Coordination Of Respiratory Muscles Research Articles

EFFECTIVENESS OF APPLYING ORIGINAL METHOD OF BREATHING EXERCISES, INCLUDING TECHNIQUES FOR MOBILIZING DIAPHRAGMAL BREATHING IN COMPLEX EARLY MEDICAL REHABILITATION OF PATIENTS WHO HAVE UNDERGONE CORONARY BYPASS GRAFT

Highlights In the physical rehabilitation of patients after coronary artery bypass surgery (CABG), special attention has recently been paid to respiratory rehabilitation. The article presents the results of studies demonstrating that a course of respiratory coordination training was associated with a decrease in the incidence of hydrothorax, improved blood oxygen saturation, increased exercise tolerance and muscle strength by reducing diaphragm dysfunction and increasing respiratory muscle strength in patients in the postoperative period. AbstractAim. To analyze the clinical effectiveness of a new method of breathing exercises developed for improving breathing control in complex early rehabilitation of patients who underwent CABG.Methods. The study involved 73 patients with coronary artery disease (CAD) who underwent CABG at the Federal State Budgetary Institution “Research Institute for Complex Issues of Cardiovascular Diseases” (Kemerovo, Russia) in 2021. During the inpatient rehabilitation, patients were randomized into two groups comparable in anamnestic and baseline clinical and functional indicators: the experimental group (38 patients) had individual breathing exercises as a part of respiratory gymnastics (with different types of exercises), and the control group (35 patients) underwent conventional exercise training.Results. Initially, there were no statistically significant differences between the groups. After 14 days the number of patients in the main group with signs of hydrothorax was significantly lower compared with the control group: 7 (18.4%) vs 11 (31.4%), respectively, p = 0.001. The ultrasound examination of the pleural space revealed the same pattern - hydrothorax was less pronounced in the main group compared with the control group: 0.9 [0.5; 1.5] vs 1.7 [0.6; 2.5] mL, p = 0.049. Analysis of oxygen saturation (SpO₂,%), reflecting the functional status of the oxygen transport system, showed higher blood oxygen saturation rates in the main group compared with the control group: 98 [96; 99] vs 95.2[94; 97]%, p = 0.04, respectively. At the same time, the exercise tolerance (ET) estimated with bicycle ergometry was comparable at baseline in both groups, and at the end of the inpatient rehabilitation ET in the main group was significantly higher than in the control group with conventional exercise training: 74. 9 [50; 100] vs 55.1[25; 75] W, p = 0.005, respectively.Conclusion. Respiratory gymnastics facilitates cardiac and respiratory rehabilitation mainly by improving the coordination of respiratory muscles and preparing them for respiratory gymnastics within short period of early inpatient rehabilitation.

Onset and Offset Detection of Respiratory EMG Data Based on Energy Operator Signal.

Onset and offset detection of electromyography (EMG) data is an important step in respiratory muscle coordination assessment. Impaired respiratory coordination can indicate breathing disorders and lung diseases. In this paper, we present an algorithm for onset and offset timing detection of real-world EMG signals from respiratory muscles, which are contaminated with electrocardiogram (ECG) artifacts. The algorithm is based on the Energy Operator signal, has a low computational cost, and includes a filtering procedure to remove ECG artifacts from EMG. Analysis of EMG signals from 2 respiratory muscles of 5 participants' data shows high agreement between the algorithm and manual method with a mean difference between two methods of 0.0407 seconds.

Thoracoabdominal asynchrony associates with exercise intolerance in fibrotic interstitial lung diseases.

