Interaction between the canine diaphragm and intercostal muscles in lung expansion

2005 ◽  
Vol 98 (3) ◽  
pp. 795-803 ◽  
Author(s):  
André De Troyer
Keyword(s):  
Endotracheal Tube ◽  
Functional Residual Capacity ◽  
Phrenic Nerve ◽  
Intrathoracic Pressure ◽  
Abdominal Pressure ◽  
Intercostal Muscles ◽  
Individual Volume ◽  
Lung Expansion ◽  
Residual Capacity ◽  
The Individual

Changes in intrathoracic pressure produced by the various inspiratory intercostals are essentially additive, but the interaction between these muscles and the diaphragm remains uncertain. In the present study, this interaction was assessed by measuring the changes in airway opening (ΔPao) or transpulmonary pressure (ΔPtp) in vagotomized, phrenicotomized dogs during spontaneous inspiration (isolated intercostal contraction), during isolated rectangular or ramp stimulation of the peripheral ends of the transected C5 phrenic nerve roots (isolated diaphragm contraction), and during spontaneous inspiration with superimposed phrenic nerve stimulation (combined diaphragm-intercostal contraction). With the endotracheal tube occluded at functional residual capacity, ΔPao during combined diaphragm-intercostal contraction was nearly equal to the sum of the ΔPao produced by the two muscle groups contracting individually. However, when the endotracheal tube was kept open, ΔPtp during combined contraction was 123% of the sum of the individual ΔPtp ( P < 0.001). The increase in lung volume during combined contraction was also 109% of the sum of the individual volume increases ( P < 0.02). Abdominal pressure during combined contraction was invariably lower than during isolated diaphragm contraction. It is concluded, therefore, that the canine diaphragm and intercostal muscles act synergistically during lung expansion and that this synergism is primarily due to the fact that the intercostal muscles reduce shortening of the diaphragm. When the lung is maintained at functional residual capacity, however, the synergism is obscured because the greater stiffness of the rib cage during diaphragm contraction enhances the ΔPao produced by the isolated diaphragm and reduces the ΔPao produced by the intercostal muscles.

Abdominal distension alters regional pleural pressures and chest wall mechanics in pigs in vivo

1991 ◽  
Vol 70 (6) ◽  
pp. 2611-2618 ◽  
Author(s):  
T. Mutoh ◽  
W. J. Lamm ◽  
L. J. Embree ◽  
J. Hildebrandt ◽  
R. K. Albert
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Functional Residual Capacity ◽  
Total Lung Capacity ◽  
Abdominal Cavity ◽  
Abdominal Distension ◽  
Abdominal Pressure ◽  
Lung Capacity ◽  
Lung Expansion ◽  
Residual Capacity

Abdominal distension (AD) occurs in pregnancy and is also commonly seen in patients with ascites from various causes. Because the abdomen forms part of the "chest wall," the purpose of this study was to clarify the effects of AD on ventilatory mechanics. Airway pressure, four (vertical) regional pleural pressures, and abdominal pressure were measured in five anesthetized, paralyzed, and ventilated upright pigs. The effects of AD on the lung and chest wall were studied by inflating a liquid-filled balloon placed in the abdominal cavity. Respiratory system, chest wall, and lung pressure-volume (PV) relationships were measured on deflation from total lung capacity to residual volume, as well as in the tidal breathing range, before and 15 min after abdominal pressure was raised. Increasing abdominal pressure from 3 to 15 cmH2O decreased total lung capacity and functional residual capacity by approximately 40% and shifted the respiratory system and chest wall PV curves downward and to the right. Much smaller downward shifts in lung deflation curves were seen, with no change in the transdiaphragmatic PV relationship. All regional pleural pressures increased (became less negative) and, in the dependent region, approached 0 cmH2O at functional residual capacity. Tidal compliances of the respiratory system, chest wall, and lung were decreased 43, 42, and 48%, respectively. AD markedly alters respiratory system mechanics primarily by "stiffening" the diaphragm/abdomen part of the chest wall and secondarily by restricting lung expansion, thus shifting the lung PV curve as seen after chest strapping. The less negative pleural pressures in the dependent lung regions suggest that nonuniformities of ventilation could also be accentuated and gas exchange impaired by AD.

