Effect of hypercapnia and PEEP on expiratory muscle EMG and shortening

1989 ◽  
Vol 66 (3) ◽  
pp. 1408-1413 ◽  
Author(s):  
A. Oliven ◽  
S. G. Kelsen
Keyword(s):  
Electrical Activity ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Emg Activity ◽  
Expiratory Muscle ◽  
Integrated Emg ◽  
Length Changes ◽  
Expiratory Muscles ◽  
External Oblique ◽  
Spontaneously Breathing

The present study examined the effects of hypercapnia and positive end-expiratory pressure (PEEP) on the electromyographic (EMG) activity and tidal length changes of the expiratory muscles in 12 anesthetized, spontaneously breathing dogs. The integrated EMG activity of both abdominal (external oblique, internal oblique, rectus abdominis, and transverse abdominis) and thoracic (triangularis sterni, internal intercostal) expiratory muscles increased linearly with increasing PCO2 and PEEP. However, with both hypercapnia and PEEP, the percent increase in abdominal muscle electrical activity exceeded that of thoracic expiratory muscle activity. Both hypercapnia and PEEP increased the tidal shortening of the external oblique and rectus abdominis muscles. Changes in tidal length correlated closely with simultaneous increases in muscle electrical activity. However, during both hypercapnia and PEEP, length changes of the external oblique were significantly greater than those of the rectus abdominis. We conclude that both progressive hypercapnia and PEEP increase the electrical activity of all expiratory muscles and augment their tidal shortening but produce quantitatively different responses in the several expiratory muscles.

Changes in the neural drive to abdominal expiratory muscles in hemorrhagic hypotension

1994 ◽  
Vol 266 (6) ◽  
pp. H2423-H2429 ◽  
Author(s):  
R. F. Fregosi
Keyword(s):  
Pulmonary Ventilation ◽  
Respiratory Rhythm ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Abdominal Muscles ◽  
Neural Drive ◽  
Hemorrhagic Hypotension ◽  
Severe Hypotension ◽  
Expiratory Muscles ◽  
External Oblique

The purpose of this study was to test the hypothesis that hemorrhage-induced hypotension increases the neural drive to the abdominal expiratory muscles in chloralose-urethan-anesthetized cats that are studied under conditions of constant arterial PCO2 (PaCO2) and hyperoxia. A secondary aim was to describe in detail the concomitant changes in inspired pulmonary ventilation (VI) and the pattern of breathing under these conditions. The rectified and integrated electromyogram (EMG) of the external oblique and rectus abdominis muscles and VI were recorded in moderate and severe hemorrhagic hypotension, leading to reductions in mean blood pressure of approximately 30 and 60%, respectively. The PaCO2 was prevented from falling, and the arterial PO2 was maintained at a hyperoxic level (> 200 mmHg) by adding CO2 and O2 to the inspired gas mixture. VI increased by 2.5- and 5-fold in moderate and severe hypotension (P < 0.05). The changes in VI were mediated exclusively by changes in tidal volume, indicating that the reflex did not alter the activity of respiratory rhythm-generating structures. The EMG of external oblique muscles averaged 2, 44, and 100% in control conditions and in moderate and severe hypotension, respectively; corresponding values in rectus abdominis muscles were 10, 28, and 100% (P < 0.05 for both muscles). Bilateral cervical vagotomy caused a one- to three-fold decrease in the ventilatory response to hemorrhage and abolished the increase in abdominal muscle EMG activities. In conclusion, hemorrhagic hypotension reflexly increases pulmonary ventilation and the neural drive to the abdominal muscles. The reflex is vagally mediated, but the location of the receptors was not identified.

scholarly journals Quantification of the Differences in Electromyographic Activity Magnitude Between the Upper and Lower Portions of the Rectus Abdominis Muscle During Selected Trunk Exercises

2001 ◽  
Vol 81 (5) ◽  
pp. 1096-1101 ◽  
Author(s):  
Gregory J Lehman ◽  
Stuart M McGill
Keyword(s):  
Muscle Activity ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Oblique Muscle ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Rectus Abdominis Muscle ◽  
Emg Signal ◽  
External Oblique Muscle ◽  
External Oblique

Abstract Background and Purpose. Controversy exists around exercises and clinical tests that attempt to differentially activate the upper or lower portions of the rectus abdominis muscle. The purpose of this study was to assess the activation of the upper and lower portions of the rectus abdominis muscle during a variety of abdominal muscle contractions. Subjects. Subjects (N=11) were selected from a university population for athletic ability and low subcutaneous fat to optimize electromyographic (EMG) signal collection. Methods. Controlling for spine curvature, range of motion, and posture (and, therefore, muscle length), EMG activity of the external oblique muscle and upper and lower portions of rectus abdominis muscle was measured during the isometric portion of curl-ups, abdominal muscle lifts, leg raises, and restricted or attempted leg raises and curl-ups. A one-way repeated-measures analysis of variance was used to test for differences in activity between exercises in the external oblique and rectus abdominis muscles as well as between the portions of the rectus abdominis muscle. Results. No differences in muscle activity were found between the upper and lower portions of the rectus abdominis muscle within and between exercises. External oblique muscle activity, however, showed differences between exercises. Discussion and Conclusion. Normalizing the EMG signal led the authors to believe that the differences between the portions of the rectus abdominis muscle are small and may lack clinical or therapeutic relevance.