The precise coordination of respiratory muscles during exercise minimizes work of breathing and avoids exercise intolerance. Fibrotic interstitial lung disease (f-ILD) patients are exercise-intolerant. We assessed whether respiratory muscle incoordination and thoracoabdominal asynchrony (TAA) occur in f-ILD during exercise, and their relationship with pulmonary function and exercise performance. We compared breathing pattern, respiratory mechanics, TAA and respiratory muscle recruitment in 31 f-ILD patients and 31 healthy subjects at rest and during incremental cycle exercise. TAA was defined as phase angle (PhAng) >20°. During exercise, when compared with controls, f-ILD patients presented increased and early recruitment of inspiratory rib cage muscle (p< 0.05), and an increase in PhAng, indicating TAA. TAA was more frequent in f-ILD patients than in controls, both at 50% of the maximum workload (42.3% vs. 10.7%, p= 0.01) and at the peak (53.8% vs. 23%, p= 0.02). Compared with f-ILD patients without TAA, f-ILD patients with TAA had lower lung volumes (forced vital capacity, p< 0.01), greater dyspnoea (Medical Research Council > 2 in 64.3%, p= 0.02), worse exercise performance (lower maximal work rate % predicted, p= 0.03; lower tidal volume, p= 0.03; greater desaturation and dyspnoea, p< 0.01) and presented higher oesophageal inspiratory pressures with lower gastric inspiratory pressures and higher recruitment of scalene (p< 0.05). Exercise induces TAA and higher recruitment of inspiratory accessory muscle in ILD patients. TAA during exercise occurred in more severely restricted ILD patients and was associated with exertional dyspnoea, desaturation and limited exercise performance.

Modification des capacités ventilatoires chez un enfant polyhandicapé sévère, infecté par cytomégalovirus par stimulations de réflexes locomoteurs dans l’approche Vojta : propos d’un cas clinique

Children with severe neurological disorders (such as cerebral palsy) may suffer from severe disorders of the coordination of respiratory muscles. The relative immobility of these patients, the thoracic deformities they suffer, and in addition epileptic seizures and gastro-esophageal reflux lead to problems with ventilation, perfusion and swallowing difficulty. These disorders can also lead to atelectasis of the lungs and a high occurrence of recurrent infections, which represent the leading cause of death. The present case study concerns a 3-year-old child with a severe neurological impairment produced by the sequels of congenital encephalopathy by a cytomegalovirus (CMV). The patient seroconverted during the first trimester of pregnancy, and consulted a general doctor with an X ray of the lungs revealing a partial atelectasis of both lungs. The object of this report is to show the clinical progress made by this child following 2 weeks of Vojta therapy, assessed by comparing its imaging and clinical assessments before and following the above-mentioned intervention.

Coordination of the Respiratory Muscles in Hypercapnic and Hypoxic Environments

Breathing is dependent on the coordination of respiratory muscles. The timing and contribution of the respiratory muscles determine the balance between breathing frequency and tidal volume. At rest, the mammalian breathing cycle has three phases: active inspiration (I), expiratory braking (E1) and an expiratory pause (E2). With elevated respiratory drive, expiratory muscles may contract to produce active expiration. This study investigated how respiratory muscles are recruited under hypercapnic and hypoxic conditions. These stimuli modify the breathing response by primarily increasing tidal volume or breathing frequency, respectively. EMG electrodes were placed in the diaphragm, intercostal and abdominal muscles. Anesthetized and unanesthetized rats were then exposed to progressive hypercapnia and hypoxia. Progressive hypercapnia (0% to 10% CO2) induced active expiration at the end of the breathing cycle (E3 phase) at 8% and 10% inspired CO2 in unanesthetized rats. The placement in E3 correlated with an increase in tidal volume. Active expiration was not observed in anesthetized rats, even at the highest level of CO2. Progressive hypoxia (21% to 9% O2) never induced active expiration, in either unanesthetized or anesthetized rats indicating that passive expiration was sufficient even at the highest breathing frequencies. This further suggests that the control mechanisms that coordinate the respiratory muscles during hypercapnia and hypoxia are different and dependent on higher brain centers. Supported by the NSERC of Canada.

Disturbance of respiratory muscle control in a patient with early-stage multiple sclerosis

