scholarly journals Mechanical advantage of the canine triangularis sterni

1998 ◽  
Vol 84 (2) ◽  
pp. 562-568 ◽  
Author(s):  
André De Troyer ◽  
Alexandre Legrand
Keyword(s):  
Geometric Analysis ◽  
Muscle Length ◽  
Respiratory Muscles ◽  
Linear Increase ◽  
Maximal Effect ◽  
Volume Increase ◽  
Rib Cage ◽  
Inspiratory Muscles ◽  
Airway Opening ◽  
Residual Capacity

De Troyer, André, and Alexandre Legrand.Mechanical advantage of the canine triangularis sterni. J. Appl. Physiol. 84(2): 562–568, 1998.—Recent studies on the canine parasternal intercostal, sternomastoid, and scalene muscles have shown that the maximal changes in airway opening pressure (ΔPao) obtained per unit muscle mass (ΔPao/ m) during isolated contraction are closely related to the fractional changes in muscle length per unit volume increase of the relaxed chest wall. In the present study, we have examined the validity of this relationship for the triangularis sterni, an important expiratory muscle of the rib cage in dogs. Passive inflation above functional residual capacity (FRC) induced a virtually linear increase in muscle length, such that, with a 1.0-liter inflation, the muscle lengthened by 17.9 ± 1.6 (SE) % of its FRC length. When the muscle in one interspace was maximally stimulated at FRC, Pao increased by 0.84 ± 0.11 cmH2O. However, in agreement with the length-tension characteristics of the muscle, when lung volume was increased by 1.0 liter before stimulation, the rise in Pao amounted to 1.75 ± 0.12 cmH2O. At the higher volume, ΔPao/ m therefore averaged + 0.53 ± 0.05 cmH2O/g, such that the coefficient of proportionality between the change in triangularis sterni length during passive inflation and ΔPao/ mwas the same as that previously obtained for the parasternal intercostal and neck inspiratory muscles. These observations, therefore, confirm that there is a unique relationship between the fractional changes in length of the respiratory muscles, both inspiratory and expiratory, during passive inflation and their ΔPao/ m. Consequently, the maximal effect of a particular muscle on the lung can be predicted on the basis of its change in length during passive inflation and its mass. A geometric analysis of the rib cage also established that the lengthening of the canine triangularis sterni during passive inflation is much greater than the shortening of the parasternal intercostals because, in dogs, the costal cartilages slope downward from the sternum.

scholarly journals Rib cage muscle interaction in airway pressure generation

1998 ◽  
Vol 85 (1) ◽  
pp. 198-203 ◽  
Author(s):  
Alexandre Legrand ◽  
Theodore A. Wilson ◽  
André De Troyer
Keyword(s):  
Muscle Length ◽  
Fractional Change ◽  
Volume Increase ◽  
Rib Cage ◽  
Maximum Activation ◽  
Airway Opening ◽  
Simultaneous Activation ◽  
Separate Activation ◽  
Pressure Changes ◽  
Potential Pressure

We have previously demonstrated in dogs that the change in airway opening pressure (ΔPao) produced by isolated maximum activation of the parasternal intercostal or triangularis sterni muscle in a single interspace, the sternomastoids, and the scalenes is proportional to the product of muscle mass and the fractional change in muscle length per unit volume increase of the relaxed chest wall. In the present study, we have assessed the interactions between these muscles by comparing the ΔPao obtained during simultaneous activation of a pair of muscles (measured ΔPao) to the sum of the ΔPao values obtained during their separate activation (predicted ΔPao). Measured and predicted ΔPao values were compared for the following pairs of muscles: the parasternal intercostals in two interspaces, the parasternal intercostals in one interspace and either the sternomastoids or the scalenes, two segments of the triangularis sterni, and the interosseous intercostals in two contiguous interspaces. For all these pairs, the measured ΔPao was within ∼10% of the predicted value. We therefore conclude that 1) the pressure changes generated by the rib cage muscles are essentially additive; and 2) measurements of the mass of a particular muscle and of its fractional change in length during passive inflation can be used to estimate the potential pressure-generating ability of the muscle during coordinated activity as well as during isolated activation.

