Effects of an increase in end-expiratory volume on the pattern of thoracoabdominal movement

doi:10.1016/0034-5687(83)90119-6

Respiration Physiology

Volume 53, Issue 3, September 1983, Pages 273-283

Respiration Physiolo...

https://doi.org/10.1016/0034-5687(83)90119-6 Get rights and content

Abstract

Changes in end-expiratory lung volume can alter the mechanical function of the muscles of inspiration and may affect the pattern of thoracoabdominal movements. The present study examined the effect of increasing end-expiratory lung volume on the motion of the rib cage and abdomen during inspiration. In six seated subjects, end-expiratory volume was increased by expiratory threshold loading. The end-expiratory thoracoabdominal configuration shifted to the left of the relaxation curve presumably as a result of the activation of the abdominal expiratory muscles. There was outward displacement of both the rib cage and the abdomen with inspiration at the elevated volume but the relative volumetric contribution of abdominal displacement to the inspired volume was significantly less than during breathing from FRC. When at an enlarged lung volume subjects were constrained to initiate inspiration from a point on the thoracoabdominal relaxation configuration, there was inward movement of the abdomen and a decrease in abdominal dimensions during inspiration. Inward abdominal movement occurred despite large increases in diaphragm electrical activity and was associated with an inspiratory fall in gastric pressure. These results suggest that at large lung volumes, the function of the diaphragm as an agonist is lost and its function as a fixator may be impaired unless there is an activation of the abdominal muscles and the diaphragm is appropriately lengthened.

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Cited by (17)

