all ages. Airway obstruction is a typical feature of asthma and it can be assessed with several lung function techniques. Spirometry, respiratory resistance and reactance, and lung volumes are available to measure it at different ages and in children. The assessment of a bronchodilator response is always recommended to show the reversibility of the obstruction. Poor lung function is a predictor of poor asthma outcome and a low Forced Expiratory Volume in the first second of expiration percent predicted measured with spirometry, has been shown to be associated with a higher risk of having an exacerbation during the following year independently of the presence of asthma symptoms. In severe asthma lung function assessment is used to distinguish different phenotypes, children with severe asthma have worse airflow limitation prior to administration of a bronchodilator than children with non severe asthma. Airway resistance and reactance are indirect measurements of airway obstruction and they can be measured with the forced oscillation technique, which is feasible also in non-collaborative children. This technique can be more informative in discriminating patients with asthma from healthy controls and is able to indicate a more peripheral involvement of the airways. The role of this technique in severe asthma is still debated. In conclusion lung function is useful in the clinical management of children with severe asthma.
PubMed: 30013960
DOI: 10.3389/fped.2018.00189 -
Nutricion Hospitalaria Jun 2016Heart failure (HF) patients develop important changes in body composition, but only a small number of studies have evaluated the associations between these changes and...
BACKGROUND
Heart failure (HF) patients develop important changes in body composition, but only a small number of studies have evaluated the associations between these changes and functional class deterioration in a prospective manner.
OBJECTIVE
The aim of this study was to evaluate whether changes in bioimpedance parameters were associated with NYHA functional class deterioration over six months.
METHODS
A total of 275 chronic stable HF patients confirmed by echocardiography were recruited. Body composition measurements were obtained by whole body bioelectrical impedance with multiple frequency equipment (BodyStat QuadScan 4000). We evaluated functional class using the New York Heart Association (NYHA) classification at baseline and after six months.
RESULTS
According to our results, 66 (24%) subjects exhibited functional class deterioration, while 209 improved or exhibited no change. A greater proportion of patients exhibited higher extracellular water (> 5%), and these patients developed hypervolemia, according to location on the resistance/reactance graph. A 5% decrease in resistance/height was associated with functional class deterioration with an OR of 1.42 (95% CI 1.01-2.0, p = 0.04).
CONCLUSIONS
Body composition assessment through bioelectrical impedance exhibited a valuable performance as a marker of functional class deterioration in stable HF patients.
Topics: Aged; Aged, 80 and over; Body Composition; Disease Progression; Electric Impedance; Extravascular Lung Water; Female; Heart Failure; Humans; Longitudinal Studies; Male; Middle Aged; Prospective Studies
PubMed: 27513497
DOI: 10.20960/nh.270 -
Physiological Reports Jan 2019Developed over six decades ago, pulmonary oscillometry has re-emerged as a noninvasive and effort-independent method for evaluating respiratory-system impedance in... (Clinical Trial)
Clinical Trial
Developed over six decades ago, pulmonary oscillometry has re-emerged as a noninvasive and effort-independent method for evaluating respiratory-system impedance in patients with obstructive lung disease. Here, we evaluated the relationships between hyperpolarized He ventilation-defect-percent (VDP) and respiratory-system resistance, reactance and reactance area (A ) measurements in 175 participants including 42 never-smokers without respiratory disease, 56 ex-smokers with chronic-obstructive-pulmonary-disease (COPD), 28 ex-smokers without COPD and 49 asthmatic never-smokers. COPD participants were dichotomized based on x-ray computed-tomography (CT) evidence of emphysema (relative-area CT-density-histogram ≤ 950HU (RA ) ≥ 6.8%). In asthma and COPD subgroups, MRI VDP was significantly related to the frequency-dependence of resistance (R ; asthma: ρ = 0.48, P = 0.0005; COPD: ρ = 0.45, P = 0.0004), reactance at 5 Hz (X : asthma, ρ = -0.41, P = 0.004; COPD: ρ = -0.38, P = 0.004) and A (asthma: ρ = 0.47, P = 0.0007; COPD: ρ = 0.43, P = 0.0009). MRI VDP was also significantly related to R in COPD participants without emphysema (ρ = 0.54, P = 0.008), and to X in COPD participants with emphysema (ρ = -0.36, P = 0.04). A was weakly related to VDP in asthma (ρ = 0.47, P = 0.0007) and COPD participants with (ρ = 0.39, P = 0.02) and without (ρ = 0.43, P = 0.04) emphysema. A is sensitive to obstruction but not specific to the type of obstruction, whereas the different relationships for MRI VDP with R and X may reflect the different airway and parenchymal disease-specific biomechanical abnormalities that lead to ventilation defects.
