scholarly journals Upper airway pressure-flow relationships and pharyngeal constrictor EMG activity during prolonged expiration in awake goats

2008 ◽  
Vol 105 (1) ◽  
pp. 100-108
Author(s):  
K. D. O'Halloran ◽  
G. E. Bisgard
Keyword(s):  
Airway Pressure ◽  
Muscle Activation ◽  
Upper Airway ◽  
Systemic Administration ◽  
Emg Activity ◽  
Airway Closure ◽  
Pressure Flow ◽  
Airway Occlusion ◽  
Adductor Muscles ◽  
Tracheal Pressure

We undertook the present investigation to establish whether narrowing/closure of the upper airway occurs during spontaneous and provoked respiratory rhythm disturbances and whether pharyngeal constrictor muscle recruitment occurs coincident with upper airway occlusion during prolonged expiratory periods. Upper airway pressure-flow relationships and middle pharyngeal constrictor (mPC) EMG activities were recorded in 11 adult female goats during spontaneous and provoked prolongations in expiratory time (Te). A total of 213 spontaneous prolongations of expiration were recorded. Additionally, 169 prolonged expiratory events preceded by an augmented breath were included in the analyses. In separate trials on different days, Te was prolonged by systemic administration of dopamine, by raising the inspired fraction of O2 from 0.10 to 1.00 during poikilocapnic conditions or by systemic administration of clonidine. Continuous tonic activation of the mPC EMG was observed during each prolonged Te period regardless of the duration or initiating cause. However, significant increases in subglottic tracheal pressure, with expiratory airflow braking indicative of upper airway narrowing or closure, was only observed during spontaneous events without a preceding augmented breath and during clonidine-induced events. Tonic mPC activation proved an unreliable indicator of airway occlusion. Furthermore, mPC muscle activation alone is not sufficient to induce pharyngeal occlusion during prolonged expiration. Our data suggest that airway closure is not a common occurrence during provoked respiratory disturbances in awake goats. We propose that airway closure, when present during prolonged Te, is more likely dependent on activation of laryngeal adductor muscles with glottic braking independent of pharyngeal narrowing.

Respiratory-related activity of soft palate muscles: augmentation by negative upper airway pressure

1994 ◽  
Vol 76 (1) ◽  
pp. 424-432 ◽  
Author(s):  
T. Van der Touw ◽  
N. O'Neill ◽  
A. Brancatisano ◽  
T. Amis ◽  
J. Wheatley ◽  
...  
Keyword(s):  
Soft Palate ◽  
Airway Pressure ◽  
Upper Airway ◽  
Substantial Contribution ◽  
Emg Activity ◽  
Nasal Breathing ◽  
Related Activity ◽  
Tracheal Pressure ◽  
Upper Airway Muscles ◽  
Muscle Responses

We studied respiratory-related activity of the soft palate muscles in 10 anesthetized tracheostomized supine dogs. Moving time average (MTA) electromyographic (EMG) activity was measured in the palatinus (PAL), levator veli palatini (LP), and tensor veli palatini (TP) with bipolar fine-wire electrodes and in the diaphragm with bipolar hook electrodes. Measurements were made during tracheostomy breathing and nasal breathing with the mouth sealed (NB). During tracheostomy breathing, all soft palate muscles displayed respiratory-related phasic inspiratory and expiratory as well as tonic EMG activity. During NB, peak inspiratory EMG activity increased in PAL, LP, and TP because of an increase in both phasic inspiratory and tonic MTA activity. In contrast, phasic expiratory activity did not change. A constant negative pressure equal to peak inspiratory tracheal pressure during NB was applied to the caudal end of the isolated upper airway with the nose occluded. This was associated with soft palate muscle responses qualitatively similar to the responses during NB but accounted for only 39, 25, and 32% of the magnitude of the peak inspiratory MTA EMG responses to NB in PAL, LP, and TP, respectively. Our results demonstrate that the soft palate muscles exhibit respiratory-related activity in common with other upper airway muscles. Furthermore, such activity is augmented in each soft palate muscle during NB, and negative upper airway pressure makes a substantial contribution to the recruitment of soft palate muscle activity.

