Chest wall impedance partitioned into rib cage and diaphragm-abdominal pathways

1989 ◽  
Vol 66 (1) ◽  
pp. 350-359 ◽  
Author(s):  
G. M. Barnas ◽  
K. Yoshino ◽  
D. Stamenovic ◽  
Y. Kikuchi ◽  
S. H. Loring ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Chest Wall ◽  
Viscoelastic Properties ◽  
Vital Capacity ◽  
Wall Surface ◽  
Body Plethysmography ◽  
Frequency Range ◽  
Entire Frequency Range ◽  
Rib Cage ◽  
Pressure Changes

We measured chest wall "pathway impedances" (ratios of pressure changes to rates of volume displacement at the surface) with esophageal and gastric balloons and inductance plethysmographic belts around the rib cage and abdomen during forced volume oscillations (5% vital capacity, 0.5–4 Hz) at the mouth of five relaxed, seated subjects. Volume displacements of the total chest wall surface, measured by summing the rib cage and abdominal signals, approximated measurements using volume-displacement, body plethysmography over the entire frequency range. Resistance (R) and elastance (E) of the diaphragm-abdomen pathway were several times greater than those of the rib cage pathway, except at the highest frequencies where diaphragm-abdominal E was small. R and E of the diaphragm-abdomen pathway and of the rib cage pathway showed the same frequency dependencies as that of the total chest wall: R decreased markedly as frequency increased, and E (especially in the diaphragm-abdomen) decreased at the highest frequencies. These results suggest that the chest wall can be reasonably modeled, over the frequency range studied, as a system with two major pathways for displacement. Each pathway seems to exhibit behavior that reflects nonlinear, rate-independent dissipation as well as viscoelastic properties. Impedances of these pathways are useful indexes of changes in chest wall mechanical behavior in different situations.

Rib cage vs. abdominal displacement in dogs during forced oscillation to 32 Hz

1989 ◽  
Vol 67 (4) ◽  
pp. 1472-1478 ◽  
Author(s):  
B. R. Boynton ◽  
G. Glass ◽  
I. D. Frantz ◽  
J. J. Fredberg
Keyword(s):  
Mechanical Behavior ◽  
Tidal Volume ◽  
Chest Wall ◽  
Forced Oscillation ◽  
Body Plethysmography ◽  
Volume Changes ◽  
Volume Increase ◽  
Rib Cage ◽  
Anesthetized Dogs ◽  
Inductive Plethysmography

Allen et al. (J. Clin. Invest. 76: 620–629, 1985) reported that during oscillatory forcing the base of isolated canine lungs distends preferentially relative to the apex as frequency and tidal volume increase. The tendency toward such nonuniform phasic lung distension might influence phasic displacement of the rib cage (RC) relative to the abdomen (ABD). To test this hypothesis we measured RC and ABD displacement in four anesthetized dogs during forced oscillation. Sinusoidal volume changes were delivered through a tracheostomy at 1–32 Hz and measured by body plethysmography. RC and ABD displacements were measured by inductive plethysmography. During oscillation with air at fixed tidal volumes (10–80 ml) RC, normalized to unity at 1 Hz, increased to 2.06–2.22 at 8 Hz (P less than 0.001) and then decreased to 1.06–1.35 (P less than 0.0025) at 32 Hz. ABD, normalized to unity at 1 Hz, was 1.12–1.16 at 4 Hz (P less than 0.001) and decreased to 0.12–0.14 at 32 Hz (P less than 0.001). Displacement of ABD relative to RC did not increase systematically with increasing tidal volume during sinusoidal forcing at any frequency. Thus we found no discernible influence of nonuniform phasic lung distension on chest wall behavior. We infer that in the dog the nonuniform mechanical behavior of the chest wall dominates the nonuniform (but opposing) mechanical tendency of the lung.

