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Oscillometry in Lung Function Assessment: A Comprehensive Review of Current Insights and Challenges.Cureus Oct 2023Oscillometry, a non-invasive technique for assessing lung function, has gained significant recognition and importance in modern pulmonary medicine. This comprehensive... (Review)
Review
Oscillometry, a non-invasive technique for assessing lung function, has gained significant recognition and importance in modern pulmonary medicine. This comprehensive review thoroughly explores its principles, applications, advantages, limitations, recent innovations, and future directions. Oscillometry's primary strength lies in its ability to offer a holistic assessment of lung mechanics. Unlike traditional spirometry, oscillometry captures the natural airflow during quiet breathing, making it suitable for patients of all ages and those with severe respiratory conditions. It provides a comprehensive evaluation of airway resistance, reactance, and compliance, offering insights into lung function that were previously challenging to obtain. In clinical practice, oscillometry finds extensive application in diagnosing and managing respiratory diseases. It plays a pivotal role in asthma, chronic obstructive pulmonary disease (COPD), and interstitial lung diseases. By detecting subtle changes in lung function before symptoms manifest, oscillometry facilitates early interventions, improving disease management and patient outcomes. Oscillometry's non-invasive and patient-friendly nature is precious in pediatric care, where traditional spirometry may be challenging for young patients. It aids in diagnosing and monitoring pediatric respiratory disorders, ensuring that children receive the care they need from an early age. Despite its many advantages, oscillometry faces challenges, such as the need for standardized protocols and the complexity of data interpretation. However, ongoing efforts to establish global standards and provide education and training for healthcare professionals aim to address these issues. Looking ahead, oscillometry holds great promise in the field of personalized medicine. With its ability to tailor treatment plans based on individualized lung function data, healthcare providers can optimize therapy selection and dosing, ultimately improving patient care and quality of life. In conclusion, oscillometry is poised to play an increasingly pivotal role in modern pulmonary medicine. As standardization efforts continue and technology evolves, it is an indispensable tool in the clinician's arsenal for diagnosing, managing, and personalizing respiratory care, ultimately leading to improved patient outcomes and better respiratory health.
PubMed: 38034137
DOI: 10.7759/cureus.47935 -
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 -
Diseases (Basel, Switzerland) Aug 2023The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has had significant impacts on pulmonary function. This study aimed to comprehensively evaluate pulmonary function...
The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has had significant impacts on pulmonary function. This study aimed to comprehensively evaluate pulmonary function and structure in patients 40 days post-SARS-CoV-2 infection, employing an array of testing methodologies including spirometry, plethysmography, forced oscillometry, and CT scanning. It also sought to establish potential correlations between these metrics and evaluate if forced oscillometry could provide additional value in post-infective lung function assessment. A 40-day post-infection follow-up observational study was conducted involving 66 patients with confirmed SARS-CoV-2 infection. The results revealed decreases in FVC and FEF25-75 with the increasing severity of COVID-19. Specifically, patients with severe symptoms exhibited statistically significant decreases in FVC (mean = 86.8) compared with those with mild symptoms (mean = 106.0; = 0.018). The FEF25-75 showed a similar trend, with severe patients exhibiting a mean of 77.7 compared with 82.9 in the mild group ( = 0.017). Furthermore, resonant frequency (RF) increased with disease severity, with the severe group exhibiting a statistically significant increase (mean = 17.4) compared with the mild group (mean = 14.3; = 0.042). CT scans showed an increase in ground-glass opacities with disease severity, with 81.8% of severe patients demonstrating this finding ( = 0.037). Multiple regression analysis revealed that Reactance at 4 Hz (X4), Forced Expiratory Flow 25-75% (FEF25-75), and Resonant Frequency (RF) were significantly related to COVID-19 severity. Specifically, for each unit increase in these factors, the risk of the event was estimated to increase by a factor of 3.16, 2.09, and 1.90, respectively. Conversely, Resistance at 4 Hz (R4) and Airway Resistance (RAW) were found to significantly decrease the event hazard, highlighting their potential protective role. Spirometry, plethysmography, and forced oscillometry are effective in assessing these changes. Forced oscillometry may be particularly beneficial in identifying subtle changes in lung function post-COVID-19. Further studies are warranted to validate these findings and develop strategies to manage post-infective pulmonary changes in SARS-CoV-2 patients.