Effect of artificial surfactant on pulmonary function in preterm and full-term lambs

1990 ◽  
Vol 69 (2) ◽  
pp. 465-472 ◽  
Author(s):  
I. M. Gladstone ◽  
A. O. Ray ◽  
C. M. Salafia ◽  
J. Perez-Fontan ◽  
M. R. Mercurio ◽  
...  
Keyword(s):  
Surface Tension ◽  
Functional Residual Capacity ◽  
Dynamic Compliance ◽  
Full Term ◽  
Tween 20 ◽  
Minimum Surface ◽  
Natural Surfactant ◽  
Equilibrium Surface Tension ◽  
Lung Expansion ◽  
Residual Capacity

We hypothesized that agents very different from surfactant may still support lung function. To test this hypothesis, we instilled FC-100, a fluorocarbon, and Tween 20, a detergent, which have higher minimum surface tensions and less hysteresis than surfactant, into 15 full-term and 14 preterm lambs. FC-100 and Tween 20 were as efficient as natural surfactant in improving gas exchange and compliance in preterm lambs with respiratory failure. Dynamic compliance correlated with the equilibrium surface tension of the alveolar wash in both full-term (P less than 0.02) and preterm (P less than 0.008) lambs. Functional residual capacity in full-term and preterm lambs was lower after treatment with the two test agents than with surfactant, findings consistent with qualitative histology. Oxygenation in full-term lambs correlated with mean lung volumes (P less than 0.003), suggesting that the hysteresis and/or low minimum surface tension of surfactant may improve mean lung volume, and hence oxygenation, by maintaining functional residual capacity. The effects of the test agents suggest that agents with biophysical properties different from surfactant may still aid lung expansion.

Diaphragmatic function during immersion

1977 ◽  
Vol 43 (2) ◽  
pp. 297-301 ◽  
Author(s):  
V. D. Minh ◽  
G. F. Dolan ◽  
P. G. Linaweaver ◽  
P. J. Friedman ◽  
R. G. Konopka ◽  
...  
Keyword(s):  
Respiratory System ◽  
Functional Residual Capacity ◽  
Lung Volume ◽  
Intrathoracic Pressure ◽  
Fold Increase ◽  
Hydrostatic Compression ◽  
Base Line ◽  
Factors Affecting ◽  
Diaphragmatic Function ◽  
Residual Capacity

Diaphragmatic function during immersion to midneck level was studied in upright mongrel dogs, using constant electrophrenic stimulation. Effectiveness of diaphragmatic contraction was analyzed in terms of inspired volume (VT) (with airways open), and change in intrathoracic pressure (Pmus) (with the respiratory system occluded). Hydrostatic compression of the immersed body decreased functional residual capacity (FRC) to 55% base-line value (FRCO), resulting in a 2.8-fold increase in Pmus. In spite of this Pmus increase, VT often decreased during immersion, averaging only 83% VTO (base-line value in air). Hence, immersion was associated with a marked stiffening of the respiratory system. The Pmus increase during immersion persisted after restoration of FRC to FRCO, and was related to diaphragmatic length being greater in water than in air under condition of iso-lung volume. In all, there were three factors affecting diaphragmatic function during immersion: FRC reduction, change in thoracic configuration, and stiffening of the respiratory system.

Inhomogeneous activation of the parasternal intercostals during breathing

1995 ◽  
Vol 79 (1) ◽  
pp. 55-62 ◽  
Author(s):  
A. De Troyer ◽  
A. Legrand
Keyword(s):  
Functional Residual Capacity ◽  
Spontaneous Breathing ◽  
Maximal Activity ◽  
Intercostal Nerve ◽  
Mechanical Advantage ◽  
Intercostal Muscles ◽  
Resistive Loading ◽  
Residual Capacity ◽  
Supramaximal Stimulation ◽  
Stimulation Of

