-
Chest Apr 2023The purpose of this study was to investigate physiological phenotypes of asthma in obesity.
BACKGROUND
The purpose of this study was to investigate physiological phenotypes of asthma in obesity.
RESEARCH QUESTION
Do physiological responses during bronchoconstriction distinguish different groups of asthma in people with obesity, and also differentiate from responses simply related to obesity?
STUDY DESIGN AND METHODS
Cross-sectional study of people with obesity (31 with asthma and 22 without lung disease). Participants underwent methacholine challenge testing with measurement of spirometry and respiratory system impedance by oscillometry.
RESULTS
Participants had class III obesity (BMI, 46.7 ± 6.6 kg/m in control subjects and 47.2 ± 8.2 kg/m in people with asthma). Most participants had significant changes in peripheral airway impedance in response to methacholine: in control subjects, resistance at 5 Hz measured by oscillometry increased by 45% ± 27% and area under the reactance curve (AX) by 268% ± 236% in response to 16 mg/mL methacholine; in people with asthma, resistance at 5 Hz measured by oscillometry increased by 52% ± 38% and AX by 361% ± 295% in response to provocation concentration producing a 20% fall in FEV dose of methacholine. These responses suggest that obesity predisposes to peripheral airway reactivity. Two distinct groups of asthma emerged based on respiratory system impedance: one with lower reactance (baseline AX, 11.8; interquartile range, 9.9-23.4 cm HO/L) and more concordant bronchoconstriction in central and peripheral airways; the other with high reactance (baseline AX, 46.7; interquartile range, 23.2-53.7 cm HO/L) and discordant bronchoconstriction responses in central and peripheral airways. The high reactance asthma group included only women, and reported significantly more gastroesophageal reflux disease, worse chest tightness, more wheeze, and more asthma exacerbations than the low reactance group.
INTERPRETATION
Peripheral airway reactivity detected by oscillometry is common in obese control subjects and obese people with asthma. There is a subgroup of obese asthma characterized by significant peripheral airway dysfunction by oscillometry out of proportion to spirometric airway dysfunction. This peripheral dysfunction represents clinically significant respiratory disease not readily assessed by spirometry.
Topics: Female; Humans; Methacholine Chloride; Cross-Sectional Studies; Asthma; Respiratory System; Spirometry; Bronchial Provocation Tests; Obesity; Airway Resistance; Forced Expiratory Volume
PubMed: 36610669
DOI: 10.1016/j.chest.2022.12.030 -
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 Mar 2023Small airways dysfunction (SAD) in asthma is difficult to measure and a gold standard is lacking. The aim of this study was to develop a simple tool including items of...
BACKGROUND
Small airways dysfunction (SAD) in asthma is difficult to measure and a gold standard is lacking. The aim of this study was to develop a simple tool including items of the Small Airways Dysfunction Tool (SADT) questionnaire, basic patient characteristics and respiratory tests available depending on the clinical setting to predict SAD in asthma.
METHODS
This study was based on the data of the multinational ATLANTIS (Assessment of Small Airways Involvement in Asthma) study including the earlier developed SADT questionnaire. Key SADT items together with clinical information were now used to build logistic regression models to predict SAD group (less likely or more likely to have SAD). Diagnostic ability of the models was expressed as area under the receiver operating characteristic curve (AUC) and positive likelihood ratio (LR+).
RESULTS
SADT item 8, "I sometimes wheeze when I am sitting or lying quietly", and the patient characteristics age, age at asthma diagnosis and body mass index could reasonably well detect SAD (AUC 0.74, LR+ 2.3). The diagnostic ability increased by adding spirometry (percentage predicted forced expiratory volume in 1 s: AUC 0.87, LR+ 5.0) and oscillometry (resistance difference between 5 and 20 Hz and reactance area: AUC 0.96, LR+ 12.8).
CONCLUSIONS
If access to respiratory tests is limited ( primary care in many countries), patients with SAD could reasonably well be identified by asking about wheezing at rest and a few patient characteristics. In (advanced) hospital settings patients with SAD could be identified with considerably higher accuracy using spirometry and oscillometry.