PubMed: 37606473
DOI: 10.3390/diseases11030102 -
Pediatric Pulmonology Jul 2022Spirometry plays an important role in the assessment of possible respiratory failure in children with neuromuscular diseases (NMDs). However, obtaining reliable...
INTRODUCTION
Spirometry plays an important role in the assessment of possible respiratory failure in children with neuromuscular diseases (NMDs). However, obtaining reliable spirometry results is a major challenge. We studied the relation between oscillometry and spirometry results. Oscillometry is an easy, noninvasive method to measure respiratory resistance R and reactance X. We hypothesized an increased R and reduced X in patients with more reduced lung function.
METHODS
In this prospective single-center study, we included all children with NMDs able to perform spirometry. We consecutively measured R and X at 5, 11, and 19 Hz and (forced) vital capacity, peak expiratory flow. Spearman correlation coefficients and positive and negative predictive values were calculated. Regression curves were estimated.
RESULTS
We included 148 patients, median age 13 years (interquartile range: 8-16). A negative correlation was found between R and spirometry outcomes (Spearman correlation coefficient [ρ]: -0.5 to -0.6, p < 0.001). A positive correlation was found between X (i.e., less negative outcomes) and spirometry outcomes (ρ: 0.4-0.6, p < 0.001). Highest correlation was found at lower frequencies. Regression analysis showed a nonlinear relation. Measurement of inspiratory and expiratory R and X did not provide added value. Positive predictive values of 80%-85% were found for z-scores of R measured at 5 Hz versus (F)VC ≤ 60%.
CONCLUSION
We found a nonlinear relation between oscillometry and spirometry results with increased R and reduced X in patients with more restrictive lung function decline. Given the difficulties with performing spirometry, oscillometry may be a promising substitute.
Topics: Adolescent; Child; Forced Expiratory Volume; Humans; Lung; Neuromuscular Diseases; Oscillometry; Prospective Studies; Spirometry
PubMed: 35441830
DOI: 10.1002/ppul.25923 -
Canadian Respiratory Journal 2022Impairment of pulmonary function was evaluated in chronic bronchitis patients with preserved ratio impaired spirometry (PRISm). We retrospectively collected clinical...
Impairment of pulmonary function was evaluated in chronic bronchitis patients with preserved ratio impaired spirometry (PRISm). We retrospectively collected clinical data from 157 chronic bronchitis (CB) and 186 chronic obstructive pulmonary disease (COPD) patients between October 2014 and September 2017. These patients were assigned to three groups: control (normal pulmonary function), PRISm (forced expiratory volume in 1 second [FEV1]/forced vital capacity [FVC] ≥ 0.7, FEV1 < 80% of predicted value), and COPD (FEV1/FVC <0.7) groups. Because small airway function was the main focus, in the COPD group, only patients in accordance with the Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades 1 and 2 were included. Evaluation of pulmonary function (including impulse oscillometry) was performed and compared among these groups. Compared with the control group, the PRISm and COPD groups showed statistically significant differences in the predicted FEV1% ( < 0.001), maximal expiratory flow (MEF) 25% ( < 0.001), MEF50% ( < 0.001), maximal midexpiratory flow (MMEF) 25-75% ( < 0.001), residual volume (RV)/total lung capacity (TLC; < 0.001), FVC% ( < 0.001), total respiratory resistance and proximal respiratory resistance (R5-R20; < 0.001), respiratory system reactance at 5 Hz (X5; < 0.001), resonant frequency (Fres; < 0.001), and area of reactance (Ax; < 0.001). However, the predicted FEV1% and RV/TLC were similar between the PRISm and COPD groups (=0.992 and 0.122, respectively). PRISm is a nonspecific pattern of pulmonary function that indicates small airway dysfunction and may increase the risk of transformation to obstructive ventilation dysfunction. This trial is registered with ChiCTR-OCH-14004904.
Topics: Bronchitis, Chronic; Forced Expiratory Volume; Humans; Lung; Oscillometry; Pulmonary Disease, Chronic Obstructive; Retrospective Studies; Spirometry
PubMed: 36060828
DOI: 10.1155/2022/4201786 -
International Journal of Chronic... 2021To explore the correlation of respiratory resistance in stable COPD patients measured by broadband 3-dimensional impulse oscillometry (3D-IOS) and traditional pulmonary...