Mechanical advantage of sternomastoid and scalene muscles in dogs

1997 ◽  
Vol 82 (5) ◽  
pp. 1517-1522 ◽  
Author(s):  
Alexandre Legrand ◽  
Vincent Ninane ◽  
André De Troyer
Keyword(s):  
Muscle Mass ◽  
Muscle Tension ◽  
Muscle Length ◽  
Respiratory Muscles ◽  
Maximal Effect ◽  
Relaxation Length ◽  
Cross Sectional ◽  
Mechanical Advantage ◽  
Airway Opening ◽  
Anesthetized Dogs

Legrand, Alexandre, Vincent Ninane, and André De Troyer. Mechanical advantage of sternomastoid and scalene muscles in dogs. J. Appl. Physiol. 82(5): 1517–1522, 1997.—Theoretical studies have led to the prediction that the maximal effect of a given respiratory muscle on airway opening pressure (Pao) is the product of muscle mass, the maximal active muscle tension per unit cross-sectional area, and the fractional change in muscle length per unit volume increase of the relaxed chest wall. It has previously been shown that the parasternal intercostals behave in agreement with this prediction (A. De Troyer, A. Legrand, and T. A. Wilson. J. Physiol. (Lond.) 495: 239–246, 1996; A. Legrand, T. A. Wilson, and A. De Troyer. J. Appl. Physiol. 80: 2097–2101, 1996). In the present study, we have tested the prediction further by measuring the response to passive inflation and the pressure-generating ability of the sternomastoid and scalene muscles in eight anesthetized dogs. With 1-liter passive inflation, the sternomastoids and scalenes shortened by 2.03 ± 0.17 and 5.98 ± 0.43%, respectively, of their relaxation length ( P < 0.001). During maximal stimulation, the two muscles caused similar falls in Pao. However, the sternomastoids had greater mass such that the change in Pao (ΔPao) per unit muscle mass was −0.19 ± 0.02 cmH2O/g for the scalenes and only −0.07 ± 0.01 cmH2O/g for the sternomastoids ( P < 0.001). After extension of the neck, there was a reduction in both the muscle shortening during passive inflation and the fall in Pao during stimulation. The ΔPao per unit muscle mass was thus closely related to the change in length; the slope of the relationship was 3.1. These observations further support the concept that the fractional changes in length of the respiratory muscles during passive inflation can be used to predict their pressure-generating ability.

scholarly journals Respiratory effects of the scalene and sternomastoid muscles in humans

2003 ◽  
Vol 94 (4) ◽  
pp. 1467-1472 ◽  
Author(s):  
Alexandre Legrand ◽  
Emmanuelle Schneider ◽  
Pierre-Alain Gevenois ◽  
André De Troyer
Keyword(s):  
Muscle Mass ◽  
Muscle Length ◽  
Maximal Contraction ◽  
Respiratory Effects ◽  
Computed Tomographic ◽  
Inspiratory Muscles ◽  
Airway Opening ◽  
Residual Capacity ◽  
Normal Humans ◽  
The Masses

Previous studies have shown that in normal humans the change in airway opening pressure (ΔPao) produced by all the parasternal and external intercostal muscles during a maximal contraction is approximately −18 cmH2O. This value is substantially less negative than ΔPao values recorded during maximal static inspiratory efforts in subjects with complete diaphragmatic paralysis. In the present study, therefore, the respiratory effects of the two prominent inspiratory muscles of the neck, the sternomastoids and the scalenes, were evaluated by application of the Maxwell reciprocity theorem. Seven healthy subjects were placed in a computed tomographic scanner to determine the fractional changes in muscle length during inflation from functional residual capacity to total lung capacity and the masses of the muscles. Inflation induced greater shortening of the scalenes than the sternomastoids in every subject. The inspiratory mechanical advantage of the scalenes thus averaged (mean ± SE) 3.4 ± 0.4%/l, whereas that of the sternomastoids was 2.0 ± 0.3%/l ( P < 0.001). However, sternomastoid muscle mass was much larger than scalene muscle mass. As a result, ΔPao generated by a maximal contraction of either muscle would be 3–4 cmH2O, which is about the same as ΔPao generated by the parasternal intercostals in all interspaces.

