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Clinical Physiology and Functional... Sep 2021The forced oscillation technique (FOT) provides detailed information about the mechanics of the respiratory system, while requiring minimal co-operation by the patient....
BACKGROUND
The forced oscillation technique (FOT) provides detailed information about the mechanics of the respiratory system, while requiring minimal co-operation by the patient. FOT may be abnormal in subjects with normal spirometry and appears to be more closely related to airway symptoms. It is, therefore, attractive in epidemiological studies, where a large number of different examinations are made in each subjects in a short period of time. Current technical standards recommend the mean of three consecutive measurements to be used, but there is limited information regarding within-session variability of FOT measurements.
OBJECTIVE
The purpose of this study was to examine the within-session variability in FOT measurements in a large, population-based sample.
METHODS
We performed three consecutive FOT measurements in 700 subjects using the impulse oscillometry system. The first measurement was compared to the mean of three measurements for resistance at 5 and 20 Hz (R5 and R20, respectively), R5-R20, reactance at 5 Hz (X5) and resonant frequency (f ).
RESULTS
The differences between the first and the mean of three measurements (median, interquartile range) were minimal, for example 0.002, -0.008 to 0.014 kPa L s for R5 and -0.001, -0.008 to 0.005 kPa L s for X5. Findings were numerically similar for men and women as well as for subjects with and without airflow obstruction at spirometry.
CONCLUSIONS
We conclude that, whereas in clinical situations, three FOT measurements are to be preferred, a single measurement may suffice in epidemiological studies.
Topics: Airway Resistance; Female; Forced Expiratory Volume; Humans; Male; Oscillometry; Pulmonary Disease, Chronic Obstructive; Reproducibility of Results; Spirometry
PubMed: 33914403
DOI: 10.1111/cpf.12706 -
Allergy, Asthma & Immunology Research Mar 2022There are reports concerning mucus plugs detected on high-resolution computed tomography images and airflow obstruction in asthma and chronic obstructive pulmonary...
PURPOSE
There are reports concerning mucus plugs detected on high-resolution computed tomography images and airflow obstruction in asthma and chronic obstructive pulmonary disease (COPD). However, little is known about the associations between mucus plugs and small airway dysfunction (SAD). We evaluated the relationship between mucus plugs and pulmonary function in patients with asthma, COPD, and asthma-COPD overlap (ACO), and investigated the relevance to SAD and type 2 inflammation in a retrospective study.
METHODS
Subjects included 49 asthmatic, 40 ACO, and 41 COPD patients. ACO was diagnosed based on the Japanese Respiratory Society ACO guidelines. Clinical and laboratory parameters, including blood eosinophil count, serum total IgE levels, fractional exhaled nitric oxide (FeNO), spirometry, and forced oscillation technique (FOT), were compared between patients with and without mucus plugs.
RESULTS
Mucus plugs were found in 29 (59%) asthmatic, 25 (65%) ACO, 17 (41%) COPD patients. Patients with mucus plugs had reduced spirometry and larger FOT parameters, especially in COPD patients. Mucus scores correlated positively with IgE in ACO and FeNO in asthmatic patients, but not in COPD patients. Multivariate logistic regression analysis revealed that SAD parameters, including forced vital capacity and resonant frequency, a respiratory reactance parameter, were significantly associated with the presence of mucus plugs in the whole studied population.
CONCLUSIONS
SAD, rather than large airway dysfunction, was associated with mucus plugs in asthma, ACO, and COPD patients.
PubMed: 35255537
DOI: 10.4168/aair.2022.14.2.196 -
Respiratory Research Mar 2022Pulmonary involvement in individuals with transthyretin cardiac amyloidosis is unclear. The aim of this study was to quantify Tc-hydroxy methylene diphosphonate (HMDP)...
BACKGROUND
Pulmonary involvement in individuals with transthyretin cardiac amyloidosis is unclear. The aim of this study was to quantify Tc-hydroxy methylene diphosphonate (HMDP) lung retention in hereditary transthyretin (ATTRv) cardiac amyloidosis patients and to relate tracer uptake intensity to pulmonary function and aerobic capacity.
METHODS
We prospectively enrolled 20 patients with biopsy-proven ATTRv cardiac amyloidosis and 20 control subjects. Cardiac involvement was confirmed by echocardiography and nuclear imaging using Tc-HMDP. Semi-quantitative analysis of the heart, rib and lung retention was assessed using a simple region of interest technique. Pulmonary function was evaluation by the means of whole-body plethysmography, diffusing capacity of the lung for carbon monoxide, forced oscillation technique and cardiopulmonary exercise testing.