Topics: Humans; Asthma; Respiratory Function Tests; Spirometry; Forced Expiratory Volume; ROC Curve
PubMed: 36517179
DOI: 10.1183/13993003.00558-2022 -
Journal of Applied Physiology... Jan 2023Airway resistance measurements using oscillometry provide a potential alternative to spirometry in assessing airway obstruction and dynamics due to measurements taken...
Airway resistance measurements using oscillometry provide a potential alternative to spirometry in assessing airway obstruction and dynamics due to measurements taken during tidal breathing. Oscillometry typically requires participants to form a tight seal around a mouthpiece that can prove challenging for some people. To address this challenge, we conducted a prospective study to evaluate the effect of different interfaces like mouthpiece, mouth mask, and nasal mask on respiratory impedance results from oscillometry in a cohort of healthy adults. Ten healthy adults [7 females; mean age: 38.9 yr (SD ±15.5)] underwent oscillometry using each of the three interfaces. We measured resistance at 5 Hz (Rrs), frequency dependence of resistance at 5-20 Hz (Rrs), and reactance area (Ax). Rrs was not different when using the mouthpiece compared with the mouth mask [mean 2.98 cmHO/L/s (SD ±0.68) vs. mean 3.2 cmHO/L/s (SD ±0.81); = 0.92; 95% CI -0.82 to +0.38], respectively. Nasal mask Rrs measurements were significantly higher than mouthpiece measurements (mean 7.31 cmHO/L/s; SD ±2.62; < 0.01; 95%CI -6.91 to -1.75). With Ax, we found a mean of 4.01 cmHO/L (SD ±2.04) with the mouth mask compared with a mean of 4.02 cmHO/L (SD ±1.87; = 1.0 95% CI -1.86 to +1.87) for the mouthpiece, however, we found a significant difference between the mouthpiece and nasal mask for Ax (mean = 10.71; SD ±7.0 HO/L; = 0.04, 95% CI -12.96 to -0.43). Our findings show that oscillometry using a mouth mask may be just as effective as using a mouthpiece in assessing airway dynamics and resistance. This is the first study to compare the use of different interfaces: mouthpiece, mouth mask, and nasal mask, for oscillometry in an adult population. We report that using a mouth mask in oscillometry may provide a valid alternative to a mouthpiece in cohorts who may struggle to form the required tight seal that is typically required in oscillometry or spirometry.
Topics: Female; Humans; Adult; Oscillometry; Prospective Studies; Airway Resistance; Lung; Spirometry; Mouth
PubMed: 36476160
DOI: 10.1152/japplphysiol.00491.2022 -
Scientific Reports Nov 2022The effect of anti-vascular endothelial growth factor on neonatal lung development was inconclusive. To evaluate pulmonary function in school-age children who have...
The effect of anti-vascular endothelial growth factor on neonatal lung development was inconclusive. To evaluate pulmonary function in school-age children who have received intravitreal bevacizumab (IVB) for retinopathy of prematurity (ROP), this study included 118 school-aged children who were grouped into three groups: full-term control children (group 1), preterm children who had not received IVB treatment (group 2) and preterm children with ROP who had received IVB treatment (group 3). Pulmonary function was measured by spirometry and impulse oscillometry. Pulmonary function was significantly better in group 1 than in groups 2 and 3 (all p < 0.05 in forced vital capacity (FVC), forced expiratory volume in 1 s (FEV), forced expiratory flow between 25 and 75% of FVC (FEF), and respiratory resistance at 5 Hz and difference between respiratory resistance at 5 and 20 Hz (R5-R20). There were no statistically significant differences between group 2 and group 3 in all pulmonary function parameters, including FVC, FEV, ratio of FEV to FVC, FEF, R5, R20, R5-R20, and respiratory reactance at 5 Hz. In conclusion, our study revealed that preterm infants receiving IVB for ROP had comparable pulmonary function at school age to their preterm peers who had not received IVB treatment.
Topics: Infant; Child; Humans; Infant, Newborn; Bevacizumab; Retinopathy of Prematurity; Intravitreal Injections; Infant, Premature; Forced Expiratory Volume; Lung
PubMed: 36335152
DOI: 10.1038/s41598-022-22338-2 -
Frontiers in Physiology 2022Chronic lung allograft dysfunction (CLAD) is the major cause of death beyond 2 years after lung transplantation and develops in 50% of all patients by 5 years...