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.

Effects of body position change on thoracoabdominal motion

1978 ◽  
Vol 45 (4) ◽  
pp. 581-589 ◽  
Author(s):  
V. P. Vellody ◽  
M. Nassery ◽  
W. S. Druz ◽  
J. T. Sharp
Keyword(s):  
Supine Position ◽  
Muscle Force ◽  
Body Position ◽  
Tidal Breathing ◽  
Position Change ◽  
Rib Cage ◽  
Inspiratory Muscles ◽  
Residual Capacity ◽  
Lateral Decubitus ◽  
Local Compliance

With a linearized respiratory magnetometer, measurements of anteroposterior and lateral diameters of both the rib cage and the abdomen were made at functional residual capacity and continuously during tidal breathing. Twenty-five subjects with normal respiratory systems were studied in the sitting, supine, lateral decubitus, and prone body positions. When subjects changed from sitting to supine position anteroposterior diameters of both rib cage and abdomen decreased while their lateral diameters increased. Both anteroposterior and lateral tidal excursions of the rib cage decreased; those of the abdomen increased. When subjects turned from supine to lateral decubitus position both anteroposterior diameters increased and the lateral diameters decreased. This was associated with an increase in both lateral excursions and a decrease in the abdominal anteroposterior excursions. Diameters and tidal excursions in the prone position resembled those in the supine position. Diameter changes could be explained by gravitational effects. Differences in tidal excursions accompanying body position change were probably related to 1) differences in the distribution of respiratory muscle force, 2) differences in the activity or mechanical advantage of various inspiratory muscles, and 3) local compliance changes in parts of the rib cage and abdomen.

Importance of inspiratory muscle tone in maintenance of FRC in the newborn

1981 ◽  
Vol 51 (4) ◽  
pp. 830-834 ◽  
Author(s):  
J. Lopes ◽  
N. L. Muller ◽  
M. H. Bryan ◽  
A. C. Bryan
Keyword(s):  
Muscle Tone ◽  
Inspiratory Muscle ◽  
Rapid Eye Movement Sleep ◽  
Sleep State ◽  
Quiet Sleep ◽  
Rib Cage ◽  
Surface Electrodes ◽  
Inspiratory Muscles ◽  
Residual Capacity ◽  
Behavioral Criteria

The importance of inspiratory muscle tone in the maintenance of functional residual capacity (FRC) in newborns was studied in eight premature infants with birth weights of 1,166 +/- 217 g and gestational age 29 +/- 1.9 wk (mean +/- SD). Rib cage and abdominal anteroposterior diameters were monitored with magnetometers, and electromyograms of the diaphragm and intercostal muscles were recorded with surface electrodes. Sleep state was monitored using electrooculogram and behavioral criteria. We assessed the decrease in tonic activity of the inspiratory muscles and the fall in end-expiratory lung volume during apnea compared with the period just preceding apnea. A total of 98 apneas were analyzed. In all instances a decrease in diaphragmatic and intercostal tone was associated with a decrease in the anteroposterior diameter of both rib cage and abdomen, indicating a fall in FRC. These changes were more marked during quiet sleep than during rapid-eye-movement sleep (P less than 0.01). Our results suggest that inspiratory muscle tone is a major determinant of FRC in the newborn.

Transdiaphragmatic pressure and rib motion in area of apposition during paralysis

1988 ◽  
Vol 65 (3) ◽  
pp. 1296-1300 ◽  
Author(s):  
E. Agostoni ◽  
L. Zocchi ◽  
P. T. Macklem
Keyword(s):  
Abdominal Pressure ◽  
Transdiaphragmatic Pressure ◽  
Lung Inflation ◽  
Volume Increase ◽  
Rib Cage ◽  
Pleural Surface ◽  
Supine Posture ◽  
Residual Capacity ◽  
Lateral Posture ◽  
Volume Decrease

