Vagal contributions to respiratory muscle activity during eupnea in the awake dog

1992 ◽  
Vol 72 (4) ◽  
pp. 1355-1361 ◽  
Author(s):  
D. M. Ainsworth ◽  
C. A. Smith ◽  
B. D. Johnson ◽  
S. W. Eicker ◽  
K. S. Henderson ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Transversus Abdominis ◽  
Emg Activity ◽  
Expiratory Muscle ◽  
Vagal Blockade ◽  
Inspiratory Activity ◽  
Vagal Cooling ◽  
Respiratory Muscle Activity

We examined the effects of reversible vagal cooling on respiratory muscle activities in awake chronically instrumented tracheotomized dogs. We specifically analyzed electromyographic (EMG) activity and its ventilatory correlates, end-expiratory lung volume (EELV) and diaphragmatic resting length via sonomicrometry. Elimination of phasic and tonic mechanoreceptor activity by vagal cooling doubled the EMG activity of the costal, crural, and parasternal muscles, with activation occurring sooner relative to the onset of inspiratory flow. Diaphragmatic postinspiration inspiratory activity in the intact dog coincided with a brief mechanical shortening of the diaphragm during early expiration; vagal blockade removed both the electrical activity and the mechanical shortening. Vagal blockade also doubled the EMG activity of a rib cage expiratory muscle, the triangularis sterni, but reduced that of an abdominal expiratory muscle, the transversus abdominis. Within-breath electrical activity of both muscles occurred sooner relative to the onset of expiratory flow during vagal blockade. Vagal cooling was also associated with a 12% increase in EELV and a 5% decrease in end-expiratory resting length of the diaphragm. We conclude that vagal input significantly modulates inspiratory and expiratory muscle activities, which help regulate EELV efficiently and optimize diaphragmatic length during eupneic breathing in the awake dog.

Vagal modulation of respiratory muscle activity in awake dogs during exercise and hypercapnia

1992 ◽  
Vol 72 (4) ◽  
pp. 1362-1367 ◽  
Author(s):  
D. M. Ainsworth ◽  
C. A. Smith ◽  
B. D. Johnson ◽  
S. W. Eicker ◽  
K. S. Henderson ◽  
...  
Keyword(s):  
Lung Volume ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Treadmill Exercise ◽  
Rib Cage ◽  
Expiratory Muscle ◽  
Vagal Modulation ◽  
Vagal Cooling ◽  
Respiratory Muscle Activity

Using chronically instrumented awake tracheotomized dogs, we examined the contributions of vagal feedback to respiratory muscle activities, both electrical and mechanical, during normoxic hypercapnia (inspired CO2 fraction = 0.03, 0.04, 0.05, and 0.06) and during mild treadmill exercise (3, 4.3, and 6.4 km/h). Cooling exteriorized vagal loops eliminated both phasic and tonic mechanoreceptor input during either of these hyperpneas. At a given chemical or locomotor stimulus, vagal cooling caused a further increase in costal, crural, parasternal, and rib cage expiratory (triangularis sterni) muscles. No further change in abdominal expiratory muscle activity occurred secondary to vagal cooling during these hyperpneas. However, removal of mechanoreceptor input during hypercapnia was not associated with consistent changes in end-expiratory lung volume, as measured by the He-N2 rebreathe technique. We conclude that during these hyperpneas 1) vagal input is not essential for augmentation of expiratory muscle activity and 2) decrements in abdominal expiratory muscle activity may be offset by increments in rib cage expiratory muscle activity and contribute to the regulation of end-expiratory lung volume.

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.

Changes in respiratory muscle activity in ponies when end-expiratory lung volume is increased

1994 ◽  
Vol 76 (5) ◽  
pp. 2015-2025 ◽  
Author(s):  
B. K. Erickson ◽  
H. V. Forster ◽  
T. F. Lowry ◽  
L. G. Pan ◽  
M. J. Korducki ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Lung Volume ◽  
Negative Pressure ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Transversus Abdominis ◽  
Vagal Afferents ◽  
Breathing Frequency ◽  
Respiratory Muscle Activity

