Effect of sleep-induced increases in upper airway resistance on 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.

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Respiratory muscle activity during repeated airflow interruption

Journal of Applied Physiology ◽

10.1152/jappl.1988.64.6.2314 ◽

1988 ◽

Vol 64 (6) ◽

pp. 2314-2317 ◽

Cited By ~ 10

Author(s):

J. Mead ◽

M. B. Reid

Keyword(s):

Muscle Activity ◽

Respiratory Muscle ◽

Rapid Succession ◽

Expiratory Muscles ◽

Respiratory Muscle Activity

We observed striking differences in respiratory muscle electromyogram activity when active expirations were interrupted in rapid succession, depending on the mode of interruption. When the interruptions were produced at the level of the glottis (utterances, uh-uh-uh-uh, at 5–8 Hz) there were synchronous bursts of activity from expiratory muscles in all three subjects during the periods of no flow and rapid bursts of diaphragmatic activity during the flow phases in one subject. In contrast, when similarly rapid interruptions of active expirations were produced with the tongue on a mouthpiece (utterance, te-te-te-te) or with an external valve, no synchronous bursts were observed. Since all interruptions would have been mechanically similar at expiratory muscular and pulmonary levels, we reasoned that the bursts with glottic interruptions were either programmed centrally or driven reflexly at the laryngeal level.

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

BMC Anesthesiology ◽

10.1186/s12871-019-0863-y ◽

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.

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Effect of dorsolateral pontine lesions on diaphragmatic activity during REMS

Journal of Applied Physiology ◽

10.1152/jappl.1990.68.4.1435 ◽

1990 ◽

Vol 68 (4) ◽

pp. 1435-1442 ◽

Cited By ~ 9

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.

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Effect of airway impedance on CO2 retention and respiratory muscle activity during NREM sleep

Journal of Applied Physiology ◽

10.1152/jappl.1988.65.4.1676 ◽

1988 ◽

Vol 65 (4) ◽

pp. 1676-1685 ◽

Cited By ~ 52

Author(s):

J. B. Skatrud ◽

J. A. Dempsey ◽

S. Badr ◽

R. L. Begle

Keyword(s):

Steady State ◽

Muscle Activity ◽

Respiratory Muscle ◽

Upper Airway ◽

Mechanical Impedance ◽

Nrem Sleep ◽

Load Compensation ◽

End Tidal ◽

Reduced Density ◽

Respiratory Muscle Activity

We hypothesized that a sleep-induced increase in mechanical impedance contributes to CO2 retention and respiratory muscle recruitment during non-rapid-eye-movement (NREM) sleep. The effect NREM sleep on respiratory muscle activity and CO2 retention was measured in healthy subjects who increased maximum total pulmonary resistance (RLmax, 1-81 cmH2O.l-1.s) from awake to NREM sleep. We determined the effects of this sleep-induced increase in airway impedance by steady-state inhalation of a reduced-density gas mixture (79% He-21% O2, He-O2). Both arterialized blood PCO2 (PaCO2) and end-tidal PCO2 (PETCO2) were measured. Inspiratory (EMGinsp) and expiratory (EMGexp) respiratory muscle electromyogram activity was measured. NREM sleep caused 1) RLmax to increase (7 +/- 3 vs. 39 +/- 28 cmH2O.l-1.s), 2) PaCO2 and/or PETCO2 to increase in all subjects (40 +/- 2 vs. 44 +/- 3 Torr), and 3) EMGinsp to increase in 8 of 9 subjects and EMGexp to increase in 9 of 17 subjects. Compared with steady-state air breathing during NREM sleep, steady-state He-O2 breathing 1) reduced RLmax by 38%, 2) decreased PaCO2 and PETCO2 by 2 Torr, and 3) decreased both EMGinsp (-20%) and EMGexp (-54%). We concluded that the sleep-induced increase in upper airway resistance accompanied by the absence of immediate load compensation is an important determinant of CO2 retention, which, in turn, may cause augmentation of inspiratory and expiratory muscle activity above waking levels during NREM sleep.

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Surface Recordings of Respiratory Muscle Activity during Speech

Journal of Speech Language and Hearing Research ◽

10.1044/jshr.3203.657 ◽

1989 ◽

Vol 32 (3) ◽

pp. 657-667 ◽

Cited By ~ 18

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.

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

Journal of Applied Physiology ◽

10.1152/jappl.1992.72.4.1355 ◽

1992 ◽

Vol 72 (4) ◽

pp. 1355-1361 ◽

Cited By ~ 8

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.

