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

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Nickolaos G. Koulouris ◽  
Georgios Kaltsakas ◽  
Anastasios F. Palamidas ◽  
Sofia-Antiopi Gennimata
Keyword(s):  
Transpulmonary Pressure ◽  
Flow Limitation ◽  
Expiratory Flow Limitation ◽  
Exercise Limitation ◽  
Non Invasive ◽  
Airway Injury ◽  
Volume Curve ◽  
Copd Patients ◽  
Flow Volume Curve ◽  
Expiratory Flow

Patients with severe COPD often exhale along the same flow-volume curve during quite breathing as during forced expiratory vital capacity manoeuvre, and this has been taken as indicating expiratory flow limitation at rest (EFLT). Therefore,EFLT, namely, attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow.EFLTleads to small airway injury and promotes dynamic pulmonary hyperinflation with concurrent dyspnoea and exercise limitation. In fact,EFLToccurs commonly in COPD patients (mainly in GOLD III and IV stage) in whom the latter symptoms are common. The existing up-to-date physiological methods for assessing expiratory flow limitation (EFLT) are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure (NEP) has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, non invasive, most practical, and accurate new technique.

Detection of expiratory flow limitation during exercise in COPD patients

1997 ◽  
Vol 82 (3) ◽  
pp. 723-731 ◽  
Author(s):  
Nickolaos G. Koulouris ◽  
Ioanna Dimopoulou ◽  
Päivi Valta ◽  
Richard Finkelstein ◽  
Manuel G. Cosio ◽  
...  
Keyword(s):  
Normal Subjects ◽  
Chronic Obstructive ◽  
Flow Limitation ◽  
Expiratory Flow Limitation ◽  
Obstructive Pulmonary Disease ◽  
Normal Limits ◽  
Volume Curve ◽  
Copd Patients ◽  
Flow Volume Curve ◽  
Expiratory Flow

Koulouris, Nickolaos G., Ioanna Dimopoulou, Päivi Valta, Richard Finkelstein, Manuel G. Cosio, and J. Milic-Emili.Detection of expiratory flow limitation during exercise in COPD patients. J. Appl. Physiol. 82(3): 723–731, 1997.—The negative expiratory pressure (NEP) method was used to detect expiratory flow limitation at rest and at different exercise levels in 4 normal subjects and 14 patients with chronic obstructive pulmonary disease (COPD). This method does not require performance of forced expirations, nor does it require use of body plethysmography. It consists in applying negative pressure (−5 cmH2O) at the mouth during early expiration and comparing the flow-volume curve of the ensuing expiration with that of the preceding control breath. Subjects in whom application of NEP does not elicit an increase in flow during part or all of the tidal expiration are considered flow limited. The four normal subjects were not flow limited up to 90% of maximal exercise power output (W˙max). Five COPD patients were flow limited at rest, 9 were flow limited at one-third W˙max, and 12 were flow limited at two-thirdsW˙max. Whereas in all patients who were flow limited at rest the maximal O2 uptake was below the normal limits, this was not the case in most of the other patients. In conclusion, NEP provides a rapid and reliable method to detect expiratory flow limitation at rest and during exercise.

scholarly journals Relationship Between Spontaneous Expiratory Flow-Volume Curve Pattern and Air-Flow Obstruction in Elderly COPD Patients

2013 ◽  
Vol 58 (10) ◽  
pp. 1643-1648 ◽  
Author(s):  
M. Nozoe ◽  
K. Mase ◽  
S. Murakami ◽  
M. Okada ◽  
T. Ogino ◽  
...  
Keyword(s):  
Air Flow ◽  
Flow Volume ◽  
Curve Pattern ◽  
Volume Curve ◽  
Copd Patients ◽  
Flow Volume Curve ◽  
Expiratory Flow

scholarly journals Clinical characteristics of COPD patients with tidal expiratory flow limitation

2017 ◽  
Vol Volume 12 ◽  
pp. 1503-1506 ◽  
Author(s):  
James Dean ◽  
Umme Kolsum ◽  
Paul Hitchen ◽  
Vanadana Gupta ◽  
Dave Singh
Keyword(s):  
Clinical Characteristics ◽  
Flow Limitation ◽  
Expiratory Flow Limitation ◽  
Copd Patients ◽  
Expiratory Flow

scholarly journals Effect of nocturnal EPAP titration to abolish tidal expiratory flow limitation in COPD patients with chronic hypercapnia: a randomized, cross-over pilot study