Total and local impedances of the chest wall up to 10 Hz

1990 ◽  
Vol 68 (4) ◽  
pp. 1409-1414 ◽  
Author(s):  
G. M. Barnas ◽  
K. Yoshino ◽  
J. Fredberg ◽  
Y. Kikuchi ◽  
S. H. Loring ◽  
...  
Keyword(s):  
Chest Wall ◽  
Healthy Subjects ◽  
Vital Capacity ◽  
Respiratory Muscles ◽  
Volume Changes ◽  
Impedance Measurements ◽  
Rib Cage ◽  
Gastric Pressure ◽  
Local Properties ◽  
Diameter Change

To understand how bical mechanical chest wall (CW) properties are related to those of the CW as a whole, we measured esophageal and gastric pressures, CW volume changes (measured with a head-out body plethysmograph), and anteroposterior and transverse CW diameter changes (measured with magnetometers attached to the surface) during sinusoidal forcing at the mouth (2.5% vital capacity, 0.5-10 Hz) in four healthy subjects. Total CW resistance decreased sharply as frequency rose to 3-4 Hz and remained relatively constant at higher frequencies. Total CW reactance became less negative with increasing frequency but showed no tendency to change sign. Above 2 Hz, diameters measured at different locations changed asynchronously between and within the rib cage and abdomen. “Local pathway impedances” (ratios of esophageal or gastric pressure to a rate of diameter change) showed frequency dependence similar to that of the total CW less than 3 Hz. Local pathway impedances increased during contraction of respiratory muscles acting on the pathway. We conclude that 1) total CW behavior is mainly a reflection of its individual local properties at less than or equal to 3 Hz, 2) local impedances within the rib cage or within the abdomen can change independently in some situations, and 3) asynchronies that develop within the CW during forcing greater than 3 Hz suggest that two compartments may be insufficient to describe CW properties from impedance measurements.

Static features of the passive rib cage and abdomen-diaphragm

1965 ◽  
Vol 20 (6) ◽  
pp. 1187-1193 ◽  
Author(s):  
Emilio Agostoni ◽  
Piero Mognoni ◽  
Giorgio Torri ◽  
Ada Ferrario Agostoni
Keyword(s):  
Chest Wall ◽  
Lung Volume ◽  
Vital Capacity ◽  
Small Volume ◽  
Respiratory Muscles ◽  
Muscular Activity ◽  
Pressure Curve ◽  
Rib Cage ◽  
Expiratory Muscles ◽  
Volume Pressure Curves

The static relation between lung volume and rib cage circumference has been determined over the vital capacity range, during relaxation and activity of the respiratory muscles with open airway. At small volume the circumference is larger during relaxation; the reverse occurs at large volume. During relaxation at full expiration the cross section of the rib cage becomes more elliptical and in some subjects also greater. Hence the shape of the chest wall during muscular activity is different from that during relaxation. Because of this change of chest wall shape the outward recoil of the passive rib cage at full expiration, in the seven subjects examined, is higher than that given by the conventional volume-pressure curve during relaxation. The volume displacements of the rib cage and of the abdomen-diaphragm have been calculated and the volume-pressure curves of the passive rib cage and abdomen-diaphragm have been constructed, taking into account the changes of the chest wall shape occurring during relaxation. change of chest wall shape during relaxation; relation between lung volume and rib cage circumference during relaxation; relation between pleural pressure and rib cage circumference during relaxation; recoil of the passive rib cage; pressure exerted by the expiratory muscles at full expiration; volume-pressure curve of the passive rib cage; volume-pressure curve of the passive abdomen-diaphragm Submitted on September 14, 1964

Mechanical coupling of the rib cage, abdomen, and diaphragm through their area of apposition

1991 ◽  
Vol 70 (3) ◽  
pp. 1235-1244 ◽  
Author(s):  
B. R. Boynton ◽  
G. M. Barnas ◽  
J. T. Dadmun ◽  
J. J. Fredberg
Keyword(s):  
Chest Wall ◽  
Lung Volume ◽  
Abdominal Pressure ◽  
Rib Cage ◽  
Mechanical Coupling ◽  
Reported Data ◽  
Pressure Changes ◽  
Limiting Case ◽  
Point Of Departure ◽  
Very High

