Structural change of the thorax in chronic obstructive pulmonary disease

1992 ◽  
Vol 72 (4) ◽  
pp. 1270-1278 ◽  
Author(s):  
J. M. Walsh ◽  
C. L. Webber ◽  
P. J. Fahey ◽  
J. T. Sharp
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Structural Change ◽  
Pulmonary Disease ◽  
Volume Change ◽  
Structural Changes ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Rib Cage ◽  
Diaphragm Position

This study examines structural changes of the thorax in hyperinflated subjects with chronic obstructive pulmonary disease (COPD). Age-matched normal subjects were used for comparison. Thoracic dimensions were determined using anteroposterior and lateral chest radiographs performed at total lung capacity, functional residual capacity, and residual volume. Rib cage dimensions (lateral diameter, rib angle, anteroposterior diameter) and diaphragm position were determined at each lung volume. There were no significant differences in rib cage dimension between the COPD and normal subjects for all lung volumes. In contrast, the diaphragm was significantly lower in the COPD subjects. The change of rib cage dimensions in the COPD subjects (for a similar volume change) was not different from that in normal subjects, whereas the change of diaphragm position in the COPD subjects (for a similar volume change) was reduced. In conclusion, the primary structural change of the thorax in COPD with chronic hyperinflation is confined to the diaphragm, with no appreciable structural change in the rib cage.

Effect of simulated breath sounds on ventilation

1964 ◽  
Vol 19 (2) ◽  
pp. 233-235 ◽  
Author(s):  
M. Henry Williams ◽  
Cecile Kane
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Normal Subjects ◽  
Alveolar Ventilation ◽  
Respiratory Frequency ◽  
Auditory Stimuli ◽  
Chronic Obstructive ◽  
Breathing Rate ◽  
Obstructive Pulmonary Disease ◽  
Breath Sounds

When normal subjects listened to simulated breath sounds while breathing at their natural respiratory frequency there was a significant decrease of alveolar Pco2. The alveolar Pco2 did not fall further when these subjects listened to the simulator and breathed slowly, but when they breathed with the simulator at a very rapid frequency there was further fall of the PaCOCO2. When patients with chronic obstructive pulmonary disease listened to simulated breath sounds while breathing at their natural respiratory frequency there was a decrease of arterial Pco2 which fell further when the subjects breathed with the simulator at a slow respiratory rate. breathing, effect of auditory stimuli on; breathing rate and pulmonary function on chronic obstructive pulmonary disease; alveolar ventilation and auditory respiratory stimuli; respiratory frequency and ventilation Submitted on July 12, 1963

scholarly journals Effect of L-arginine on renal blood flow in normal subjects and patients with hypoxic chronic obstructive pulmonary disease.

Thorax ◽  
1996 ◽  
Vol 51 (5) ◽  
pp. 516-519 ◽  
Author(s):  
T. Q. Howes ◽  
S. E. Keilty ◽  
V. L. Maskrey ◽  
C. R. Deane ◽  
S. V. Baudouin ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Blood Flow ◽  
Renal Blood Flow ◽  
Pulmonary Disease ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease

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.

Sign in / Sign up

Export Citation Format

Share Document