OBJECTIVE
To explore the correlation of respiratory resistance in stable COPD patients measured by broadband 3-dimensional impulse oscillometry (3D-IOS) and traditional pulmonary function test (PFT). To access the diagnostic value of 3D-IOS in COPD.
METHODS
A total of 107 COPD patients and 61 healthy subjects as controls were chosen to collect and statistically analyze the data of R5, R5-R20, R20, X5 and Fres measured by broadband 3D-IOS and FEV1%pred, FVC%pred and FEV1/FVC by PFTs. The diagnostic value of broadband 3D-IOS parameters in COPD was evaluated by receiver operating characteristic curve (ROC). 3D-colored images used to show dynamic changes of respiratory resistance in COPD.
RESULTS
The COPD group showed significant increases in R5, R20, R5-R20 and Fres, and a decrease in X5 (<0.05). With the increase of GOLD grade, R5, R5-R20 and Fres increased whereas X5 decreased (<0.05). Compared with FEV1%pred, FVC%pred and FEV1/FVC in the COPD group, R5, R5-R20 and Fres were negatively collated (<0.05), whereas X5 was positively collated (<0.01). R20 was uncorrelated with the traditional lung function parameters (>0.05). Fres and FEV1/FVC (r=-0.467), and X5 and FEV1%pred (r=0.412) showed the strongest correlation. The AUC of R5, R5-R20, X5 and Fres was 0.7808, 0.7659, 0.8947 and 0.9095, respectively. Typical 3D-colored images of COPD displayed a green pattern in the inhalation phase and yellow-red-blue graduation in the expiration phase.
CONCLUSION
R5, R5-R20, X5 and Fres measured by broadband 3D-IOS can reflect the change of respiratory resistance in COPD. And they have good correlation with the traditional lung function parameters (FEV1%pred, FVC%pred, FEV1/FVC). Fres has the highest diagnostic accuracy. Comprehensive analysis of R5, R5-R20, Fres and X5 helps to determine the degree of respiratory obstruction in COPD. X5 and Fres can reflect changes in lung tissue compliance. 3D-colored images can visually show the change of respiratory resistance and reactance in COPD.
Topics: Forced Expiratory Volume; Humans; Oscillometry; Pulmonary Disease, Chronic Obstructive; Respiratory Function Tests; Spirometry
PubMed: 33574662
DOI: 10.2147/COPD.S285927 -
Pediatric Pulmonology Aug 2020Several studies have shown that exposure to air pollutants affects lung growth and development and can result in poor respiratory health in early life.
BACKGROUND
Several studies have shown that exposure to air pollutants affects lung growth and development and can result in poor respiratory health in early life.
METHODS
We included a subsample of 772 Mexican preschoolers whose mothers participated in a Prenatal Omega-3 fatty acid Supplements, GRowth, And Development birth cohort study with the aim to evaluate the impact of prenatal exposure to volatile organic compounds and nitrogen oxides on lung function measured by oscillation tests. The preschoolers were followed until 5 years of age. Anthropometric measurements and forced oscillation tests were performed at 36, 48, and 60 months of age. Information on sociodemographic and health characteristics was obtained during follow up. Prenatal exposure to volatile organic compounds and nitrogen oxides was evaluated using a land use regression models and the association between them was tested using a lineal regression and longitudinal linear mixed effect models adjusting for potential confounders.
RESULTS
Overall, the mean (standard deviation) of the measurements of respiratory system resistance and respiratory system reactance at 6, 8, and 10 Hz during the follow-up period was 11.3 (2.4), 11.1 (2.4), 10.3 (2.2) and -5.2 (1.6), -4.8 (1.7), and -4.6 hPa s L (1.6), respectively. We found a significantly positive association between respiratory resistance (β = 0.011; 95%CI: 0.001, 0.023) (P < .05) and prenatal exposure to nitrogen dioxide and a marginally negatively association between respiratory reactance (β = -11.40 95%CI: -25.26, 1.17 and β = -11.91 95%CI: -26.51, 1.43) (P = .07) and prenatal exposure to xylene.
CONCLUSION
Prenatal exposure to air pollutants was significantly associated with the alteration of lung function measured by oscillation tests in these preschool children.
Topics: Air Pollutants; Child, Preschool; Cohort Studies; Environmental Exposure; Female; Humans; Lung; Male; Maternal-Fetal Exchange; Nitrogen Oxides; Pregnancy; Prenatal Exposure Delayed Effects; Respiratory Function Tests; Volatile Organic Compounds
PubMed: 32510180
DOI: 10.1002/ppul.24889 -
Respiratory Medicine Jun 2023Welders are exposed to gas and particle emissions that can cause severe lung disease, such as chronic obstructive pulmonary disease (COPD), a leading cause of mortality...