Abdominal muscle activity during hypercapnia in awake dogs

1994 ◽  
Vol 77 (3) ◽  
pp. 1393-1398 ◽  
Author(s):  
A. M. Leevers ◽  
J. D. Road
Keyword(s):  
Tidal Volume ◽  
Muscle Layer ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Transversus Abdominis ◽  
Emg Activity ◽  
Abdominal Muscles ◽  
Co2 Rebreathing ◽  
External Oblique ◽  
Internal Oblique

We previously found the internal abdominal muscle layer to be preferentially recruited during expiratory threshold loading in anesthetized and awake dogs. Expiratory threshold loading increases end-expiratory lung volume and hence can activate reflex pathways such as tonic vagal reflexes, which could influence abdominal muscle recruitment. Our objectives in the present study were to determine the effects of hypercapnia on abdominal muscle activation and the pattern of recruitment in awake dogs. Five tracheotomized dogs were chronically implanted with sonomicrometer transducers and fine-wire electromyogram (EMG) electrodes in each of the four abdominal muscles: transversus abdominis, internal oblique, external oblique, and rectus abdominis. Muscle length changes and EMG activity were studied in the awake dog at rest and during CO2 rebreathing. CO2 rebreathing produced a tripling of tidal volume and activation of the abdominal muscles. Despite the increase in tidal volume, there was no significant change in abdominal muscle end-inspiratory length. Both tonic and phasic expiratory shortening were greater in the internal muscle layer (transversus abdominis and internal oblique) than in the external muscle layer (external oblique and rectus abdominis). We conclude that the internal abdominal muscles are preferentially recruited by hypercapnia and vagal reflexes probably do not contribute to this differential recruitment but that segmental reflexes may be involved. The mechanical consequences of this recruitment are discussed.

Responses of the anterolateral abdominal muscles during cough and expiratory threshold loading in the cat

2000 ◽  
Vol 88 (4) ◽  
pp. 1207-1214 ◽  
Author(s):  
Donald C. Bolser ◽  
Paul J. Reier ◽  
Paul W. Davenport
Keyword(s):  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Transversus Abdominis ◽  
Emg Activity ◽  
Abdominal Muscles ◽  
Cough Reflex ◽  
Gastric Pressure ◽  
Simultaneous Activation ◽  
External Oblique ◽  
Internal Oblique

The present study was conducted to determine the pattern of activation of the anterolateral abdominal muscles during the cough reflex. Electromyograms (EMGs) of the rectus abdominis, external oblique, internal oblique, transversus abdominis, and parasternal muscles were recorded along with gastric pressure in anesthetized cats. Cough was produced by mechanical stimulation of the lumen of the intrathoracic trachea or larynx. The pattern of EMG activation of these muscles during cough was compared with that during graded expiratory threshold loading (ETL; 1–30 cmH2O). ETL elicited differential recruitment of abdominal muscle EMG activity (transversus abdominis > internal oblique > rectus abdominis ≅ external oblique). In contrast, both laryngeal and tracheobronchial cough resulted in simultaneous activation of all four anterolateral abdominal muscles with peak EMG amplitudes 3- to 10-fold greater than those observed during the largest ETL. Gastric pressures during laryngeal and tracheobronchial cough were at least eightfold greater than those produced by the largest ETL. These results suggest that, unlike their behavior during expiratory loading, the anterolateral abdominal muscles act as a unit during cough.

Effects of posture on abdominal muscle shortening in awake dogs

1993 ◽  
Vol 75 (4) ◽  
pp. 1452-1459 ◽  
Author(s):  
A. M. Leevers ◽  
J. D. Road
Keyword(s):  
Respiratory Activity ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Transversus Abdominis ◽  
Abdominal Muscles ◽  
Muscle Shortening ◽  
Lateral Decubitus ◽  
Length Changes ◽  
External Oblique ◽  
Internal Oblique

