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ERJ Open Research Oct 2020Although the utility of oscillometry for predicting disease severity in idiopathic pulmonary fibrosis (IPF) had been researched, little has been reported on the...
Although the utility of oscillometry for predicting disease severity in idiopathic pulmonary fibrosis (IPF) had been researched, little has been reported on the mechanism of why respiratory impedance reflects disease severity. In addition, traction bronchiectasis has been considered to reduce respiratory resistance and correlate negatively with airflow obstruction, but this hypothesis has not been validated. The present study aimed to investigate the correlations between oscillometric parameters and fibrosis-related lung abnormalities in IPF and to assess the utility of oscillometry as a surrogate marker for traction bronchiectasis and airflow obstruction. Eighty Japanese patients with IPF underwent high-resolution computed tomography (HRCT), spirometry, and oscillometry and were retrospectively investigated. Fibrosis-related HRCT findings were scored regarding airspace consolidation, honeycombing, architectural distortion, traction bronchiectasis, and fibrosis. Correlations between the HRCT scores, spirometric parameters, and oscillometric parameters were analysed. Respiratory reactance correlated positively with all fibrosis-related HRCT scores. Vital capacity and forced vital capacity (FVC) correlated negatively with oscillometric parameters and HRCT scores, reflecting the severity of restrictive ventilatory deficiency. Respiratory resistance was not related to any of the HRCT scores or forced expiratory volume in 1 s/FVC. However, forced expiratory volume in 1 s/FVC correlated positively with HRCT scores, which showed that airflow obstruction became milder as the disease progressed. In conclusion, respiratory reactance reflects fibrosis and restrictive ventilatory deficiency in IPF. Moreover, respiratory resistance is independent of traction bronchiectasis and airflow obstruction in patients with IPF, which implies that respiratory resistance might reflect different properties of the airways.
PubMed: 33344627
DOI: 10.1183/23120541.00391-2020 -
Environmental Research Oct 2023Poly- and perfluoroalkyl substances (PFAS) are used in a wide range of products. Experimental studies suggested impaired lung development and pro-inflammatory response...
BACKGROUND
Poly- and perfluoroalkyl substances (PFAS) are used in a wide range of products. Experimental studies suggested impaired lung development and pro-inflammatory response following exposure to some PFAS. We aimed to assess the associations between prenatal exposure to PFAS and children respiratory health.
METHODS
The study is based on 433 mother-child pairs. 26 PFAS were measured in maternal serum collected during pregnancy. Lung function parameters were measured at 2 months using tidal breathing flow-volume loops and multiple-breath nitrogen washout and at 36 months using oscillometry. Incidence of respiratory health diseases (asthma, wheeze, bronchitis, bronchiolitis) in the first 36 months of life was assessed by repeated questionnaires. A cluster-based analysis was applied to identify prenatal PFAS exposure patterns. Adjusted linear and logistic regressions were performed to assess the associations between PFAS exposure patterns as well as individual PFAS, and each respiratory health parameter.
RESULTS
We excluded 13 PFAS due to low quantification (<5%). Relying on the 13 remaining PFAS, we identified three exposure clusters, characterized by low (N = 163), medium (N = 236) and high (N = 51) pregnancy PFAS concentrations. Compared to children belonging to the low exposure group, children in the moderate exposure group had higher reactance at 7 Hz (X) and lower frequency dependence of resistance between 7 Hz and 19 Hz (R) at 36 months, suggesting better lung function. No association of any exposure metric was detected with respiratory diseases in the first 3 years of life.
CONCLUSIONS
Our study relying on both mixture and uni-pollutant analyses, does not provide evidence for a deleterious effect of prenatal PFAS exposure on respiratory health at an early age.
Topics: Pregnancy; Female; Humans; Prenatal Exposure Delayed Effects; Fluorocarbons; Environmental Pollutants; Asthma; Incidence; Alkanesulfonic Acids
PubMed: 37406719
DOI: 10.1016/j.envres.2023.116544 -
The European Respiratory Journal Sep 2020Telemonitoring trials for early detection of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have provided mixed results. Day-to-day variations in...
