Frequency characteristics of airway and tissue impedances in respiratory diseases

1991 ◽  
Vol 71 (1) ◽  
pp. 259-270 ◽  
Author(s):  
M. Mishima ◽  
K. Kawakami ◽  
K. Higashiya ◽  
T. Fukunaga ◽  
T. Ooka ◽  
...  
Keyword(s):  
Chest Wall ◽  
Random Noise ◽  
Peripheral Resistance ◽  
Normal Subjects ◽  
Frequency Characteristics ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
The Real ◽  
Peripheral Airway ◽  
Chronic Pulmonary Emphysema

We measured the frequency characteristics (at 10–40 Hz) of airway (Za) and tissue (Zt) impedances in cases of chronic obstructive pulmonary disease [asthmatic bronchitis (AB), chronic pulmonary emphysema (CPE)] and interstitial pneumonitis (IP) by use of an improved random noise oscillation and body box method. The results were then compared with those obtained for normal subjects. The real part of Za was markedly elevated in patients with AB but only slightly elevated in those with CPE. To interpret these data we used an electromechanical analogue including serial inhomogeneity with shunt impedance. From this model we concluded that AB causes both the central and peripheral airway resistances to increase, while CPE brings about a rise mainly in peripheral resistance. In IP patients, only the imaginary part of Zt decreased, which might reflect the decrease in both lung and chest wall compliance. In CPE patients, but not in AB patients, the real part of Zt fell. These data were consistent with the assumption that the decrease in mass per unit volume of lung tissue and hyperinflation of the chest wall in CPE patients might lower the tissue resistances.

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.

In vivo characterization of the transitional bronchioles by aerosol-derived airway morphometry

1999 ◽  
Vol 87 (3) ◽  
pp. 920-927 ◽  
Author(s):  
Kirby L. Zeman ◽  
Gerhard Scheuch ◽  
Knut Sommerer ◽  
James S. Brown ◽  
William D. Bennett
Keyword(s):  
Ex Vivo ◽  
Normal Subjects ◽  
Characteristic Line ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Lung Capacity ◽  
Single Breath ◽  
In Vivo Characterization

Effective airway dimensions (EADs) were determined in vivo by aerosol-derived airway morphometry as a function of volumetric lung depth (VLD) to identify and characterize, noninvasively, the caliber of the transitional bronchiole region of the human lung and to compare the EADs by age, gender, and disease. By logarithmically plotting EAD vs. VLD, two distinct regions of the lung emerged that were identified by characteristic line slopes. The intersection of proximal and distal segments was defined as VLDtransand associated EADtrans. In our normal subjects ( n = 20), VLDtrans [345 ± 83 (SD) ml] correlated significantly with anatomic dead space (224 ± 34 ml) and end of phase II of single-breath nitrogen washout (360 ± 53 ml). The corresponding EADtranswas 0.42 ± 0.07 mm, in agreement with other ex vivo measurements of the transitional bronchioles. VLDtrans was smaller (216 ± 64 ml) and EADtrans was larger (0.83 ± 0.04 mm) in our patients with chronic obstructive pulmonary disease ( n = 13). VLDtrans increased with age for children (age 8–18 yr; P = 0.006, n = 26) and with total lung capacity for age 8–81 yr ( P < 0.001, n = 61). This study extends the usefulness of aerosol-derived airway morphometry to in vivo measurements of the transitional bronchioles.

Effect of chest wall vibration on dyspnea during exercise in chronic obstructive pulmonary disease

2002 ◽  
Vol 130 (3) ◽  
pp. 305-316 ◽  
Author(s):  
Toshihide Fujie ◽  
Naoko Tojo ◽  
Naohiko Inase ◽  
Nobuo Nara ◽  
Ikuo Homma ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Chest Wall ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease

scholarly journals Regenerative pharmacology for COPD: breathing new life into old lungs

Thorax ◽  
2019 ◽  
Vol 74 (9) ◽  
pp. 890-897 ◽  
Author(s):  
John-Poul Ng-Blichfeldt ◽  
Reinoud Gosens ◽  
Charlotte Dean ◽  
Mark Griffiths ◽  
Matthew Hind
Keyword(s):  
Large Scale ◽  
Biologically Active ◽  
Health Concern ◽  
Chronic Obstructive ◽  
Small Airways ◽  
Obstructive Pulmonary Disease ◽  
Molecular Control ◽  
Mild Disease ◽  
Peripheral Airway ◽  
Alveolar Tissue

Chronic obstructive pulmonary disease (COPD) is a major global health concern with few effective treatments. Widespread destruction of alveolar tissue contributes to impaired gas exchange in severe COPD, and recent radiological evidence suggests that destruction of small airways is a major contributor to increased peripheral airway resistance in disease. This important finding might in part explain the failure of conventional anti-inflammatory treatments to restore lung function even in patients with mild disease. There is a clear need for alternative pharmacological strategies for patients with COPD/emphysema. Proposed regenerative strategies such as cell therapy and tissue engineering are hampered by poor availability of exogenous stem cells, discouraging trial results, and risks and cost associated with surgery. An alternative therapeutic approach is augmentation of lung regeneration and/or repair by biologically active factors, which have potential to be employed on a large scale. In favour of this strategy, the healthy adult lung is known to possess a remarkable endogenous regenerative capacity. Numerous preclinical studies have shown induction of regeneration in animal models of COPD/emphysema. Here, we argue that given the widespread and irreversible nature of COPD, serious consideration of regenerative pharmacology is necessary. However, for this approach to be feasible, a better understanding of the cell-specific molecular control of regeneration, the regenerative potential of the human lung and regenerative competencies of patients with COPD are required.

Assessment of transdiaphragmatic pressure in humans

1985 ◽  
Vol 58 (5) ◽  
pp. 1469-1476 ◽  
Author(s):  
D. Laporta ◽  
A. Grassino
Keyword(s):  
Pulmonary Disease ◽  
Visual Feedback ◽  
Random Order ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Disease Group ◽  
Obstructive Pulmonary Disease ◽  
Transdiaphragmatic Pressure ◽  
Residual Capacity ◽  
Group 1

Maximal force developed by the diaphragm at functional residual capacity is a useful index to establish muscle weakness; however, great disparity in its reproducibility can be observed among reports in the literature. We evaluated five maneuvers to measure maximal transdiaphragmatic pressure (Pdimax) in order to establish best reproducibility and value. Thirty-five naive subjects, including 10 normal subjects (group 1), 12 patients with chronic obstructive pulmonary disease (group 2), and 13 patients with restrictive pulmonary disease (group 3), were studied. Each subject performed five separate maneuvers in random order that were repeated until reproducible values were obtained. The maneuvers were Mueller with (A) and without mouthpiece (B), abdominal expulsive effort with open glottis (C), two-step (maneuver C combined with Mueller effort) (D), and feedback [two-step with visual feedback of pleural (Ppl) and abdominal (Pab) pressure] (E). The greatest reproducible Pdimax values were obtained with maneuver E (P less than 0.01) (group 1: 180 +/- 14 cmH2O). The second best maneuvers were A, B, and D (group 1: 154 +/- 25 cmH2O). Maneuver C produced the lowest values. For all maneuvers, group 1 produced higher values than groups 2 and 3 (P less than 0.001), which were similar. The Ppl to Pdi ratio was 0.6 in maneuvers A and B, 0.4 in D and E, and 0.2 in C. We conclude that visual feedback of Ppl and Pab helped the subjects to elicit maximal diaphragmatic effort in a reproducible fashion. It is likely that the great variability of values in Pdimax previously reported are the result of inadequate techniques.

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