scholarly journals Effects of Inhaled Fenoterol and Positive End-Expiratory Pressure on the Respiratory Mechanics of Patients with Chronic Obstructive Pulmonary Disease

2005 ◽  
Vol 12 (6) ◽  
pp. 329-335 ◽  
Author(s):  
Claude Guerin ◽  
Pierre-Guy Durand ◽  
Cécile Pereira ◽  
Jean-Christophe Richard ◽  
Jean-Charles Poupelin ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Respiratory System ◽  
Lung Volume ◽  
Respiratory Mechanics ◽  
Chronic Obstructive ◽  
Flow Limitation ◽  
Total Resistance ◽  
Positive End Expiratory Pressure ◽  
Expiratory Flow Limitation ◽  
Obstructive Pulmonary Disease

BACKGROUND: During acute ventilatory failure in patients with chronic obstructive pulmonary disease (COPD), applying external positive end-expiratory pressure (PEEPe) will reopen small airways and, thus, may enhance peripheral deposition as well as the physiological effects of inhaled beta-2 agonists.OBJECTIVE: To investigate the efficacy of inhaled fenoterol applied by zero end-expiratory pressure (ZEEPe) or PEEPe.METHODS: Ten patients with COPD who were intubated and mechanically ventilated received fenoterol (10 mg/4 mL) via the ventilator using a jet nebulizer for 30 min on ZEEPe and PEEPe set at 80% of the total PEEP in a random order. The total resistance of the respiratory system (rapid airway occlusion technique), change in end-expiratory lung volume and expiratory flow limitation were assessed before and 5 min, 15 min, 30 min, 60 min and 240 min after fenoterol inhalation.RESULTS: Before inhalation and 60 min after inhalation, the total PEEP, the change in end-expiratory lung volume and the total resistance of the respiratory system were 8±3 cmH2O and 6±3 cmH2O, 0.61±0.34 L and 0.43±0.32 L, and 26±7 cmH2O/L/s and 23±6 cmH2O/L/s, respectively, with ZEEPe, and 9±3 cmH2O and 8±3 cmH2O (P<0.05 versus ZEEPe), 0.62±0.34 L and 0.62±0.37 L (P<0.05 versus ZEEPe), and 26±9 H2O/L/s and 25±9 H2O/L/s, respectively, with PEEPe. Three patients became not flow-limited under the combination of PEEPe and fenoterol.CONCLUSIONS: In patients with COPD, fenoterol combined with PEEPe has opposing effects on respiratory mechanics. First, it does not significantly reduce lung hyperinflation or inspiratory resistances. Second, it allows expiratory flow limitation reversal in some patients. These findings result from the net effect on end-expiratory lung volume of each intervention. This implies that if fenoterol is used in combination with PEEPe, the level of PEEPe should be reassessed during the time course of the drug to prevent any further lung hyperinflation.

scholarly journals Alternative methods for assessing bronchodilator reversibility in chronic obstructive pulmonary disease

Thorax ◽  
2001 ◽  
Vol 56 (9) ◽  
pp. 713-720
Author(s):  
J Hadcroft ◽  
P M A Calverley
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Lung Volume ◽  
Tidal Flow ◽  
Airflow Limitation ◽  
Alternative Methods ◽  
Chronic Obstructive ◽  
Flow Limitation ◽  
Inspiratory Capacity ◽  
Obstructive Pulmonary Disease

BACKGROUNDBronchodilator reversibility testing is recommended in all patients with chronic obstructive pulmonary disease (COPD) but does not predict improvements in breathlessness or exercise performance. Two alternative ways of assessing lung mechanics—measurement of end expiratory lung volume (EELV) using the inspiratory capacity manoeuvre and application of negative expiratory pressure (NEP) during tidal breathing to detect tidal airflow limitation—do relate to the degree of breathlessness in COPD. Their usefulness as end points in bronchodilator reversibility testing has not been examined.METHODSWe studied 20 patients with clinically stable COPD (mean age 69.9 (1.5) years, 15 men, forced expiratory volume in one second (FEV1) 29.5 (1.6)% predicted) with tidal flow limitation as assessed by their maximum flow-volume loop. Spirometric parameters, slow vital capacity (SVC), inspiratory capacity (IC), and NEP were measured seated, before and after nebulised saline, and at intervals after 5 mg nebulised salbutamol and 500 μg nebulised ipratropium bromide. The patients attended twice and the treatment order was randomised.RESULTSMean FEV1, FVC, SVC, and IC were unchanged after saline but the degree of tidal flow limitation varied. FEV1 improved significantly after salbutamol and ipratropium (0.11 (0.02) l and 0.09 (0.02) l, respectively) as did the other lung volumes with further significant increases after the combination. Tidal volume and mean expiratory flow increased significantly after all bronchodilators but breathlessness fell significantly only after the combination treatment. The initial NEP score was unrelated to subsequent changes in lung volume.CONCLUSIONSNEP is not an appropriate measurement of acute bronchodilator responsiveness. Changes in IC were significantly larger than those in FEV1and may be more easily detected. However, our data showed no evidence for separation of “reversible” and “irreversible” groups whatever outcome measure was adopted.

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.

scholarly journals Respiratory system reactance reflects communicating lung volume in chronic obstructive pulmonary disease

2019 ◽  
Vol 126 (5) ◽  
pp. 1223-1231 ◽  
Author(s):  
Stephen Milne ◽  
Kanika Jetmalani ◽  
David G. Chapman ◽  
Joseph M. Duncan ◽  
Claude S. Farah ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Respiratory System ◽  
Lung Volume ◽  
Forced Oscillation ◽  
Chronic Obstructive ◽  
Forced Oscillation Technique ◽  
Obstructive Pulmonary Disease ◽  
Volume Relationship ◽  
Residual Capacity

Respiratory system reactance (Xrs) measured by the forced oscillation technique (FOT) is theoretically and experimentally related to lung volume. In chronic obstructive pulmonary disease (COPD), the absolute volume measured by body plethysmography includes a proportion that is inaccessible to pressure oscillations applied via the mouth, that is, a “noncommunicating” lung volume. We hypothesized that in COPD the presence of noncommunicating lung would disrupt the expected Xrs-volume relationship compared with plethysmographic functional residual capacity (FRCpleth). Instead, Xrs would relate to estimates of communicating volume, namely, expiratory reserve volume (ERV) and single-breath alveolar volume (VaSB). We examined FOT and lung function data from people with COPD ( n = 51) and from healthy volunteers ( n = 40). In healthy volunteers, we observed an expected inverse relationship between reactance at 5 Hz (X5) and FRCpleth. In contrast, there was no such relationship between X5 and FRCpleth in COPD subjects. However, there was an inverse relationship between X5 and both ERV and VaSB. Hence the theoretical Xrs-volume relationship is present in COPD but only when considering the communicating volume rather than the absolute lung volume. These findings confirm the role of reduced communicating lung volume as an important determinant of Xrs and therefore advance our understanding and interpretation of FOT measurements in COPD. NEW & NOTEWORTHY To investigate the determinants of respiratory system reactance (Xrs) measured by the forced oscillation technique (FOT) in chronic obstructive pulmonary disease (COPD), we examine the relationship between Xrs and lung volume. We show that Xrs does not relate to absolute lung volume (functional residual capacity) in COPD but instead relates only to the volume of lung in communication with the airway opening. This communicating volume may therefore be fundamental to our interpretation of FOT measurements in COPD and other pulmonary diseases.

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