BACKGROUND
Telemonitoring trials for early detection of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have provided mixed results. Day-to-day variations in lung function measured by the forced oscillation technique (FOT) may yield greater insight. We evaluated the clinical utility of home telemonitoring of variability in FOT measures in terms of 1) the relationship with symptoms and quality of life (QoL); and 2) the timing of variability of FOT measures and symptom changes prior to AECOPD.
METHODS
Daily FOT parameters at 5 Hz (resistance (R) and reactance (X); Resmon Pro Diary, Restech Srl, Milan, Italy), daily symptoms (COPD Assessment Test (CAT)) and 4-weekly QoL data (St George's Respiratory Questionnaire (SGRQ)) were recorded over 8-9 months from chronic obstructive pulmonary disease (COPD) patients. Variability of R and X was calculated as the standard deviation (sd) over 7-day running windows and we also examined the effect of varying window size. The relationship of FOT CAT and SGRQ was assessed using linear mixed modelling, daily changes in FOT variability and CAT prior to AECOPD using one-way repeated measures ANOVA.
RESULTS
Fifteen participants with a mean±sd age of 69±10 years and a % predicted forced expiratory volume in 1 s (FEV) of 39±10% had a median (interquartile range (IQR)) adherence of 95.4% (79.0-98.8%). Variability of the inspiratory component of X (indicated by the standard deviation of inspiratory reactance (SDX)) related to CAT and weakly to SGRQ (fixed effect estimates 1.57, 95% CI 0.65-2.49 (p=0.001) and 4.41, 95% CI -0.06 to 8.89 (p=0.05), respectively). SDX changed significantly on the same day as CAT (1 day before AECOPD, both p=0.02) and earlier when using shorter running windows (3 days before AECOPD, p=0.01; accuracy=0.72 for 5-day windows).
CONCLUSIONS
SDX from FOT telemonitoring reflects COPD symptoms and may be a sensitive biomarker for early detection of AECOPD.
Topics: Forced Expiratory Volume; Humans; Italy; Pulmonary Disease, Chronic Obstructive; Quality of Life; Respiratory Function Tests
PubMed: 32430416
DOI: 10.1183/13993003.01739-2019 -
Frontiers in Physiology 2019Lung mechanics using the forced oscillation technique (FOT) is suggested to be equivalent and more sensitive in determining exercise-induced bronchoconstriction (EIB)...
Lung mechanics using the forced oscillation technique (FOT) is suggested to be equivalent and more sensitive in determining exercise-induced bronchoconstriction (EIB) than spirometry. Dynamic alterations in minute ventilation (V) may affect this measurement. We investigated changes in FOT parameters post exercise challenge (EC) in people with asthma as compared to spirometry. The rate of recovery and any effect of raised V following exercise on FOT parameters were also assessed. Airway resistance (R) and reactance (X) at 5 Hz and V were measured prior to forced expiratory volume in 1 s (FEV) before and up to 20 min after a standard EC in people with asthma and healthy controls. Airway hyperresponsiveness to the hyperosmolar mannitol test was measured in the asthmatic subjects within 1 week of the EC. Baseline and sequential measures were assessed using repeated measures ANOVA and Pearson's correlation. Group demographics and recovery data were compared using an unpaired test. Subjects with current asthma ( = 19, mean ± SD age 28 ± 6 years) and controls ( = 10, 31 ± 5 years) were studied. Baseline FEV, R, X, and V were similar between groups ( > 0.09). Airway hyperresponsiveness was present in 12/19 asthmatic subjects. The EC max % change of R and X correlated with FEV ( > 0.90) and were only different to controls in those with asthma that responded by FEV criteria ( < 0.01). EC recovery of R was similar to FEV; however, X was greater ( = 0.03). Elevated V post EC did not affect the % change in FOT parameters across all subjects ( > 0.3). R and X were highly sensitive in determining a positive EC response (80-86%), but X was more specific (93 vs. 80%). FOT parameters tracked with forced maneuvers and were not influenced by increased ventilation following an exercise challenge designed to elicit EIB. FOT identified EIB similarly to spirometry in patients with asthma.
