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Archives of Razi Institute Jun 2022This study was performed to evaluate the prognostic value of relative changes from admission to discharge (Δ%) of integrated congestion assessment to predict adverse...
This study was performed to evaluate the prognostic value of relative changes from admission to discharge (Δ%) of integrated congestion assessment to predict adverse outcomes in patients with irreversible heart failure (HF) during a one-year follow-up. The study included 122 patients (60% males, median age of 69 years) with decompensated HF. Most of the patients (92%) had a history of arterial hypertension, 53.3% had coronary heart disease, and 40.2% had type 2 diabetes mellitus. All patients underwent assessments, including NT-proBNP, lung ultrasound (LUS) B-line score, liver stiffness by transient elastography, and resistance and reactance by bioimpedance vector analysis (BIVA). The assessments were performed at admission and discharge, and a relative change from admission (delta percentage, Δ%) was calculated. Long-term clinical outcomes were assessed by a structured interview conducted 1, 3, 6, and 12 months after discharge. The cut-offs for the occurrence of the endpoint events were Δ% NT-proBNP of ≥ -25, Δ% liver stiffness of ≥ -44, Δ% B-line score on lung ultrasound of ≥ -73, Δ% BIVA resistance of ≤ 18, and Δ% BIVA reactance of ≤ 40. It was revealed that 55% of endpoint events, including 22 (18%) deaths and 33 (27%) readmissions, occurred within a median of 74 days (interquartile range: 33-147). Patients with an endpoint event had significantly worse values of all studied parameters in contrast to patients without it. There was a significant direct association between Δ% NT-proBNP and Δ% B-lines (r=0.18; =0.04), and a highly reliable inverse association was observed between Δ% liver stiffness and Δ% BIVA reactance (r=-0.4; <0.001). No significant associations were found between the other parameters. Univariate Cox regression analysis demonstrated the independent prognostic value of all congestion markers under study (NT-proBNP, LUS B-lines, liver stiffness, and BIVA reactance) for predicting the combined endpoint. Multivariate Cox regression analysis confirmed the independent prognostic value in predicting the risk of endpoint event for the following parameters: NT-proBNP (hazard rate [HR] 2.5, =0.001), liver stiffness (HR 2.3, =0.012), LUS B-line score (HR 2.2, =0.008). However, it did not find any significant prognostic value for BIVA resistance and reactance. The relative admission-to-discharge change in the integral assessment of congestion had a prognostic value for predicting the risk of adverse outcomes (all-cause mortality and readmission rate) in patients with decompensated HF during a one-year follow-up.
Topics: Aged; Female; Humans; Male; Diabetes Mellitus, Type 2; Heart Failure; Patient Discharge; Prognosis; Prospective Studies
PubMed: 36618279
DOI: 10.22092/ARI.2022.357393.2033 -
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 -
Journal of Visualized Experiments : JoVE Feb 2022There is increasing interest in the use of the forced oscillation technique (FOT) or oscillometry to characterize respiratory mechanics in healthy and diseased...
There is increasing interest in the use of the forced oscillation technique (FOT) or oscillometry to characterize respiratory mechanics in healthy and diseased individuals. FOT, a complementary method to traditional pulmonary function testing, utilizes a range of oscillatory frequencies superimposed on tidal breathing to measure the functional relationship between airway pressure and flow. This passive assessment provides an estimate of respiratory system resistance (Rrs) and reactance (Xrs) that reflect airway caliber and energy storage and dissipation, respectively. Despite the recent increase in popularity and updated Technical Standards, clinical adoption has been slow which relates, in part, to the lack of standardization regarding the acquisition and reporting of FOT data. The goal of this article is to address the lack of standardization across laboratories by providing a comprehensive written protocol for FOT and an accompanying video. To illustrate that this protocol can be utilized irrespective of a particular device, three separate FOT devices have been employed in the case examples and video demonstration. This effort is intended to standardize the use and interpretation of FOT, provide practical suggestions, as well as highlight future questions that need to be addressed.
