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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 -
Cold Spring Harbor Perspectives in... Jan 2020Ionized calcium (Ca) is the most versatile cellular messenger. All cells use Ca signals to regulate their activities in response to extrinsic and intrinsic stimuli.... (Review)
Review
Ionized calcium (Ca) is the most versatile cellular messenger. All cells use Ca signals to regulate their activities in response to extrinsic and intrinsic stimuli. Alterations in cellular Ca signaling and/or Ca homeostasis can subvert physiological processes into driving pathological outcomes. Imaging of living cells over the past decades has demonstrated that Ca signals encode information in their frequency, kinetics, amplitude, and spatial extent. These parameters alter depending on the type and intensity of stimulation, and cellular context. Moreover, it is evident that different cell types produce widely varying Ca signals, with properties that suit their physiological functions. This primer discusses basic principles and mechanisms underlying cellular Ca signaling and Ca homeostasis. Consequently, we have cited some historical articles in addition to more recent findings. A brief summary of the core features of cellular Ca signaling is provided, with particular focus on Ca stores and Ca transport across cellular membranes, as well as mechanisms by which Ca signals activate downstream effector systems.
Topics: Animals; Binding Sites; Calcium; Calcium Channels; Calcium Signaling; Cell Membrane; Homeostasis; Humans; Kinetics; Oscillometry; Signal Transduction
PubMed: 31427372
DOI: 10.1101/cshperspect.a038802 -
Pediatric Pulmonology Jul 2023The purpose of this study was to describe the feasibility of respiratory oscillometry (RO) in schoolchildren with asthma, and the concordance of its results with those...
OBJECTIVE
The purpose of this study was to describe the feasibility of respiratory oscillometry (RO) in schoolchildren with asthma, and the concordance of its results with those of spirometry, to determine its clinical usefulness.
METHODS
RO and spirometry were performed in 154 children (6 to 14-year-old) with asthma, following strict quality criteria for the tests. Their feasibility (probability of valid test, time of execution, number of maneuvers needed to achieve a valid test, and perceived difficulty) was compared. The factors that influence feasibility were analyzed with multivariate methods. FEV1, FEV1/FVC, FVC and FEF25-75 for spirometry, and R5, AX and R5-19 for RO, were converted into z-scores and their concordance was investigated through intraclass correlation coefficients (ICC) and kappa indices for normal/abnormal values.
RESULTS
There were no differences in the probability of obtaining a valid RO or spirometry (83.1% vs. 81.8%, p = 0.868). RO required a lower number of maneuvers [mean (SD) 4.2 (1.8) versus 6.0 (1.6), p < 0.001] and less execution time [5.1 (2.7) versus 7.6 (2.4) minutes, p < 0.001], and patients considered it less difficult. Age increased the probability of obtaining valid RO and spirometry. The concordance of results between RO and spirometry was low, and only between zFEV1 and zAX could it be considered moderate (ICC = 0.412, kappa = 0.427).
CONCLUSION
RO and spirometry are feasible in children with asthma. RO has some practical advantages, but the concordance of its results with spirometry is low.
Topics: Child; Humans; Adolescent; Oscillometry; Feasibility Studies; Asthma; Spirometry; Forced Expiratory Volume
PubMed: 37067397
DOI: 10.1002/ppul.26409 -
European Respiratory Review : An... Sep 2023Pulmonary chronic graft--host disease (cGVHD) is a substantial cause of pulmonary morbidity and mortality post-haematopoietic stem cell transplantation (HSCT). Current... (Review)
Review
Pulmonary chronic graft--host disease (cGVHD) is a substantial cause of pulmonary morbidity and mortality post-haematopoietic stem cell transplantation (HSCT). Current spirometry-based monitoring strategies have significant limitations. Understanding the utility of novel peripheral airway function tests - multiple breath washout (MBW) and oscillometry - is critical in efforts to improve detection, facilitate earlier intervention and improve outcomes. In this scoping review, we identified 17 studies investigating MBW or oscillometry, or both, after allogenic HSCT. Despite small study numbers limiting the ability to draw firm conclusions, several themes were evident. Detectable peripheral airway abnormality in MBW occurred in a substantial proportion prior to HSCT. MBW indices post-HSCT were more frequently abnormal than spirometry when reporting group data and among those with extrapulmonary cGVHD and pulmonary cGVHD. Changes in MBW indices over time may be more indicative of pulmonary complications than absolute values at any given time point. Oscillometry indices were often normal at baseline, but more frequently abnormal in those who developed pulmonary cGVHD. Pooling currently available individual participant data across these studies may improve our ability to formally compare their respective sensitivity and specificity at specific time points and assess the trajectory of MBW and oscillometry indices over time.