RESULTS
Pulmonary tracer uptake estimated by lung to rib retention ratio was higher in ATTRv amyloidosis patients compared with control subjects: median 0.62 (0.55-0.69) vs 0.51 (0.46-0.60); p = 0.014. Analysis of relation between lung Tc-HMDP retention and pulmonary function parameters shown statistically significant correlations with total lung volume (% predicted), lung reactance (X 5 Hz) and peak VO, suggesting total lung capacity restriction impaired elastic properties of the lung and poor aerobic capacity.
CONCLUSION
Our study suggests that some grade of pulmonary retention of Tc-HMDP may occur in patients with cardiac ATTRv amyloidosis, which can elicit deleterious effects on patient's lung function and aerobic capacity.
Topics: Amyloidosis; Humans; Lung; Prealbumin; Radionuclide Imaging; Radiopharmaceuticals; Technetium Tc 99m Medronate
PubMed: 35346209
DOI: 10.1186/s12931-022-01995-x -
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 -
Scientific Reports Aug 2021The low-grade inflammation associated with metabolic syndrome (MS) triggers functional and structural alterations in several organs. Whereas lung function impairment is... (Comparative Study)
Comparative Study
The low-grade inflammation associated with metabolic syndrome (MS) triggers functional and structural alterations in several organs. Whereas lung function impairment is well reported for older adult population, the effect of MS on functional and immunological responses in the lungs remains unclear. In this cross-sectional study we determined whether MS alters pulmonary function, and immunological responses in older adults with MS. The study sample consisted of older adults with MS (68 ± 3 years old; n = 77) and without MS (67 ± 3 years old; n = 77). Impulse oscillometry was used to evaluate airway and tissue resistance, and reactance. Biomarkers of inflammation and fibrosis were assessed in the blood and in breath condensate. The total resistance of the respiratory system (R5Hz; p < 0.009), and the resistance of the proximal (R20Hz; p < 0.001) and distal (R5Hz-R20Hz; p < 0.004) airways were higher in MS individuals compared to those without MS. Pro-inflammatory (leptin, IL-1beta, IL-8, p < 0.001; TNF-alpha, p < 0.04) and anti-inflammatory cytokines (adiponectin, IL-1ra, IL-10, p < 0.001), anti-fibrotic (relaxin 1, relaxin 3, Klotho, p < 0.001) and pro-fibrotic (VEGF, p < 0.001) factors were increased in sera and in breath condensate individuals with MS. The results show that MS adversely affect lung mechanics, function, and immunological response in older adults. The data offer a metabolic basis for the inflammaging of the lungs and suggest the lungs as a potential therapeutic target for controlling the immune response and delaying the onset of impaired lung function in older adults with MS.
Topics: Aged; Anthropometry; Biomarkers; Cross-Sectional Studies; Cytokines; Female; Hand Strength; Humans; Inflammation; Lung; Male; Metabolic Syndrome; Middle Aged; Muscle Strength; Oscillometry; Pulmonary Fibrosis; Respiratory Function Tests; Respiratory Physiological Phenomena
PubMed: 34462482
DOI: 10.1038/s41598-021-96766-x -
Pediatric Pulmonology Nov 2023Mechanisms underlying lung dysfunction after preterm birth are poorly understood. Studying phenotypes of prematurity-associated lung disease may aid understanding of...
INTRODUCTION
Mechanisms underlying lung dysfunction after preterm birth are poorly understood. Studying phenotypes of prematurity-associated lung disease may aid understanding of underlying mechanisms. Preterm-born children with and without lung dysfunction and term controls were assessed using oscillometry before and after exercise, and after postexercise bronchodilation.
METHODS
Preterm-born children, born at gestation of 34 weeks or less, were classified into those with prematurity-associated obstructive lung disease (POLD; FEV < LLN, FEV /FVC < LLN), prematurity-associated preserved ratio of impaired spirometry (pPRISm; FEV < LLN, FEV /FVC ≥ LLN) and compared to preterm (FEV ≥ LLN) and term controls (%predicted FEV > 90%). All children underwent cardiopulmonary exercise, and oscillometry assessment at baseline, postexercise, and after postexercise bronchodilator administration.
