Rib cage deformation during static inspiratory efforts

1979 ◽  
Vol 46 (6) ◽  
pp. 1071-1075 ◽  
Author(s):  
N. A. Saunders ◽  
S. M. Kreitzer ◽  
R. H. Ingram
Keyword(s):  
Lung Volume ◽  
Respiratory Muscles ◽  
Normal Subjects ◽  
Esophageal Pressure ◽  
Lung Volumes ◽  
Transdiaphragmatic Pressure ◽  
Rib Cage ◽  
Opposite Change ◽  
Accessory Muscles ◽  
Lateral Diameter

Patterns of rib cage (RC) deformation were studied in six normal subjects during moderate static inspiratory efforts such that esophageal pressure (Pes) as an index of transthoracic pressure fell to between -30 and -60 cmH2O during each maneuver. At lung volumes below 50% inspiratory capacity (IC), static inspiratory efforts deformed RC to a more elliptical shape; RC lateral diameter became smaller and RC lateral diameter became larger. However, at high lung volumes (greater than 50% IC) the opposite change in RC dimensions occurred despite similar changes in Pes, i.e., the RC became more circular. These differences in RC deformation did not appear to be a possive consequence of increased lung volume because the RC could be voluntarily deformed to a more circular shape at low lung volume when a) subjects performed static inspiratory efforts mainly with their intercostal and accessory muscles rather than their diaphragm as judged by a smaller change in transdiaphragmatic pressure for the same Pes; or b) subjects statically contracted their diaphragm with it held in a relatively flattened configuration as assessed by a large abdominal AP dimension. We suggest that deformation of the RC during static inspiratory efforts is not as predictable as has previously been suggested but depends on the pattern of contraction and configuration of the respiratory muscles.

scholarly journals Respiratory dynamics during laughter

2001 ◽  
Vol 90 (4) ◽  
pp. 1441-1446 ◽  
Author(s):  
Mario Filippelli ◽  
Riccardo Pellegrino ◽  
Iacopo Iandelli ◽  
Gianni Misuri ◽  
Joseph R. Rodarte ◽  
...  
Keyword(s):  
Chest Wall ◽  
Lung Volume ◽  
Dynamic Compression ◽  
Three Dimensional ◽  
Normal Subjects ◽  
Average Frequency ◽  
Abdominal Pressure ◽  
Sudden Increase ◽  
Lung Volumes ◽  
Transdiaphragmatic Pressure

Lung and chest wall mechanics were studied during fits of laughter in 11 normal subjects. Laughing was naturally induced by showing clips of the funniest scenes from a movie by Roberto Benigni. Chest wall volume was measured by using a three-dimensional optoelectronic plethysmography and was partitioned into upper thorax, lower thorax, and abdominal compartments. Esophageal (Pes) and gastric (Pga) pressures were measured in seven subjects. All fits of laughter were characterized by a sudden occurrence of repetitive expiratory efforts at an average frequency of 4.6 ± 1.1 Hz, which led to a final drop in functional residual capacity (FRC) by 1.55 ± 0.40 liter ( P < 0.001). All compartments similarly contributed to the decrease of lung volumes. The average duration of the fits of laughter was 3.7 ± 2.2 s. Most of the events were associated with sudden increase in Pes well beyond the critical pressure necessary to generate maximum expiratory flow at a given lung volume. Pga increased more than Pes at the end of the expiratory efforts by an average of 27 ± 7 cmH2O. Transdiaphragmatic pressure (Pdi) at FRC and at 10% and 20% control forced vital capacity below FRC was significantly higher than Pdi at the same absolute lung volumes during a relaxed maneuver at rest ( P < 0.001). We conclude that fits of laughter consistently lead to sudden and substantial decrease in lung volume in all respiratory compartments and remarkable dynamic compression of the airways. Further mechanical stress would have applied to all the organs located in the thoracic cavity if the diaphragm had not actively prevented part of the increase in abdominal pressure from being transmitted to the chest wall cavity.

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.