Topics: Adult; Humans; Oscillometry; Respiration; Respiratory Function Tests; Respiratory Mechanics
PubMed: 35225293
DOI: 10.3791/63165 -
American Journal of Respiratory and... Jun 2020Acute cellular rejection (ACR) is common during the initial 3 months after lung transplant. Patients are monitored with spirometry and routine surveillance...
Acute cellular rejection (ACR) is common during the initial 3 months after lung transplant. Patients are monitored with spirometry and routine surveillance transbronchial biopsies. However, many centers monitor patients with spirometry only because of the risks and insensitivity of transbronchial biopsy for detecting ACR. Airway oscillometry is a lung function test that detects peripheral airway inhomogeneity with greater sensitivity than spirometry. Little is known about the role of oscillometry in patient monitoring after a transplant. To characterize oscillometry measurements in biopsy-proven clinically significant (grade ≥2 ACR) in the first 3 months after a transplant. We enrolled 156 of the 209 double lung transplant recipients between December 2017 and March 2019. Weekly outpatient oscillometry and spirometry and surveillance biopsies at Weeks 6 and 12 were conducted at our center. Of the 138 patients followed for 3 or more months, 15 patients had 16 episodes of grade 2 ACR (AR2) and 44 patients had 64 episodes of grade 0 ACR (AR0) rejection associated with stable and/or improving spirometry. In 15/16 episodes of AR2, spirometry was stable or improving in the weeks leading to transbronchial biopsy. However, oscillometry was markedly abnormal and significantly different from AR0 ( < 0.05), particularly in integrated area of reactance and the resistance between 5 and 19 Hz, the indices of peripheral airway obstruction. By 2 weeks after biopsy, after treatment for AR2, oscillometry in the AR2 group improved and was similar to the AR0 group. Oscillometry identified physiological changes associated with AR2 that were not discernible by spirometry and is useful for graft monitoring after a lung transplant.
Topics: Acute Disease; Airway Resistance; Biopsy; Bronchoscopy; Elasticity; Forced Expiratory Volume; Glucocorticoids; Graft Rejection; Humans; Immunity, Cellular; Lung Transplantation; Methylprednisolone; Oscillometry; Respiratory Function Tests; Spirometry
PubMed: 32135068
DOI: 10.1164/rccm.201908-1539OC -
Pediatric Pulmonology Nov 2023The utility of the forced oscillations technique (FOT) in cystic fibrosis (CF) remains uncertain. The aim of this study was to explore the ability of lower-frequency FOT...
BACKGROUND
The utility of the forced oscillations technique (FOT) in cystic fibrosis (CF) remains uncertain. The aim of this study was to explore the ability of lower-frequency FOT indices, alone and after adjustment for the lung volume, to assess the extent of ventilation inhomogeneity in CF patients with varying disease severity.
METHODS
Forty-five children, adolescents, and adults with CF (age 6.9-27 years) underwent spirometry, FOT, and nitrogen multiple-breath washout (N2-MBW) measurements. The respiratory resistance and reactance at 5 Hz (Rrs5 and Xrs5, respectively) were recorded, and a novel FOT index, the specific respiratory conductance (sGrs), was computed as the reciprocal of Rrs5 divided by the functional residual capacity.
RESULTS
The sGrs correlated well with the lung clearance index (LCI) (Spearman's r: -.797), whereas the correlation of Rrs5 and Xrs5 with the LCI, albeit significant, was weaker (r: .643 and -.631, respectively). The sGrs emerged as the most robust predictor of LCI regardless of the severity of lung disease, as reflected by patients' age and lung function measurements. Most importantly, the relationship between sGrs and LCI remained unaffected by lung hyperinflation, as opposed to that of the LCI with the spirometric and standard FOT indices.
CONCLUSIONS
In CF patients, the FOT indices at 5 Hz and the novel, volume-adjusted parameter sGrs, reflect the extent of lung involvement and the underlying ventilation inhomogeneity in a way comparable to N2-MBW. Future research should explore the role of lower-frequency FOT in assessing the severity and monitoring the progression of CF lung disease.