RESULTS
From 241 participants aged 7-12 years, complete data were available from 179: 15 children with POLD and 11 with pPRISm were compared with 93 preterm and 60 term controls. POLD group, when compared to both control groups, had impaired impedance, greater resistance, more negative (greater magnitude) reactance at low frequencies, and also had decreased compliance. pPRISm group demonstrated impaired reactance and compliance compared to term controls. No differences were noted between the preterm and term controls. Exercise had little impact on oscillometry values, but children with POLD had greatest improvements after postexercise bronchodilator administration, with decreased resistance and decreased magnitude of reactance, particularly at low frequencies.
CONCLUSION
Preterm-born children with obstructive airway disease had the greatest oscillometry impairments and the largest improvements after postexercise bronchodilator compared to control groups. Oscillometry can potentially be used to identify preterm-born children with lung disease to institute treatment.
Topics: Child; Female; Humans; Infant, Newborn; Bronchodilator Agents; Oscillometry; Forced Expiratory Volume; Premature Birth; Lung; Lung Diseases; Lung Diseases, Obstructive; Spirometry; Infant, Newborn, Diseases
PubMed: 37701982
DOI: 10.1002/ppul.26658 -
Brazilian Journal of Medical and... 2023Scoliosis is a condition that affects the spine and causes chest rotation and trunk distortion. Individuals with severe deformities may experience dyspnea on exertion...
Scoliosis is a condition that affects the spine and causes chest rotation and trunk distortion. Individuals with severe deformities may experience dyspnea on exertion and develop respiratory failure. Respiratory oscillometry is a simple and non-invasive method that provides detailed information on lung mechanics. This work aims to investigate the potential of oscillometry in the evaluation of respiratory mechanics in patients with scoliosis and its association with physical performance. We analyzed 32 volunteers in the control group and 32 in the scoliosis group. The volunteers underwent traditional pulmonary function tests, oscillometry, and the 6-minute walk test (6MWT). Oscillometric analysis showed increased values of resistance at 4 Hz (R4, P<0.01), 12 Hz (R12, P<0.0001), and 20 Hz (R20, P<0.01). Similar analysis showed reductions in dynamic compliance (Cdyn, P<0.001) and ventilation homogeneity, as evaluated by resonance frequency (fr, P<0.001) and reactance area (Ax, P<0.001). Respiratory work, described by the impedance modulus, also showed increased values (Z4, P<0.01). Functional capacity was reduced in the group with scoliosis (P<0.001). A significant direct correlation was found between Cobb angle and R12, AX, and Z4 (P=0.0237, P=0.0338, and P=0.0147, respectively), and an inverse correlation was found between Cdyn and Cobb angle (P=0.0190). These results provided new information on respiratory mechanics in scoliosis and are consistent with the involved pathophysiology, suggesting that oscillometry may improve lung function tests for patients with scoliosis.
Topics: Humans; Scoliosis; Oscillometry; Lung; Respiratory Function Tests; Respiratory Mechanics
PubMed: 37937601
DOI: 10.1590/1414-431X2023e12898 -
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 -
Scientific Reports Aug 2022This descriptive case series retrospectively reviewed medical records from thirty-one previously healthy, war-fighting veterans who self-reported exposure to airborne...
