Partitioning of work of breathing in mechanically ventilated COPD patients

1993 ◽  
Vol 75 (4) ◽  
pp. 1711-1719 ◽  
Author(s):  
M. L. Coussa ◽  
C. Guerin ◽  
N. T. Eissa ◽  
C. Corbeil ◽  
M. Chasse ◽  
...  
Keyword(s):  
Work Of Breathing ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Mechanically Ventilated ◽  
Airway Occlusion ◽  
Copd Patients ◽  
Additional Resistance ◽  
Work Done ◽  
Inspiratory Muscle Fatigue

In 10 sedated paralyzed mechanically ventilated chronic obstructive pulmonary disease (COPD) patients, we measured the inspiratory mechanical work done per breath on the respiratory system (WI,rs). We measured the tracheal and esophageal pressures to assess the lung (L) and chest wall (W) components of WI and used the technique of rapid airway occlusion during constant-flow inflation to partition WI into static work [Wst, including work due to intrinsic positive end-expiratory pressure (WPEEPi)], dynamic work due to airway resistance, and the additional resistance offered by the respiratory tissues. Although the patients were hyperinflated, the slope of the static volume-pressure relationships of the lung did not decrease with inflation volume up to 0.8 liter. WI,W was similar in COPD patients and normal subjects. All components of WI,L were higher in COPD patients. The increase in Wst,rs was due entirely to WPEEPi. Our data suggest that, during spontaneous breathing, COPD patients would probably develop inspiratory muscle fatigue, unless continuous positive airway pressure were applied to reduce WPEEPi.

Lung and chest wall mechanics in mechanically ventilated COPD patients

1993 ◽  
Vol 74 (4) ◽  
pp. 1570-1580 ◽  
Author(s):  
C. Guerin ◽  
M. L. Coussa ◽  
N. T. Eissa ◽  
C. Corbeil ◽  
M. Chasse ◽  
...  
Keyword(s):  
Chest Wall ◽  
Time Constant ◽  
Viscoelastic Behavior ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Mechanically Ventilated ◽  
Airway Occlusion ◽  
Chest Wall Mechanics ◽  
Copd Patients

By use of the technique of rapid airway occlusion, the effects of inspiratory flow, volume, and time on lung and chest wall mechanics were investigated in 10 chronic obstructive pulmonary disease (COPD) patients mechanically ventilated for acute respiratory failure. We measured the interrupter resistance (Rint), which in humans reflects airway resistance; the additional resistances due to time constant inequality and viscoelastic pressure dissipations within the lungs (delta RL) and the chest wall; and the static and dynamic elastances of lung and chest wall. We observed that 1) static elastances of lung and chest wall in COPD patients were similar to those of normal subjects; 2) Rint of the lung was markedly increased and flow dependent in COPD patients, whereas Rint of the chest wall was negligible as in normal subjects; and 3) in COPD patients, delta RL was markedly increased at all inflation flows and volumes, reflecting increased time constant inequalities within the lungs and/or altered viscoelastic behavior. The results imply increased dynamic work due to Rint and delta RL and marked time dependency of pulmonary resistance and elastance in COPD patients.

scholarly journals Patient-ventilator asynchrony as a predictor of weaning failure in mechanically ventilated COPD patients

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Samiaa H. Sadek ◽  
Maha M. El-kholy ◽  
Marwa S. Abdulmoez ◽  
Reham M. El-Morshedy
Keyword(s):  
Prolonged Mechanical Ventilation ◽  
Work Of Breathing ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Asynchrony Index ◽  
Mechanically Ventilated ◽  
Early Predictors ◽  
Copd Patients ◽  
Weaning Failure ◽  
Successful Weaning

Abstract Background Patient-ventilator asynchrony is a common problem in mechanically ventilated patients. It is associated with adverse effects including increased work of breathing, patient discomfort, increased need for sedation, prolonged mechanical ventilation, weaning difficulties, and weaning failure. The purpose of the present was to describe patient-ventilator asynchrony and its impact on weaning outcomes in mechanically ventilated chronic obstructive pulmonary disease (COPD) patients. Results One hundred mechanically ventilated COPD patients were enrolled in this prospective study. Weaning failure (need of NIV or reintubation within 48 h) was noticed in 27 (27%) patients while 73 (73%) patients had successful weaning. Patients with failed weaning had significantly higher asynchrony index (A.I) and ineffective trigger index (ITI) in comparison with those with successful weaning (7.69 ± 3.71, 3.46 ± 2.59 versus 6.27 ± 3.14, 2.47 ± 2.08, respectively; P value< 0.04). Data were expressed as mean ± standard deviation. Conclusion High asynchrony index and high ineffective trigger index may be early predictors of weaning failure in mechanically ventilated COPD patients.

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.