Mechanics of the human diaphragm during voluntary contraction: statics

1978 ◽  
Vol 44 (6) ◽  
pp. 829-839 ◽  
Author(s):  
A. Grassino ◽  
M. D. Goldman ◽  
J. Mead ◽  
T. A. Sears
Keyword(s):  
Volume Change ◽  
Lung Volume ◽  
Voluntary Contraction ◽  
Electromyographic Activity ◽  
Lung Volumes ◽  
Transdiaphragmatic Pressure ◽  
Rib Cage ◽  
The Relationship ◽  
Closed Airway

We related diaphragm electromyographic activity (Edi) to transdiaphragmatic pressure (Pdi) in man during graded inspiratory efforts. Estimates of rib cage and abdominal volume displacements were based on their anteroposterior (AP) diameter changes. The diaphragm was assumed to contract isometrically when subjects performed inspiratory efforts against a closed airway at specified abdominothoracic configurations, increasing Edi and Pdi while holding lung volume and rib case and abdominal AP diameters constant. The relationship between Pdi and Edi depends primarily on abdominothoracic configuration rather than lung volume. For equal increments in lung volume, the Pdi developed at constant Edi is four to eight times more sensitive to changes in abdominal than in rib cage AP diameter. We demonstrate an isofunctional state of the diaphragm at different lung volumes, when increases in lung volume and rib cage AP diameter are compensated for by slight decreases in abdominal AP diameter, resulting in a constant relationship between Edi and Pdi. We conclude that diaphragm shortening is reflected more directly in abdominal displacement than in lung volume change.

Acute effects of thixotropy conditioning of inspiratory muscles on end-expiratory chest wall and lung volumes in normal humans

2006 ◽  
Vol 101 (1) ◽  
pp. 298-306 ◽  
Author(s):  
Masahiko Izumizaki ◽  
Michiko Iwase ◽  
Yasuyoshi Ohshima ◽  
Ikuo Homma
Keyword(s):  
Chest Wall ◽  
Lung Volume ◽  
Human Subjects ◽  
Esophageal Pressure ◽  
Acute Effects ◽  
Lung Volumes ◽  
Rib Cage ◽  
Inspiratory Muscles ◽  
Normal Human ◽  
Inflated Lung

Thixotropy conditioning of inspiratory muscles consisting of maximal inspiratory effort performed at an inflated lung volume is followed by an increase in end-expiratory position of the rib cage in normal human subjects. When performed at a deflated lung volume, conditioning is followed by a reduction in end-expiratory position. The present study was performed to determine whether changes in end-expiratory chest wall and lung volumes occur after thixotropy conditioning. We first examined the acute effects of conditioning on chest wall volume during subsequent five-breath cycles using respiratory inductive plethysmography ( n = 8). End-expiratory chest wall volume increased after conditioning at an inflated lung volume ( P < 0.05), which was attained mainly by rib cage movements. Conditioning at a deflated lung volume was followed by reductions in end-expiratory chest wall volume, which was explained by rib cage and abdominal volume changes ( P < 0.05). End-expiratory esophageal pressure decreased and increased after conditioning at inflated and deflated lung volumes, respectively ( n = 3). These changes in end-expiratory volumes and esophageal pressure were greatest for the first breath after conditioning. We also found that an increase in spirometrically determined inspiratory capacity ( n = 13) was maintained for 3 min after conditioning at a deflated lung volume, and a decrease for 1 min after conditioning at an inflated lung volume. Helium-dilution end-expiratory lung volume increased and decreased after conditioning at inflated and deflated lung volumes, respectively (both P < 0.05; n = 11). These results suggest that thixotropy conditioning changes end-expiratory volume of the chest wall and lung in normal human subjects.

scholarly journals Influence of acute lung volume change on contractile properties of human diaphragm

1998 ◽  
Vol 85 (4) ◽  
pp. 1322-1328 ◽  
Author(s):  
Michael I. Polkey ◽  
Carl-Hugo Hamnegård ◽  
Philip D. Hughes ◽  
Gerrard F. Rafferty ◽  
Malcolm Green ◽  
...  
Keyword(s):  
Functional Residual Capacity ◽  
Lung Volume ◽  
Phrenic Nerve ◽  
Stimulus Frequency ◽  
Normal Subjects ◽  
Lung Volumes ◽  
Transdiaphragmatic Pressure ◽  
Residual Capacity ◽  
Interstimulus Intervals

The effect of stimulus frequency on the in vivo pressure generating capacity of the human diaphragm is unknown at lung volumes other than functional residual capacity. The transdiaphragmatic pressure (Pdi) produced by a pair of phrenic nerve stimuli may be viewed as the sum of the Pdi elicited by the first (T1 Pdi) and second (T2 Pdi) stimuli. We used bilateral anterior supramaximal magnetic phrenic nerve stimulation and a digital subtraction technique to obtain the T2 Pdi at interstimulus intervals of 999, 100, 50, 33, and 10 ms in eight normal subjects at lung volumes between residual volume and total lung capacity. The reduction in T2 Pdi that we observed as lung volume increased was greatest at long interstimulus intervals, whereas the T2 Pdi obtained with short interstimulus intervals remained relatively stable over the 50% of vital capacity around functional residual capacity. For all interstimulus intervals, the total pressure produced by the pair decreased as a function of increasing lung volume. These data demonstrate that, in the human diaphragm, hyperinflation has a disproportionately severe effect on the summation of pressure responses elicited by low-frequency stimulations; this effect is distinct from and additional to the known length-tension relationship.

