Methods for Assessing Expiratory Flow Limitation during Tidal Breathing in COPD Patients

Koulouris, Nikolaos; Kaltsakas, Georgios; Palamidas, Anastasios; Gennimata, Sofia-Antiopi

doi:10.1155/2012/234145

Cited by 15 publications

(13 citation statements)

References 49 publications

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“…Although a number of techniques has been designed to identify tidal EFL, it is not routinely measured in clinical practice [2,[10][11][12][13]. Disadvantages in many of these techniques preventing more widespread use are that they are invasive, time-consuming, technically demanding, use bulky equipment or they need post-test analysis, such as visual inspection of flow/volume curves.…”

Section: Introductionmentioning

confidence: 99%

Variability of within-breath reactance in COPD patients and its association with dyspnoea

et al. 2014

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The forced oscillation technique can identify expiratory flow limitation (EFL) when a large difference in inspiratory and expiratory reactance (ΔXrs) occurs. However, flow limitation can vary from breath to breath, and so we compared a multiple-breath ΔXrs approach to the traditional breath-by-breath assessment of EFL. We investigated the within-and between-day reproducibility and the factors that affect the size of ΔXrs when used as a continuous measurement over multiple breaths. In addition, we examined how multiple-breath ΔXrs relates to the sensation of breathlessness.425 moderate to very severe chronic obstructive pulmonary disease (COPD) patients and 229 controls were included. Spirometry and impedance measurements were performed on a MasterScope CT Impulse Oscillation System.Median ΔXrs approached zero in healthy controls with little variation between measurements. COPD patients generally had higher ΔXrs and higher variability. The COPD patients with ΔXrs >0.1 kPa·Lwere prone to be more breathless and had a higher modified Medical Research Council dyspnoea scale score. In controls, the 95th percentile of ΔXrs was as low as 0.07 kPa·L −1 ·s −1 . We describe a new method to assess EFL at a patient level and propose a cut-off, mean ΔXrs >0.1 kPa·L −1 ·s −1 , as a way to identify COPD patients who are more likely to report dyspnoea. @ERSpublications Within-breath reactance in COPD correlates with dyspnoea and adds information beyond that of spirometry alone

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Section: Introductionmentioning

confidence: 99%

Variability of within-breath reactance in COPD patients and its association with dyspnoea

et al. 2014

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“…Negative expiratory pressure is a clinical tool that has been used to evaluate expiratory flow limitation in people with COPD (Koulouris et al . ). More recently, it has been used in people with OSA to assess changes in breathing and airway collapsibility during early expiration with stimuli of about half the magnitude to that used in the current study (∼−5 cmH 2 O) (Hirata et al .…”

Section: Discussionmentioning

confidence: 97%

“…This would provide the opportunity to investigate between-individual differences in airway collapsibility during expiration that was not possible in the current study due to ceiling effects. Negative expiratory pressure is a clinical tool that has been used to evaluate expiratory flow limitation in people with COPD (Koulouris et al 2012). More recently, it has been used in people with OSA to assess changes in breathing and airway collapsibility during early expiration with stimuli of about half the magnitude to that used in the current study (ß−5 cmH 2 O) (Hirata et al 2016).…”

Section: Figure 7 Example Of Waveform Average Responses For Mask Andmentioning

confidence: 99%

Changes in pharyngeal collapsibility and genioglossus reflex responses to negative pressure during the respiratory cycle in obstructive sleep apnoea

