scholarly journals Double tracer gas single-breath washout: reproducibility in healthy subjects and COPD

2014 ◽  
Vol 44 (5) ◽  
pp. 1210-1222 ◽  
Author(s):  
Kim Husemann ◽  
Nina Berg ◽  
Jennifer Engel ◽  
Johannes Port ◽  
Christoph Joppek ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Vital Capacity ◽  
Intraclass Correlation ◽  
Phase Iii ◽  
Chronic Obstructive ◽  
Clinical Settings ◽  
Tracer Gas ◽  
Obstructive Pulmonary Disease ◽  
Single Breath ◽  
Multiple Breath Washout

The applicability and interpretation of inert tracer gas washout tests is hampered by the lack of feasible protocols and reproducibility data. We assessed feasibility, variability and reproducibility of a new easy to perform double tracer gas (DTG) single-breath washout (SBW) test and compared this with conventional nitrogen washouts.In 40 healthy nonsmokers and 20 patients with stable chronic obstructive pulmonary disease (COPD), we performed three N2 vital capacity SBWs, three N2 multiple-breath washouts and three tidal DTG-SBW tests. Follow-up was after 1 week, 1 month and 6 months. Main outcomes were the lung clearance index (LCI) (N2 multiple-breath washout), slope of phase III (dN2) (N2 vital capacity SBW) and slope of phase III (SIIIDTG) (DTG-SBW).In healthy subjects, mean±sd LCI at baseline was 6.94±0.61, dN2 0.99±0.42% N2 per litre and SIIIDTG −0.206±0.108 g·mol−1·L−1. In COPD, LCI and dN2 were significantly higher (LCI 12.23±2.67, dN2 7.43±5.38% N2 per litre; p<0.001) and SIIIDTG significantly steeper (−0.653±0.428 g·mol−1·L−1, p<0.001). Reproducibility was high for main outcome parameters: the intraclass correlation coefficient over 6 months was 0.77 (0.86 in COPD) for LCI, 0.82 (0.89) for dN2 and 0.83 (0.93) for SIIIDTG.The tidal DTG-SBW is a reproducible test in healthy and COPD subjects that seems attractive for use in routine clinical settings.

scholarly journals Acute effects of long-acting bronchodilators on small airways detected in COPD patients by single-breath N2 test and lung P-V curve

2017 ◽  
Vol 123 (5) ◽  
pp. 1266-1275 ◽  
Author(s):  
Matteo Pecchiari ◽  
Pierachille Santus ◽  
Dejan Radovanovic ◽  
Edgardo DʼAngelo
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Phase Iii ◽  
Chronic Obstructive ◽  
Closing Volume ◽  
Small Airways ◽  
Acute Effects ◽  
Obstructive Pulmonary Disease ◽  
Single Breath ◽  
Volume Curve

Small airways represent the key factor of chronic obstructive pulmonary disease (COPD) pathophysiology. The effect of different classes of bronchodilators on small airways is still poorly understood and difficult to assess. Hence the acute effects of tiotropium (18 µg) and indacaterol (150 µg) on closing volume (CV) and ventilation inhomogeneity were investigated and compared in 51 stable patients (aged 70 ± 7 yr, mean ± SD; 82% men) with moderate to very severe COPD. Patients underwent body plethysmography, arterial blood gas analysis, tidal expiratory flow limitation (EFL), dyspnea assessment, and simultaneous recording of single-breath N2 test and transpulmonary pressure-volume curve (PL-V), before and 1 h after drug administration. The effects produced by indacaterol on each variable did not differ from those caused by tiotropium, independent of the severity of disease, assessed according to the Global Initiative for Chronic Obstructive Pulmonary Disease (GOLD) scale and the presence of EFL. Bronchodilators significantly decreased the slope of phase III and CV (−5 ± 4 and −2.5 ± 2.1%, respectively, both P < 0.001), with an increase in both slope and height of phase IV and of the anatomical dead space. Arterial oxygen pressure and saturation significantly improved (3 ± 3 mmHg and 2 ± 2%, respectively, both P < 0.001); their changes negatively correlated with those of phase III slope ( r = −0.659 and r = −0.454, respectively, both P < 0.01). The vital capacity (VC) increased substantially, but the PL-V/VC curve above CV was unaffected. In conclusion, bronchodilators reduce the heterogeneity of peripheral airway mechanical properties and the extent of their closure, with minor effects on critical closing pressure. This should lessen the risk of small-airway damage and positively affect gas exchange. NEW & NOTEWORTHY This is the first study investigating in stable chronic obstructive pulmonary disease patients the acute effects of two long-acting bronchodilators, a β-agonist and a muscarinic antagonist, on peripheral airways using simultaneous lung pressure-volume curve and single-breath N2 test. By lessening airway mechanical property heterogeneity, both drugs similarly reduced ventilation inhomogeneity and extent of small-airway closure, as indicated by the decrease of phase III slope, increased oxygen saturation, and fall of closing volume, often below expiratory reserve volume.