Topics: Adult; Aged; Aged, 80 and over; Asthma; Female; Humans; Lung; Magnetic Resonance Imaging; Male; Middle Aged; Oscillometry; Pulmonary Disease, Chronic Obstructive; Respiratory Function Tests
PubMed: 30632309
DOI: 10.14814/phy2.13955 -
Indian Journal of Endocrinology and... 2023Obesity is known to induce lung function impairment. Previous studies of decline in lung function associated with obesity are well established.
BACKGROUND
Obesity is known to induce lung function impairment. Previous studies of decline in lung function associated with obesity are well established.
MATERIALS AND METHODS
In this cross-sectional study, to evaluate the effects of different obesity indices on lung mechanics, healthy subjects (males-23 and females-22) were recruited. Anthropometric parameters like body mass index (BMI), waist circumference (WC), hip circumference (HC) and neck circumference (NC) were measured and waist-hip ratio (WHR) was derived. Spirometry, impulse oscillometry (IOS) and fractional exhaled nitric oxide (FeNO) measurements were performed to assess lung function. Subgroups were divided and analysed.
RESULTS
In males, increased WHR is associated with increased total airway resistance (R). BMI correlates positively with R, R% predicted, resistance at 20 Hz (R) and R% predicted; likewise, WHR shows a positive correlation with R. In females, increased WHR has significantly higher R, R% predicted, R, R% predicted, area of reactance (Ax), resonant frequency (Fres) and decreased reactance at 5 Hz (X), reactance at 20 Hz (X), X% predicted. The female group with higher WC shows significantly increased R, R% predicted, R, R% predicted, Ax, Fres and lower fixed ratio of forced expiratory volume in 1 s (FEV)/forced vital capacity (FVC), X, X, X% predicted. The group with higher NC has a lower FEV/FVC ratio. WHR positively correlated with R% predicted and Fres while WC correlated positively with R, R% predicted, Ax and Fres; same way, NC with X% predicted.
CONCLUSION
Obesity/overweight causes significant changes in lung volumes, capacity and airway mechanics, Higher WC and WHR are associated with significant changes in lung mechanics, which are more prominent in females than in males. NC is not associated with changes in lung mechanics.
PubMed: 37292068
DOI: 10.4103/ijem.ijem_363_22 -
Tanaffos 2016Input impedance of the respiratory system is measured by forced oscillation technique (FOT). Multiple prior studies have attempted to match the electromechanical models... (Review)
Review
Input impedance of the respiratory system is measured by forced oscillation technique (FOT). Multiple prior studies have attempted to match the electromechanical models of the respiratory system to impedance data. Since the mechanical behavior of airways and the respiratory system as a whole are similar to an electrical circuit in a combination of series and parallel formats some theories were introduced according to this issue. It should be noted that, the number of elements used in these models might be less than those required due to the complexity of the pulmonary-chest wall anatomy. Various respiratory models have been proposed based on this idea in order to demonstrate and assess the different parts of respiratory system related to children and adults data. With regard to our knowledge, some of famous respiratory models in related to obstructive, restrictive diseases and also Acute Respiratory Distress Syndrome (ARDS) are reviewed in this article.
PubMed: 27904536
DOI: No ID Found