Mechanical effects of pharyngeal constrictor activation on pharyngeal airway function

1999 ◽  
Vol 86 (1) ◽  
pp. 411-417 ◽  
Author(s):  
Samuel T. Kuna ◽  
Christi R. Vanoye
Keyword(s):  
Axial Force ◽  
Airway Pressure ◽  
Muscle Activation ◽  
Upper Airway ◽  
Stimulation Frequency ◽  
Airway Patency ◽  
Pharyngeal Airway ◽  
Mechanical Effects ◽  
Airway Function ◽  
Pharyngeal Branch

The mechanical effects of pharyngeal constrictor (PC) muscle activation on pharyngeal airway function were determined in 20 decerebrate, tracheotomized cats. In 10 cats, a high-compliance balloon attached to a pressure transducer was partially inflated to just occlude the pharyngeal airway. During progressive hyperoxic hypercapnia, changes in pharyngeal balloon pressure were directly related to phasic expiratory hyopharyngeus (middle PC) activity. In two separate protocols in 10 additional cats, the following measurements were obtained with and without bilateral electrical stimulation (0.2-ms duration, threshold voltage) of the distal cut end of the vagus nerve’s pharyngeal branch supplying PC motor output: 1) pressure-volume relationships in an isolated, sealed upper airway at a stimulation frequency of 30 Hz and 2) rostrally directed axial force over a stimulation frequency range of 0–40 Hz. Airway compliance determined from the pressure-volume relationships decreased with PC stimulation at and below resting airway volume. Compared with the unstimulated condition, PC stimulation increased airway pressure at airway volumes at and above resting volume. This constrictor effect progressively diminished as airway volume was brought below resting volume. At relatively low airway volumes below resting volume, PC stimulation decreased airway pressure compared with that without stimulation. PC stimulation generated a rostrally directed axial force that was directly related to stimulation frequency. The results indicate that PC activation stiffens the pharyngeal airway, exerting both radial and axial effects. The radial effects are dependent on airway volume: constriction of the airway at relatively high airway volumes, and dilation of the airway at relatively low airway volumes. The results imply that, under certain conditions, PC muscle activation may promote pharyngeal airway patency.

scholarly journals Geniohyoid muscle function in awake canines

2003 ◽  
Vol 95 (2) ◽  
pp. 810-817 ◽  
Author(s):  
M. Yokoba ◽  
H. G. Hawes ◽  
P. A. Easton
Keyword(s):  
Muscle Function ◽  
Breathing Pattern ◽  
Muscle Length ◽  
Upper Airway ◽  
Mechanical Action ◽  
Emg Activity ◽  
Airway Occlusion ◽  
Lateral Decubitus ◽  
The Right ◽  
Emg Electrodes

The geniohyoid (Genio) upper airway muscle shows phasic, inspiratory electrical activity in awake humans but no activity and lengthening in anesthetized cats. There is no information about the mechanical action of the Genio, including length and shortening, in any awake, nonanesthetized mammal during respiration (or swallowing). Therefore, we studied four canines, mean weight 28.8 kg, 1.5 days after Genio implantation with sonomicrometry transducers and bipolar electromyogram (EMG) electrodes. Awake recordings of breathing pattern, muscle length and shortening, and EMG activity were made with the animal in the right lateral decubitus position during quiet resting, CO2-stimulated breathing, inspiratory-resisted breathing (80 cmH2O · l-1 · s), and airway occlusion. Genio length and activity were also measured during swallowing, when it shortened, showing a 9.31% change from resting length, and its EMG activity increased 6.44 V. During resting breathing, there was no phasic Genio EMG activity at all, and Genio showed virtually no movement during inspiration. During CO2-stimulated breathing, Genio showed minimal lengthening of only 0.07% change from resting length, whereas phasic EMG activity was still absent. During inspiratory-resisted breathing and airway occlusion, Genio showed phasic EMG activity but still lengthened. We conclude that the Genio in awake, nonanesthetized canines shows active contraction and EMG activity only during swallowing. During quiet or stimulated breathing, Genio is electrically inactive with passive lengthening. Even against resistance, Genio is electrically active but still lengthens during inspiration.