Influence of lung volume and electrode position on electromyography of the diaphragm

1976 ◽  
Vol 40 (6) ◽  
pp. 971-975 ◽  
Author(s):  
A. E. Grassino ◽  
W. A. Whitelaw ◽  
J. Milic-Emili
Keyword(s):  
Lung Tissue ◽  
Lung Volume ◽  
Phrenic Nerve ◽  
Negligible Effect ◽  
Electrode Position ◽  
Lung Volumes ◽  
Small Surface ◽  
Transdiaphragmatic Pressure ◽  
Rib Cage ◽  
Electrical Stimuli

In cats anesthetized with Nembutal, electromyograms of the diaphragm (Edi) were recorded from an anchored esophageal electrode, a pair of silver hooks inserted in the paratendinous region, and a pair of silver hooks and a pair of clips of small surface inserted in the costal region of the diaphragm facing the rib cage at FRC but covered with lung tissue at FRC + 80 ml. When single supramaximal electrical stimuli were applied to an isolated phrenic nerve, changes in lung volume from RV to near TLC had a negligible effect on muscle potentials from esophageal or paratendinous hooks, but increased the amplitude of potentials recorded from peripheral hooks and clips. In addition, it was found that small displacements of the esophageal electrode caused substantial changes in the amplitude of the recorded muscle potentials. The integration of the Edi spontaneously generated during occluded inspirations, recorded from paratendinous hooks and the esophageal electrode was linearly related to transdiaphragmatic pressure up to 50 cmH2O at all lung volumes. Above that level, esophageal electrode recordings showed a curvilinear Edi/Pdi relationship, while hook recordings showed a rectilinear relationship.

Respiratory muscle action inferred from rib cage and abdominal V-P partitioning

1976 ◽  
Vol 41 (5) ◽  
pp. 739-751 ◽  
Author(s):  
G. Grimby ◽  
M. Goldman ◽  
J. Mead
Keyword(s):  
Respiratory Muscle ◽  
Human Subjects ◽  
Respiratory Muscles ◽  
Transdiaphragmatic Pressure ◽  
Rib Cage ◽  
Pressure Drops ◽  
Diaphragmatic Function ◽  
Relationship Of ◽  
The Relationship ◽  
Accessory Muscles

We measured separate volume-pressure (V-P) relationships or rib cage anddiaphragm-abdomen in seven human subjects during voluntary relaxation of the respiratory muscles, breathing at rest, during exercise, and rebreathingexpired air. Estimates of separate volume displacements of the two parallelchest wall pathways were based on analysis of rib cage and abdominal anteroposterior diameter changes. The pressure developed across each pathway (transthoracic pressure) was partitioned into two serial pressure drops: transdiaphragmatic pressure and transabdominal pressure. We develop the concept that the relationship of volume displacements of structures to pressures developed by the structures during breathing, as compared to the relaxed state,reflects action of respiratory muscles in the structure. We interpret therelationship of rib cage volume displacements to transabdominal pressure(during breathing vs. relaxation) as indicating action of intercostal and accessory muscles only, the separate action of diaphragm on rib cage being measured by transdiaphragmatic pressure. At rest, the diaphragm is the only importantly active respiratory muscle. During increased ventilation activityofother respiratory muscles appears coordinated to assist the optimize diaphragmatic function.

Breathing at low lung volumes and chest strapping: a comparison of lung mechanics

1981 ◽  
Vol 50 (3) ◽  
pp. 650-657 ◽  
Author(s):  
N. J. Douglas ◽  
G. B. Drummond ◽  
M. F. Sudlow
Keyword(s):  
Lung Volume ◽  
Maximum Flow ◽  
Normal Subjects ◽  
Lung Mechanics ◽  
Lung Volumes ◽  
Flow Rates ◽  
Recoil Pressure ◽  
Forced Expiratory Flow ◽  
Expiratory Flow ◽  
Expiratory Flow Rates

In six normal subjects forced expiratory flow rates increased progressively with increasing degrees of chest strapping. In nine normal subjects forced expiratory flow rates increased with the time spent breathing with expiratory reserve volume 0.5 liters above residual volume, the increase being significant by 30 s (P less than 0.01), and flow rates were still increasing at 2 min, the longest time the subjects could breathe at this lung volume. The increase in flow after low lung volume breathing (LLVB) was similar to that produced by strapping. The effect of LLVB was diminished by the inhalation of the atropinelike drug ipratropium. Quasistatic recoil pressures were higher following strapping and LLVB than on partial or maximal expiration, but the rise in recoil pressure was insufficient to account for all the observed increased in maximum flow. We suggest that the effects of chest strapping are due to LLVB and that both cause bronchodilatation.