BACKGROUND
Welders are exposed to gas and particle emissions that can cause severe lung disease, such as chronic obstructive pulmonary disease (COPD), a leading cause of mortality and morbidity worldwide. It is difficult to detect COPD early and therefore mitigating measures may be delayed. The aim of this study was to investigate lung health in welders and evaluate new sensitive methods with potential to assess early onset pulmonary changes in occupational settings.
METHODS
This study assessed the lung health and symptoms in active welders (n = 28) and controls (n = 17). Lung measurements were performed with standard spirometry and new methods: airspace dimension assessment (AiDA), oscillometry, blood serum biomarkers (club cell secretory protein 16, surfactant protein D, matrix metalloproteinases, fibroblast, hepatocyte growth factor, interleukins), and one urine biomarker (desmosine).
RESULTS
According to spirometry measurements, all participants had normal lung function. However, prevalence of cough was significantly higher among welders compared with controls and lung changes were found in welders with the novel methods. Welders had significantly higher respiratory system resistance assessed with oscillometry, serum levels of metalloproteinases 9 and hepatocyte growth factor, compared with controls. Airspace dimensions were on average higher among welders compared with controls, but the difference was not significant. The number of welding years correlated with decreased respiratory system reactance and increased serum levels of matrix metalloproteinases 9, interleukin 6, and hepatocyte growth factor. Airspace dimension assessment indices were correlated with increasing levels of inflammatory markers and matrix metalloproteinases.
CONCLUSIONS
This study indicated the potential to use new and more sensitive methods for identification of changes in lungs when standard spirometry failed to do so.
Topics: Humans; Hepatocyte Growth Factor; Metal Workers; Respiratory Function Tests; Lung; Pulmonary Disease, Chronic Obstructive; Occupational Diseases; Occupational Exposure
PubMed: 37062499
DOI: 10.1016/j.rmed.2023.107244 -
Journal of Applied Physiology... Dec 2019Bronchodilation alters both respiratory system resistance (Rrs) and reactance (Xrs) in asthma, but how changes in Rrs and Xrs compare, and respond differently in health...
Bronchodilation alters both respiratory system resistance (Rrs) and reactance (Xrs) in asthma, but how changes in Rrs and Xrs compare, and respond differently in health and asthma, in reflecting the contributions from the large and small airways has not been assessed. We assessed reversibility using spirometry and oscillometry in healthy and asthma subjects. Using a multibranch airway-tree model with the mechanics of upper airway shunt, we compared the effects of airway dilation and small airways recruitment to explain the changes in Rrs and Xrs. Bronchodilator decreased Rrs by 23.0 (19.0)% in 18 asthma subjects and by 13.5 (19.5)% in 18 healthy subjects. Estimated respiratory system elastance (Ers) decreased by 23.2 (21.4)% in asthma, with no significant decrease in healthy subjects. With the use of the model, airway recruitment of 15% across a generation of the small airways could explain the changes in Ers in asthma with no recruitment in healthy subjects. In asthma, recruitment accounted for 40% of the changes in Rrs, with the remaining explained by airway dilation of 6.8% attributable largely to the central airways. Interestingly, the same dilation magnitude explained the changes in Rrs in healthy subjects. Shunt only affected Rrs of the model. Ers was unaltered in health and unaffected by shunt in both groups. In asthma, Ers changed comparably to Rrs and could be attributed to small airways, while the change in Rrs was split between large and small airways. This implies that in asthma Ers sensed through Xrs may be a more effective measure of small airways obstruction and recruitment than Rrs. This is the first study to quantify to relative contributions of small and large airways to bronchodilator response in healthy subjects and patients with asthma. The response of the central airways to bronchodilator was similar in magnitude in both study groups, whereas the response of the small airways was significant among patients with asthma. These results suggest that low-frequency reactance and derived elastance are both sensitive measures of small airway function in asthma.
Topics: Adult; Airway Resistance; Asthma; Bronchioles; Bronchodilator Agents; Female; Humans; Male; Middle Aged; Models, Biological; Young Adult
PubMed: 31647721
DOI: 10.1152/japplphysiol.01131.2018 -
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