Supraglottic airway pressure-flow relationships during oronasal airflow partitioning in dogs

1996 ◽  
Vol 81 (5) ◽  
pp. 1958-1964 ◽  
Author(s):  
T. C. Amis ◽  
N. O’Neill ◽  
T. Van Der Touw ◽  
A. Tully ◽  
A. Brancatisano
Keyword(s):  
Electrical Stimulation ◽  
Soft Palate ◽  
Airway Pressure ◽  
Airway Resistance ◽  
Upper Airway ◽  
Oral Route ◽  
Supraglottic Airway ◽  
Respiratory Drive ◽  
Pressure Flow ◽  
Oral Airway

Amis, T. C., N. O’Neill, T. Van der Touw, A. Tully, and A. Brancatisano. Supraglottic airway pressure-flow relationships during oronasal airflow partitioning in dogs. J. Appl. Physiol. 81(5): 1958–1964, 1996.—We studied pressure-flow relationships in the supraglottic airway of eight prone mouth-open anesthetized (intravenous chloralose or pentobarbital sodium) crossbred dogs (weight 15–26 kg) during increasing respiratory drive (CO2administration; n = 4) and during graded-voltage electrical stimulation (SV; n = 4) of the soft palate muscles. During increased respiratory drive, inspiratory airflow occurred via both the nose (V˙n) and mouth (V˙m), with the ratio of V˙n toV˙m [%(V˙n/V˙m)] decreasing maximally from 16.0 ± 7.0 (SD) to 2.4 ± 1.6% ( P < 0.05). Simultaneously, oral airway resistance at peak inspiratory flow decreased from 2.1 ± 1.0 to 0.4 ± 0.4 cmH2O ( P < 0.05), whereas nasal airway resistance did not change (14.4 ± 7.2 to 13.1 ± 5.4 cmH2O; P = 0.29). Inspiratory pressure-flow plots of the oral airway were inversely curvilinear or more complex in nature. Nasal pathway plots, however, demonstrated a positive linear relationship in all animals ( r = 0.87 ± 0.11; all P < 0.001). During electrical stimulation of soft palate muscle contraction accompanied by graded constant-inspiratory airflows of 45–385 ml/s through an isolated upper airway, %(V˙n/V˙m) decreased from 69 ± 50 to 10 ± 13% at a SV of 84 ± 3% of maximal SV ( P < 0.001). At a SV of 85 ± 1% of maximum, normalized oral airway resistance (expressed as percent baseline) fell to 5 ± 3%, whereas normalized nasal resistance was 80 ± 9% (both P< 0.03). Thus control of oronasal airflow partitioning in dogs appears mediated more by alterations in oral route geometry than by closure of the nasopharyngeal airway.

Active upper airway closure during induced central apneas in lambs is complete at the laryngeal level only

2003 ◽  
Vol 95 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Pierre-Hugues Fortier ◽  
Philippe Reix ◽  
Julie Arsenault ◽  
Dominique Dorion ◽  
Jean-Paul Praud
Keyword(s):  
Upper Airway ◽  
Emg Activity ◽  
Airway Closure ◽  
Internal Branch ◽  
Laryngeal Nerves ◽  
Before And After ◽  
Subglottal Pressure ◽  
Central Apneas ◽  
Afferent Innervation ◽  
Stimulation Of

We tested the hypotheses that active upper airway closure during induced central apneas in nonsedated lambs 1) is complete and occurs at the laryngeal level and 2) is not due to stimulation of the superior laryngeal nerves (SLN). Five newborn lambs were surgically instrumented to record thyroarytenoid (TA) muscle (glottal constrictor) electromyographic (EMG) activity with supra- and subglottal pressures. Hypocapnic and nonhypocapnic central apneas were induced before and after SLN sectioning in the five lambs. A total of 174 apneas were induced, 116 before and 58 after sectioning of the internal branch of the SLN (iSLN). Continuous TA EMG activity was observed in 88% of apneas before iSLN section and in 87% of apneas after iSLN section. A transglottal pressure different from zero was observed in all apneas with TA EMG activity, with a mean subglottal pressure of 4.3 ± 0.8 cmH2O before and 4.7 ± 0.7 cmH2O after iSLN section. Supraglottal pressure was consistently atmospheric. Sectioning of both iSLNs had no effects on the results. We conclude that upper airway closure during induced central apneas in lambs is active, complete, and occurs at the glottal level only. Consequently, a positive subglottal pressure is maintained throughout the apnea. Finally, this complete active glottal closure is independent from laryngeal afferent innervation.