PubMed: 31803065
DOI: 10.3389/fphys.2019.01411 -
PloS One 2023The body posture can influence gas exchange, respiratory mechanics, and mucociliary clearance and different positions can be used as a therapeutic strategy to improve in...
BACKGROUND AND OBJECTIVE
The body posture can influence gas exchange, respiratory mechanics, and mucociliary clearance and different positions can be used as a therapeutic strategy to improve in gas exchange and can also help physiotherapists to assist patients who have difficult or restrictions to stay seated or the ones who stay in the same position for a long period. The objective of this study was to evaluate the effect of different positions on respiratory system impedance in obese and eutrophic subjects, using Impulse Oscillometry System (IOS).
METHODS
The IOS parameters were evaluated in seated (Se), right lateral decubitus (RL), left lateral decubitus (LL), and supine (Su).
RESULTS
Sixty two volunteers were allocated in obese group (OG) or eutrophic group (EG) according to BMI. In seated position, OG showed higher impedance than EG for R5: 0.55 (0.31; 0.93) and 0.33 (0.24; 0.52); R20: 0.39 (0.23; 0.54) and 0.32 (0.03; 0.41); R5-R20: 0.13 (0.02; 0.47) and 0.01 (-0.08; 0.27); X5: -0.20 (-0.51; 0.16) and -0,10 (-0.016; -0.04); Fres: 20.59 (11.54; 36.45 and 10.69 (7.56; 24.7) (p<0.05) and the impedance were higher in the Su for both groups. Compared to Se, there were differences with Su (R5, R5-20, X5), with RL (R20), and with LL (R5, R20) for OG; and with Su (R5, R5-20, X5, Fres), with RL and LL (X5) for EG. Compared to Su, there were differences with RL and LL (R5-20, X5) for OG; and with RL (R5, R5-20, X5, Fres), and LL (R5-20, X5, Fres) for EG. There were no differences between RL and LL for OG and EG.
CONCLUSION
The respiratory system impedance is increased in OG, with greater contribution of peripheral resistance. The higher values of resistance and reactance were obtained in the supine position, in both groups, with lower differences obtained in the right and left lateral decubitus.
Topics: Humans; Pulmonary Disease, Chronic Obstructive; Oscillometry; Electric Impedance; Forced Expiratory Volume; Respiratory System; Spirometry
PubMed: 36787314
DOI: 10.1371/journal.pone.0281780 -
Diagnostics (Basel, Switzerland) May 2024The fact that some SARS-CoV-2 pneumonia patients benefit from changing body position, and some from continuous positive airways pressure (CPAP), indicates the functional...
The fact that some SARS-CoV-2 pneumonia patients benefit from changing body position, and some from continuous positive airways pressure (CPAP), indicates the functional character of hypoxia. We hypothesize that such effects could be explained by the closure of small airways. To prove the hypothesis, we evaluated the patency of small airways in 30 oxygen-dependent, spontaneously breathing patients with SARS-CoV-2 pneumonia during their hospital stay using the FOT method and then compared the results with data obtained three months later. During the acute period, total resistance (R5) and peripheral resistance (R5-20) rose above the upper limit of normal (ULN) in 28% and 50% of all patients, respectively. Reactance indices X5, AX and Fres exceeded ULN in 55%, 68% and 66% of cases. Significant correlations were observed between PaO/FiO, the time spent in the hospital and R5, X5, AX and Fres. After 3 months, 18 patients were re-examined. During the hospital stay, 11 of them had risen above the upper limit of normal (ULN), for both resistance (R5-20) and reactance (X5, AX) values. Three months later, ULN for R5-20 was exceeded in only four individuals, but ULN for X5 and AX was exceeded in five individuals. Lung function examination revealed a combined restrictive/obstructive ventilatory failure and reduced CO transfer factor. We interpret these changes as lung tissue remodeling due to the process of fibrosis. We conclude that during acute period of SARS-CoV-2 pneumonia, dilated pulmonary blood vessels and parenchymal oedema induce functional closure of small airways, which in turn induce atelectasis with pulmonary right-to-left shunting, followed by the resulting hypoxemia.