Osman

Carberry

Gandevia

et al. 2020

The Journal of Physiology

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Key pointsr Impaired pharyngeal anatomy and increased airway collapsibility is a major cause of obstructive sleep apnoea (OSA) and a mediator of its severity.r Upper airway reflexes to changes in airway pressure provide important protection against airway closure. r This study shows increased pharyngeal collapsibility and attenuated genioglossus reflex responses during expiration in people with OSA.Abstract Upper airway collapse contributes to obstructive sleep apnoea (OSA) pathogenesis. Pharyngeal dilator muscle activity varies throughout the respiratory cycle and may contribute to dynamic changes in pharyngeal collapsibility. However, whether upper airway collapsibility and reflex responses to changes in airway pressure vary throughout the respiratory cycle in OSA is unclear. Thus, this study quantified differences in upper airway collapsibility and genioglossus electromyographic (EMG) activity and reflex responses during different phases of the respiratory cycle. Twelve middle-aged people with OSA (2 female) were fitted with standard polysomnography equipment: a nasal mask, pneumotachograph, two fine-wire intramuscular electrodes into the genioglossus, and a pressure catheter positioned at the epiglottis and a second at the choanae (the collapsible portion of the upper airway). At least 20 brief (ß250 ms) pressure pulses (ß−11 cmH 2 O at the mask) were delivered every 2-10 breaths during four conditions: (1) early inspiration, (2) mid-inspiration, (3) early expiration, and (4) mid-expiration. Mean baseline genioglossus EMG activity 100 ms prior to pulse delivery Amal Osman is a Research Associate at the Adelaide Institute for Sleep Health, Flinders University. She completed her PhD at the University of New South Wales and Neuroscience Research Australia. She is investigating development of simple clinical tools to measure upper airway collapsibility in obstructive sleep apnoea, a critical component in the pathogenesis of this common sleep-related breathing disorder. Current interests include understanding the mechanisms that contribute to airway closure in sleep apnoea. The hope is that this work brings us closer to developing new clinical tools to predict and optimize responses to targeted and novel treatments. J Physiol 598.3 and genioglossus reflex responses were quantified for each condition. The upper airway collapsibility index (UACI), quantified as 100 × (nadir choanal − epiglottic pressure)/nadir choanal pressure during negative pressure pulses, varied throughout the respiratory cycle (early inspiration = 43 ± 25%, mid-inspiration = 29 ± 19%, early expiration = 83 ± 19% and mid-expiration = 95 ± 11% (mean ± SD) P < 0.01). Genioglossus EMG activity was lower during expiration (e.g. mid-expiration vs. mid-inspiration = 76 ± 23 vs. 127 ± 41% of early-inspiration, P < 0.001). Similarly, genioglossus reflex excitation was delayed (39 ± 11 vs. 23 ± 7 ms, P < 0.001) and reflex excitation amplitude attenuated during mid-expiration versus early inspiration (209 ± 36 vs. 286 ± 80%, P = 0.009). These findings ...

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“…The reason for the difference may have been the presence of expiratory flow limitation (EFL) in the COPD patients. With EFL, the expiratory flow rates never increase with increased pleural pressure, and this is often seen in patients with severe COPD 19 . Ninane et al 20 reported assessment of EFL by studying whether the expiratory flow rates could be increased by increased pleural and abdominal pressures with abdominal compression during expiration.…”

Section: Discussionmentioning

confidence: 99%

Effects of chest wall compression on expiratory flow rates in patients with chronic obstructive pulmonary disease

Nozoe¹,

Mase²,

Ogino³

et al. 2016

Braz. J. Phys. Ther.

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Background: Manual chest wall compression (CWC) during expiration is a technique for removing airway secretions in patients with respiratory disorders. However, there have been no reports about the physiological effects of CWC in patients with chronic obstructive pulmonary disease (COPD). Objective: To compare the effects of CWC on expiratory flow rates in patients with COPD and asymptomatic controls. Method: Fourteen subjects were recruited from among patients with COPD who were receiving pulmonary rehabilitation at the University Hospital (COPD group). Fourteen age-matched healthy subjects were also consecutively recruited from the local community (Healthy control group). Airflow and lung volume changes were measured continuously with the subjects lying in supine position during 1 minute of quiet breathing (QB) and during 1 minute of CWC by a physical therapist. Results: During CWC, both the COPD group and the healthy control group showed significantly higher peak expiratory flow rates (PEFRs) than during QB (mean difference for COPD group 0.14 L/sec, 95% confidence interval (CI) 0.04 to 0.24, p<0.01, mean difference for healthy control group 0.39 L/sec, 95% CI 0.25 to 0.57, p<0.01). In the between-group comparisons, PEFR was significantly higher in the healthy control group than in the COPD group (-0.25 L/sec, 95% CI -0.43 to -0.07, p<0.01). However, the expiratory flow rates at the lung volume at the PEFR during QB and at 50% and 25% of tidal volume during QB increased in the healthy control group (mean difference for healthy control group 0.31 L/sec, 95% CI 0.15 to 0.47, p<0.01: 0.31 L/sec, 95% CI 0.15 to 0.47, p<0.01: 0.27 L/sec, 95% CI 0.13 to 0.41, p<0.01, respectively) but not in the COPD group (0.05 L/sec, 95% CI -0.01 to 0.12: -0.01 L/sec, 95% CI -0.11 to 0.08: 0.02 L/sec, 95% CI -0.05 to 0.90) with the application of CWC. Conclusion: The effects of chest wall compression on expiratory flow rates was different between COPD patients and asymptomatic controls.

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Methods for Assessing Expiratory Flow Limitation during Tidal Breathing in COPD Patients

Cited by 15 publications

References 49 publications

Variability of within-breath reactance in COPD patients and its association with dyspnoea

Variability of within-breath reactance in COPD patients and its association with dyspnoea

Changes in pharyngeal collapsibility and genioglossus reflex responses to negative pressure during the respiratory cycle in obstructive sleep apnoea

Effects of chest wall compression on expiratory flow rates in patients with chronic obstructive pulmonary disease

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