The objective of the present study was to determine whether lung and diaphragm afferents contribute to the changes in respiratory muscle activity when end-expiratory lung volume (EELV) is changed in ponies. We studied the responses of the diaphragm and the transversus abdominis (TA) muscles to passive increases in EELV in awake intact (I), diaphragm-deafferented (DD), pulmonary vagal- (hilar nerve) denervated (HND), and DD + HND ponies. Negative pressure of -10 or -20 cmH2O applied around the ponies′ torsos [positive transrespiratory (TR) pressure] increased (P < 0.05) EELV in all ponies; the increases were more (P < 0.05) in HND and less (P < 0.05) in DD than in I ponies. In I ponies, positive TR pressure increased (P < 0.05) the rate of rise of the integrated diaphragmatic electromyogram (EMG), reflecting increased drive to the muscle. This increase was less (P < 0.05) in DD and HND than in I ponies. In DD + HND ponies, there was no significant (P > 0.10) change in drive to the diaphragm during positive TR pressure. In I ponies, positive TR pressure increased (P < 0.05) the duration and mean activity of the TA EMG. In HND and DD + HND ponies, the TA EMG was not altered by positive TR pressure. I and DD ponies decreased (P < 0.05) breathing frequency but maintained tidal volume (VT) during positive TR pressure. HND and DD+HND ponies increased breathing frequency (P < 0.05) and decreased (P < 0.05) VT during positive TR pressure. We conclude that, during positive TR pressure when the diaphragm is presumably at a mechanical disadvantage, diaphragm and vagal afferents mediate increased drive to the diaphragm to prevent VT from decreasing. In addition, during positive TR pressure, vagal afferents mediate an increase in duration of TA activity, which minimizes the increase in EELV.

scholarly journals Respiratory muscle activity after spontaneous, neostigmine- or sugammadex-enhanced recovery of neuromuscular blockade: a double blind prospective randomized controlled trial

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Tom Schepens ◽  
Koen Janssens ◽  
Sabine Maes ◽  
Davina Wildemeersch ◽  
Jurryt Vellinga ◽  
...  
Keyword(s):  
Neuromuscular Blockade ◽  
Muscle Activity ◽  
Spontaneous Breathing ◽  
Respiratory Muscle ◽  
Secondary Outcome ◽  
Emg Activity ◽  
Double Blind ◽  
Randomized Controlled ◽  
The Moment ◽  
Respiratory Muscle Activity

Abstract Background The use of neostigmine after neuromuscular blockade (NMB) has been associated with postoperative respiratory complications. In previous studies, we found lower diaphragmatic activity after neostigmine reversal of NMB, compared to sugammadex. It is still unclear whether the adequate use of neostigmine guarantees normal respiratory muscle function after NMB. In this study, we wanted to assess the effect of commonly used degrees of NMB and their possible reversal strategies on respiratory muscle activity after the return of normal neuromuscular transmission. Methods This is a randomized, controlled, parallel-group, single-centre, double-blind study in patients scheduled for intracranial surgery at a tertiary academic hospital in Belgium. All participants received target controlled propofol/remifentanil anesthesia and were randomized into one of five groups, receiving either a shallow NMB with no reversal (shallow/saline), a shallow NMB with sugammadex reversal (shallow/sugammadex), a moderate NMB with neostigmine reversal (moderate/neostigmine), a moderate NMB with sugammadex reversal (moderate/sugammadex), or a deep NMB with sugammadex reversal (deep/sugammadex). Primary and secondary outcome parameters were diaphragm and intercostal electromyographic (EMG) activity at the moment of resumed spontaneous breathing activity, defined as a maximal interval of 10 min after the first spontaneous breath. Results For the five groups, a total of 55 patients could be included in the final analysis. Median time of spontaneous breathing analyzed was 5 min (IQR 3–9.5 min). Both the moderate/sugammadex and the moderate/neostigmine groups had lower levels of diaphragm EMG compared to the shallow/sugammadex group. The moderate/neostigmine group had lower levels of intercostal EMG activity compared to the shallow/saline group. Conclusions In this study, the depth of neuromuscular blockade and type of reversal strategy impacts respiratory muscle activity at the moment of resumed spontaneous breathing and recovery of neuromuscular blockade. Both groups that received moderate NMB had lower levels of diaphragm EMG, compared to the shallow NMB group with sugammadex reversal. Compared to the shallow NMB group with no reversal, the moderate NMB with neostigmine reversal group had lower intercostal EMG activity. Trial registration Clinicaltrials.gov NCT01962298 on October 9, 2013 and EudraCT 2013–001926-25 on October 10, 2013.

