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

Effect of gravity on chest wall mechanics

2002 ◽  
Vol 92 (2) ◽  
pp. 709-716 ◽  
Author(s):  
D. Bettinelli ◽  
C. Kays ◽  
O. Bailliart ◽  
A. Capderou ◽  
P. Techoueyres ◽  
...  
Keyword(s):  
Linear System ◽  
Chest Wall ◽  
Lung Volume ◽  
Vital Capacity ◽  
Pressure Curve ◽  
Parabolic Flights ◽  
Chest Wall Mechanics ◽  
Exponential Decrease ◽  
Volume Range

Chest wall mechanics was studied in four subjects on changing gravity in the craniocaudal direction (Gz) during parabolic flights. The thorax appears very compliant at 0 Gz: its recoil changes only from −2 to 2 cmH2O in the volume range of 30–70% vital capacity (VC). Increasing Gz from 0 to 1 and 1.8 Gzprogressively shifted the volume-pressure curve of the chest wall to the left and also caused a fivefold exponential decrease in compliance. For lung volume <30% VC, gravity has an inspiratory effect, but this effect is much larger going from 0 to 1 Gz than from 1 to 1.8 Gz. For a volume from 30 to 70% VC, the effect is inspiratory going from 0 to 1 Gz but expiratory from 1 to 1.8 Gz. For a volume greater than ∼70% VC, gravity always has an expiratory effect. The data suggest that the chest wall does not behave as a linear system when exposed to changing gravity, as the effect depends on both chest wall volume and magnitude of Gz.

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.

Effect of respiratory muscle tension on lung volume

1992 ◽  
Vol 73 (6) ◽  
pp. 2283-2288 ◽  
Author(s):  
T. A. Wilson ◽  
A. De Troyer
Keyword(s):  
Chest Wall ◽  
Lung Volume ◽  
Airway Pressure ◽  
Linear Prediction ◽  
Muscle Tension ◽  
Muscle Length ◽  
Respiratory Muscles ◽  
Active Tension ◽  
Airway Opening ◽  
Measured Change

The chest wall is modeled as a linear system for which the displacements of points on the chest wall are proportional to the forces that act on the chest wall, namely, airway opening pressure and active tension in the respiratory muscles. A standard theorem of mechanics, the Maxwell reciprocity theorem, is invoked to show that the effect of active muscle tension on lung volume, or airway pressure if the airway is closed, is proportional to the change of muscle length in the relaxation maneuver. This relation was tested experimentally. The shortening of the cranial-caudal distance between a rib pair and the sternum was measured during a relaxation maneuver. These data were used to predict the respiratory effect of forces applied to the ribs and sternum. To test this prediction, a cranial force was applied to the rib pair and a caudal force was applied to the sternum, simulating the forces applied by active tension in the parasternal intercostal muscles. The change in airway pressure, with lung volume held constant, was measured. The measured change in airway pressure agreed well with the prediction. In some dogs, nonlinear deviations from the linear prediction occurred at higher loads. The model and the theorem offer the promise that existing data on the configuration of the chest wall during the relaxation maneuver can be used to compute the mechanical advantage of the respiratory muscles.

Three degree of freedom description of movement of the human chest wall

1986 ◽  
Vol 60 (3) ◽  
pp. 928-934 ◽  
Author(s):  
J. C. Smith ◽  
J. Mead
Keyword(s):  
Chest Wall ◽  
Lung Volume ◽  
Pubic Symphysis ◽  
Degree Of Freedom ◽  
Rib Cage ◽  
Additional Degree ◽  
Wall Movement ◽  
Surface Displacements ◽  
Flexion Extension ◽  
Three Degree Of Freedom

A three degree of freedom description of movement of the human chest wall is presented. In addition to the standard variables representing surface displacements of the rib cage and abdominal wall in transverse planes, the description includes a variable representing axial displacements of the chest wall associated with postural movements of the spine and pelvis. A simple technique was developed for quantifying the axial displacements using a single measurement by magnetometry of changes in the distance between a point on the anterior surface of the rib cage near the xiphisternum and a point on the abdominal surface near the pubic symphysis. It was found that axial displacements produced by either flexion-extension of the spine or rotation of the pelvis in the standing postures can be treated as a single degree of freedom. The chest wall displacements induced over the range of axial displacement examined were as large as those normally accompanying a change in lung volume on the order of 30–50% of the vital capacity. It is concluded, however, that although this additional degree of freedom can cause large chest wall displacements, it probably cannot independently change lung volume. This implies that the system is constrained so that there are only a limited number of independent modes of chest wall movement that are capable of producing significant changes in lung volume. It also suggests that the system is constructed so that lung volume can be relatively independent of certain postural distortions of the chest wall.