The objective of this study was to examine the effects of posture on tonic and phasic expiratory activity of the abdominal muscles in awake dogs. Six tracheostomized dogs were chronically instrumented with sonomicrometer transducers and bipolar electromyographic electrodes placed in each of the four abdominal muscles. To determine the effects of posture on tonic and phasic activity of individual abdominal muscles, muscle resting length (Lr) and tidal length changes (%Lr), respectively, were measured in awake dogs in the left lateral decubitus (LLD), sitting, and standing (STAND) positions. The transversus abdominis Lr consistently shortened when the dog was moved from LLD to STAND and lengthened when the dog was moved from LLD to the sitting position, and the external oblique Lr consistently lengthened when the dog went from LLD to STAND. The internal oblique and rectus abdominis had no consistent changes in Lr with a change in position. All four abdominal muscles actively shortened (%Lr) more in the upright positions. In addition, the internal layer (transversus abdominis and internal oblique) actively shortened more than the external layer (rectus abdominis and external oblique). In conclusion, both tonic and phasic respiratory activity of the abdominal muscles, reflected by changes in Lr and %Lr, respectively, were affected by changes in posture.

scholarly journals Respiratory Muscle Effort during Expiration in Successful and Failed Weaning from Mechanical Ventilation

2018 ◽  
Vol 129 (3) ◽  
pp. 490-501 ◽  
Author(s):  
Jonne Doorduin ◽  
Lisanne H. Roesthuis ◽  
Diana Jansen ◽  
Johannes G. van der Hoeven ◽  
Hieronymus W. H. van Hees ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Electrical Activity ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Weaning From Mechanical Ventilation ◽  
Expiratory Muscle ◽  
Diaphragm Electrical Activity ◽  
Gastric Pressure ◽  
Weaning Failure ◽  
Expiratory Muscles

Abstract What We Already Know about This Topic What This Article Tells Us That Is New Background Respiratory muscle weakness in critically ill patients is associated with difficulty in weaning from mechanical ventilation. Previous studies have mainly focused on inspiratory muscle activity during weaning; expiratory muscle activity is less well understood. The current study describes expiratory muscle activity during weaning, including tonic diaphragm activity. The authors hypothesized that expiratory muscle effort is greater in patients who fail to wean compared to those who wean successfully. Methods Twenty adult patients receiving mechanical ventilation (more than 72 h) performed a spontaneous breathing trial. Tidal volume, transdiaphragmatic pressure, diaphragm electrical activity, and diaphragm neuromechanical efficiency were calculated on a breath-by-breath basis. Inspiratory (and expiratory) muscle efforts were calculated as the inspiratory esophageal (and expiratory gastric) pressure–time products, respectively. Results Nine patients failed weaning. The contribution of the expiratory muscles to total respiratory muscle effort increased in the “failure” group from 13 ± 9% at onset to 24 ± 10% at the end of the breathing trial (P = 0.047); there was no increase in the “success” group. Diaphragm electrical activity (expressed as the percentage of inspiratory peak) was low at end expiration (failure, 3 ± 2%; success, 4 ± 6%) and equal between groups during the entire expiratory phase (P = 0.407). Diaphragm neuromechanical efficiency was lower in the failure versus success groups (0.38 ± 0.16 vs. 0.71 ± 0.36 cm H2O/μV; P = 0.054). Conclusions Weaning failure (vs. success) is associated with increased effort of the expiratory muscles and impaired neuromechanical efficiency of the diaphragm but no difference in tonic activity of the diaphragm.

Interaction of lung volume and chemical drive on respiratory muscle EMG and respiratory timing

1977 ◽  
Vol 42 (2) ◽  
pp. 287-295 ◽  
Author(s):  
S. G. Kelsen ◽  
M. D. Altose ◽  
N. S. Cherniack
Keyword(s):  
Electrical Activity ◽  
Lung Volume ◽  
Respiratory Muscle ◽  
Vagal Stimulation ◽  
Abdominal Muscle ◽  
Positive Pressure ◽  
Airway Occlusion ◽  
Continuous Positive Pressure ◽  
Spontaneously Breathing

The effect of increased FRC on the change in respiratory muscle electrical activity (EMG) and the duration of inspiration (Ti) and expiration (Te) produced by increases in chemical drive (i.e., progressive hypercapnia and isocapnic hypoxia) was assessed in 15 anesthetized, spontaneously breathing dogs. FRC was raised by applying continuous positive pressure (4 and 8 cmH2O) to the airway. Progressive hypercapnia and hypoxia were produced by rebreathing techniques. At any PCO2 or PO2, increases in FRC decreased diaphragm EMG (D); increased abdominal muscle EMG (AB); and prolonged Te without affecting Ti. The effect of increased FRC on D, AB, and Te diminished as PCO2 increased or PO2 decreased. The effect of sustained increases in lung volume in the absence of phasic changes was assessed by performing airway occlusion for a single inspiration during rebreathing at both control and increased FRC. The effects of increases in FRC were present during airway occlusion but were eliminated by vagotomy. We conclude, therefore, that tonic vagal stimulation produced by increases in FRC modified the change in respiratory muscle electrical activity and timing produced by increasing chemical drive.