Topics: Adult; Child; Adolescent; Humans; Young Adult; Cystic Fibrosis; Oscillometry; Lung; Respiration; Respiratory Function Tests
PubMed: 37555768
DOI: 10.1002/ppul.26635 -
COPD Dec 2020The usefulness of the oscillometry, known as forced oscillation technique, for predicting exercise tolerance in subjects with COPD is unknown. To test the hypothesis, we... (Observational Study)
Observational Study
The usefulness of the oscillometry, known as forced oscillation technique, for predicting exercise tolerance in subjects with COPD is unknown. To test the hypothesis, we investigated whether oscillometry could predict a 6-minute walking distance (6MWD) <350 m in the 6-minute walk test (6MWT).This was a prospective, observational study. Fifty-seven subjects with COPD who attended outpatient clinics for routine checkups at Shizuoka General Hospital between April 2015 and April 2016 (54 males; median age, 70 years; and %FEV, 61.0%). Modified MRC dyspnea scale (mMRC), COPD Assessment Test (CAT), oscillometry, spirometry, and 6MWT were performed in a stable condition. The participants were classified into subjects with 6MWD ≥350 m or 6MWD <350 m, and the predictor of 6MWD <350 m was assessed.Of the 57 total subjects, 43 (75.4%) had a 6MWD ≥350 m, and 14 (24.6%) had a 6MWD <350 m. Between the two groups, there were significant differences in mMRC scale, GOLD stages, CAT scores, FEV, IC, 6MWD, lowest SpO, maximum Borg scale, respiratory resistance (Rrs), and reactance (Xrs). In multivariate regression analysis, a 6MWD <350 m was independently predicted by CAT scores (OR 1.15, 95% CI: 1.01-1.30) and inspiratory R5 (OR 6.01, 95% CI: 1.09-33.30). In receiver operating characteristic curves, the area under the curve was 0.76, 0.78, and 0.85 for CAT scores, R5, and CAT scores + R5, respectively, with the best cutoff value of 17 and 2.82 cmH0/L/s. In conclusion, the oscillatory parameter, inspiratory R5, predicted low exercise tolerance in COPD subjects.
Topics: Aged; Aged, 80 and over; Exercise Tolerance; Female; Forced Expiratory Volume; Humans; Male; Middle Aged; Oscillometry; Predictive Value of Tests; Prospective Studies; Pulmonary Disease, Chronic Obstructive; Spirometry; Walk Test
PubMed: 33183076
DOI: 10.1080/15412555.2020.1844176 -
Respirology (Carlton, Vic.) Jun 2020Fixed airflow obstruction (FAO) in asthma occurs despite optimal inhaled treatment and no smoking history, and remains a significant problem, particularly with...
BACKGROUND AND OBJECTIVE
Fixed airflow obstruction (FAO) in asthma occurs despite optimal inhaled treatment and no smoking history, and remains a significant problem, particularly with increasing age and duration of asthma. Increased lung compliance and loss of lung elastic recoil has been observed in older people with asthma, but their link to FAO has not been established. We determined the relationship between abnormal lung elasticity and airflow obstruction in asthma.
METHODS
Non-smoking asthmatic subjects aged >40 years, treated with 2 months of high-dose inhaled corticosteroid/long-acting beta-agonist (ICS/LABA), had FAO measured by spirometry, and respiratory system resistance at 5 Hz (Rrs ) and respiratory system reactance at 5 Hz (Xrs ) measured by forced oscillation technique. Lung compliance (K) and elastic recoil (B/A) were calculated from pressure-volume curves measured by an oesophageal balloon. Linear correlations between K and B/A, and forced expiratory volume in 1 s/forced vital capacity (FEV /FVC), Rrs and Xrs were assessed.
RESULTS
Eighteen subjects (11 males; mean ± SD age: 64 ± 8 years, asthma duration: 39 ± 22 years) had moderate FAO measured by spirometry ((mean ± SD z-score) post-bronchodilator FEV : -2.2 ± 0.5, FVC: -0.7 ± 1.0, FEV /FVC: -2.6 ± 0.7) and by increased Rrs (median (IQR) z-score) 2.7 (1.9 to 3.2) and decreased Xrs : -4.1(-2.4 to -7.3). Lung compliance (K) was increased in 9 of 18 subjects and lung elastic recoil (B/A) reduced in 5 of 18 subjects. FEV /FVC correlated negatively with K (r = -0.60, P = 0.008) and Rrs correlated negatively with B/A (r = -0.52, P = 0.026), independent of age. Xrs did not correlate with lung elasticity indices.