Force reserve of the diaphragm in patients with chronic obstructive pulmonary disease

1983 ◽  
Vol 55 (1) ◽  
pp. 8-15 ◽  
Author(s):  
F. Bellemare ◽  
A. Grassino
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Cycle Duration ◽  
Inspiratory Time ◽  
Obstructive Pulmonary Disease ◽  
Transdiaphragmatic Pressure ◽  
Copd Patients ◽  
Gastric Pressure

The fatigue threshold of the human diaphragm in normal subjects corresponds to a transdiaphragmatic pressure (Pdi)-inspiratory time integral (TTdi) of about 15% of Pdimax. The TTdi of resting ventilation was measured in 20 patients with chronic obstructive pulmonary disease (COPD) and ranged between 1 and 12% of Pdimax (mean 5%). TTdi was significantly related to total airway resistance (Raw) (r = 0.57; P less than 0.05). Five of these patients were asked to voluntarily modify their TI/TT (ratio of inspiratory time to total cycle duration; from 0.33 to 0.49) so as to increase their TTdi from a control value of 8% to an imposed value of 17% of Pdimax. The imposed pattern induced a progressive decline in the high-frequency (150-350 Hz)/low-frequency (20-40 Hz) power ratio (H/L) of the diaphragm electromyogram (fatigue pattern), quantitatively similar to that seen in normal subjects breathing with similar TTdi levels. The decay in H/L was followed by a progressive fall in mean Pdi meanly due to decrease in gastric pressure swings. It is concluded that 1) the force reserve of the diaphragm in COPD patients is decreased because of a decrease in Pdimax; 2) the remaining force reserve of the diaphragm can be exhausted by even minor modifications in the breathing pattern; and 3) at a TI/TT of 0.40 our COPD patients can increase their mean Pdi 3-fold before reaching a fatiguing pattern of breathing compared with 8-fold in normal subjects.

scholarly journals Use of Continuous Negative Pressure Around the Chest Increases Exercise Performance in Chronic Obstructive Pulmonary Disease Patients: A Pilot Study

2011 ◽  
Vol 18 (1) ◽  
pp. e6-e9 ◽  
Author(s):  
Rakesh K Chaturvedi ◽  
Arnold Zidulka
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pilot Study ◽  
Pulmonary Disease ◽  
Exercise Performance ◽  
Negative Pressure ◽  
Work Of Breathing ◽  
Chronic Obstructive ◽  
Positive End Expiratory Pressure ◽  
Obstructive Pulmonary Disease ◽  
Copd Patients

BACKGROUND: Patients with severe chronic obstructive pulmonary disease (COPD) often have intrinsic positive end-expiratory pressure. Continuous positive airway pressure has been shown to decrease the inspiratory work of breathing and increases exercise capacity in these patients.OBJECTIVE: To determine whether continuous negative pressure (CNP) around the chest is able to bring the positive end-expiratory pressure closer to atmospheric pressure, thereby reducing the threshold load and increasing exercise capability.METHODS: A pilot study was undertaken with eight COPD patients who had been hospitalized for exacerbation and were close to discharge. For CNP, a shell (around the thorax from under the axillae to the mid abdomen) and wrap were used. Each of the eight patients was assessed with a 6 min walk test in three modes (in randomized order) with 30 min of rest in between: a control walk with no shell or wrap; a sham CNP in which the applied CNP was negligible; and CNP, with pressure chosen by the patient that provided maximal relief of dyspnea at rest.RESULTS: At the end of each of the 6 min walk tests, there was no difference in heart rate, oxygen saturation or level of dyspnea among the three test modes. Respiratory rate was reduced with CNP compared with sham. The patients walked furthest with CNP compared with control (mean ± SD) (313±66.2 m versus 257±65.2 m; P<0.01) and compared with sham.CONCLUSIONS: In the present pilot study, COPD patients improved their exercise performance with CNP.

scholarly journals Expiratory Flow Limitation Definition, Mechanisms, Methods, and Significance

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Claudio Tantucci
Keyword(s):  
Work Of Breathing ◽  
Chronic Obstructive ◽  
Dynamic Hyperinflation ◽  
Flow Limitation ◽  
Negative Consequences ◽  
Expiratory Flow Limitation ◽  
Obstructive Pulmonary Disease ◽  
Inspiratory Muscles ◽  
Copd Patients ◽  
Expiratory Flow

When expiratory flow is maximal during tidal breathing and cannot be increased unless operative lung volumes move towards total lung capacity, tidal expiratory flow limitation (EFL) is said to occur. EFL represents a severe mechanical constraint caused by different mechanisms and observed in different conditions, but it is more relevant in terms of prevalence and negative consequences in obstructive lung diseases and particularly in chronic obstructive pulmonary disease (COPD). Although in COPD patients EFL more commonly develops during exercise, in more advanced disorder it can be present at rest, before in supine position, and then in seated-sitting position. In any circumstances EFL predisposes to pulmonary dynamic hyperinflation and its unfavorable effects such as increased elastic work of breathing, inspiratory muscles dysfunction, and progressive neuroventilatory dissociation, leading to reduced exercise tolerance, marked breathlessness during effort, and severe chronic dyspnea.

scholarly journals Correlation between cardiorespiratory coupling and six-minute walking tests in patients with chronic obstructive pulmonary disease