PubMed: 38893686
DOI: 10.3390/diagnostics14111160 -
Lung Aug 2019The forced oscillation technique (FOT) measures respiratory impedance during normal tidal breathing and requires minimal patient cooperation. (Comparative Study)
Comparative Study
BACKGROUND
The forced oscillation technique (FOT) measures respiratory impedance during normal tidal breathing and requires minimal patient cooperation.
OBJECTIVE
To compare IOS and AOS devices in patients with asthma and COPD.
METHODS
We compared two different FOT devices, namely impulse oscillometry using a loudspeaker (IOS: Jaeger Masterscreen) and airwave oscillometry using a vibrating mesh (AOS: Thorasys Tremoflo) for pre- and post-bronchodilator measurements in 84 patients with asthma and COPD.
RESULTS
The overall pattern of measurement bias was for higher resistance with IOS and higher reactance with AOS, this being the case in asthma and COPD separately. There were small but significantly higher values using IOS for resistance at 5 Hz (R5) and 20(19) Hz (R20(19)). In converse, values for reactance at 5 Hz (X5), reactance area (AX) and resonant frequency (Fres) were significantly higher using AOS but to a much larger extent. The difference in AX between devices was more pronounced in COPD than in asthma. Salbutamol reversibility as % change was greater in asthma than COPD patients with AX but not FEV1.
CONCLUSION
Our study showed evidence of better agreement for resistance than reactance when comparing IOS and AOS, perhaps inferring that AOS may be more sensitive at measuring reactance in patients with airflow obstruction.
Topics: Aged; Airway Resistance; Albuterol; Asthma; Bronchodilator Agents; Equipment Design; Female; Forced Expiratory Volume; Humans; Lung; Male; Maximal Midexpiratory Flow Rate; Middle Aged; Oscillometry; Predictive Value of Tests; Pulmonary Disease, Chronic Obstructive; Reproducibility of Results; Respiratory Function Tests; Retrospective Studies; Vital Capacity
PubMed: 31273438
DOI: 10.1007/s00408-019-00247-y -
Pediatric Research Aug 2020To determine normative data by forced oscillation technique (FOT) in non-sedated normal term neonates and test the hypothesis that infants with transient tachypnea of... (Observational Study)
Observational Study
BACKGROUND
To determine normative data by forced oscillation technique (FOT) in non-sedated normal term neonates and test the hypothesis that infants with transient tachypnea of the newborn (TTN) have higher resistance (R) and lower reactance (X) on day 1.
METHODS
Healthy term infants (n = 138) and infants with TTN (n = 17) were evaluated on postnatal days 1 through 3 (NCT03346343). FOT was measured with a mask using a TremoFlo C-100 Airwave System™. R, X, and area under the reactance curve (AX) were measured at prime frequencies 7-41 Hz for 8 s.
RESULTS
In all, 86% of control infants had adequate measurements (coherence >0.8, CV < 0.25) on day 1. Infants with TTN had higher resistance at 13 Hz (TTN 32.5 cm HO·s/L [95% CI 25.5-39.4]; controls 23.8 cm HO·s/L [95% CI 22.2 to 25.3], P = 0.007) and lower reactance from 17 to 37 Hz (TTN -35.1 to -10.5; controls -26.3 to -6.1, P < 0.05). In healthy controls, lung mechanics were unchanged from days 1 to 3. In TTN, lung mechanics normalized on days 2 and 3.
CONCLUSIONS
FOT is feasible in neonates and distinguishes normal control infants from those with TTN on postnatal day 1. Oscillometry offers a non-invasive, longitudinal technique to assess lung mechanics in newborns.
Topics: Airway Resistance; Asthma; Female; Forced Expiratory Volume; Humans; Infant, Newborn; Lung; Male; Oscillometry; Prospective Studies; Respiratory Function Tests; Respiratory Mechanics; Spirometry; Tachypnea; Vital Capacity
PubMed: 31935746
DOI: 10.1038/s41390-020-0751-7 -
ERJ Open Research Apr 2020Advanced glycation end-products (AGEs) have been implicated in the pathophysiology of chronic obstructive pulmonary disease (COPD). However, the association between AGE...