CONCLUSION
Increased lung compliance and loss of elastic recoil relate to airflow obstruction in older non-smoking asthmatic subjects, independent of ageing. Thus, structural lung tissue changes may contribute to persistent, steroid-resistant airflow obstruction.
CLINICAL TRIAL REGISTRATION
ACTRN126150000985583 at anzctr.org.au (UTN: U1111-1156-2795).
Topics: Adrenal Cortex Hormones; Aged; Asthma; Elasticity; Female; Forced Expiratory Volume; Humans; Lung; Lung Compliance; Male; Middle Aged; Pulmonary Disease, Chronic Obstructive; Respiratory Function Tests; Spirometry; Vital Capacity
PubMed: 31482693
DOI: 10.1111/resp.13688 -
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 -
BMC Pulmonary Medicine Jun 2022Oscillometry is an emerging technique that offers some advantages over spirometry as it does not require forced exhalation and may detect early changes in respiratory... (Observational Study)
Observational Study
Lung disease burden assessment by oscillometry in a systematically disadvantaged urban population experiencing homelessness or at-risk for homelessness in Ottawa, Canada from a prospective observational study.
RATIONALE
Oscillometry is an emerging technique that offers some advantages over spirometry as it does not require forced exhalation and may detect early changes in respiratory pathology. Obstructive lung disease disproportionately impacts people experiencing homelessness with a high symptoms burden, yet oscillometry is not studied in this population.
OBJECTIVES
To assess lung disease and symptom burden using oscillometry in people experiencing homelessness or at-risk of homelessness using a community-based participatory action research approach (The Bridge Model™).
METHODS
Of 80 recruited, 55 completed baseline oscillometry, 64 completed spirometry, and all completed patient-reported outcomes with demographics, health, and respiratory symptom related questionnaires in the Participatory Research in Ottawa: Management and Point-of-Care for Tobacco Dependence project. Using a two-tail t-test, we compared mean oscillometry values for airway resistance (R), reactance area under the curve (A) and reactance at 5 Hz (X) amongst individuals with fixed-ratio method (FEV/FVC ratio < 0.70) and LLN (FEV/FVC ratio ≤ LLN) spirometry diagnosed chronic obstructive pulmonary disease (COPD). We compared mean oscillometry parameters based on participants' COPD assessment test (CAT) scores using ANOVA test.
RESULTS
There was no significant difference between the pre- and post- bronchodilator values of R and A for the fixed ratio method (p = 0.63 and 0.43) and the LLN method (p = 0.45 and 0.36). There was a significant difference in all three of the oscillometry parameters, R, A and X, based on CAT score (p = 0.009, 0.007 and 0.05, respectively). There was a significant difference in R and A based on the presence of phlegm (p = 0.03 and 0.02, respectively) and the presence of wheeze (p = 0.05 and 0.01, respectively). Oscillometry data did not correlate with spirometry data, but it was associated with CAT scores and correlated with the presence of self-reported symptoms of phlegm and wheeze in this population.
CONCLUSIONS
Oscillometry is associated with respiratory symptom burden and highlights the need for future studies to generate more robust data regarding the use of oscillometry in systematically disadvantaged populations where disease burden is disproportionately higher than the general population.
TRIAL REGISTRATION
ClinicalTrails.gov-NCT03626064, Retrospective registered: August 2018, https://clinicaltrials.gov/ct2/show/NCT03626064.
Topics: Cost of Illness; Forced Expiratory Volume; Ill-Housed Persons; Humans; Lung; Oscillometry; Pulmonary Disease, Chronic Obstructive; Retrospective Studies; Spirometry; Urban Population; Vulnerable Populations
PubMed: 35710334
DOI: 10.1186/s12890-022-02030-x -
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