Although volumetric displacements of the chest wall are often analyzed in terms of two independent parallel pathways (rib cage and abdomen), Loring and Mead have argued that these pathways are not mechanically independent (J. Appl. Physiol. 53: 756-760, 1982). Because of its apposition with the diaphragm, the rib cage is exposed to two distinct pressure differences, one of which depends on abdominal pressure. Using the analysis of Loring and Mead as a point of departure, we developed a complementary analysis in which mechanical coupling of the rib cage, abdomen, and diaphragm is modeled by a linear translational transformer. This model has the advantage that it possesses a precise electrical analogue. Pressure differences and compartmental displacements are related by the transformation ratio (n), which is the mechanical advantage of abdominal over pleural pressure changes in displacing the rib cage. In the limiting case of very high lung volume, n----0 and the pathways uncouple. In the limit of very small lung volume, n----infinity and the pathways remain coupled; both rib cage and abdomen are driven by abdominal pressure alone, in accord with the Goldman-Mead hypothesis. A good fit was obtained between the model and the previously reported data for the human chest wall from 0.5 to 4 Hz (J. Appl. Physiol. 66:350-359, 1989). The model was then used to estimate rib cage, diaphragm, and abdominal elastance, resistance, and inertance. The abdomen was a high-elastance high-inertance highly damped compartment, and the rib cage a low-elastance low-inertance more lightly damped compartment. Our estimate that n = 1.9 is consistent with the findings of Loring and Mead and suggests substantial pathway coupling.

Thoracoabdominal mechanics during relaxed and forced vital capacity

1979 ◽  
Vol 47 (1) ◽  
pp. 38-42 ◽  
Author(s):  
N. M. Siafakas ◽  
A. J. Morris ◽  
M. Green
Keyword(s):  
Chest Wall ◽  
Forced Vital Capacity ◽  
Vital Capacity ◽  
High Volume ◽  
The Other ◽  
Costal Margin ◽  
Forced Expiration ◽  
Transdiaphragmatic Pressure ◽  
Rib Cage ◽  
Relaxation Characteristics

Thoracoabdominal configuration, intrathoracic (esophageal), intra-abdominal (gastric), and transdiaphragmatic pressures were studied in six normal upright subjects during relaxed (RVC) and forced vital capacity (FVC). Chest wall configuration showed substantial departure from its relaxation characteristics during FVC. Paradoxical (outward) movement was recorded for a low lateral diameter of the rib cage (on the costal margin) at high volume during RVC and during most of FVC, while the other rib cage dimensions were decreasing. Transdiaphragmatic pressure was positive during most of the FVC, particularly toward RV, reflecting active contraction of the diaphragm. We conclude that diaphragmatic activity modulates forced expiration and that the chest wall may influence the FVC maneuver.

Respiratory mechanics in the normal dog determined by expiratory flow interruption

1989 ◽  
Vol 67 (6) ◽  
pp. 2276-2285 ◽  
Author(s):  
J. H. Bates ◽  
K. A. Brown ◽  
T. Kochi
Keyword(s):  
Mechanical Behavior ◽  
Chest Wall ◽  
Lung Tissue ◽  
Respiratory System ◽  
Viscoelastic Properties ◽  
Respiratory Mechanics ◽  
Frequency Dependent ◽  
Low Frequencies ◽  
Flow Interruption ◽  
Airways Resistance

We recently proposed an eight-parameter model of the respiratory system to account for its mechanical behavior when flow is interrupted during passive expiration. The model consists of two four-parameter submodels representing the lungs and the chest wall, respectively. The lung submodel consists of an airways resistance together with elements embodying the viscoelastic properties of the lung tissues. The chest wall submodel has similar structure. We estimated the parameters of the model from data obtained in four normal, anesthetized, paralyzed, tracheostomized mongrel dogs. This model explains why lung tissue and chest wall resistances should be markedly frequency dependent at low frequencies and also permits a physiological interpretation of resistance measurements provided by the flow interruption method.