scholarly journals Is the 1-Minute Sit-To-Stand Test a Good Tool to Evaluate Exertional Oxygen Desaturation in Chronic Obstructive Pulmonary Disease?

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 159
Author(s):  
Ana L. Fernandes ◽  
Inês Neves ◽  
Graciete Luís ◽  
Zita Camilo ◽  
Bruno Cabrita ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Intraclass Correlation ◽  
Oxygen Desaturation ◽  
Walking Distance ◽  
Chronic Obstructive ◽  
Cross Sectional ◽  
Obstructive Pulmonary Disease ◽  
Stand Test ◽  
Sit To Stand

Background: Chronic obstructive pulmonary disease (COPD) is frequently associated with exertional oxygen desaturation, which may be evaluated using the 6-minute walking test (6MWT). However, it is a time-consuming test. The 1-minute sit-to-stand test (1STST) is a simpler test, already used to evaluate the functional status. The aim of this study was to compare the 1STST to the 6MWT in the evaluation of exertional desaturation. Methods: This was a cross-sectional study including 30 stable COPD patients who performed the 6MWT and 1STST on the same day. Six-minute walking distance (6MWD), number of 1STST repetitions (1STSTr), and cardiorespiratory parameters were recorded. Results: A significant correlation was found between the 6MWD and the number of 1STSTr (r = 0.54; p = 0.002). The minimum oxygen saturation (SpO2) in both tests showed a good agreement (intraclass correlation coefficient (ICC) 0.81) and correlated strongly (r = 0.84; p < 0.001). Regarding oxygen desaturation, the total agreement between the tests was 73.3% with a fair Cohen’s kappa (κ = 0.38; p = 0.018), and 93.33% of observations were within the limits of agreement for both tests in the Bland–Altman analysis. Conclusion: The 1STST seems to be a capable tool of detecting exercise-induced oxygen desaturation in COPD. Because it is a less time- and resources-consuming test, it may be applied during the outpatient clinic consultation to regularly evaluate the exercise capacity and exertional desaturation in COPD.

scholarly journals Awakening efficacy of a vibrotactile device in patients on home nocturnal ventilatory assistance and healthy subjects as family caregiver proxies

2020 ◽  
Vol 17 ◽  
pp. 147997312098333
Author(s):  
Valerie Attali ◽  
Sophie Lavault ◽  
Antoine Guerder ◽  
Saba Al-Youssef ◽  
Benjamin Dudoignon ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Vibrotactile Stimulus ◽  
Chronic Obstructive ◽  
Vibrotactile Stimulation ◽  
Obstructive Pulmonary Disease ◽  
Copd Patients ◽  
Random Intervals ◽  
Healthy Family ◽  
Central Hypoventilation ◽  
Hypoventilation Syndrome

The objective of this study was to test the capacity of vibrotactile stimulation transmitted to the wrist bones by a vibrating wristband to awaken healthy individuals and patients requiring home mechanical ventilation during sleep. Healthy subjects (n = 20) and patients with central hypoventilation (CH) (Congenital Central Hypoventilation syndrome n = 7; non-genetic form of CH n = 1) or chronic obstructive pulmonary disease (COPD) (n = 9), underwent a full-night polysomnography while wearing the wristband. Vibrotactile alarms were triggered five times during the night at random intervals. Electroencephalographic (EEG), clinical (trunk lift) and cognitive (record the time on a sheet of paper) arousals were recorded. Cognitive arousals were observed for 94% of the alarms in the healthy group and for 66% and 63% of subjects in the CH and COPD groups, respectively (p < 0.01). The percentage of participants experiencing cognitive arousals for all alarms, was 72% for healthy subjects, 37.5% for CH patients and 33% for COPD patients (ns) (94%, 50% and 44% for clinical arousals (p < 0.01) and 100%, 63% and 44% for EEG arousals (p < 0.01)). Device acceptance was good in the majority of cases, with the exception of one CH patient and eight healthy participants. In summary this study shows that a vibrotactile stimulus is effective to induce awakenings in healthy subjects, but is less effective in patients, supporting the notion that a vibrotactile stimulus could be an effective backup to a home mechanical ventilator audio alarm for healthy family caregivers.