Recent computations of the mechanical advantage of the canine intercostal muscles have suggested that the inspiratory advantage of the parasternal intercostals is not uniform. In the present studies, we have initially tested this hypothesis. Using a caliper and markers implanted in the costal cartilages, we have thus measured, in four supine paralyzed dogs, the length of the medial, middle, and lateral parasternal fibers at functional residual capacity and after a 1-liter mechanical inflation. With inflation, the medial fibers always shortened more than did the middle fibers (-9.8 +/- 0.8 vs. -6.0 +/- 0.8%; P < 0.001), whereas the lateral fibers remained virtually constant in length (-0.2 +/- 0.8%). This gradient of mechanical advantage agreed well with the gradient of orientation of the muscle fibers. Therefore, we have also recorded the electromyograms of the medial, middle, and lateral parasternal bundles during spontaneous breathing in nine anesthetized animals (20 interspaces); each activity was expressed as a percentage of the activity recorded during tetanic, supramaximal stimulation of the internal intercostal nerve (maximal activity). The medial bundle was invariably more active than was the middle bundle during resting breathing (57.3 +/- 3.3 vs. 25.5 +/- 3.4% of maximum; P < 0.001), and in 10 interspaces, medial activity consistently preceded middle activity at the onset of inspiration. These differences persisted during hypercapnia, during inspiratory resistive loading, as well as after phrenicotomy. Activity was never recorded from the lateral bundle.

scholarly journals Severe Intraoperative Bronchospasm Treated with a Vibrating-Mesh Nebulizer

2012 ◽  
Vol 59 (3) ◽  
pp. 123-126 ◽  
Author(s):  
Leonard R. Golden ◽  
Helen Ann DeSimone ◽  
Farhad Yeroshalmi ◽  
Mindaugas Pranevicius ◽  
Mana Saraghi
Keyword(s):  
Oxygen Consumption ◽  
Endotracheal Tube ◽  
Functional Residual Capacity ◽  
Status Asthmaticus ◽  
Pediatric Anesthesiologist ◽  
Medication Delivery ◽  
Consumption Rates ◽  
Residual Capacity

Bronchospasm and status asthmaticus are two of the most dreaded complications that a pediatric anesthesiologist may face. With the occurrence of severe bronchospasm and the inability to ventilate, children are particularly vulnerable to apnea and ensuing hypoxia because of their smaller airway size, smaller lung functional residual capacity, and higher oxygen consumption rates than adults. Nebulized medication delivery in intubated children is also more difficult because of smaller endotracheal tube internal diameters. This case demonstrates the potentially lifesaving use of a vibrating-mesh membrane nebulizer connected to the anesthesia circuit for treating bronchospasm.

Twitch transdiaphragmatic pressure depends critically on thoracoabdominal configuration

2000 ◽  
Vol 88 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Rongchang Chen ◽  
Bengt Kayser ◽  
Sheng Yan ◽  
Peter T. Macklem
Keyword(s):  
Functional Residual Capacity ◽  
Lung Volume ◽  
Phrenic Nerve ◽  
Fiber Length ◽  
Radius Of Curvature ◽  
Transdiaphragmatic Pressure ◽  
Velocity Of Shortening ◽  
Residual Capacity ◽  
End Tidal ◽  
Normal Men

We measured the effect of thoracoabdominal configuration on twitch transdiaphragmatic pressure (Pdi, t) in response to supramaximal, transcutaneous, bilateral phrenic nerve shocks in three thin normal men. Pdi, t was measured as a function of lung volume (Vl) in the relaxation configuration, at functional residual capacity (FRC), and at the same end-tidal Vl 1) during relaxation; 2) with the abdomen (Ab) expanded and the rib cage (RC) in its relaxed FRC configuration; 3) with RC expanded and Ab in its relaxed FRC configuration; and 4) in configuration 3 with an active transdiaphragmatic pressure similar to that required to produce configuration 2. In increasing Vl from FRC to configuration 1, Pdi, t decreased by 3.6 cmH2O; to configuration 2 by 14.8 cmH2O; to configuration 3 by 3.7 cmH2O; and to configuration 4 by 2.7 cmH2O. We argue that changes in velocity of shortening and radius of curvature are unlikely to account for these effects and suggest that changes in diaphragmatic fiber length ( L di) are primarily responsible. If so, equivolume displacements of Ab and RC change L di in a ratio of ∼4:1. We conclude that Pdi, t is exquisitely sensitive to abdominal displacements that must be rigorously controlled if Pdi, t is to be used to assess diaphragmatic contractility.