Chronic lung allograft dysfunction (CLAD) is the major cause of death beyond 2 years after lung transplantation and develops in 50% of all patients by 5 years post-transplant. CLAD is diagnosed on the basis of a sustained drop of 20% for at least 3 months in the forced expiratory volume (FEV), compared to the best baseline value achieved post-transplant. CLAD presents as two main phenotypes: bronchiolitis obliterans syndrome (BOS) is more common and has better prognosis than restrictive allograft syndrome (RAS). Respiratory oscillometry is a different modality of lung function testing that is highly sensitive to lung mechanics. The current study investigated whether spectral and intrabreath oscillometry can differentiate between CLAD-free, BOS- and RAS-CLAD at CLAD onset, i.e., at the time of the initial 20% drop in the FEV. A retrospective, cross-sectional analysis of 263 double lung transplant recipients who underwent paired testing with oscillometry and spirometry at the Toronto General Pulmonary Function Laboratory from 2017 to 2022 was conducted. All pulmonary function testing and CLAD diagnostics were performed following international guidelines. Statistical analysis was conducted using multiple comparisons. The RAS ( = 6) spectral oscillometry pattern differs from CLAD-free ( = 225) by right-ward shift of reactance curve similar to idiopathic pulmonary fibrosis whereas BOS ( = 32) has a pattern similar to obstructive lung disease. Significant differences were found in most spectral and intrabreath parameters between BOS, RAS, and time-matched CLAD-free patients. analysis revealed these differences were primarily driven by BOS instead of RAS. While no differences were found between CLAD-free and RAS patients with regards to spectral oscillometry, the intrabreath metric of reactance at end-inspiration (XeI) was significantly different ( < 0.05). BOS and RAS were differentiated by spectral oscillometry measure R5, and intrabreath resistance at end expiration, ReE ( < 0.05 for both). Both spectral and intrabreath oscillometry can differentiate BOS-CLAD from CLAD-free states while intrabreath oscillometry, specifically XeI, can uniquely distinguish RAS-CLAD from CLAD-free. Spectral and intrabreath oscillometry offer complementary information regarding lung mechanics in CLAD patients to help distinguish the two phenotypes and could prove useful in prognostication.
PubMed: 36277208
DOI: 10.3389/fphys.2022.980942 -
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 -
The Journal of Asthma : Official... Jun 2023Lung function testing is used in diagnosing asthma and assessing asthma control. Spirometry is most commonly used, but younger children can find performing this test...
OBJECTIVE
Lung function testing is used in diagnosing asthma and assessing asthma control. Spirometry is most commonly used, but younger children can find performing this test challenging. Non-volitional tests such as airwave oscillometry (AOS) may be helpful in that population. We compared the success of spirometry and AOS in assessing bronchodilator responsiveness in children.
METHODS
AOS was conducted alongside routine lung function testing. Resistance at 5 Hz (R5), the difference between the resistance at 5 and 20 Hz (R5-20) and the area under the reactance curve (AX) were assessed. Patients between 5 and 16 years old attending clinic with wheeze or asthma were assessed. Patients performed AOS, followed by spirometry and were then given 400 µg salbutamol; the tests were repeated 15 minutes later.
RESULTS
Lung function testing was performed in 47 children of whom 46 (98%) and 32 (68%) performed acceptable baseline oscillometry and spirometry, respectively ( < 0.001). Children unable to perform acceptable spirometry were younger (7.35, range: 5.4-10.3 years) than those who could (10.4, range: 5.5-16.9 years), < 0.001. The baseline z-scores of AOS R5 correlated with FEV ( = 0.499, = 0.004), FEF ( = 0.617, < 0.001), and FEV/FVC ( = 0.618, < 0.001). There was a positive bronchodilator response assessed by spirometry (change in FEV ≥ 12%) in eight children which corresponded to a change in R5 of 36% (range: 30%-50%) and a change in X5 of 39% (range: 15%-54%).
CONCLUSIONS
Oscillometry is a useful adjunct to spirometry in assessing young asthmatic children's lung function. The degree of airway obstruction, however, might affect the comparability of the results of the two techniques.