Expiratory and inspiratory action of transversus abdominis during eupnea and hypercapnic ventilation
2022, Respiratory Physiology and Neurobiology
Citation Excerpt :
These clinical interpretations are based on two physiological assumptions: 1) chest and abdominal compartment act syncronously as a unit and 2) increase in recruitment of the expiratory abdominal muscles is always pathological. However, Konno and Mead’s work established that the two compartments can function separately (Konno et al., 1967; Grimby et al., 1976), and asynchrony or “paradoxic” movement of the abdominal compartment can be independent of diaphragm fatigue (Wolfson et al., 1983; Tobin et al., 1987). This study reinforces that expiration is not physiologically a passive process, and progressive recruitment of transversus abdominis during hypercapnia suggests its role is integrated into the strategy to increase minute ventilation.
Recently, there is interest in the clinical importance of monitoring abdominal muscles during respiratory failure. The clinical interpretation relies on the assumption that expiration is a passive physiologic process and, since diaphragm and abdomen are arranged in series, any inward motion of the abdominal wall represents a sign of diaphragm dysfunction. However, previous studies suggest transversus abdominis might be active even during eupnea and is preferentially recruited over the other abdominal muscles.
1) Is transversus abdominis normally recruited during eupnea? 2) What is the degree of activation of transversus abdominis during hypercapnia? 3) Does the end-inspiratory length of transversus abdominis change during hypercapnia, while diaphragm function is normal?
In 30 spontaneously breathing canines, awake without confounding anesthetic, we measured directly both electrical activity and corresponding mechanical length and shortening of transversus abdominis during eupnea and hypercapnia.
Transversus abdominis is consistently recruited during eupnea. During hypercapnia, transversus abdominis recruitment is progressive and significant. Throughout hypercapnia, transversus abdominis baseline end-inspiratory length is not constant: baseline length decreases progressively throughout hypercapnia.
After expiration, into early inspiration, transversus abdominis shows a consistent neural mechanical post -expiratory expiratory activity (PEEA) at rest, which progressively increases during hypercapnia.
Transversus abdominis is an obligatory expiratory muscle, reinforcing the fundamental principle expiration is not a passive process. Beyond expiration, during hypercapnic ventilation, transversus abdominis contributes as an “accessory inspiratory muscle” into the early phase of inspiration. Clinical monitoring of abdominal wall motion during respiratory failure may be confounded by action of transversus abdominis.
Determinants of respiratory pump function in patients with cystic fibrosis
2015, Paediatric Respiratory Reviews
Citation Excerpt :
Concurrently, breathing tends to become swallow and rapid so that minute ventilation is preserved in the face of the increased elastic work of breathing. Although non-forced expiration in healthy individuals is a passive phenomenon, in lung disorders characterized by hyperinflation and airway obstruction, expiration becomes active and the abdominal muscles are recruited [43] At large lung volumes, the function of the diaphragm as an agonist is lost and its function as a fixator may be impaired unless there is an activation of the abdominal muscles and the diaphragm is appropriately lengthened, causing a degree of thoraco-abdominal asynchrony [44]. Cerny et al studied surface abdominal electromyography responses to graded expiratory threshold loads in CF patients and concluded that CF patients recruited abdominal muscles at lower loads, earlier in the respiratory cycle and to a higher recruitment level than healthy controls [41].
Respiratory failure constitutes the major cause of morbidity and mortality in patients with Cystic Fibrosis (CF). Respiratory failure could either be due to lung parenchyma damage or to insufficiency of the respiratory pump which consists of the respiratory muscles, the rib cage and the neuromuscular transmission pathways. Airway obstruction, hyperinflation and malnutrition have been historically recognised as the major determinants of respiratory pump dysfunction in CF. Recent research has identified chronic infection, genetic predisposition, dietary and pharmaceutical interventions as possible additional determinants of this impairment. Furthermore, new methodological approaches in assessing respiratory pump function have led to a better understanding of the pathogenesis of respiratory pump failure in CF. Finally, respiratory muscle function could be partially preserved in CF patients with structured interventions such as aerobic exercise, inspiratory muscle training and non-invasive ventilation and CF patients could consequently be relatively protected from respiratory fatigue and respiratory failure.
Preliminary investigation of a measure of dysfunctional breathing symptoms: The Self Evaluation of Breathing Questionnaire (SEBQ)
2009, International Journal of Osteopathic Medicine
Citation Excerpt :
For example, chest wall strapping of healthy volunteers sufficient to restricted normal respiratory motion resulted in the sensations of “unsatisfied respiration” and “inspiratory difficulty”28 “Unsatisfied respiration” a sense of difficulty taking a deep and satisfying breath is a common symptom in patients with impaired function of the respiratory muscles and rib cage due to hyperinflation of the lungs.29 In hyperinflation, the rib cage stiffens and respiratory muscles, in particular the diaphragm and accessory muscles of respiration, shorten which decrease their ability to respond adequately to efferent command from the motor cortex.30–33 The description of the breath as shallow is common in patients with neuromuscular and chest wall disorders and this sensation is presumed to arise from receptors in the chest wall and muscles of breathing and from efferent–reafferent dissociation.26
Dysfunctional breathing (DB) can be defined by the presence of unexplained breathing symptoms. However, validated questionnaires to comprehensively evaluate all dimensions of breathing symptoms proposed to be associated with DB have not been extensively developed. This paper discusses the development and exploration of the dimensionality of a preliminary questionnaire, the Self Evaluation of Breathing Questionnaire, whose items were derived from a popular Internet questionnaire for evaluating breathing functionality and breathing symptoms proposed in the scientific literature to be discriminative for DB.
The 17-item SEBQ was administered to 83 adults. Exploratory factor analysis was performed and correlations calculated between the SEBQ and the Nijmegen Questionnaire (NQ), which is a validated questionnaire for hyperventilation syndrome.