BACKGROUND
Advanced glycation end-products (AGEs) have been implicated in the pathophysiology of chronic obstructive pulmonary disease (COPD). However, the association between AGE accumulation in the skin measured by skin autofluorescence (SAF) and lung function in healthy subjects has not been explored in detail. We use a population-based study of 50-64-year-olds to assess spirometry, diffusing capacity of the lung for carbon monoxide ( ) and impulse oscillometry (IOS) in relation to SAF.
METHODS
Participants with information on SAF, lung function and potential confounding variables were included from the Swedish Cardiopulmonary Bioimage Study (SCAPIS) cohort (spirometry, n=4111; , n=3889; IOS, n=3970). Linear regression was used to assess changes in lung function (as measured by spirometry (forced expiratory volume in 1 s (FEV), forced vital capacity (FVC) and FEV/FVC), and IOS (resistance measured at 5 ( ) and 20 Hz ( ), - , area of reactance, reactance measured at 5 Hz ( ), and resonant frequency)) by a 1-sd increase in SAF.
RESULTS
FEV, FVC and were significantly and inversely associated with SAF after adjustment for potential confounding factors (per 1-sd increase in SAF: FEV -0.03 L (95% CI -0.04- -0.02 L), p<0.001; FVC -0.03 L (95% CI -0.05- -0.02 L), p<0.001; -0.07 mmol·min·kPa (95% CI -0.11- -0.03 mmol·min·kPa), p<0.001). This association was also found in nonsmokers and in non-COPD subjects. Pulmonary reactance ( ) but not pulmonary resistance ( , and - ) was significantly associated with SAF (per 1-sd increase in SAF: -0.001 kPa·L·s (95% CI -0.003-0.00 kPa·L·s), p=0.042), which was mirrored in non-COPD patients but not in current nonsmokers.
CONCLUSIONS
AGE accumulation, as measured by SAF, is significantly associated with lung function decrements indicative of changes in the lung parenchyma.
PubMed: 32523964
DOI: 10.1183/23120541.00356-2019 -
American Journal of Physiology. Lung... Dec 2020Recent clinical trials have shown improvements in neonatal outcomes after intratracheal administration of a combination of budesonide/surfactant (ITBS) in infants at...
Recent clinical trials have shown improvements in neonatal outcomes after intratracheal administration of a combination of budesonide/surfactant (ITBS) in infants at risk of bronchopulmonary dysplasia. However, the effect of ITBS on lung function and alveolar structure is not known. We aimed to determine the effect of ITBS on lung function, parenchymal structure, and inflammatory cytokine expression in a relevant preterm animal model for bronchopulmonary dysplasia. Premature neonatal rabbits were administered a single dose of ITBS on the day of delivery and exposed to 95% oxygen. Following 7 days of hyperoxia, in vivo forced oscillation and pressure-volume maneuvers were performed to examine pulmonary function. Histological and molecular analysis was performed to assess alveolar and extracellular matrix (ECM) morphology, along with gene expression of connective tissue growth factor (CTGF), IL-8, and CCL-2. ITBS attenuated the functional effect of hyperoxia-induced lung injury and limited the change to respiratory system impedance, measured using the forced oscillation technique. Treatment effects were most obvious in the small airways, with significant effects on small airway resistance and small airway reactance. In addition, ITBS mitigated the decrease in inspiratory capacity and static compliance. ITBS restricted alveolar septal thickening without altering the mean linear intercept and mitigated hyperoxia-induced remodeling of the ECM. These structural changes were associated with improved inspiratory capacity and lung compliance. Gene expression of CTGF, IL-8, and CCL-2 was significantly downregulated in the lung. Treatment with ITBS shortly after delivery attenuated the functional and structural consequences of hyperoxia-induced lung injury to of life in the preterm rabbit.
Topics: Animals; Budesonide; Disease Models, Animal; Humans; Hyperoxia; Lung Injury; Pulmonary Surfactants; Rabbits; Surface-Active Agents
PubMed: 32903026
DOI: 10.1152/ajplung.00162.2020