Clinical characteristics of COPD patients with tidal expiratory flow limitation

Dean, James P.; Kolsum, Umme; Hitchen, Paul G.; Gupta, Vanadana; Singh, Dave

doi:10.2147/copd.s137865

Cited by 21 publications

(33 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is mechanistically plausible that airway closure during tidal breathing in COPD, that is measured by Xrs, results in sufficient ventilatory impairment that could make it harder to exercise, perhaps by increasing breathlessness. Impairment of Xrs has been correlated with breathlessness in COPD; 11,40 this then might explain the loss of 6MWD after leaving the pulmonary rehabilitation program, that we observed in the present study. This mechanism, however, requires further investigation in future studies.…”

Section: Discussionsupporting

confidence: 69%

“…Both measurements of EFL are clinically important, however; EFL measured by the negative pressure technique predicts a greater reduction in hyperinflation following bronchodilator. 45 EFL measured by FOT is associated with worse gas trapping, 11 worse breathlessness and SGRQ, 11,46 and recovers in COPD exacerbations with treatment. 47,48 A relationship between SGRQ and EFL (DeltaXrs) was also found in the present study (see Figure 3B).…”

Section: Discussionmentioning

confidence: 99%

“…Participants were tested sitting upright with their head in a neutral position, wearing a nose clip and supporting their own cheeks and chin to minimise upper airway shunting, breathing through an anti-bacterial/-viral filter (Suregard, Bird Healthcare, Port Melbourne, Australia). After establishing stable tidal breathing; a multiple frequency signal (5,11,19 Hz) was superimposed onto tidal breathing during a single continuous acquisition of 60 s, which ended with three maximal deep inspirations from which inspiratory capacity (IC) was calculated.…”

Section: Forced Oscillation Technique (Fot)mentioning

confidence: 99%

“…The expiratory decrease in Xrs (indicating increased oscillatory lung stiffness) is a highly sensitive and specific marker of EFL in COPD 10 and is clinically important because it is associated with greater symptoms, worse quality of life, and greater gas trapping and hyperinflation. 11 In addition to pharmacological treatment, pulmonary rehabilitation also leads to a decrease in resting hyperinflation 12 and a reduction in breathing rate at a given exercise intensity. 12,13 Because Xrs parameters correlate with airway calibre, hyperinflation, dynamic airway collapse and EFL (all of which cause ventilatory limitation that impairs exercise capacity), they may also relate to exercise capacity, and to the change in exercise capacity as a result of pulmonary rehabilitation.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

<p>Relationships Between Forced Oscillatory Impedance and 6-minute Walk Distance After Pulmonary Rehabilitation in COPD</p>

Zimmermann

Thamrin

Chan

et al. 2020

COPD

View full text Add to dashboard Cite

Rationale: Pulmonary rehabilitation for chronic obstructive pulmonary disease (COPD) reduces dyspnoea and improves exercise capacity and quality of life. The improvement in exercise capacity is variable and unpredictable, however. Respiratory system impedance obtained by forced oscillation technique (FOT) as a measure of ventilatory impairment in COPD may relate to improvement in exercise capacity with pulmonary rehabilitation. We aimed to determine if baseline FOT parameters relate to changes in exercise capacity following pulmonary rehabilitation. Methods: At the start of rehabilitation, 15 COPD subjects (mean(SD) 75.2(6.1) years, FEV1 z-score −2.61(0.84)) had measurements by FOT, spirometry, plethysmographic lung volumes and 6-minute walk distance (6MWD). Respiratory system resistance (Rrs) and reactance (Xrs) parameters as the mean over all breaths (R mean , X mean), during inspiration only (R insp , X insp), and expiratory flow limitation (DeltaXrs = X insp −X exp), were calculated. FOT and 6MWD measurements were repeated at completion of rehabilitation and 3 months after completion. Results: At baseline, Xrs measures were unrelated to 6MWD. X insp improved significantly with rehabilitation (from mean(SD) −2.35(1.02) to −2.04(0.85) cmH 2 O.s.L −1 , p=0.008), while other FOT parameters did not. No FOT parameters related to the change in 6MWD at program completion. Baseline X mean, DeltaXrs, and FVC z-score correlated with the change in 6MWD between completion and 3 months after completion of rehabilitation (r s =0.62, p=0.03; r s =−0.65, p=0.02; and r s =0.62, p=0.03, respectively); with worse ventilatory impairment predicting loss of 6MWD. There were no relationships between Rrs parameters, FEV1 or FEV1/FVC z-scores and changes in 6MWD. Conclusion: Baseline reactance parameters may be helpful in predicting those patients with COPD at most risk of loss of exercise capacity following completion of pulmonary rehabilitation.