In vivo characterization of the transitional bronchioles by aerosol-derived airway morphometry

1999 ◽  
Vol 87 (3) ◽  
pp. 920-927 ◽  
Author(s):  
Kirby L. Zeman ◽  
Gerhard Scheuch ◽  
Knut Sommerer ◽  
James S. Brown ◽  
William D. Bennett
Keyword(s):  
Ex Vivo ◽  
Normal Subjects ◽  
Characteristic Line ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Lung Capacity ◽  
Single Breath ◽  
In Vivo Characterization

Effective airway dimensions (EADs) were determined in vivo by aerosol-derived airway morphometry as a function of volumetric lung depth (VLD) to identify and characterize, noninvasively, the caliber of the transitional bronchiole region of the human lung and to compare the EADs by age, gender, and disease. By logarithmically plotting EAD vs. VLD, two distinct regions of the lung emerged that were identified by characteristic line slopes. The intersection of proximal and distal segments was defined as VLDtransand associated EADtrans. In our normal subjects ( n = 20), VLDtrans [345 ± 83 (SD) ml] correlated significantly with anatomic dead space (224 ± 34 ml) and end of phase II of single-breath nitrogen washout (360 ± 53 ml). The corresponding EADtranswas 0.42 ± 0.07 mm, in agreement with other ex vivo measurements of the transitional bronchioles. VLDtrans was smaller (216 ± 64 ml) and EADtrans was larger (0.83 ± 0.04 mm) in our patients with chronic obstructive pulmonary disease ( n = 13). VLDtrans increased with age for children (age 8–18 yr; P = 0.006, n = 26) and with total lung capacity for age 8–81 yr ( P < 0.001, n = 61). This study extends the usefulness of aerosol-derived airway morphometry to in vivo measurements of the transitional bronchioles.

scholarly journals β2-Adrenergic genotypes and risk of severe exacerbations in COPD: a prospective cohort study

Thorax ◽  
2019 ◽  
Vol 74 (10) ◽  
pp. 934-940 ◽  
Author(s):  
Truls Sylvan Ingebrigtsen ◽  
Jørgen Vestbo ◽  
Line Rode ◽  
Jacob Louis Marott ◽  
Peter Lange ◽  
...  
Keyword(s):  
Adrenergic Receptor ◽  
Vital Capacity ◽  
Genetic Factors ◽  
Forced Expiratory Volume ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
General Population Study ◽  
Heart Study ◽  
Acute Admissions

BackgroundIndividual susceptibility to exacerbations in chronic obstructive pulmonary disease (COPD) is likely influenced by genetic factors; however, most such variance is unexplained. We hypothesised that β2-adrenergic receptor genotypes, Gly16Arg (rs1042713, c.46G>A) and Gln27Glu (rs1042714, c.79C>G) influence risk of severe exacerbations in COPD.MethodsAmong 96 762 individuals in the Copenhagen General Population Study, we identified 5262 with COPD (forced expiratory volume in one second divided by forced vital capacity, FEV1/FVC, below 0.7, FEV1 less than 80% of predicted value, age above 40 years and no asthma) who had genotyping performed. Severe exacerbations were defined as acute admissions due to COPD during 5 years of follow-up (mean 3.4 years). 923 individuals with COPD diagnosed similarly in the Copenhagen City Heart Study (CCHS) were used for replication analyses.ResultsWe recorded 461 severe exacerbations in 5262 subjects. The HRs for severe exacerbations were 1.62 (95% CI 1.30 to 2.03, p=0.00002) for 16Gly/Arg heterozygotes and 1.41 (1.04 to 1.91, p=0.03) for 16Arg homozygotes, compared with 16Gly homozygotes. HRs were 1.35 (1.03 to 1.76, p=0.03) for 27Gln/Glu heterozygotes and 1.49 (1.12 to 1.98, p=0.006) for 27Gln homozygotes, compared with 27Glu homozygotes. Similar trends were observed in the CCHS. Among 27Gln homozygotes only, HRs were 5.20 (1.81 to 14.9, p=0.002) for 16Gly/Arg heterozygotes and 4.03 (1.40 to 11.6, p=0.01) for 16Arg homozygotes, compared with 16Gly homozygotes.ConclusionCommon β2-adrenergic receptor genotypes influence risk of severe exacerbations in COPD, potentially mainly by genetic influence of the 16Arg allele in rs1042713.