scholarly journals Core Muscle Activity during Physical Fitness Exercises: A Systematic Review

2020 ◽  
Vol 17 (12) ◽  
pp. 4306 ◽  
Author(s):  
José M. Oliva-Lozano ◽  
José M. Muyor
Keyword(s):  
Systematic Review ◽  
Physical Fitness ◽  
Rectus Abdominis ◽  
Core Stability ◽  
Erector Spinae ◽  
Transversus Abdominis ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Lumbar Multifidus ◽  
External Oblique

The aim of this study was to systematically review the current literature on the electromyographic (EMG) activity of six core muscles (the rectus abdominis, the internal and external oblique, the transversus abdominis, the lumbar multifidus, and the erector spinae) during core physical fitness exercises in healthy adults. A systematic review of the literature was conducted on the Cochrane, EBSCO, PubMed, Scopus, and Web of Science electronic databases for studies from January 2012 to March 2020. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used. The inclusion criteria were as follows: (a) the full text available in English; (b) a cross-sectional or longitudinal (experimental or cohorts) study design; (c) the reporting of electromyographic activity as a percentage of maximum voluntary contraction (% MVIC), millivolts or microvolts; (d) an analysis of the rectus abdominis (RA), transversus abdominis (TA), lumbar multifidus (MUL), erector spinae (ES), and the internal (IO) or external oblique (EO); (e) an analysis of physical fitness exercises for core training; and (f) healthy adult participants. The main findings indicate that the greatest activity of the RA, EO, and ES muscles was found in free-weight exercises. The greatest IO activity was observed in core stability exercises, while traditional exercises showed the greatest MUL activation. However, a lack of research regarding TA activation during core physical fitness exercises was revealed, in addition to a lack of consistency between the studies when applying methods to measure EMG activity.

Electrical activation of expiratory muscles increases with time in pentobarbital-anesthetized dogs

1992 ◽  
Vol 72 (6) ◽  
pp. 2285-2291 ◽  
Author(s):  
D. O. Warner ◽  
M. J. Joyner ◽  
K. Rehder
Keyword(s):  
Electrical Activity ◽  
Important Variable ◽  
Transversus Abdominis ◽  
Implanted Electrodes ◽  
Expiratory Muscle ◽  
Inspiratory Muscles ◽  
Anesthetized Dogs ◽  
Expiratory Muscles ◽  
Muscle Groups ◽  
Over Time

Although the pentobarbital-anesthetized dog is often used as a model in studies of respiratory muscle activity during spontaneous breathing, there is no information regarding the stability of the pattern of breathing of this model over time. The electromyograms of several inspiratory and expiratory muscle groups were measured in six dogs over a 4-h period by use of chronically implanted electrodes. Anesthesia was induced with pentobarbital sodium (25 mg/kg iv), with supplemental doses to maintain constant plasma pentobarbital concentrations. Phasic electrical activity increased over time in the triangularis sterni, transversus abdominis, and external oblique muscles (expiratory muscles). The electrical activity of the costal diaphragm, crural diaphragm, and parasternal intercostal muscles (inspiratory muscles) was unchanged. These changes in electrical activity occurred despite stable plasma levels of pentobarbital and arterial PCO2. They were associated with changes in chest wall motion and an increased tidal volume with unchanged breathing frequency. We conclude that expiratory muscle groups are selectively activated with time in pentobarbital-anesthetized dogs lying supine. Therefore the duration of anesthesia is an important variable in studies using this model.

Electrical Activity of Powerhouse Muscles During the Teaser Exercise of Pilates Using Different Types of Apparatus

2016 ◽  
Vol 124 (2) ◽  
pp. 452-461 ◽  
Author(s):  
Débora da Rocha Werba ◽  
Débora Cantergi ◽  
Leandro Tolfo Franzoni ◽  
Alex de Oliveira Fagundes ◽  
Jefferson Fagundes Loss ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Gluteus Medius ◽  
Emg Activity ◽  
Mean Square ◽  
Kinematic Data ◽  
Wall Unit ◽  
Different Types ◽  
Pilates Method ◽  
External Oblique ◽  
Adductor Longus

We compared the electrical activity of certain powerhouse muscles—External Oblique, Multifidus, Adductor Longus, and Gluteus Medius—during the teaser exercise of the Pilates Method, performed on various types of apparatus—the Mat, Reformer, and Wall Unit. Fifteen female practitioners of the Classic Pilates Method (32.6 ± 7.7 years old; 21.9 ± 1.9 body mass index) performed the teaser in each situation while electromyographic (EMG) and kinematic data were collected. Root mean square values of the flexion phase were compared. All muscles showed higher EMG activity in Reformer compared with Wall Unit, and Multifidus, Adductor Longus, and Gluteus Medius showed higher EMG activity in Mat compared with Wall Unit. No difference was found between Reformer and Mat.

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