Changes in pleural surface pressure in area of apposition of diaphragm to rib cage (delta Ppl,ap), changes in abdominal pressure (delta Pab), and redial displacement of the 11th rib have been recorded in anesthetized, paralyzed dogs during lung inflation or deflation. Above functional residual capacity (FRC) changes in transdiaphragmatic pressure in area of apposition (delta Pdi,ap) were essentially nil in intact (INT) dogs either in lateral or supine posture, and in partially eviscerated (EVS) dogs in lateral posture, either in the 10th or 11th intercostal space. Below FRC delta Pdi,ap could be positive (INT lateral and EVS), nil (EVS), or negative (INT supine and EVS); it could be different in the 10th and 11th intercostal spaces. Hence, with stretched (like with contracted) diaphragm, delta Ppl,ap measured at one site often differs from delta Pab and is not representative of average pressure acting on area of apposition. With volume increase above FRC, the 11th rib moved slightly in and then out in EVS and linearly out in INT. With volume decrease below FRC it moved out progressively in EVS, and it moved in and eventually reversed in INT. In paralyzed dogs in lateral posture the factor having the greatest influence on displacement of the abdominal rib cage is Pab. Mechanical linkage with pulmonary rib cage becomes relevant at large volume, whereas insertional traction of diaphragm becomes relevant at low volume.

Ventilatory compensation for changes in functional residual capacity during sleep

1987 ◽  
Vol 62 (3) ◽  
pp. 1299-1306 ◽  
Author(s):  
R. L. Begle ◽  
J. B. Skatrud ◽  
J. A. Dempsey
Keyword(s):  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Minute Ventilation ◽  
Muscle Length ◽  
Normal Subjects ◽  
Conscious State ◽  
Inspiratory Muscle ◽  
Compensatory Response ◽  
Inspiratory Muscles ◽  
Residual Capacity

The role of conscious factors in the ventilatory compensation for shortened inspiratory muscle length and the potency of this compensatory response were studied in five normal subjects during non-rapid-eye-movement sleep. To shorten inspiratory muscles, functional residual capacity (FRC) was increased and maintained for 2–3 min at a constant level (range of increase 160–1,880 ml) by creating negative pressure within a tank respirator in which the subjects slept. Minute ventilation was maintained in all subjects over the entire range of increased FRC (mean change +/- SE = -3 +/- 1%) through preservation of tidal volume (-2 +/- 2%) despite slightly decreased breathing frequency (-6 +/- 2%). The decrease in frequency (-13 +/- 2%) was due to a prolongation in expiratory time. Inspiratory time shortened (-10 +/- 1%). Mean inspiratory flow increased 15 +/- 3% coincident with an increase in the slope of the moving time average of the integrated surface diaphragmatic electromyogram (67 +/- 21%). End-tidal CO2 did not rise. In two subjects, control tidal volume was increased 35–50% with CO2 breathing. This augmented tidal volume was still preserved when FRC was increased. We concluded that the compensatory response to inspiratory muscle shortening did not require factors associated with the conscious state. In addition, the potency of this response was demonstrated by preservation of tidal volume despite extreme shortening of the inspiratory muscles and increase in control tidal volumes caused by CO2 breathing. Finally, the timing changes we observed may be due to reflexes following shortening of inspiratory muscle length, increase in abdominal muscle length, or cardiovascular changes.

Inferences about Respiratory Muscle Use after Cardiac Surgery from Compartmental Volume and Pressure Measurements

1995 ◽  
Vol 82 (6) ◽  
pp. 1318-1327. ◽  
Author(s):  
F. Clergue ◽  
W. A. Whitelaw ◽  
J. C. Charles ◽  
I. Gandjbakhch ◽  
J. L. Pansard ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Abdominal Surgery ◽  
Tidal Volume ◽  
Respiratory Muscle ◽  
Muscle Length ◽  
Abdominal Pressure ◽  
Abdominal Muscles ◽  
Muscle Action ◽  
Rib Cage ◽  
Inspiratory Muscles