show abstract

Section: Discussionsupporting

confidence: 69%

Section: Discussionmentioning

confidence: 99%

Section: Forced Oscillation Technique (Fot)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

<p>Relationships Between Forced Oscillatory Impedance and 6-minute Walk Distance After Pulmonary Rehabilitation in COPD</p>

Zimmermann

Thamrin

Chan

et al. 2020

COPD

View full text Add to dashboard Cite

show abstract

“…The presence of EFL has been found to predict the severity of breathlessness in COPD better than forced expiratory volume in 1 s (FEV1) [12,13]. EFL may also represent a marker of disease severity and associated morbidity in terms of symptoms, functional impairment, degree of airflow obstruction and extent of gas trapping [14]. However, conventional methods of detecting EFL have either been invasive in nature (e.g.…”

Section: Detection Of Expiratory Flow Limitationmentioning

confidence: 99%

Dismantling airway disease with the use of new pulmonary function indices

2019

View full text Add to dashboard Cite

We are currently limited in our abilities to diagnose, monitor disease status and manage chronic airway disease like asthma and chronic obstructive pulmonary disease (COPD). Conventional lung function measures often poorly reflect patient symptoms or are insensitive to changes, particularly in the small airways where disease may originate or manifest. Novel pulmonary function tests are becoming available which help us better characterise and understand chronic airway disease, and their translation and adoption from the research arena would potentially enable individualised patient care.In this article, we aim to describe two emerging lung function tests yielding novel pulmonary function indices, the forced oscillation technique (FOT) and multiple breath nitrogen washout (MBNW). With a particular focus on asthma and COPD, this article demonstrates how chronic airway disease mechanisms have been dismantled with the use of the FOT and MBNW. We describe their ability to assess detailed pulmonary mechanics for diagnostic and management purposes including response to bronchodilation and other treatments, relationship with symptoms, evaluation of acute exacerbations and recovery, and telemonitoring. The current limitations of both tests, as well as open questions/directions for further research, are also discussed.

show abstract

Addressing Reduced Laboratory-Based Pulmonary Function Testing During a Pandemic

Kouri

Gupta

Yadollahi

et al. 2020

Chest

View full text Add to dashboard Cite

To reduce the spread of the severe acute respiratory syndrome coronavirus 2, many pulmonary function testing (PFT) laboratories have been closed or have significantly reduced their testing capacity. Because these mitigation strategies may be necessary for the next 6 to 18 months to prevent recurrent peaks in disease prevalence, fewer objective measurements of lung function will alter the diagnosis and care of patients with chronic respiratory diseases. PFT, which includes spirometry, lung volume, and diffusion capacity measurement, is essential to the diagnosis and management of patients with asthma, COPD, and other chronic lung conditions.Both traditional and innovative alternatives to conventional testing must now be explored.These may include peak expiratory flow devices, electronic portable spirometers, portable exhaled nitric oxide measurement, airwave oscillometry devices, and novel digital health tools such as smartphone microphone spirometers and mobile health technologies along with integration of machine learning approaches. The adoption of some novel approaches may not merely replace but could improve existing management strategies and alter common diagnostic paradigms. With these options comes important technical, privacy, ethical, financial, and medicolegal barriers that must be addressed. However, the coronavirus disease 19 pandemic also presents a unique opportunity to augment conventional testing by including innovative and emerging approaches to measuring lung function remotely in patients with respiratory disease.The benefits of such an approach have the potential to enhance respiratory care and empower patient self-management well beyond the current global pandemic.

show abstract

Clinical characteristics of COPD patients with tidal expiratory flow limitation

Cited by 21 publications

References 15 publications

<p>Relationships Between Forced Oscillatory Impedance and 6-minute Walk Distance After Pulmonary Rehabilitation in COPD</p>

<p>Relationships Between Forced Oscillatory Impedance and 6-minute Walk Distance After Pulmonary Rehabilitation in COPD</p>

Dismantling airway disease with the use of new pulmonary function indices

Addressing Reduced Laboratory-Based Pulmonary Function Testing During a Pandemic

Contact Info

Product

Resources

About