Two dimensions were found in the SEBQ. One dimension named “lack of air” appears to reflect sensations of air hunger that may relate more to chemoreceptor aspects of breathing sensation. The other dimension named “perception of inappropriate or restricted breathing” appears to reflect sensations and observations about the work of breathing and may relate more to the biomechanical aspects of breathing sensation. The correlations between the SEBQ and the NQ were .6 for the 17-item SEBQ and .3 for the final 12-item SEBQ which contained the strongest items of the two dimensions.
Breathing symptoms associated with dysfunctional breathing arising from predominately biomechanical aspects of breathing might be distinguishable from symptoms arising from factors reflecting chemoreceptor input. The two dimensions of the SEBQ may represent related but distinct aspects of dysfunctional breathing symptoms that appear different to those assessed by the Nijmegen Questionnaire. The SEBQ, if further developed, may be a useful clinical assessment tool that could more discriminatively evaluate the response of separate dimensions of breathing symptoms to treatments that aim to improve the functionality of breathing.
The functions of breathing and its dysfunctions and their relationship to breathing therapy
2009, International Journal of Osteopathic Medicine
Citation Excerpt :
However paradoxical inward motion of the abdomen during inspiration is not always dysfunctional. In fact inward abdominal motion during inspiration can be a normal and functional response to increased lung volume, physical activity, rapid respiratory maneuvers or standing posture that maintains abdominal pressure and helps the diaphragm to maintain a more ideal length and curvature.21,22 During inhalation, paradoxical breathing is clearly dysfunctional when it is not adequately compensated by lateral motion of the rib cage and it is observed that the lower rib cage narrows instead of widening during inspiration.22
Breathing is unquestionably a key function of the human body; it sustains life by providing oxygen needed for metabolism and removing the by-product of these reactions, carbon dioxide. Breathing, however, has other functions apart from the ventilation of air and the maintenance of oxygen and carbon dioxide. Breathing affects motor control and postural stability and plays several roles in physiological and psychological regulation. Breathing can influence homeostatic functions in other system including the autonomic nervous system, the circulatory system, chemical regulation and metabolism.
Breathing becomes dysfunctional when the person is unable to breathe efficiently or when breathing is inappropriate, unhelpful or inefficient in responding to environmental conditions and the changing needs of the individual.
Impairment of the functions of breathing affects people's lives, challenging homeostasis, creating symptoms and compromising health. The efficiency with which breathing fulfills its various functions can be diminished because of musculo-skeletal dysfunction, disease, chronic psychological stress or other factors that affect respiratory drive and respiratory control. The neurological control of breathing shows high levels of neuroplasticity as shown by its ability to adapt to a wide range of internal and external conditions.
Breathing therapy generally aims to either correct dysfunctions of breathing or enhance its functions. Breathing, unlike most physiological functions, can be controlled voluntarily and it can serve as an entry point for physiological and psychological regulation.
Control of abdominal muscles
1998, Progress in Neurobiology
Abdominal muscles serve many roles; in addition to breathing, especially at higher levels of chemical drive or at increased end-expiratory lung volumes, they are responsible for, or contribute to, such protective reflexes as cough, sneeze, and vomiting, generate the high intra-abdominal pressures necessary for defecation and parturition, are active during postural adjustments, and play an essential role in vocalization in many species. Despite this widespread involvement, however, their control has, with rare exceptions, received little attention for two major reasons.
First, in most anesthetized or decerebrate preparations, they are relatively inactive at rest, in part because the position of the preparation (supine or prone with abdomen supported), reduces lung volume and, therefore, their activity.
Second, unlike phrenic motoneurons innervating the diaphragm, identification of motoneurons to a particular abdominal muscle is difficult.
At the lumbar level, a given motoneuron may innervate any one of the four abdominal muscles; at the thoracic level, they are also intermixed with those innervating the intercostals.
The two internal muscles, the internal oblique and the transverse abdominis, respond more to increases in chemical or volume-related drive than the two external muscles, the rectus abdominis and external oblique; the basis for this differential sensitivity is unknown.
Segmental reflexes at the thoracic and lumbar levels are sufficient to activate abdominal motoneurons in the absence of descending drive but the basis for these reflex effects is also unknown.
Neuroanatomical experiments demonstrate many more inputs to, and outputs from, the nucleus retroambigualis, the brainstem region in which the premotor neurons are located, than can be accounted for by their respiratory role alone. These other connections likely subserve activities other than respiration.
Studies of the multifunctional roles of the abdominal muscles, on the basis of recent work, hold considerable promise for improving our understanding of their control.
Changes in human diaphragmatic electromyogram with positive pressure breathing
1986, Neuroscience Letters
An increase in diaphragmatic electromyogram (EMG) recorded via oesphageal electrodes during positive pressure breathing has been reported to indicate an increase in the neural outflow to the muscle. However, using similar techniques, the size of compound muscle action potentials produced by supramaximal phrenic nerve stimulation also increased during positive pressure breathing. It is concluded that a change in EMG recording conditions rather than in central respiratory outflow may explain the increase in diaphragmatic EMG produced by positive airway pressure.

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Effects of an increase in end-expiratory volume on the pattern of thoracoabdominal movement

Abstract

Chest

Abdominal and thoracic pressures at different lung volumes

J. Appl. Physiol.

Relative contributions of the rib cage and the diaphragm to ventilation in man

J. Appl. Physiol.

Abdominal muscle activity during respiration

The behavior of the abdominal muscles and the intra-abdominal pressure during quiet breathing and increased pulmonary ventilation; a study in man

J. Physiol. (London)

Relationship between respiratory nerve and muscle force output

J. Appl. Physiol.

Mechanical interaction between the diaphragm and rib cage

J. Appl. Physiol.

Effects of hyperinflation of the thorax on the mechanics of breathing

J. Appl. Physiol.

Mechanics of the human diaphragm during voluntary contraction: statics

J. Appl. Physiol.

Configuration of the chest wall and occlusion pressures in awake humans

J. Appl. Physiol.

Relative contribution of rib cage and abdomen to ventilation during exercise

J. Appl. Physiol.

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

J. Appl. Physiol.