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

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.

Mechanics of compartmental models of the chest wall

1988 ◽  
Vol 65 (5) ◽  
pp. 2261-2264 ◽  
Author(s):  
T. A. Wilson
Keyword(s):  
Mechanical Properties ◽  
Chest Wall ◽  
Muscle Tension ◽  
Formal Theory ◽  
Compliance Matrix ◽  
Rib Cage ◽  
Linear Elastic ◽  
Gastric Pressure ◽  
Definition Of ◽  
Stomach Volume

Standard methods for describing the mechanical properties of a linear elastic system are applied to the two- and three-compartment models of the chest wall. The compliance matrix and the experiments required to determine the entries in this matrix and thereby to describe the mechanical properties of the relaxed chest wall are described. The effective forces exerted by external loads and muscle tension are defined. The formal theory is used to identify relations among variables. From the definition of effective force, it follows that the ratio of the forces exerted by the diaphragm on the rib cage and abdomen is the same as the ratio of the dependence of diaphragm length on rib cage and abdominal volumes. As an example of relations among variables that follow from the symmetry of the compliance matrix, it is shown that the change of gastric pressure caused by raising pleural pressure is related to the change in lung volume caused by changing stomach volume.

Rib cage distortion during voluntary and involuntary breathing acts

1985 ◽  
Vol 58 (5) ◽  
pp. 1703-1712 ◽  
Author(s):  
F. D. McCool ◽  
S. H. Loring ◽  
J. Mead
Keyword(s):  
Chest Wall ◽  
Relative Motion ◽  
Spontaneous Breathing ◽  
Normal Subjects ◽  
Esophageal Pressure ◽  
Transmural Pressure ◽  
Muscle Coordination ◽  
Rib Cage ◽  
Gastric Pressure ◽  
Natural Breathing

We examined chest wall and rib cage configuration in seven normal subjects during a variety of breathing maneuvers. Magnetometers were used to measure lower rib cage anteroposterior, lower rib cage transverse, upper rib cage anteroposterior, and abdomen anteroposterior diameters. Changes of these diameters were recorded during voluntary maneuvers, rebreathing, reading, and “natural” breathing. Relative motion of the rib cage and abdomen was displayed with the rib cage represented by the product of its lower anteroposterior and transverse diameters. During spontaneous breathing the rib cage and chest wall are near their relaxation configuration. During chemically driven ventilation the chest wall and rib cage progressively depart from this configuration. Much greater distortions of the chest wall and rib cage occurred during some voluntary maneuvers. Additionally, esophageal pressure and gastric pressure were measured during voluntary distortion of the rib cage. Substantial changes in lower rib cage shape occurred during voluntary maneuvers when compared with spontaneous breaths at the same transmural pressure. We conclude that the unitary behavior of the rib cage in normal subjects requires muscle coordination.

Volumes and Breathing Patterns during Speech in Healthy and Asthmatic Subjects

1988 ◽  
Vol 31 (2) ◽  
pp. 219-227 ◽  
Author(s):  
Robert G. Loudon ◽  
Linda Lee ◽  
Barbara J. Holcomb
Keyword(s):  
Gas Exchange ◽  
Lung Volume ◽  
Healthy Subjects ◽  
Vital Capacity ◽  
Breathing Patterns ◽  
Volume Changes ◽  
Lung Volumes ◽  
Flow Rates ◽  
Communication Needs ◽  
Limited Period

The lung volumes and ventilatory patterns used by 10 healthy subjects and 14 patients with varying degrees of asthma were studied. The protocol included conversation, monologue, and counting at two loudness levels. Lung-volume changes were measured with a Respitrace and recorded with associated speech sounds. Volumes, durations, and flows were analyzed for sequences of respiratory cycles. Asthmatics used a greater percentage of their reduced vital capacity. Their inspiratory flow rates were slower, and expiratory rates faster. Asthmatics spent a greater proportion of the total respiratory cycle time on inspiration, and expired a greater volume of gas without sound. Patterns of ventilation suggested that asthmatics favored respiratory over communication needs to a greater extent than healthy subjects. Activities that forced priority to communication needs (counting to a metronome) were inadequate for gas exchange in asthmatics and could be sustained for only a limited period of time.

Chest wall distortion during resistive inspiratory loading

1985 ◽  
Vol 58 (5) ◽  
pp. 1646-1653 ◽  
Author(s):  
E. R. Ringel ◽  
S. H. Loring ◽  
J. Mead ◽  
R. H. Ingram
Keyword(s):  
Chest Wall ◽  
Wall Motion ◽  
Respiratory Muscles ◽  
Underlying Mechanism ◽  
Abdominal Muscles ◽  
Transdiaphragmatic Pressure ◽  
Rib Cage ◽  
Circular Configuration ◽  
Chest Wall Motion ◽  
Resistive Loads