To the Editor: Respiratory dysfunction from multiple sclerosis (MS) is most commonly of insidious onset and related to progressive respiratory muscle weakness [1]. Disorders of respiratory muscle coordination are poorly recognised and challenging to diagnose. We present a case of a patient with MS and no clear muscle weakness whose dyspnoea was associated with a disorder of respiratory muscle control. The potential utility of oesophageal manometry for diagnosis of unexplained dyspnoea is highlighted. A 54-year-old female with relapsing-remitting MS presented with 2 weeks of dyspnoea and orthopnoea. She was ambulatory with a low extended disability score of 1.5. 6 months earlier she started cyclophosphamide for disease progression recognised by magnetic resonance imaging (MRI). A week after her last infusion she developed severe dyspnoea and orthopnoea. She had no other symptoms. Her vital signs were normal. Her laboratory tests and arterial blood gas were unremarkable. Chest computed tomography showed no pulmonary parenchymal disease. Echocardiography was unremarkable. Pulmonary function testing (PFTs) demonstrated severe restriction, with a 14% lower vital capacity in the supine position. Her dyspnoea and PFTs improved over the following 1–2 months, but she did not return to her baseline level of pulmonary function. Electromyography (EMG) with phrenic nerve conduction studies demonstrated no abnormalities. MRI was prohibited by her orthopnoea. Previously, MRI demonstrated extensive demyelination in the brain and brainstem that was asymptomatic. Oesophageal manometry was performed to exclude the possibility of bilateral diaphragmatic dysfunction and to elucidate her unexplained dyspnoea. A balloon-catheter was inserted via the nose to position the balloon in the distal oesophagus to estimate pleural pressure. Repeated attempts to perform a forced vital capacity manoeuvre consistently demonstrated fluctuating exhalations, as evidenced by the saw tooth pattern of the flow volume curve (fig. …

Coordination of respiratory muscles assessed by means of nonlinear forecasting of demodulated myographic signals

Pulmonary diseases such as obstructive sleep apnea syndrome (OSAS) affect function of respiratory muscles. Individuals with OSAS suffer intermittent collapse of the upper airways during sleep due to unbalanced forces generated by the contraction of the diaphragm and upper airway dilator muscles. Respiratory rhythm and pattern generation can be described via nonlinear or coupled oscillators; therefore, the resulting activation of different respiratory muscles may be related to complex nonlinear interactions. The aims of this work were: to evaluate locally linear models for fitting and prediction of demodulated myographic signals from respiratory muscles; and to analyze quantitatively the influence of a pulmonary disease on this nonlinear forecasting related to low and moderate levels of respiratory effort. Electromyographic and mechanomyographic signals from three respiratory muscles (genioglossus, sternomastoid and diaphragm) were recorded in OSAS patients and controls while awake during an increased respiratory effort. Variables related to auto and cross prediction between muscles were calculated from the r 2 coefficient and the estimation of residuals, as functions of prediction horizon. In general, prediction improved linearly with higher levels of effort. A better prediction between muscle activities was obtained in OSAS patients when using genioglossus as the predictor signal. The prediction was significant for more than two respiratory cycles in OSAS patients compared to only a half cycle in controls. It could be concluded that nonlinear forecasting applied to genioglossus coupling with other muscles provides a promising assessment to monitor pulmonary diseases.

The brainstem respiratory network: An overview of a half century of research

This review aims at summarizing the work performed over 40 years by Professor Armand Bianchi and the research team he directed, which was devoted to the study of the central respiratory network. The major steps towards the understanding of this complex network will be presented together with methodological considerations. This includes the sequential progress that was made in the identification and characterization of respiratory neurons as deduced from inferences gleaned from intracellular recordings, which revealed putative synaptic connections within the respiratory network. Also reviewed is a comparison of in vivo versus in vitro approaches. The search for the "real" respiratory neurons must consider that those neurons are redundantly represented within the brainstem and express a wide variety of patterns. The last part of this review focuses on the concept that the brainstem respiratory circuitry forms part of a multifunctional network subserving both respiration and non-respiratory motor behaviors. Numerous data provide evidence that the respiratory network operates as a dynamic assembly of neurons, some of which can belong to several networks involved in the coordination of respiratory muscles during functions that include coughing, swallowing and vomiting.

Chest wall kinematics, respiratory muscle action and dyspnoea during arm vs. leg exercise in humans

We hypothesize that different patterns of chest wall (CW) kinematics and respiratory muscle coordination contribute to sensation of dyspnoea during unsupported arm exercise (UAE) and leg exercise (LE). In six volunteer healthy subjects, we evaluated the volumes of chest wall (V(cw)) and its compartments, the pulmonary apposed rib cage (V(rc,p)), the diaphragm-abdomen apposed rib cage (V(rc,a)) and the abdomen (V(ab)), by optoelectronic plethysmography. Oesophageal, gastric and trans-diaphragmatic pressures were simultaneously measured. Chest wall relaxation line allowed the measure of peak rib cage inspiratory muscle, expiratory muscle and abdominal muscle pressures. The loop V(rc,p)/V(rc,a) allowed the calculation of rib cage distortion. Dyspnoea was assessed by a modified Borg scale. There were some differences and similarities between UAE and LE. Unlike LE with UAE: (i) V(cw) and V(rc,p) at end inspiration did not increase, whereas a decrease in V(rc,p) contributed to decreasing CW end expiratory volume; (ii) pressure production of inspiratory rib cage muscles did not significantly increase from quiet breathing. Not unlike LE, the diaphragm limited its inspiratory contribution to ventilation with UAE with no consistent difference in rib cage distortion between UAE and LE. Finally, changes in abdominal muscle pressure, and inspiratory rib cage muscle pressure predicted 62% and 41.4% of the variability in Borg score with UAE and LE, respectively (P < 0.01). Leg exercise and UAE are associated with different patterns of CW kinematics, respiratory muscle coordination, and production of dyspnoea.