Topics: Humans; Oscillometry; Lung; Respiratory Function Tests; Spirometry; Hematopoietic Stem Cell Transplantation
PubMed: 37495248
DOI: 10.1183/16000617.0251-2022 -
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 -
Annals of Allergy, Asthma & Immunology... Sep 2021Separating individuals with viral-induced wheezing from those with asthma is challenging, and there are no guidelines for children under 6 years of age. Impulse... (Observational Study)
Observational Study
BACKGROUND
Separating individuals with viral-induced wheezing from those with asthma is challenging, and there are no guidelines for children under 6 years of age. Impulse oscillometry, however, is feasible in 4-year-old children.
OBJECTIVE
To explore the use of impulse oscillometry in diagnosing and monitoring asthma in young children and evaluating treatment response to inhaled corticosteroid (ICS).
METHODS
A total of 42 children (median age 5.3 years, range 4.0-7.9 years) with physician-diagnosed asthma and lability in oscillometry were followed for 6 months after initiation of ICS treatment. All children performed the 6-minute free-running test and impulse oscillometry at 3 time points. After the baseline, they attended a second visit when they had achieved good asthma control and a third visit approximately 60 days after the second visit. A positive ICS response was defined as having greater than 19 points in asthma control test and no hyperreactivity on the third visit.
RESULTS
In total, 38 of 42 children responded to ICS treatment. Exercise-induced increases of resistance at 5 Hz decreased after ICS treatment (61% vs 18% vs 13.5%, P < .001), and running distance during the 6-minute test was lengthened (800 m vs 850 m vs 850 m, P = .001). Significant improvements in childhood asthma control scores occurred between the baseline and subsequent visits (21 vs 24 vs 24, P < .001) and acute physicians' visits for respiratory symptoms (1, (0-6) vs 0, (0-2), P = .001). Similar profiles were observed in children without aeroallergen sensitization and among those under 5 years of age.
CONCLUSION
Impulse oscillometry is a useful tool in diagnosing asthma and monitoring lung function in young children.
Topics: Administration, Inhalation; Adrenal Cortex Hormones; Asthma; Child; Child, Preschool; Female; Humans; Lung; Male; Oscillometry; Respiratory Function Tests
PubMed: 33819614
DOI: 10.1016/j.anai.2021.03.030 -
Anesthesiology Feb 2021The optimal method for blood pressure monitoring in obese surgical patients remains unknown. Arterial catheters can cause potential complications, and noninvasive...
BACKGROUND
The optimal method for blood pressure monitoring in obese surgical patients remains unknown. Arterial catheters can cause potential complications, and noninvasive oscillometry provides only intermittent values. Finger cuff methods allow continuous noninvasive monitoring. The authors tested the hypothesis that the agreement between finger cuff and intraarterial measurements is better than the agreement between oscillometric and intraarterial measurements.
METHODS
This prospective study compared intraarterial (reference method), finger cuff, and oscillometric (upper arm, forearm, and lower leg) blood pressure measurements in 90 obese patients having bariatric surgery using Bland-Altman analysis, four-quadrant plot and concordance analysis (to assess the ability of monitoring methods to follow blood pressure changes), and error grid analysis (to describe the clinical relevance of measurement differences).
RESULTS
The difference (mean ± SD) between finger cuff and intraarterial measurements was -1 mmHg (± 11 mmHg) for mean arterial pressure, -7 mmHg (± 14 mmHg) for systolic blood pressure, and 0 mmHg (± 11 mmHg) for diastolic blood pressure. Concordance between changes in finger cuff and intraarterial measurements was 88% (mean arterial pressure), 85% (systolic blood pressure), and 81% (diastolic blood pressure). In error grid analysis comparing finger cuff and intraarterial measurements, the proportions of measurements in risk zones A to E were 77.1%, 21.6%, 0.9%, 0.4%, and 0.0% for mean arterial pressure, respectively, and 89.5%, 9.8%, 0.2%, 0.4%, and 0.2%, respectively, for systolic blood pressure. For mean arterial pressure and diastolic blood pressure, absolute agreement and trending agreement between finger cuff and intraarterial measurements were better than between oscillometric (at each of the three measurement sites) and intraarterial measurements. Forearm performed better than upper arm and lower leg monitoring with regard to absolute agreement and trending agreement with intraarterial monitoring.