Dynamics of the Chest Wall during Speech Production: Function of the Thorax, Rib Cage, Diaphragm, and Abdomen

1976 ◽  
Vol 19 (2) ◽  
pp. 297-356 ◽  
Author(s):  
Thomas J. Hixon ◽  
Jere Mead ◽  
Michael D. Goldman
Keyword(s):  
Speech Production ◽  
Chest Wall ◽  
Relative Motion ◽  
Supine Position ◽  
Vital Capacity ◽  
Body Position ◽  
Normal Subjects ◽  
Conversational Speech ◽  
Rib Cage ◽  
Graphic Solution

Anteroposterior diameters of the rib cage and abdomen and esophageal and gastric pressures were measured in normal subjects in upright and supine body positions during respiratory maneuvers and utterance tasks. Data were charted in relative motion diagrams and various motion-pressure diagrams which enabled graphic solution for muscular pressures exerted by the chest wall and individually by the thorax, rib cage, diaphragm, and abdomen during utterances. Behaviors of the chest wall and its parts were found to depend upon lung volume, utterance loudness, body position, and utterance task. For utterances encompassing most of the vital capacity, chest wall effort was at first net inspiratory and later net expiratory. The former was governed predominately by the rib cage and the abdomen in the upright body position and by the diaphragm in the supine position. For conversational speech, chest wall effort was continuously expiratory, control being vested in the rib cage and the abdomen in the upright body position and typically in the rib cage alone in the supine position. Mechanisms operating during the utterances are discussed, particularly those involved with conversational speech production. We conclude that the abdomen occupies an especially important role in running conversational speech in that it mechanically tunes the diaphragm to increase the latter’s inspiratory efficiency and thus enables man to minimally interrupt his ongoing speech for needed inspiratory pauses. We also discuss the relevance of our findings to clinical endeavors.

Chest wall muscle atrophy as a contributory factor for forced vital capacity decline in systemic sclerosis-associated interstitial lung disease

Rheumatology ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 250-255
Author(s):  
Takashi Nawata ◽  
Yuichiro Shirai ◽  
Mikito Suzuki ◽  
Masataka Kuwana
Keyword(s):  
Interstitial Lung Disease ◽  
Lung Disease ◽  
Chest Wall ◽  
Muscle Atrophy ◽  
Forced Vital Capacity ◽  
Vital Capacity ◽  
Pulmonary Function Tests ◽  
Potential Contribution ◽  
Muscle Area ◽  
Chest Wall Muscle

Abstract Objective To investigate the potential contribution of accessory respiratory muscle atrophy to the decline of forced vital capacity (FVC) in patients with SSc-associated interstitial lung disease (ILD). Methods This single-centre, retrospective study enrolled 36 patients with SSc-ILD who underwent serial pulmonary function tests and chest high-resolution CT (HRCT) simultaneously at an interval of 1–3 years. The total extent of ILD and chest wall muscle area at the level of the ninth thoracic vertebra on CT images were evaluated by two independent evaluators blinded to the patient information. Changes in the FVC, ILD extent, and chest wall muscle area between the two measurements were assessed in terms of their correlations. Multiple regression analysis was conducted to identify the independent contributors to FVC decline. Results Interval changes in FVC and total ILD extent were variable among patients, whereas chest wall muscle area decreased significantly with time (P=0.0008). The FVC change was negatively correlated with the change in ILD extent (r=−0.48, P=0.003) and was positively correlated with the change in the chest wall muscle area (r = 0.53, P=0.001). Multivariate analysis revealed that changes in total ILD extent and chest wall muscle area were independent contributors to FVC decline. Conclusion In patients with SSc-ILD, FVC decline is attributable not only to the progression of ILD but also to the atrophy of accessory respiratory muscles. Our findings call attention to the interpretation of FVC changes in patients with SSc-ILD.

scholarly journals Lung surface deformation prediction from spirometry measurement and chest wall surface motion

2016 ◽  
Vol 43 (10) ◽  
pp. 5493-5502 ◽  
Author(s):  
Joubin Nasehi Tehrani ◽  
Alistair McEwan ◽  
Jing Wang
Keyword(s):  
Chest Wall ◽  
Surface Deformation ◽  
Wall Surface ◽  
Deformation Prediction ◽  
Surface Motion
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