Effect of sleep-induced increases in upper airway resistance on respiratory muscle activity

1991 ◽  
Vol 70 (1) ◽  
pp. 158-168 ◽  
Author(s):  
K. G. Henke ◽  
J. A. Dempsey ◽  
M. S. Badr ◽  
J. M. Kowitz ◽  
J. B. Skatrud
Keyword(s):  
Muscle Activity ◽  
Respiratory Muscle ◽  
Peak Flow ◽  
Nrem Sleep ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Stage 2 Sleep ◽  
Expiratory Muscles ◽  
Resistive Loads ◽  
Respiratory Muscle Activity

To investigate the response of inspiratory and expiratory muscles to naturally occurring inspiratory resistive loads in the absence of conscious control, five male "snorers" were studied during non-rapid-eye-movement (NREM) sleep with and without continuous positive airway pressure (CPAP). Diaphragm (EMGdi) and scalene (EMGsc) electromyographic activity were monitored with surface electrodes and abdominal EMG activity (EMGab) with wire electrodes. Subjects were studied in the following conditions: 1) awake, 2) stage 2 sleep, 3) stage 3/4 sleep, 4) CPAP during stage 3/4 sleep, 5) CPAP plus end-tidal CO2 pressure (PETCO2) isocapnic to stage 2 sleep, and 6) CPAP plus PETCO2 isocapnic to stage 3/4 sleep. Inspired pulmonary resistance (RL) at peak flow rate and PETCO2 increased in all stages of sleep. Activity of EMGdi, EMGsc, and EMGab increased significantly in stage 3/4 sleep. CPAP reduced RL at peak flow, increased tidal volume and expired ventilation, and reduced PETCO2. EMGdi and EMGsc were reduced, and EMGab was silenced. During CPAP, with CO2 added to make PETCO2 isocapnic to stage 3/4 sleep, EMGsc and EMGab increased, but EMGdi was augmented in only one-half of the trials. EMG activity in this condition, however, was only 75% (EMGsc) and 43% (EMGab) of the activity observed during eupneic breathing in stage 3/4 sleep when PETCO2 was equal but RL was much higher. We conclude that during NREM sleep 1) inspiratory and expiratory muscles respond to internal inspiratory resistive loads and the associated dynamic airway narrowing and turbulent flow developed throughout inspiration, 2) some of the augmentation of respiratory muscle activity is also due to the hypercapnia that accompanies loading, and 3) the abdominal muscles are the most sensitive to load and CO2 and the diaphragm is the least sensitive.

Variations in respiratory muscle activity during echolocation when stationary in three species of bat (Microchiroptera: Vespertilionidae)

2001 ◽  
Vol 204 (24) ◽  
pp. 4185-4197
Author(s):  
Winston C. Lancaster ◽  
J. R. Speakman
Keyword(s):  
Muscle Activity ◽  
Respiratory Muscle ◽  
Respiratory Muscles ◽  
Transversus Abdominis ◽  
Abdominal Muscles ◽  
Pteronotus Parnellii ◽  
Economic Production ◽  
Morphological Adaptations ◽  
The Family ◽  
Respiratory Muscle Activity

SUMMARY Echolocating bats use respiratory muscles to power the production of biosonar vocalisations. The physical characteristics of these calls vary among species of bat, and variations also exist in the timing and patterns of respiratory muscle recruitment during echolocation. We recorded electromyograms from the respiratory muscles of three species of bat (Family Vespertilionidae) while the animals vocalised from stationary positions. Activity was recorded consistently from the lateral abdominal muscles (internal abdominal oblique and transversus abdominis) from all calling bats, but we found much variation within and among species. Bats in the family Vespertilionidae devoted longer periods of expiratory muscle activity to each call than did the mormoopid bat Pteronotus parnellii. These differences correlate negatively with the duration of calls. We suggest that morphological adaptations in some bats may facilitate the economic production of echolocation calls at rest.

scholarly journals Dyspnea: an update

2010 ◽  
Vol 5 ◽  
Author(s):  
Giorgio Scano
Keyword(s):  
Muscle Activity ◽  
Respiratory Muscle ◽  
Expiratory Muscle ◽  
The Relationship ◽  
Respiratory Muscle Activity

Our understanding of the nature and mechanisms of dyspnea has greatly evolved over the last two centuries. Although the relationship was never form- ally specified, discomfort was always assumed to accompany respiratory muscle activity. Hypotheses and theories of dyspnea thus became synonymous with the factors controlling the extremes of respira- tory muscle activity, with expiratory muscle activity and discomfort now being known to be controlled by the same factors.