Pleural pressure increases during inspiration in the zone of apposition of diaphragm to rib cage

1988 ◽  
Vol 65 (5) ◽  
pp. 2207-2212 ◽  
Author(s):  
W. F. Urmey ◽  
A. De Troyer ◽  
K. B. Kelly ◽  
S. H. Loring
Keyword(s):  
Esophageal Pressure ◽  
Pleural Pressure ◽  
Abdominal Pressure ◽  
Transdiaphragmatic Pressure ◽  
Rib Cage ◽  
Direct Measurements ◽  
Anesthetized Dogs ◽  
Theoretical Mechanism ◽  
Phrenic Stimulation ◽  
Anatomic Region

The zone of apposition of diaphragm to rib cage provides a theoretical mechanism that may, in part, contribute to rib cage expansion during inspiration. Increases in intra-abdominal pressure (Pab) that are generated by diaphragmatic contraction are indirectly applied to the inner rib cage wall in the zone of apposition. We explored this mechanism, with the expectation that pleural pressure in this zone (Pap) would increase during inspiration and that local transdiaphragmatic pressure in this zone (Pdiap) must be different from conventionally determined transdiaphragmatic pressure (Pdi) during inspiration. Direct measurements of Pap, as well as measurements of pleural pressure (Ppl) cephalad to the zone of apposition, were made during tidal inspiration, during phrenic stimulation, and during inspiratory efforts in anesthetized dogs. Pab and esophageal pressure (Pes) were measured simultaneously. By measuring Ppl's with cannulas placed through ribs, we found that Pap consistently increased during both maneuvers, whereas Ppl and Pes decreased. Whereas changes in Pdi of up to -19 cmH2O were measured, Pdiap never departed from zero by greater than -4.5 cmH2O. We conclude that there can be marked regional differences in Ppl and Pdi between the zone of apposition and regions cephalad to the zone. Our results support the concept of the zone of apposition as an anatomic region where Pab is transmitted to the interior surface of the lower rib cage.

Inspiratory muscles during exercise: a problem of supply and demand

1988 ◽  
Vol 64 (6) ◽  
pp. 2482-2489 ◽  
Author(s):  
P. Leblanc ◽  
E. Summers ◽  
M. D. Inman ◽  
N. L. Jones ◽  
E. J. Campbell ◽  
...  
Keyword(s):  
Lung Volume ◽  
Static Pressure ◽  
Total Lung Capacity ◽  
Supply And Demand ◽  
Normal Subjects ◽  
Esophageal Pressure ◽  
Maximum Exercise ◽  
Lung Capacity ◽  
Inspiratory Muscles ◽  
Residual Capacity

The capacity of inspiratory muscles to generate esophageal pressure at several lung volumes from functional residual capacity (FRC) to total lung capacity (TLC) and several flow rates from zero to maximal flow was measured in five normal subjects. Static capacity was 126 +/- 14.6 cmH2O at FRC, remained unchanged between 30 and 55% TLC, and decreased to 40 +/- 6.8 cmH2O at TLC. Dynamic capacity declined by a further 5.0 +/- 0.35% from the static pressure at any given lung volume for every liter per second increase in inspiratory flow. The subjects underwent progressive incremental exercise to maximum power and achieved 1,800 +/- 45 kpm/min and maximum O2 uptake of 3,518 +/- 222 ml/min. During exercise peak esophageal pressure increased from 9.4 +/- 1.81 to 38.2 +/- 5.70 cmH2O and end-inspiratory esophageal pressure increased from 7.8 +/- 0.52 to 22.5 +/- 2.03 cmH2O from rest to maximum exercise. Because the estimated capacity available to meet these demands is critically dependent on end-inspiratory lung volume, the changes in lung volume during exercise were measured in three of the subjects using He dilution. End-expiratory volume was 52.3 +/- 2.42% TLC at rest and 38.5 +/- 0.79% TLC at maximum exercise.

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