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Emanuela Zannin ◽  
Ilaria Milesi ◽  
Roberto Porta ◽  
Simona Cacciatore ◽  
Luca Barbano ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Work Of Breathing ◽  
Lung Mechanics ◽  
Intrinsic Peep ◽  
Chronic Obstructive ◽  
Flow Limitation ◽  
Expiratory Flow Limitation ◽  
Copd Patients ◽  
Ineffective Efforts ◽  
Expiratory Flow

Abstract Background Tidal expiratory flow limitation (EFLT) promotes intrinsic PEEP (PEEPi) in patients with chronic obstructive pulmonary disease (COPD). Applying non-invasive ventilation (NIV) with an expiratory positive airway pressure (EPAP) matching PEEPi improves gas exchange, reduces work of breathing and ineffective efforts. We aimed to evaluate the effects of a novel NIV mode that continuously adjusts EPAP to the minimum level that abolishes EFLT. Methods This prospective, cross-over, open-label study randomized patients to one night of fixed-EPAP and one night of EFLT-abolishing-EPAP. The primary outcome was transcutaneous carbon dioxide pressure (PtcCO2). Secondary outcomes were: peripheral oxygen saturation (SpO2), frequency of ineffective efforts, breathing patterns and oscillatory mechanics. Results We screened 36 patients and included 12 in the analysis (age 72 ± 8 years, FEV1 38 ± 14%Pred). The median EPAP did not differ between the EFLT-abolishing-EPAP and the fixed-EPAP night (median (IQR) = 7.0 (6.0, 8.8) cmH2O during night vs 7.5 (6.5, 10.5) cmH2O, p = 0.365). We found no differences in mean PtcCO2 (44.9 (41.6, 57.2) mmHg vs 54.5 (51.1, 59.0), p = 0.365), the percentage of night time with PtcCO2 > 45 mm Hg was lower (62(8,100)% vs 98(94,100)%, p = 0.031) and ineffective efforts were fewer (126(93,205) vs 261(205,351) events/hour, p = 0.003) during the EFLT-abolishing-EPAP than during the fixed-EPAP night. We found no differences in oxygen saturation and lung mechanics between nights. Conclusion An adaptive ventilation mode targeted to abolish EFLT has the potential to reduce hypercapnia and ineffective efforts in stable COPD patients receiving nocturnal NIV. Trial registration: ClicalTrials.gov, NCT04497090. Registered 29 July 2020—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04497090.

Exacerbation History In COPD Patients With And Without Expiratory Flow Limitation (EFL)

2012 ◽  
Author(s):  
Bernt B. Aarli ◽  
Peter M. Calverley ◽  
Per Bakke ◽  
Tomas M.L. Eagan ◽  
Jon A. Hardie
Keyword(s):  
Flow Limitation ◽  
Expiratory Flow Limitation ◽  
Copd Patients ◽  
Expiratory Flow

scholarly journals Tidal expiratory flow limitation induces expiratory looping of the alveolar pressure-flow relation in COPD patients

2020 ◽  
Vol 129 (1) ◽  
pp. 75-83
Author(s):  
Matteo Pecchiari ◽  
Dejan Radovanovic ◽  
Camilla Zilianti ◽  
Laura Saderi ◽  
Giovanni Sotgiu ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Chronic Obstructive ◽  
Flow Limitation ◽  
Alveolar Pressure ◽  
Expiratory Flow Limitation ◽  
Obstructive Pulmonary Disease ◽  
Copd Patients ◽  
Expiratory Flow ◽  
Spontaneously Breathing

In stable chronic obstructive pulmonary disease (COPD) patients spontaneously breathing at rest, tidal expiratory flow limitation is the major determinant of the occurrence of expiratory looping in the plethysmographic flow-alveolar pressure diagram. In these patients the magnitude and the characteristics of the loop can be used as predictors of the presence of tidal expiratory flow limitation.

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