Human Chest Wall Function while Awake and during Halothane Anesthesia 

1995 ◽  
Vol 82 (1) ◽  
pp. 6-19 ◽  
Author(s):  
David O. Warner ◽  
Mark A. Warner ◽  
Erik L. Ritman
Keyword(s):  
Chest Wall ◽  
Blood Volume ◽  
Functional Residual Capacity ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Halothane Anesthesia ◽  
Intercostal Muscles ◽  
Residual Capacity ◽  
Gas Volume ◽  
Respiratory Muscle Activity

Background Data concerning chest wall configuration and the activities of the major respiratory muscles that determine this configuration during anesthesia in humans are limited. The aim of this study was to determine the effects of halothane anesthesia on respiratory muscle activity and chest wall shape and motion during spontaneous breathing. Methods Six human subjects were studied while awake and during 1 MAC halothane anesthesia. Respiratory muscle activity was measured using fine-wire electromyography electrodes. Chest wall configuration was determined using images of the thorax obtained by three-dimensional fast computed tomography. Tidal changes in gas volume were measured by integrating respiratory gas flow, and the functional residual capacity was measured by a nitrogen dilution technique. Results While awake, ribcage expansion was responsible for 25 +/- 4% (mean +/- SE) of the total change in thoracic volume (delta Vth) during inspiration. Phasic inspiratory activity was regularly present in the diaphragm and parasternal intercostal muscles. Halothane anesthesia (1 MAC) abolished activity in the parasternal intercostal muscles and increased phasic expiratory activity in the abdominal muscles and lateral ribcage muscles. However, halothane did not significantly change the ribcage contribution to delta Vth (18 +/- 4%). Intrathoracic blood volume, measured by comparing changes in total thoracic volume and gas volume, increased significantly during inspiration both while awake and while anesthetized (by approximately 20% of delta Vth, P &lt; 0.05). Halothane anesthesia significantly reduced the functional residual capacity (by 258 +/- 78 ml), primarily via an inward motion of the end-expiratory position of the ribcage. Although the diaphragm consistently changed shape, with a cephalad displacement of posterior regions and a caudad displacement of anterior regions, the diaphragm did not consistently contribute to the reduction in the functional residual capacity. Halothane anesthesia consistently increased the curvature of the thoracic spine measured in the saggital plane. Conclusions The authors conclude that (1) ribcage expansion is relatively well preserved during halothane anesthesia despite the loss of parasternal intercostal muscle activity; (2) an inward displacement of the ribcage accounts for most of the decrease in functional residual capacity caused by halothane anesthesia, accompanied by changes in diaphragm shape that may be related to motion of its insertions on the thoracoabdominal wall; and (3) changes in intrathoracic blood volume constitute a significant fraction of delta Vth during tidal breathing.

Action of costal and crural parts of the diaphragm on the rib cage in dog

1982 ◽  
Vol 53 (1) ◽  
pp. 30-39 ◽  
Author(s):  
A. De Troyer ◽  
M. Sampson ◽  
S. Sigrist ◽  
P. T. Macklem
Keyword(s):  
Lung Volume ◽  
Phrenic Nerve ◽  
Intact Animal ◽  
Mechanical Action ◽  
Abdominal Pressure ◽  
Nerve Roots ◽  
Rib Cage ◽  
Residual Capacity ◽  
Crural Diaphragm ◽  
Segmental Innervation

We studied the action of the costal and crural (vertebral) parts of the diaphragm on the lower rib cage in normal supine dogs. The two parts of the diaphragm were separately stimulated by electrodes directly implanted in the muscle or via the different phrenic nerve roots in the neck. The results of the experiments indicate the following. 1) The costal and crural parts of the diaphragm have a different segmental innervation and a different mechanical action on the rib cage. 2) The costal diaphragm expands the lower rib cage when it contracts. This rib-cage expansion is due mostly to the fulcrum of the abdominal contents and partly to the rise in abdominal pressure that takes place during diaphragmatic contraction. The pericardial attachments play no role in this action of the diaphragm. 3) The action of the crural diaphragm on the lower rib cage depends only on the balance between the inspiratory force exerted by the rise in abdominal pressure and the expiratory force exerted by the fall in pleural pressure. In the intact animal at functional residual capacity, these two opposite effects cancel each other. 4) The inflationary action of both parts on the rib cage decreases progressively as lung volume increases. The findings also suggest that the rise in abdominal pressure which occurs when the diaphragm contracts expands the lower rib cage by acting through the area of apposition of the diaphragm to the rib cage. These findings also strengthen the idea that the diaphragm actually consists of two muscles.

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