Chronically instrumented goats are a viable model to further elucidate the role of pontine nuclei in the control of breathing in both the awake and sleep states

Controversies regarding the role of pontine nuclei in the control of breathing and paucity of studies during physiologic conditions have prompted us to chronically implant microtubules into the pons of 2 goats, one caudally (bilateral) and one rostrally (unilateral). Both goats recovered uneventfully and 3 weeks thereafter resting PaCO2 and CO2 sensitivity were near normal. However, both goats had abnormal post-inspiratory diaphragm activity following implantation. Injection of atropine (500nL, 5mM) during the day decreased CO2 sensitivity without altering resting PaCO2. Dialysis of atropine (50mM) at night disrupted activation patterns of respiratory muscles and depressed and destabilized breathing which was state independent. Injection of ibotenic acid during the day also acutely destabilized breathing and disrupted coordination of respiratory muscles, transiently altered PaCO2 and CO2 sensitivity, and chronically altered REM generating mechanisms at night. Subsequent histological analysis of the pons of both goats implicates the medial parabrachial nucleus in the caudally implanted goat and the pedunculopontine tegmental nucleus in the rostrally implanted goat. These findings suggest that chronically instrumented goats are a viable model to further elucidate the role of pontine nuclei in the control of breathing. Supported by NIH HL-25739 and by the Department of Veterans Affairs.

117th ENMC Workshop: Ventilatory Support in Congenital Neuromuscular Disorders — Congenital Myopathies, Congenital Muscular Dystrophies, Congenital Myotonic Dystrophy and SMA (II) 4–6 April 2003, Naarden, The Netherlands

Eighteen participants from Australia, Austria, Denmark, Finland, France, Germany, The Netherlands, the UK, and the USA met in Naarden, representing a variety of disciplines with experience in the respiratory management of patients with neuromuscular disorders (NMD). The aims of the workshop were to agree upon and report minimum recommendations for the investigation and treatment of respiratory involvement in congenital muscular disorders, and to identify areas where further research is needed. The workshop specifically excluded patients with Duchenne muscular dystrophy where evidence for the need for and efficacy of the treatment of respiratory failure is better established. All participants contributed to the review and assessment of published evidence in the field, and current practice amongst the group was also compared. Despite the individual rarity of the conditions under consideration in this workshop, the accumulated experience of the group represented the care of more than 545 patients with these disorders, of whom around one-third were receiving mechanical ventilation.

Respiratory muscle coordination in acute spinal dogs

Our objectives were (1) to test whether respiratory muscles of spinal dogs can generate the alternating pattern of activation seen in intact animals and (2) to characterize the responsiveness of spinal rhythms to mechanical ventilation. We recorded the electromyographic activities of inspiratory muscles (diaphragm and parasternal intercostals) and expiratory muscles (triangularis sterni and transversus abdominis) in ten anesthetized dogs before and after transection of the cervical cord at levels C1–C2 ( n = 2), C2–C3 ( n = 6), and C8 ( n = 2). In 9 10 dogs, we observed short lasting (3–4 min) rhythmic ventilatory muscle activity for up to 3 h after transection. Inspiratory and expiratory muscles contracted simultaneously, suggesting an absence of mechanism(s) responsible for reciprocal muscle activation on a spinal level. Five of ten dogs showed tonic rib cage activity during apnea that was phasically modulated during mechanical ventilation. From the absence of alternating inspiratory and expiratory muscle activity in acute spinalized dogs, we conclude that dogs do not have a spinal pattern generator for respiration.