CONCLUSIONS
The agreement between finger cuff and intraarterial measurements was better than the agreement between oscillometric and intraarterial measurements for mean arterial pressure and diastolic blood pressure in obese patients during surgery. Forearm oscillometry exhibits better measurement performance than upper arm or lower leg oscillometry.
Topics: Bariatric Surgery; Blood Pressure; Blood Pressure Determination; Catheterization, Peripheral; Female; Fingers; Humans; Male; Middle Aged; Monitoring, Intraoperative; Obesity; Oscillometry; Prospective Studies; Reproducibility of Results
PubMed: 33326001
DOI: 10.1097/ALN.0000000000003636 -
Revista Paulista de Pediatria : Orgao... 2024To investigate the effect of bronchodilator on the respiratory mechanics and pulmonary function of children and adolescents with cystic fibrosis.
OBJECTIVE
To investigate the effect of bronchodilator on the respiratory mechanics and pulmonary function of children and adolescents with cystic fibrosis.
METHODS
Cross-sectional study on clinically stable children and adolescents with cystic fibrosis aged from six to 15 years. Participants underwent impulse oscillometry and spirometry evaluations before and 15 minutes after bronchodilator inhalation. The Kolmogorov-Smirnov test was applied to verify the sample distribution, and the Student's t-test and Wilcoxon test were used to compare the data before and after bronchodilator inhalation.
RESULTS
The study included 54 individuals with a mean age of 9.7±2.8 years. The analysis showed a statistically significant improvement in impulse oscillometry and spirometry parameters after bronchodilator inhalation. However, according to the American Thoracic Society (ATS) and European Respiratory Society (ERS) recommendations (2020 and 2021), this improvement was not sufficient to classify it as a bronchodilator response.
CONCLUSIONS
The use of bronchodilator medication improved respiratory mechanics and pulmonary function parameters of children and adolescents with cystic fibrosis; however, most patients did not show bronchodilator response according to ATS/ERS recommendations.
Topics: Humans; Cystic Fibrosis; Child; Adolescent; Cross-Sectional Studies; Spirometry; Female; Male; Oscillometry; Bronchodilator Agents; Respiratory Mechanics; Respiratory Function Tests
PubMed: 38808869
DOI: 10.1590/1984-0462/2024/42/2023162 -
Pediatric Research Jun 2022Children with Down syndrome are at risk for significant pulmonary co-morbidities, including recurrent respiratory infections, dysphagia, obstructive sleep apnea, and...
BACKGROUND
Children with Down syndrome are at risk for significant pulmonary co-morbidities, including recurrent respiratory infections, dysphagia, obstructive sleep apnea, and pulmonary vascular disease. Because the gold standard metric of lung function, spirometry, may not be feasible in children with intellectual disabilities, we sought to assess the feasibility of both airwave oscillometry and spirometry in children with Down syndrome.
METHODS
Thirty-four children with Down syndrome aged 5-17 years were recruited. Participants performed airwave oscillometry and spirometry before and 10 min after albuterol. Outcomes include success rates, airway resistance and reactance pre- and post-bronchodilator, and bronchodilator response.
RESULTS
Participants were median age 9.2 years (interquartile range 7.2, 12.0) and 47% male. Airwave oscillometry was successful in 26 participants (76.5%) and 4 (11.8%) were successful with spirometry. No abnormalities in airway resistance were detected, and 16/26 (61.5%) had decreased reactance. A positive bronchodilator response by oscillometry was observed in 5/23 (21.7%) of those with successful pre- and post-bronchodilator testing.
CONCLUSIONS
Measures of pulmonary function were successfully obtained using airwave oscillometry in children with Down syndrome, which supports its use in this high-risk population.
IMPACT
Children with Down syndrome are at risk for significant pulmonary co-morbidities, but the gold standard metric of lung function, spirometry, may not be feasible in children with intellectual disabilities. This may limit the population's enrollment in clinical trials and in standardized clinical care. In this prospective study of lung function in children with Down syndrome, airwave oscillometry was successful in 76% of participants but spirometry was successful in only 12%. This study reinforces that measures of pulmonary function can be obtained successfully using airwave oscillometry in children with Down syndrome, which supports its use in this high-risk population.
Topics: Asthma; Bronchodilator Agents; Child; Down Syndrome; Female; Humans; Intellectual Disability; Lung; Male; Oscillometry; Prospective Studies; Spirometry
PubMed: 34326475
DOI: 10.1038/s41390-021-01664-7 -
American Journal of Respiratory and... Mar 2024
Topics: Child; Child, Preschool; Humans; Oscillometry; Ghana; Air Pollution; Lung
PubMed: 38290112
DOI: 10.1164/rccm.202311-2197ED