Respiratory muscle coordination and diaphragm length during expiratory threshold loading

1991 ◽  
Vol 70 (4) ◽  
pp. 1554-1562 ◽  
Author(s):  
J. D. Road ◽  
A. M. Leevers ◽  
E. Goldman ◽  
A. Grassino
Keyword(s):  
Lung Volume ◽  
Respiratory Muscle ◽  
Abdominal Muscles ◽  
Muscle Coordination ◽  
Rib Cage ◽  
Relative Contribution ◽  
Volume Functional ◽  
Residual Capacity ◽  
Anesthetized Dogs ◽  
Expiratory Muscles

Active expiration is produced by the abdominal muscles and the rib cage expiratory muscles. We hypothesized that the relative contribution of these two groups to expiration would affect diaphragmatic length and, hence, influence the subsequent inspiration. To address this question we measured the respiratory muscle response to expiratory threshold loading in spontaneously breathing anesthetized dogs. Prevagotomy, the increase in lung volume (functional residual capacity) and decrease in initial resting length of the diaphragm were attenuated by greater than 50% of values predicted by the passive relationships. Diaphragmatic activation (electromyogram) increased and tidal volume (VT) was preserved. Postvagotomy, effective expiratory muscle recruitment was abolished. The triangularis sterni muscle remained active, and the increase in lung volume was attenuated by less than 15% of that predicted by the passive relationship. Diaphragmatic length was shorter than predicted. VT was not restored, even though costal diaphragmatic and parasternal intercostal electromyogram increased. During expiratory threshold loading with abdominal muscles resected and vagus intact, recruitment of the rib cage expiratory muscles produced a reduction in lung volume comparable with prevagotomy; however, diaphragmatic length decreased markedly. Both the rib cage and abdominal expiratory muscles may defend lung volume; however, their combined action is important to restore diaphragmatic initial length and, accordingly, to preserve VT.

Expiratory muscle contribution to tidal volume in head-up dogs

1989 ◽  
Vol 67 (4) ◽  
pp. 1438-1442 ◽  
Author(s):  
G. A. Farkas ◽  
M. Estenne ◽  
A. De Troyer
Keyword(s):  
Tidal Volume ◽  
Lung Volume ◽  
Muscle Relaxation ◽  
Rib Cage ◽  
Expiratory Muscle ◽  
Residual Capacity ◽  
Anesthetized Dogs ◽  
Expiratory Muscles ◽  
S Period ◽  
Average Contribution

A change from the supine to the head-up posture in anesthetized dogs elicits increased phasic expiratory activation of the rib cage and abdominal expiratory muscles. However, when this postural change is produced over a 4- to 5-s period, there is an initial apnea during which all the muscles are silent. In the present studies, we have taken advantage of this initial silence to determine functional residual capacity (FRC) and measure the subsequent change in end-expiratory lung volume. Eight animals were studied, and in all of them end-expiratory lung volume in the head-up posture decreased relative to FRC [329 +/- 70 (SE) ml]. Because this decrease also represents the increase in lung volume as a result of expiratory muscle relaxation at the end of the expiratory pause, it can be used to determine the expiratory muscle contribution to tidal volume (VT). The average contribution was 62 +/- 6% VT. After denervation of the rib cage expiratory muscles, the reduction in end-expiratory lung volume still amounted to 273 +/- 84 ml (49 +/- 10% VT). Thus, in head-up dogs, about two-thirds of VT result from the action of the expiratory muscles, and most of it (83%) is due to the action of the abdominal rather than the rib cage expiratory muscles.

Regional coupling between chest wall and lung expansion during HFV: a positron imaging study

1993 ◽  
Vol 74 (5) ◽  
pp. 2242-2252 ◽  
Author(s):  
J. G. Venegas ◽  
K. Tsuzaki ◽  
B. J. Fox ◽  
B. A. Simon ◽  
C. A. Hales
Keyword(s):  
Chest Wall ◽  
Lung Volume ◽  
Gas Transport ◽  
Regional Scale ◽  
Regional Distribution ◽  
Imaging Study ◽  
High Frequency Ventilation ◽  
Rib Cage ◽  
Lung Expansion ◽  
Frequency Ventilation