Topics: Humans; Child; Child, Preschool; Adolescent; Asthma; Bronchodilator Agents; Oscillometry; Forced Expiratory Volume; Spirometry
PubMed: 36218195
DOI: 10.1080/02770903.2022.2134795 -
Frontiers in Physiology 2022Metrics used in spirometry caught on in respiratory medicine not only because they provide information of clinical importance but also because of a keen understanding of... (Review)
Review
Metrics used in spirometry caught on in respiratory medicine not only because they provide information of clinical importance but also because of a keen understanding of what is being measured. The forced expiratory volume in 1 s (FEV), for example, is the maximal volume of air that can be expelled during the first second of a forced expiratory maneuver starting from a lung inflated to total lung capacity (TLC). Although it represents a very gross measurement of lung function, it is now used to guide the diagnosis and management of many lung disorders. Metrics used in oscillometry are not as concrete. Resistance, for example, has several connotations and its proper meaning in the context of a lung probed by an external device is not always intuitive. I think that the popularization of oscillometry and its firm implementation in respiratory guidelines starts with a keen understanding of what exactly is being measured. This review is an attempt to clearly explain the basic metrics of oscillometry. In my opinion, the fundamentals of oscillometry can be understood using a simple example of an excised strip of lung tissue subjected to a sinusoidal strain. The key notion is to divide the sinusoidal reacting force from the tissue strip into two sinusoids, one in phase with the strain and one preceding the strain by exactly a quarter of a cycle. Similar notions can then be applied to a whole lung subjected to a sinusoidal flow imposed at the mouth by an external device to understand basic metrics of oscillometry, including resistance, elastance, impedance, inertance, reactance and resonant frequency.
PubMed: 36203932
DOI: 10.3389/fphys.2022.978332 -
Frontiers in Physiology 2022Obesity impairs lung function and mechanics and leads to low-grade inflammation, but the effects of combined physical exercise (CPE) on that are unknown. We...
Obesity impairs lung function and mechanics and leads to low-grade inflammation, but the effects of combined physical exercise (CPE) on that are unknown. We investigated the effects of 12 weeks of combined physical exercise (aerobic + resistance training), in non-obese ( = 12), overweight ( = 17), and obese grade I ( = 11) women. Lung function and lung mechanics were evaluated. The systemic immune response was evaluated by whole blood analysis and biomarker measurements, while pulmonary fibrotic biomarkers were evaluated in the breath condensate. CPE improved forced vital capacity (FVC) % ( < 0.001) and peak expiratory flow (PEF) % ( < 0.0003) in the obese group; resistance of the respiratory system (R5Hz) in non-obese ( < 0.0099), overweight ( < 0.0005), and obese ( < 0.0001) groups; resistance of proximal airways (R20Hz) in non-obese ( < 0.01), overweight ( < 0.0009), and obese ( < 0.0001) groups; resistance of distal airways (R5Hz-R20Hz) in non-obese ( < 0.01), overweight ( < 0.0012), and obese ( < 0.0001) groups; reactance of the respiratory system (X5Hz) in non-obese ( < 0.01), overweight ( < 0.0006), and obese ( < 0.0005) groups; impedance of the respiratory system (Z5Hz) in non-obese ( < 0.0099), overweight ( < 0.0005), and obese ( < 0.0001) groups; central resistance (RCentral) in non-obese ( < 0.01), overweight ( < 0.001), and obese ( < 0.0003) groups; and the peripheral resistance (RPeripheral) in non-obese ( < 0.03), overweight ( < 0.001), and obese ( < 0.0002) groups. CPE reduced the pro-fibrotic IGF-1 levels in BC in overweight ( < 0.0094) and obese groups ( < 0.0001) and increased anti-fibrotic Klotho levels in BC in obese ( < 0.0001) groups, and reduced levels of exhaled nitric oxide in overweight ( < 0.03) and obese ( < 0.0001) groups. CPE improves lung function, mechanics, and pulmonary immune response in overweight and obese grade I women by increasing anti-fibrotic protein Klotho and reducing pro-fibrotic IGF-1.
PubMed: 36160852
DOI: 10.3389/fphys.2022.946402