This descriptive case series retrospectively reviewed medical records from thirty-one previously healthy, war-fighting veterans who self-reported exposure to airborne hazards while serving in Iraq and Afghanistan between 2003 and the present. They all noted new-onset dyspnea, which began during deployment or as a military contractor. Twenty-one subjects underwent non-invasive pulmonary diagnostic testing, including maximum expiratory pressure (MEP) and impulse oscillometry (IOS). In addition, five soldiers received a lung biopsy; tissue results were compared to a previously published sample from a soldier in our Iraq Afghanistan War Lung Injury database and others in our database with similar exposures, including burn pits. We also reviewed civilian control samples (5) from the Stony Brook University database. Military personnel were referred to our International Center of Excellence in Deployment Health and Medical Geosciences, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell under the auspices of Northwell IRB: 17-0140-FIMR Feinstein Institution for Medical Research "Clinicopathologic characteristics of Iraq Afghanistan War Lung Injury." We retrospectively examined medical records, including exposure data, radiologic imaging, and non-invasive pulmonary function testing (MGC Diagnostic Platinum Elite Plethysmograph) using the American Thoracic Society (ATS) standard interpretation based on Morgan et al., and for a limited cohort, biopsy data. Lung tissue, when available, was examined for carbonaceous particles, polycyclic aromatic hydrocarbons (Raman spectroscopy), metals, titanium connected to iron (Brookhaven National Laboratory, National Synchrotron Light Source II, Beamline 5-ID), oxidized metals, combustion temperature, inflammatory cell accumulation and fibrosis, neutrophil extracellular traps, Sirius red, Prussian Blue, as well as polarizable crystals/particulate matter/dust. Among twenty-one previously healthy, deployable soldiers with non-invasive pulmonary diagnostic tests, post-deployment, all had severely decreased MEP values, averaging 42% predicted. These same patients concurrently demonstrated abnormal airways reactance (X5Hz) and peripheral/distal airways resistance (D5-D20%) via IOS, averaging - 1369% and 23% predicted, respectively. These tests support the concept of airways hyperresponsiveness and distal airways narrowing, respectively. Among the five soldiers biopsied, all had constrictive bronchiolitis. We detected the presence of polycyclic aromatic hydrocarbons (PAH)-which are products of incomplete combustion-in the lung tissue of all five warfighters. All also had detectable titanium and iron in the lungs. Metals were all oxidized, supporting the concept of inhaling burned metals. Combustion temperature was consistent with that of burned petrol rather than higher temperatures noted with cigarettes. All were nonsmokers. Neutrophil extracellular traps were reported in two biopsies. Compared to our prior biopsies in our Middle East deployment database, these histopathologic results are similar, since all database biopsies have constrictive bronchiolitis, one has lung fibrosis with titanium bound to iron in fixed mathematical ratios of 1:7 and demonstrated polarizable crystals. These results, particularly constrictive bronchiolitis and polarizable crystals, support the prior data of King et al. (N. Engl. J. Med. 365:222-230, 2011) Soldiers in this cohort deployed to Iraq and Afghanistan since 2003, with exposure to airborne hazards, including sandstorms, burn pits, and improvised explosive devices, are at high risk for developing chronic clinical respiratory problems, including: (1) reduction in respiratory muscle strength; (2) airways hyperresponsiveness; and (3) distal airway narrowing, which may be associated with histopathologic evidence of lung damage, reflecting inhalation of burned particles from burn pits along with particulate matter/dust. Non-invasive pulmonary diagnostic tests are a predictor of burn pit-induced lung injury.
Topics: Afghan Campaign 2001-; Afghanistan; Bronchiolitis Obliterans; Dust; Humans; Incineration; Iraq; Iraq War, 2003-2011; Iron; Lung; Lung Injury; Particulate Matter; Polycyclic Aromatic Hydrocarbons; Retrospective Studies; Titanium; United States
PubMed: 36038588
DOI: 10.1038/s41598-022-18252-2 -
ERJ Open Research Apr 2022Single nucleotide polymorphisms (SNPs) in various genes have been shown to associate with COPD, suggesting a role in disease pathogenesis. Sulfatase modifying factor...
Single nucleotide polymorphisms (SNPs) in various genes have been shown to associate with COPD, suggesting a role in disease pathogenesis. Sulfatase modifying factor (SUMF1) is a key modifier in connective tissue remodelling, and we have shown previously that several SNPs in are associated with COPD. The aim of this study was to investigate the association between SNPs and advanced lung function characteristics. Never-, former and current smokers with (n=154) or without (n=405) COPD were genotyped for 21 SNPs in and underwent spirometry, body plethysmography, diffusing capacity of the lung for carbon monoxide ( ) measurement and impulse oscillometry. Four SNPs (rs793391, rs12634248, rs2819590 and rs304092) showed a significantly decreased odds ratio of having COPD when heterozygous for the variance allele, together with a lower forced expiratory volume in 1 s (FEV) and FEV/forced vital capacity (FVC) ratio and an impaired peripheral resistance and reactance. Moreover, individuals homozygous for the variance allele of rs3864051 exhibited a strong association to COPD, a lower FEV/FVC, FEV and , and an impaired peripheral resistance and reactance. Other SNPs (rs4685744, rs2819562, rs2819561 and rs11915920) were instead associated with impaired lung volumes and exhibited a lower FVC, total lung capacity and alveolar volume, in individuals having the variance allele. Several SNPs in the gene are shown to be associated with COPD and impaired lung function. These genetic variants of may cause a deficient sulfation balance in the extracellular matrix of the lung tissue, thereby contributing to the development of COPD.
PubMed: 35586453
DOI: 10.1183/23120541.00668-2021