scholarly journals Maximum phonation time in the pulmonary function assessment

Revista CEFAC ◽  
2021 ◽  
Vol 23 (4) ◽  
Author(s):  
Edvania Gomes Henrique Moreno ◽  
Bianca Teixeira Calassa ◽  
Daniela Vitoria Silva Oliveira ◽  
Maylanne Iris Nascimento Silva ◽  
Laienne Carla Barbosa de Barros Albuquerque ◽  
...  
Keyword(s):  
Vital Capacity ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Descriptive Statistics ◽  
Healthy Individuals ◽  
Reliability Study ◽  
Maximum Phonation Time ◽  
Intraclass Correlation Coefficients ◽  
Single Breath ◽  
Examiner Agreement

ABSTRACT Purpose: to evaluate the reliability of the maximum phonation time (MPT) and Vital Capacity intra and inter-examiner, by means of the single-breath counting test (CT) and the sustained /a/ phoneme, and the slow vital capacity (SVC). Methods: a reliability study carried out in three groups of healthy individuals, each group with 30 volunteers, allocated according to age. SVC was measured using a spirometer, while the MPT was assessed by the phoneme /a/ and CT. The data were analyzed using SPSS version 20.0. Initially, descriptive statistics were used and for data reliability, the intraclass correlation coefficient (ICC). Results: the Intraclass Correlation Coefficients (ICC) were considered excellent, with significant results above 0.92 for SVC and greater than 0.79 for CT and phoneme /a/. Regarding the inter-examiner evaluation, the ICCs were also significant for both SVC with values greater than 0.96, and for CT and the phoneme /a/ with values greater than 0.85. The error inherent in the technique was assessed using the standard error of the measurement for intra and inter-examiner analyses with values ranging from 1.79 to 3.29 for phoneme /a/, 3.20 to 6.58 for CT and 65, 05 to 206.73 for SVCml. Conclusion: phonation techniques with the phoneme /a/ and CT, as well as SVC, have an excellent reliability, due to intra and inter-examiner agreement measures.

scholarly journals Inter-day test–retest reliability and feasibility of isokinetic, isometric, and isotonic measurements to assess quadriceps endurance in people with chronic obstructive pulmonary disease: A multicenter study

2018 ◽  
Vol 16 ◽  
pp. 147997311881649 ◽  
Author(s):  
Erik Frykholm ◽  
Sarah Géphine ◽  
Didier Saey ◽  
Hieronymus van Hees ◽  
Arthur Lemson ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Intraclass Correlation ◽  
Forced Expiratory Volume ◽  
Chronic Obstructive ◽  
Total Work ◽  
Obstructive Pulmonary Disease ◽  
Relative Reliability ◽  
Very High ◽  
Absolute Reliability

The aims were to determine reliability and feasibility of measurements to assess quadriceps endurance in people with chronic obstructive pulmonary disease. Sixty participants (forced expiratory volume in one second (mean ± standard deviation) 55 ± 18% of predicted, age 67 ± 8 years) were tested in an inter-day, test–retest design. Isokinetic, isometric, and isotonic protocols were performed using a computerized dynamometer. Test–retest relative and absolute reliability was determined via intraclass correlation coefficient (ICC), coefficient of variation (CV%), and limits of agreement (LoA%). Isokinetic total work demonstrated very high relative reliability (ICC: [95% confidence interval] = 0.98 [0.94–0.99]) and the best absolute reliability (CV% (LoA%) = 6.5% (18.0%)). Isokinetic fatigue index, isometric, and isotonic measures demonstrated low-to-high relative reliability (ICC = 0.64 [0.46–0.77], 0.88 [0.76–0.94], 0.91 [0.85–0.94]), and measures of absolute reliability (CV% (LoA%)) were 20.3% (56.4%), 14.9% (40.8%), and 15.8% (43.1%). For isokinetic total work and isometric measurements, participants performed better on retest (4.8% and 10.0%, respectively). The feasibility was similar across protocols with an average time consumption of less than 7.5 minutes. In conclusion, isokinetic, isometric, and isotonic measurements of quadriceps endurance were feasible to a similar extent and presented low-to-very high relative reliability. Absolute reliability seems to favor isokinetic total work measurements.