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Semi-automated Detection of the Timing of Respiratory Muscle Activity: Validation and First Application

Frontiers in Physiology ◽

10.3389/fphys.2021.794598 ◽

2022 ◽

Vol 12 ◽

Author(s):

Antenor Rodrigues ◽

Luc Janssens ◽

Daniel Langer ◽

Umi Matsumura ◽

Dmitry Rozenberg ◽

...

Keyword(s):

Muscle Activity ◽

Respiratory Muscle ◽

Respiratory Muscles ◽

Failure Surface ◽

Surface Emg ◽

Emg Activity ◽

Emg Signal ◽

Activity Duration ◽

Millisecond Accuracy ◽

Respiratory Muscle Activity

Background: Respiratory muscle electromyography (EMG) can identify whether a muscle is activated, its activation amplitude, and timing. Most studies have focused on the activation amplitude, while differences in timing and duration of activity have been less investigated. Detection of the timing of respiratory muscle activity is typically based on the visual inspection of the EMG signal. This method is time-consuming and prone to subjective interpretation.Aims: Our main objective was to develop and validate a method to assess the respective timing of different respiratory muscle activity in an objective and semi-automated manner.Method: Seven healthy adults performed an inspiratory threshold loading (ITL) test at 50% of their maximum inspiratory pressure until task failure. Surface EMG recordings of the costal diaphragm/intercostals, scalene, parasternal intercostals, and sternocleidomastoid were obtained during ITL. We developed a semi-automated algorithm to detect the onset (EMG, onset) and offset (EMG, offset) of each muscle’s EMG activity breath-by-breath with millisecond accuracy and compared its performance with manual evaluations from two independent assessors. For each muscle, the Intraclass Coefficient correlation (ICC) of the EMG, onset detection was determined between the two assessors and between the algorithm and each assessor. Additionally, we explored muscle differences in the EMG, onset, and EMG, offset timing, and duration of activity throughout the ITL.Results: More than 2000 EMG, onset s were analyzed for algorithm validation. ICCs ranged from 0.75–0.90 between assessor 1 and 2, 0.68–0.96 between assessor 1 and the algorithm, and 0.75–0.91 between assessor 2 and the algorithm (p < 0.01 for all). The lowest ICC was shown for the diaphragm/intercostal and the highest for the parasternal intercostal (0.68 and 0.96, respectively). During ITL, diaphragm/intercostal EMG, onset occurred later during the inspiratory cycle and its activity duration was shorter than the scalene, parasternal intercostal, and sternocleidomastoid (p < 0.01). EMG, offset occurred synchronously across all muscles (p ≥ 0.98). EMG, onset, and EMG, offset timing, and activity duration was consistent throughout the ITL for all muscles (p > 0.63).Conclusion: We developed an algorithm to detect EMG, onset of several respiratory muscles with millisecond accuracy that is time-efficient and validated against manual measures. Compared to the inherent bias of manual measures, the algorithm enhances objectivity and provides a strong standard for determining the respiratory muscle EMG, onset.

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Effects of expiratory loading on respiration in humans

Journal of Applied Physiology ◽

10.1152/jappl.1980.49.4.601 ◽

1980 ◽

Vol 49 (4) ◽

pp. 601-608 ◽

Cited By ~ 19

Author(s):

B. Gothe ◽

N. S. Cherniack

Keyword(s):

Muscle Activity ◽

Healthy Subjects ◽

Respiratory Muscle ◽

Resistive Load ◽

Similar Magnitude ◽

Occlusion Pressure ◽

Ventilatory Responses ◽

Residual Capacity ◽

Resistive Loads ◽

The Difference

We examined the effects of expiratory resistive loads of 10 and 18 cmH2O.l-1.s in healthy subjects on ventilation and occlusion pressure responses to CO2, respiratory muscle electromyogram, pattern of breathing, and thoracoabdominal movements. In addition, we compared ventilation and occlusion pressure responses to CO2 breathing elicited by breathing through an inspiratory resistive load of 10 cmH2O.l-1.s to those produced by an expiratory load of similar magnitude. Both inspiratory and expiratory loads decreased ventilatory responses to CO2 and increased the tidal volume achieved at any given level of ventilation. Depression of ventilatory responses to Co2 was greater with the larger than with the smaller expiratory load, but the decrease was in proportion to the difference in the severity of the loads. Occlusion pressure responses were increased significantly by the inspiratory resistive load but not by the smaller expiratory load. However, occlusion pressure responses to CO2 were significantly larger with the greater expiratory load than control. Increase in occlusion pressure observed could not be explained by changes in functional residual capacity or chemical drive. The larger expiratory load also produced significant increases in electrical activity measured during both inspiration and expiration. These results suggest that sufficiently severe impediments to breathing, even when they are exclusively expiratory, can enhance inspiratory muscle activity in conscious humans.

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