Background After upper abdominal surgery, patients have been observed to have alterations in respiratory movements of the rib cage and abdomen and respiratory shifts in pleural and abdominal pressure that suggest dysfunction of the diaphragm. The validity of making such deductions about diaphragm function from these observations is open to discussion. Methods In eight adult patients, American Society of Anesthesiologists physical status 2, scheduled for elective cardiac surgery, we measured respiratory rate, tidal volume, rib cage and abdominal cross-section changes, and esophageal (Pes) and gastric (Pga) pressures preoperatively, 1 day postoperatively, and 5 days postoperatively. These data were analyzed in detail by following the variables through each respiratory cycle. Results Mean delta Pga/delta Pes decreased from 0.73 preoperatively to -0.56 1 day postoperatively and recovered to 0.47 5 days postoperatively. Plots of Pes against Pga and rib cage against abdominal expansion (Konno-Mead diagrams) were constructed. Six patients showed a postoperative pattern of breathing similar to that seen in patients who have undergone abdominal surgery: a decrease in the ratio of delta Pga/delta Pes and a shift toward rib cage expansion, with an increase in breathing rate and a decrease in tidal volume. This change was accomplished in most cases by the use of abdominal muscles in expiration with an increase in inspiratory intercostal muscle action without an increase in diaphragm activation, that is, a shift in the normal balance of respiratory muscle use in favor of muscles other than the diaphragm. A different ventilatory pattern was observed in the other two patients, consisting of minimal rib cage excursion and a large abdominal excursion. In these cases tidal volume was generated largely by contraction and relaxation of abdominal muscles with probable reduction in diaphragm activity. In addition, five patients exhibited positive changes in Pes at the end of inspiration that corresponded to closure of the upper airway, relaxation of inspiratory muscles, and subsequent opening of the airway with sudden exhalation, producing a grunt. Conclusions Indirect measurements of respiratory muscle action based on pressure and chest wall motion are easier than are assessments based on implanted electromyogram electrodes and sonomicrometers that measure electric activity and muscle length, respectively, directly. Interpretation requires numerous assumptions and detailed analysis of phase relations among the variables. In patients after thoracic surgery, however, these measurements strongly point to a shift in the distribution of motor output toward muscles other than the diaphragm.

Continuous negative airway pressure increases tonic activity in diaphragm and intercostal muscles in humans

1994 ◽  
Vol 77 (3) ◽  
pp. 1256-1262 ◽  
Author(s):  
N. E. Meessen ◽  
C. P. van der Grinten ◽  
S. C. Luijendijk ◽  
H. T. Folgering
Keyword(s):  
Airway Pressure ◽  
Breathing Circuit ◽  
Minute Ventilation ◽  
Mean Values ◽  
Intercostal Muscles ◽  
Inspiratory Muscles ◽  
Airway Opening ◽  
Residual Capacity ◽  
And Control ◽  
Negative Airway Pressure

The main objective of the present study was to quantify the increase in tonic inspiratory activity (delta TIA) in response to continuous negative airway pressure (CNAP) in humans. TIA represents the activity in inspiratory muscles at the end of expiration. In 20 subjects, electromyograms (EMGs) were recorded from the diaphragm and parasternal intercostal muscles (ICM) with surface electrodes during control and at three different levels of CNAP (-0.3, -0.6, and -0.9 kPa; 1 kPa approximately 10 cmH2O). From these recordings we determined delta TIA and the amplitudes of phasic EMG activities (EMGphas) during CNAP and control. To evaluate the effects of CNAP on functional residual capacity (FRC), respiratory frequency, tidal volume, and minute ventilation, the subjects were connected to a closed breathing circuit. When the pressure at the airway opening was -0.9 kPa, mean values of delta TIA were 53 and 49% of control EMGphas for the diaphragm and ICM, respectively. In addition, EMGphas at airway opening pressure of -0.9 kPa had increased to 195 and 162% of control EMGphas for the diaphragm and ICM, respectively. The concomitant decrease in FRC was on average 18.7% of predicted FRC. Minute ventilation had increased significantly (P < 0.05) at all levels of CNAP compared with control. We conclude that CNAP is a forceful stimulus to increase TIA in humans in both the diaphragm and the ICM.

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