2020 ◽  
Author(s):  
Yu-Chen Huang ◽  
Ting-Yu Lin ◽  
Hau-Tieng Wu ◽  
Po-Jui Chang ◽  
Chun-Yu Lo ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Normal Subjects ◽  
Walking Distance ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Copd Patients ◽  
Forward Stepwise ◽  
Cardiorespiratory Coupling ◽  
Clinical Potential

Abstract Background : Cardiovascular disease is a common comorbidity and cause of mortality among patients with chronic obstructive pulmonary disease (COPD). However, the interaction between the heart and lungs in COPD patients has yet to be fully elucidated.Aim : Our objective in this study was to characterize cardiorespiratory interactions in terms of cardiorespiratory coupling (CRC) using the synchrogram index of the heart rate and respiration flow signals.Methods : This prospective study examined 10 normal subjects and 55 COPD patients. Linear regression and forward stepwise regression were used to determine the correlation between the synchrogram index and the six-minute walking test.Results : K-means clustering analysis was used to separate the 55 COPD patients into a synchronized group (median 0.89 (0.64-0.97), n=43) and a desynchronized group (median 0.23 (0.02-0.51), n=12) based on the synchrogram index. In this study, the synchrogram index was significantly correlated with the six-minute walking distance (r 2 =0.3, sigma T=0.02) and the distance saturation product (r 2 =0.3, sigma T =0.03). Note that age was a significant confounding factor.Conclusion : The synchrogram index shows clinical potential for the stratification of COPD patients for treatment.

COMPARISON BETWEEN CURB-65 AND BAP-65 IN THE PREDICTION OF MECHANICAL VENTILATION IN PATIENTS WITH THE EXACERBATION OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE

2017 ◽  
pp. 60-63
Author(s):  
Van Dong Tran ◽  
Van Chi Nguyen ◽  
Ngoc Son Do
Keyword(s):  
Mechanical Ventilation ◽  
Pulmonary Disease ◽  
Area Under Curve ◽  
Invasive Mechanical Ventilation ◽  
High Accuracy ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Mechanically Ventilated ◽  
Copd Patients ◽  
Exacerbation Of Copd

Objectives: to compare between CURB-65 and BAP-65 in the prediction of mechanical ventilation in patients with the exacerbation of chronic obstrutive pulmonary disease (COPD). Study design: Retrospective study. Subjects and methods: 419 COPD patients were admitted to Emergency Department of Bach Mai Hospital from January 01, 2013 to June 06, 2014. Results: There were 378 patients (90.2%) who were not mechanically ventilated, 41 patients (9.8%) who were on invasive mechanical ventilation. The area under curve (AUROC) of BAP-65 was higher than that of CURB-65 in the predection of mechanical ventilation : 0.93 95% CI: 0.90-0.95) and 0.90 95% CI: 0.87-0.93) (p= 0,272) respectively. Conclusions: Both BAP-65 and CURB-65 could be seen as a useful tool for the risk statification for initiation of mechanical ventilation on patients with the exacerbation of COPD, however, BAP-65 was high accuracy than that of CURB-65. Key words: Mechanical ventilation, CURB-65, BAP-65, Exacerbation of COPD.

Thixotropy of rib cage respiratory muscles in normal subjects

2000 ◽  
Vol 89 (5) ◽  
pp. 1753-1758 ◽  
Author(s):  
Ikuo Homma ◽  
Karl-Erik Hagbarth
Keyword(s):  
Skeletal Muscles ◽  
Respiratory Muscles ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Quiet Breathing ◽  
Obstructive Pulmonary Disease ◽  
Rib Cage ◽  
Airway Occlusion ◽  
Before And After ◽  
Thixotropic Behavior

In this study, we searched for signs of thixotropic behavior in human rib cage respiratory muscles. If rib cage respiratory muscles possess thixotropic properties similar to those seen in other skeletal muscles in animals and humans, we expect resting rib cage circumference would be temporarily changed after deep rib cage inflations or deflations and that these aftereffects would be particularly pronounced in trials that combine conditioning deep inflations or deflations with forceful isometric contractions of the respiratory muscles. We used induction plethysmography to obtain a continuous relative measure of rib cage circumference changes during quiet breathing in 12 healthy subjects. Rib cage position at the end of the expiratory phase (EEP) was used as an index of resting rib cage circumference. Comparisons were made between EEP values of five spontaneous breaths immediately before and after six types of conditioning maneuvers: deep inspiration (DI); deep expiration (DE); DI combined with forceful effort to inspire (FII) or expire (FEI); and DE combined with forceful effort to inspire (FIE) or expire (FEE), both with temporary airway occlusion. The aftereffects of the conditioning maneuvers on EEP values were consistent with the supposition that human respiratory muscles possess thixotropic properties. EEP values were significantly enhanced after all conditioning maneuvers involving DI, and the aftereffects were particularly pronounced in the FII and FEI trials. In contrast, EEP values were reduced after DE maneuvers. The aftereffects were statistically significant for the FEE and FIE, but not DE, trials. It is suggested that respiratory muscle thixotropy may contribute to the pulmonary hyperinflation seen in patients with chronic obstructive pulmonary disease.

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