Mode shift of an inhaled aerosol bolus is correlated with flow sequencing in the human lung

2002 ◽  
Vol 92 (3) ◽  
pp. 1232-1238 ◽  
Author(s):  
Christopher N. Mills ◽  
Chantal Darquenne ◽  
G. Kim Prisk
Keyword(s):  
Vital Capacity ◽  
Normal Subjects ◽  
Phase Iii ◽  
Mode Shift ◽  
Nitrogen Washout ◽  
Single Breath ◽  
Posture Change ◽  
Supine Posture ◽  
Residual Capacity ◽  
Phase Iii Slope

We studied the effects on aerosol bolus inhalations of small changes in convective inhomogeneity induced by posture change from upright to supine in nine normal subjects. Vital capacity single-breath nitrogen washout tests were used to determine ventilatory inhomogeneity change between postures. Relative to upright, supine phase III slope was increased 33 ± 11% (mean ± SE, P < 0.05) and phase IV height increased 25 ± 11% ( P < 0.05), consistent with an increase in convective inhomogeneity likely due to increases in flow sequencing. Subjects also performed 0.5-μm-particle bolus inhalations to penetration volumes (Vp) between 150 and 1,200 ml during a standardized inhalation from residual volume to 1 liter above upright functional residual capacity. Mode shift (MS) in supine posture was more mouthward than upright at all Vp, changing by 11.6 ml at Vp = 150 ml ( P < 0.05) and 38.4 ml at Vp = 1,200 ml ( P < 0.05). MS and phase III slope changes correlated positively at deeper Vp. Deposition did not change at any Vp, suggesting that deposition did not cause the MS change. We propose that the MS change results from increased sequencing in supine vs. upright posture.

Voluntary activation of the human diaphragm in health and disease

1998 ◽  
Vol 85 (6) ◽  
pp. 2146-2158 ◽  
Author(s):  
Christer Sinderby ◽  
Jennifer Beck ◽  
Jadranka Spahija ◽  
Jan Weinberg ◽  
Alex Grassino
Keyword(s):  
Healthy Subjects ◽  
Total Lung Capacity ◽  
Voluntary Activation ◽  
Chronic Obstructive ◽  
Quiet Breathing ◽  
Obstructive Pulmonary Disease ◽  
Transdiaphragmatic Pressure ◽  
Lung Capacity ◽  
Copd Patients ◽  
Crural Diaphragm

Intersubject comparison of the crural diaphragm electromyogram, as measured by an esophageal electrode, requires a reliable means for normalizing the signal. The present study set out 1) to evaluate which voluntary respiratory maneuvers provide high and reproducible diaphragm electromyogram root-mean-square (RMS) values and 2) to determine the relative diaphragm activation and mechanical and ventilatory outputs during breathing at rest in healthy subjects ( n = 5), in patients with severe chronic obstructive pulmonary disease (COPD, n = 5), and in restrictive patients with prior polio infection (PPI, n = 6). In all groups, mean voluntary maximal RMS values were higher during inspiration to total lung capacity than during sniff inhalation through the nose ( P = 0.035, ANOVA). The RMS (percentage of voluntary maximal RMS) during quiet breathing was 8% in healthy subjects, 43% in COPD patients, and 45% in PPI patients. Despite the large difference in relative RMS ( P = 0.012), there were no differences in mean transdiaphragmatic pressure ( P= 0.977) and tidal volumes ( P = 0.426). We conclude that voluntary maximal RMS is reliably obtained during an inspiration to total lung capacity but a sniff inhalation could be a useful complementary maneuver. Severe COPD and PPI patients breathing at rest are characterized by increased diaphragm activation with no change in diaphragm pressure generation.

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