We studied six (1 naive and 5 experienced) subjects breathing with added inspiratory resistive loads while we recorded chest wall motion (anteroposterior rib cage, anteroposterior abdomen, and lateral rib cage) and tidal volumes. In the five experienced subjects, transdiaphragmatic and pleural pressures, and electromyographs of the sternocleidomastoid and abdominal muscles were also measured. Subjects inspired against the resistor spontaneously and then with specific instructions to reach a target pleural or transdiaphragmatic pressure or to maximize selected electromyographic activities. Depending on the instructions, a wide variety of patterns of inspiratory motion resulted. Although the forces leading to a more elliptical or circular configuration of the chest wall can be identified, it is difficult to analyze or predict the configurational results based on insertional and pressure-related contributions of a few individual respiratory muscles. Although overall chest wall respiratory motion cannot be readily inferred from the electromyographic and pressure data we recorded, it is clear that responses to loading can vary substantially within and between individuals. Undoubtedly, the underlying mechanism for the distortional changes with loading are complex and perhaps many are behavioral rather than automatic and/or compensatory.

scholarly journals Adaptation of lung, chest wall, and respiratory muscles during pregnancy: preparing for birth

2019 ◽  
Vol 127 (6) ◽  
pp. 1640-1650 ◽  
Author(s):  
Antonella LoMauro ◽  
Andrea Aliverti ◽  
Peter Frykholm ◽  
Daniela Alberico ◽  
Nicola Persico ◽  
...  
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Respiratory Muscles ◽  
Active Role ◽  
Normal Pregnancy ◽  
Abdominal Muscles ◽  
Noninvasive Methods ◽  
Rib Cage ◽  
Optoelectronic Plethysmography ◽  
Noninvasive Analysis

A plethora of physiological and biochemical changes occur during normal pregnancy. The changes in the respiratory system have not been as well elucidated, in part because radioimaging is usually avoided during pregnancy. We aimed to use several noninvasive methods to characterize the adaptation of the respiratory system during the full course of pregnancy in preparation for childbirth. Eighteen otherwise healthy women (32.3 ± 2.8 yr) were recruited during early pregnancy. Spirometry, optoelectronic plethysmography, and ultrasonography were used to study changes in chest wall geometry, breathing pattern, lung and thoraco-abdominal volume variations, and diaphragmatic thickness in the first, second, and third trimesters. A group of nonpregnant women were used as control subjects. During the course of pregnancy, we observed a reorganization of rib cage geometry, in shape but not in volume. Despite the growing uterus, there was no lung restriction (forced vital capacity: 101 ± 15% predicted), but we did observe reduced rib cage expansion. Breathing frequency and diaphragmatic contribution to tidal volume and inspiratory capacity increased. Diaphragm thickness was maintained (1st trimester: 2.7 ± 0.8 mm, 3rd trimester: 2.5 ± 0.9 mm; P = 0.187), possibly indicating a conditioning effect to compensate for the effects of the growing uterus. We conclude that pregnancy preserved lung volumes, abdominal muscles, and the diaphragm at the expense of rib cage muscles. NEW & NOTEWORTHY Noninvasive analysis of the kinematics of the chest wall and the diaphragm during resting conditions in pregnant women revealed significant changes in the pattern of thoracoabdominal breathing across the trimesters. That is, concomitant with the progressive changes of chest wall shape, the diaphragm increased its contribution to both spontaneous and maximal breathing, maintaining its thickness despite its lengthening due to the growing uterus. These results suggest that during pregnancy the diaphragm is conditioned to optimize its active role provided during parturition.

Passive mechanics of upright human chest wall during immersion from hips to neck

1986 ◽  
Vol 60 (5) ◽  
pp. 1561-1570 ◽  
Author(s):  
M. B. Reid ◽  
S. H. Loring ◽  
R. B. Banzett ◽  
J. Mead
Keyword(s):  
Chest Wall ◽  
Esophageal Pressure ◽  
Vertical Surface ◽  
Repeated Measurements ◽  
Transdiaphragmatic Pressure ◽  
Rib Cage ◽  
Inspiratory Muscles ◽  
Gastric Pressure ◽  
Length Changes ◽  
Accessory Muscles

We have determined the mechanical effects of immersion to the neck on the passive chest wall of seated upright humans. Repeated measurements were made at relaxed end expiration on four subjects. Changes in relaxed chest wall configuration were measured using magnetometers. Gastric and esophageal pressures were measured with balloon-tipped catheters in three subjects; from these, transdiaphragmatic pressure was calculated. Transabdominal pressure was estimated using a fluid-filled, open-tipped catheter referenced to the abdomen's exterior vertical surface. We found that immersion progressively reduced mean transabdominal pressure to near zero and that the relaxed abdominal wall was moved inward 3–4 cm. The viscera were displaced upward into the thorax, gastric pressure increased by 20 cmH2O, and transdiaphragmatic pressure decreased by 10–15 cmH2O. This lengthened the diaphragm, elevating the diaphragmatic dome 3–4 cm. Esophageal pressure became progressively more positive throughout immersion, increasing by 8 cmH2O. The relaxed rib cage was elevated and expanded by raising water from hips to lower sternum; this passively shortened the inspiratory intercostals and the accessory muscles of inspiration. Deeper immersion distorted the thorax markedly: the upper rib cage was forced inward while lower rib cage shape was not systematically altered and the rib cage remained elevated. Such distortion may have passively lengthened or shortened the inspiratory muscles of the rib cage, depending on their location. We conclude that the nonuniform forcing produced by immersion provides unique insights into the mechanical characteristics of the abdomen and rib cage, that immersion-induced length changes differ among the inspiratory muscles according to their locations and the depth of immersion, and that such length changes may have implications for patients with inspiratory muscle deficits.

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.

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