Effect of dorsolateral pontine lesions on diaphragmatic activity during REMS

1990 ◽  
Vol 68 (4) ◽  
pp. 1435-1442 ◽  
Author(s):  
J. C. Hendricks ◽  
L. R. Kline ◽  
R. O. Davies ◽  
A. I. Pack
Keyword(s):  
Muscle Activity ◽  
Respiratory Muscle ◽  
Sleep Disordered Breathing ◽  
Average Rate ◽  
Emg Activity ◽  
Rapid Eye Movement Sleep ◽  
Muscle Atonia ◽  
Before And After ◽  
Respiratory Muscle Activity ◽  
Diaphragm Activity

Muscle atonia is a feature of normal rapid-eye-movement sleep (REMS). The suppression of accessory respiratory muscle activity has been investigated and a role for sleep-disordered breathing hypothesized, but the suppression of diaphragmatic activity has rarely been considered. We hypothesized that the activity of the diaphragm was suppressed by an area of the dorsolateral pons during REMS. Lesions in this region have previously been shown to abolish the atonia of REMS. The diaphragmatic electromyogram (EMG) activity was analyzed in five naturally sleeping cats before and after pontine lesions leading to REMS without atonia. Although respiratory timing parameters were not altered by the lesion, the inspiratory rate of rise was significantly increased in all cats, and the brief pauses (40-100 ms) in the diaphragmatic EMG normally seen in REMS were virtually abolished. We conclude that the dorsolateral pons has a role in suppressing diaphragmatic activation during REMS. This suppression affects the average rate of rise of diaphragmatic activity and also leads to brief intermittent complete cessation of ongoing muscle activity. These decrements in diaphragm activity could jeopardize ventilation during REMS.

Surface Recordings of Respiratory Muscle Activity during Speech

1989 ◽  
Vol 32 (3) ◽  
pp. 657-667 ◽  
Author(s):  
David H. McFarland ◽  
Anne Smith
Keyword(s):  
Chest Wall ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Respiratory Muscles ◽  
Emg Activity ◽  
Breathing Cycle ◽  
Surface Electrodes ◽  
Disk Electrodes ◽  
Respiratory Muscle Activity ◽  
Accessory Respiratory Muscles

Bipolar electromyographic (EMG) recordings were made from six chest wall and nasal sites with disk electrodes attached to the skin. Electrode locations were based on previous studies of nonspeech breathing and were designed to sample the activity of both primary and accessory respiratory muscles. EMG activity was sampled while subjects performed a series of speech and nonspeeeh tasks. The results revealed that surface electrodes could sample the activity of respiratory muscles during speech and other ventilatory tasks, particularly during the expiratory phases of the breathing cycle.

Effects of pulse lung inflation on chest wall expiratory motor activity

2007 ◽  
Vol 102 (1) ◽  
pp. 485-491 ◽  
Author(s):  
Jaroslaw R. Romaniuk ◽  
Thomas E. Dick ◽  
Krzysztof E. Kowalski ◽  
Anthony F. DiMarco
Keyword(s):  
Motor Activity ◽  
Muscle Activity ◽  
Transversus Abdominis ◽  
Emg Activity ◽  
Abdominal Muscles ◽  
Phase Duration ◽  
Lung Inflation ◽  
Expiratory Phase ◽  
Expiratory Muscle ◽  
Bilateral Vagotomy

The effects of pulse lung inflation (LI) on expiratory muscle activity and phase duration (Te) were determined in anesthetized, spontaneously breathing dogs ( n = 20). A volume syringe was used to inflate the lungs at various times during the expiratory phase. The magnitude of lung volume was assessed by the corresponding change in airway pressure (Paw; range 2–20 cmH2O). Electromyographic (EMG) activities were recorded from both thoracic and abdominal muscles. Parasternal muscle EMG was used to record inspiratory activity. Expiratory activity was assessed from the triangularis sterni (TS), internal intercostal (IIC), and transversus abdominis (TA) muscles. Lung inflations <7 cmH2O consistently inhibited TS activity but had variable effects on TA and IIC activity and expiratory duration. Lung inflations resulting in Paw values >7 cmH2O, however, inhibited expiratory EMG activity of each of the expiratory muscles and lengthened Te in all animals. The responses of expiratory EMG and Te were directly related to the magnitude of the lung inflation. The inhibition of expiratory motor activity was independent of the timing of pulse lung inflation during the expiratory phase. The inhibitory effects of lung inflation were eliminated by bilateral vagotomy and could be reproduced by electrical stimulation of the vagus nerve. We conclude that pulse lung inflation resulting in Paw between 7 and 20 cmH2O produces a vagally mediated inhibition of expiratory muscle activity that is directly related to the magnitude of the inflation. Lower inflation pressures produce variable effects that are muscle specific.

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