Control of respiratory activity of the genioglossus muscle in micrognathic infants

1986 ◽  
Vol 61 (4) ◽  
pp. 1523-1533 ◽  
Author(s):  
J. L. Roberts ◽  
W. R. Reed ◽  
O. P. Mathew ◽  
B. T. Thach
Keyword(s):  
Upper Airway ◽  
Esophageal Pressure ◽  
Progressive Increase ◽  
Emg Activity ◽  
Nasal Breathing ◽  
Airway Patency ◽  
Tongue Muscle ◽  
Airway Occlusion ◽  
Pharyngeal Airway ◽  
Obstructive Sleep

The genioglossus (GG) muscle activity of four infants with micrognathia and obstructive sleep apnea was recorded to assess the role of this tongue muscle in upper airway maintenance. Respiratory air flow, esophageal pressure, and intramuscular GG electromyograms (EMG) were recorded during wakefulness and sleep. Both tonic and phasic inspiratory GG-EMG activity was recorded in each of the infants. On occasion, no phasic GG activity could be recorded; these silent periods were unassociated with respiratory embarrassment. GG activity increased during sigh breaths. GG activity also increased when the infants spontaneously changed from oral to nasal breathing and, in two infants, with neck flexion associated with complete upper airway obstruction, suggesting that GG-EMG activity is influenced by sudden changes in upper airway resistance. During sleep, the GG-EMG activity significantly increased with 5% CO2 breathing (P less than or equal to 0.001). With nasal airway occlusion during sleep, the GG-EMG activity increased with the first occluded breath and progressively increased during the subsequent occluded breaths, indicating mechanoreceptor and suggesting chemoreceptor modulation. During nasal occlusion trials, there was a progressive increase in phasic inspiratory activity of the GG-EMG that was greater than that of the diaphragm activity (as reflected by esophageal pressure excursions). When pharyngeal airway closure occurred during a nasal occlusion trial, the negative pressure at which the pharyngeal airway closed (upper airway closing pressure) correlated with the GG-EMG activity at the time of closure, suggesting that the GG muscle contributes to maintaining pharyngeal airway patency in the micrognathic infant.

Role of carotid sinus and aortic nerves in respiratory control of infant rats

1986 ◽  
Vol 251 (4) ◽  
pp. R811-R817 ◽  
Author(s):  
M. A. Hofer
Keyword(s):  
Airway Obstruction ◽  
Carotid Sinus ◽  
Respiratory Control ◽  
Upper Airway ◽  
Airway Occlusion ◽  
Infant Rats ◽  
Tracheal Pressure ◽  
Recovery Times ◽  
Prolonged Recovery ◽  
Low Amplitude

The roles of carotid sinus (CSN) and aortic depressor nerves (ADN) in the maintenance of rhythmic respiration and in the response to airway occlusion were investigated in 8- to 10-day-old infant rats. Cutting the CSN led to a periodic loss of rhythmic respiration with arrhythmic low-amplitude waveforms, frequent end-expiratory pauses, and occasional apneas observed in unanesthetized unrestrained pups studied in their home cage nests by impedance pneumography. Cutting the ADN alone did not have this effect. Sinoaortic denervation (SAD) in which both nerves were cut, produced a more severe disturbance that was not relieved by tracheostomy, indicating that it was not due to upper airway obstruction. Tracheal pressure recordings from anesthetized SAD infants in response to short periods of external airway obstruction showed reduced respiratory efforts and prolonged recovery times, deficits that may play a role in the mortality previously reported after SAD in infant rats.

Differential response of respiratory muscles to airway occlusion in infants

1985 ◽  
Vol 59 (3) ◽  
pp. 847-852 ◽  
Author(s):  
W. A. Carlo ◽  
M. J. Miller ◽  
R. J. Martin
Keyword(s):  
Total Duration ◽  
Respiratory Muscles ◽  
Upper Airway ◽  
Peak Amplitude ◽  
Emg Activity ◽  
Inspiratory Time ◽  
Surface Electrodes ◽  
Airway Occlusion ◽  
The Right ◽  
Respiratory Muscle Activity