Apparently conflicting differences between the regional chest wall motion and gas transport have been observed during high-frequency ventilation (HFV). To elucidate the mechanism responsible for such differences, a positron imaging technique capable of assessing dynamic chest wall volumetric expansion, regional lung volume, and regional gas transport was developed. Anesthetized supine dogs were studied at ventilatory frequencies (f) ranging from 1 to 15 Hz and eucapnic tidal volumes. The regional distribution of mean lung volume was found to be independent of f, but the apex-to-base ratio of regional chest wall expansion favored the lung bases at low f and became more homogeneous at higher f. Regional gas transport per unit of lung volume, assessed from washout maneuvers, was homogeneous at 1 Hz, favored the bases progressively as f increased to 9 Hz, and returned to homogeneity at 15 Hz. Interregional asynchrony (pendelluft) and right-to-left differences were small at this large regional scale. Analysis of the data at a higher spatial resolution showed that the motion of the diaphragm relative to the excursions of the rib cage decreased as f increased. These differences from apex to base in regional chest wall expansion and gas transport were consistent with a simple model including lung, rib cage, and diaphragm regional impedances and a viscous coupling between lungs and chest wall caused by the relative sliding between pleural surfaces. To further test this model, we studied five additional animals under open chest conditions. These studies resulted in a homogeneous and f-independent regional gas transport. We conclude that the apex-to-base distribution of gas transport observed during HFV is not caused by intrinsic lung heterogeneity but rather is a result of chest wall expansion dynamics and its coupling to the lung.

Modulation of chest wall intermuscular coherence: effects of lung volume excursion and transcranial direct current stimulation

2013 ◽  
Vol 110 (3) ◽  
pp. 680-687 ◽  
Author(s):  
Corey R. Tomczak ◽  
Krista R. Greidanus ◽  
Carol A. Boliek
Keyword(s):  
Chest Wall ◽  
Lung Volume ◽  
Vital Capacity ◽  
Healthy Adults ◽  
Cortical Control ◽  
Tidal Breathing ◽  
Wall Area ◽  
Speech Breathing ◽  
Intermuscular Coherence ◽  
Chest Wall Kinematics

Chest wall muscle recruitment varies as a function of the breathing task performed. However, the cortical control of the chest wall muscles during different breathing tasks is not known. We studied chest wall intermuscular coherence during various task-related lung volume excursions in 10 healthy adults (34 ± 15 yr; 2 men, 8 women) and determined if transcranial direct current stimulation (tDCS) could modulate chest wall intermuscular coherence during these tasks. Simultaneous assessment of regional intercostal and oblique electromyographic activity was measured while participants performed standardized tidal breathing, speech, maximum phonation, and vital capacity tasks. Lung volume and chest wall kinematics were determined using variable inductance plethysmography. We found that chest wall area of intermuscular coherence was greater during tidal and speech breathing compared with phonation and vital capacity (all P < 0.05) and between tidal breathing compared with speech breathing ( P < 0.05). Anodal tDCS increased chest wall area of intermuscular coherence from 0.04 ± 0.09 prestimulation to 0.18 ± 0.19 poststimulation for vital capacity ( P < 0.05). Sham tDCS and cathodal tDCS had no effect on coherence during lung volume excursions. Chest wall kinematics were not affected by tDCS. Our findings indicate that lung volume excursions about the midrange of vital capacity elicit a greater area of chest wall intermuscular coherence compared with lung volume excursions spanning the entire range of vital capacity in healthy adults. Our findings also demonstrate that brief tDCS may modulate the cortical control of the chest wall muscles in a stimulation- and lung volume excursion task-dependent manner but does not affect chest wall kinematics in healthy adults.

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.

A model of the respiratory pump

1987 ◽  
Vol 63 (3) ◽  
pp. 951-961 ◽  
Author(s):  
D. R. Hillman ◽  
K. E. Finucane
Keyword(s):  
Chest Wall ◽  
Volume Change ◽  
Active Component ◽  
Wall Motion ◽  
Respiratory Muscles ◽  
Passive Components ◽  
Rib Cage ◽  
Lever System ◽  
Chest Wall Motion ◽  
Applied Forces

The interaction of forces that produce chest wall motion and lung volume change is complex and incompletely understood. To aid understanding we have developed a simple model that allows prediction of the effect on chest wall motion of changes in applied forces. The model is a lever system on which the forces generated actively by the respiratory muscles and passively by impedances of rib cage, lungs, abdomen, and diaphragm act at fixed sites. A change in forces results in translational and/or rotational motion of the lever; motion represents volume change. The distribution and magnitude of passive relative to active forces determine the locus and degree of rotation and therefore the effect of an applied force on motion of the chest wall, allowing the interaction of diaphragm, rib cage, and abdomen to be modeled. Analysis of moments allow equations to be derived that express the effect on chest wall motion of the active component in terms of the passive components. These equations may be used to test the model by comparing predicted with empirical behavior. The model is simple, appears valid for a variety of respiratory maneuvers, is useful in interpreting relative motion of rib cage and abdomen and may be useful in quantifying the effective forces acting on the rib cage.

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