Clinical Assessment of the Respiratory Muscles

This review examines approaches to evaluation of the respiratory muscles and describes new techniques that may be more quantitative, less effort dependent, and less invasive than conventional methods. To evaluate strength of the respiratory muscles, maximum inspiratory and expiratory pressures remain useful measures. Potential methodologic errors, however, necessitate careful technique. Evaluation of the twitch response to direct phrenic nerve stimulation may ultimately prove more quantitative and less effort dependent than measurements of maximum pressure. Many techniques are also available to measure endurance of respiratory muscles, but most are less than satisfactory outside the research environment because of poor reproducibility and other procedural difficulties. The maximum incremental resistive loading test, however, has proven to be practical and well tolerated. There is little substitute for careful clinical observation of respiratory muscle coordination and movement, particularly in the patient with suspected respiratory muscle weakness or chest wall distortion. In conclusion, though the respiratory muscles are difficult to evaluate, techniques are available that can be quite helpful for assessment, particularly in response to interventions such as rehabilitation.

Respiratory muscle coordination and diaphragm length during expiratory threshold loading

Active expiration is produced by the abdominal muscles and the rib cage expiratory muscles. We hypothesized that the relative contribution of these two groups to expiration would affect diaphragmatic length and, hence, influence the subsequent inspiration. To address this question we measured the respiratory muscle response to expiratory threshold loading in spontaneously breathing anesthetized dogs. Prevagotomy, the increase in lung volume (functional residual capacity) and decrease in initial resting length of the diaphragm were attenuated by greater than 50% of values predicted by the passive relationships. Diaphragmatic activation (electromyogram) increased and tidal volume (VT) was preserved. Postvagotomy, effective expiratory muscle recruitment was abolished. The triangularis sterni muscle remained active, and the increase in lung volume was attenuated by less than 15% of that predicted by the passive relationship. Diaphragmatic length was shorter than predicted. VT was not restored, even though costal diaphragmatic and parasternal intercostal electromyogram increased. During expiratory threshold loading with abdominal muscles resected and vagus intact, recruitment of the rib cage expiratory muscles produced a reduction in lung volume comparable with prevagotomy; however, diaphragmatic length decreased markedly. Both the rib cage and abdominal expiratory muscles may defend lung volume; however, their combined action is important to restore diaphragmatic initial length and, accordingly, to preserve VT.

The Influence of Chronic Cerebellar Stimulation on Respiratory Muscle Coordination in a Patient with Cerebral Palsy

The effect of chronic cerebellar stimulation on respiratory muscle coordination has been evaluated using a relatively simple and objective target breathing test on one patient. Seven normal subjects were used as controls. Magnetometer recordings were used to determine whether abdominal and rib cage expansion were in phase. Subjects were asked to match their breathing frequency to a metronome signal. Their ability to control respiratory timing voluntarily was assessed in terms of the coefficient of variation (CV) of inspiratory time (Ti) and of expiratory time (Te). The CV's of Ti and Te were much greater in the patient in the absence of cerebrellar stimulation than they were in normal subjects. Both at 3 weeks and 6 months after implantation of the stimulator, a significant improvement in the performance of the patient was demonstrable with the stimulator on, although normal values were never achieved. This demonstrable influence of chronic cerebellar stimulation on respiratory muscle coordination has important implications for both the avoidance of respiratory complications and the potential improvement of speech in patients with cerebral palsy.

The influence of chronic cerebellar stimulation on respiratory muscle coordination in a patient with cerebral palsy

The influence of chronic cerebellar stimulation on respiratory muscle coordination in a patient with cerebral palsy

The Respiratory Muscles and the Mechanics of Breathing.

This is a thorough description of the performance of the muscles used in breathing. Included are history of previous concepts of the role played by various muscle groups, the anatomy and mechanical actions of respiratory structures, and electromyographic data obtained during respiration. These are correlated by the author to present a concept of the mechanics of breathing. The muscle groups so studied include those of the thorax, neck, back, abdomen, and larynx. They are studied both in quiet respiration and in varying degrees of hyperventilation. Most studies were done on normal patients, but some data are included on emphysematous subjects. A brief discussion of control and coordination of respiratory muscles and the work of breathing is included. There is also a discussion of the pressurevolume diagram of the thorax. The material is presented in a concise manner and in terminology which is readily understood. Graphs and actual recordings are used