The effect of end-expiratory occlusion on respiratory muscle activity was studied in 10 unsedated preterm infants during sleep. Electromyograms (EMG) of the upper airway were recorded from surface electrodes placed over the submental (SM) area; diaphragm (DIA) EMGs were obtained with identical electrodes over the right subcostal margin. Phasic SM EMG accompanied 56 +/- 36% of breaths during spontaneous breathing and increased to 80 +/- 26% (P less than 0.05) on the first inspiratory effort after occlusion. Occlusion increased peak amplitude (P less than 0.001) and total duration (P less than 0.005) of the SM EMG without significant changes in its initial rate of rise. In contrast, only the total duration of the DIA EMG increased (P less than 0.005) during occlusion. Inspiratory time increased from 470 +/- 120 to 720 +/- 210 ms (P less than 0.001) during the first occluded effort, but expiratory time did not change. With sustained occlusion, peak amplitude of the SM EMG progressively increased, but DIA EMG only significantly increased by the third occluded effort. Pharyngeal patency was invariably maintained throughout the induced airway occlusions. Sharp bursts of SM EMG activity coincided with resolution of spontaneous obstructive apneic episodes in four infants. The immediate increase in SM EMG associated with airway occlusion may be a mechanism that prevents the development of obstructive apnea.

Upper airway muscle activity during nasal occlusion in newborn babies

1989 ◽  
Vol 66 (3) ◽  
pp. 1328-1335 ◽  
Author(s):  
G. Cohen ◽  
D. J. Henderson-Smart
Keyword(s):  
Gestational Age ◽  
Muscle Activity ◽  
Upper Airway ◽  
Airway Closure ◽  
Term Infants ◽  
Airway Occlusion ◽  
Postmenstrual Age ◽  
Preterm Babies ◽  
The Stability ◽  
Upper Airway Muscles

Submental electromyorgams (SM EMG) were recorded from 20 preterm babies (gestational age 30 +/- 2 wk, postmenstrual age at study 35 +/- 2 wk) (mean +/- SD) and 3 full-term infants (7–14 days old). SM EMG was evaluated during eupnea and brief experimental airway occlusion. Phasic inspiratory SM EMG was rarely seen during eupnea. SM EMG tended to increase on the first occluded effort, although this increase was not statistically significant in most babies. All infants showed progressive breath-by-breath augmentation of phasic SM EMG during occlusions in rapid-eye-movement (REM) as well as quiet (QS) sleep; phasic increases in SM EMG were similar during REM and QS occlusions in the majority (16/22) of babies. Periods of airway closure were detected during 24 occlusions in 5 infants; phasic SM EMG was reduced on these occasions. The results are consistent with the idea that recruitment of upper airway muscles contributes to the stability of the airway of the preterm human.

scholarly journals Continuous positive airway pressure treatment does not normalize the prolonged reflex inhibition to inspiratory loading in obstructive sleep apnea

2016 ◽  
Vol 121 (4) ◽  
pp. 910-916
Author(s):  
Nicholas P. S. Murray ◽  
David K. McKenzie ◽  
Simon C. Gandevia ◽  
Jane E. Butler
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Continuous Positive Airway Pressure ◽  
Airway Obstruction ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Upper Airway ◽  
Cpap Therapy ◽  
Airway Occlusion ◽  
Obstructive Sleep

In obstructive sleep apnea (OSA), the short-latency inhibitory reflex (IR) of inspiratory muscles to airway occlusion is prolonged in proportion to the severity of the OSA. The mechanism underlying the prolongation may relate to chronic inspiratory muscle loading due to upper airway obstruction or sensory changes due to chronic OSA-mediated inflammation. Continuous positive airway pressure (CPAP) therapy prevents upper airway obstruction and reverses inflammation. We therefore tested whether CPAP therapy normalized the IR abnormality in OSA. The IR responses of scalene muscles to brief airway occlusion were measured in 37 adult participants with untreated, mostly severe, OSA, of whom 13 were restudied after the initiation of CPAP therapy (usage >4 h/night). Participants received CPAP treatment as standard clinical care, and the mean CPAP usage between initial and subsequent studies was 6.5 h/night (range 4.1-8.8 h/night) for a mean of 19 mo (range 4–41 mo). The duration of the IR in scalene muscles in response to brief (250 ms) inspiratory loading was confirmed to be prolonged in the participants with OSA. The IR was assessed before and after CPAP therapy. CPAP treatment did not normalize the prolonged duration of the IR to airway occlusion (60 ± 21 ms pretreatment vs. 59 ± 18 ms posttreatment, means ± SD) observed in participants with severe OSA. This suggests that the prolongation of IR reflects alterations in the reflex pathway that may be irreversible, or a specific disease trait.

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