Pharyngeal airway-stabilizing function of sternohyoid and sternothyroid muscles in the rabbit

1984 ◽  
Vol 57 (6) ◽  
pp. 1790-1795 ◽  
Author(s):  
J. L. Roberts ◽  
W. R. Reed ◽  
B. T. Thach
Keyword(s):  
Upper Airway ◽  
Progressive Increase ◽  
Electromyographic Activity ◽  
Tidal Breathing ◽  
Mechanical Tension ◽  
Airway Occlusion ◽  
Pharyngeal Airway ◽  
Airway Collapse ◽  
Closing Pressure ◽  
Stimulation Of

The upper airway is vulnerable to collapse from negative intraluminal pressures during inspiration. The tongue muscles, the genioglossi and geniohyoids, by contracting during inspiration, appear to function to resist this collapse. This study supports the hypothesis that two cervical strap muscles, the sternohyoid and sternothyroid, have a similar function. First, phasic inspiratory electromyographic activity was recorded from the sternohyoid and sternothyroid muscles of nine anesthetized rabbits during tidal breathing. Furthermore, each muscle showed a progressive increase in electromyographic activity with airway occlusion. Second, in eight rabbits, by determining the amount of negative pressure required to collapse the upper airway (airway closing pressure determination), it was shown that upper airway stability improved with electrical stimulation of either the paired sternohyoid or sternothyroid muscles. In addition, in 12 freshly killed rabbits, mechanical tension, mimicking the contraction of either the sternohyoid or sternothyroid, improved airway stability. Finally, observations of the pharyngeal lumen utilizing a fiber-optic endoscope, revealed concentric narrowing of the oro- and nasopharynx when airway pressure was lowered and concentric widening when tension was increased in the sternohyoid or sternothyroid muscles. These findings support the hypothesis that phasic inspiratory contraction of the sternohyoid and sternothyroid muscles functions to resist pharyngeal airway collapse due to negative intraluminal pressures.

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.

A neuromuscular mechanism maintaining extrathoracic airway patency

1979 ◽  
Vol 46 (4) ◽  
pp. 772-779 ◽  
Author(s):  
R. T. Brouillette ◽  
B. T. Thach
Keyword(s):  
Negative Pressure ◽  
Hyoid Bone ◽  
Electromyographic Activity ◽  
Depth Of Anesthesia ◽  
Blood Gas ◽  
Nerve Section ◽  
Airway Patency ◽  
Airway Occlusion ◽  
Extrathoracic Airway ◽  
Closing Pressure

The ability of the extrathoracic airway (ETA) to remain open when exposed to negative pressure was investigated in rabbits. Postmortem, the ETA collapsed at -6.3 +/- 0.6 cmH2O whereas, during airway occlusion maneuvers in lightly anesthetized animals, it remained patent at pressures as low as -80 cmH2O. This discrepancy suggested that a neuromuscular mechanism maintains ETA patency. Four findings indicated that the genioglossus and geniohyoid muscles, which pull the tongue and hyoid bone anteriorly, help maintain ETA patency: 1) anterior movement of the hyoid bone increased the negative pressure at which the ETA collapsed postmortem, 2) ETA closure during occluded inspirations occurred after 12th nerve section abolished electromyographic activity in these muscles and 3) after deep anesthesia depressed such activity, and 4) closing pressure was linearly related to peak integrated electromyograms of the two muscles. After 12th nerve section, ETA closing pressure became more negative with progressive asphyxia greatly exceeding postmortem closing pressure, which suggests that other muscles also help maintain ETA patency. Blood gas tensions, respiratory system mechanoreceptors, and depth of anesthesia appear to influence genioglossus and geniohyoid activity.

Effects of Recurrent Laryngeal Nerve Transection and Vagotomy on Respiratory Contraction of the Cricothyroid Muscle

1989 ◽  
Vol 98 (5) ◽  
pp. 373-378 ◽  
Author(s):  
Gayle E. Woodson
Keyword(s):  
Recurrent Laryngeal Nerve ◽  
Superior Laryngeal Nerve ◽  
Upper Airway ◽  
Vocal Folds ◽  
Laryngeal Nerve ◽  
Electromyographic Activity ◽  
Airway Occlusion ◽  
Cricothyroid Muscle ◽  
Bilateral Vagotomy ◽  
Posterior Cricoarytenoid

The cricothyroid muscle (CT) appears to be an accessory muscle of respiration. Phasic inspiratory contraction is stimulated by increasing respiratory demand. Reflex activation of the CT may be responsible for the paramedian position of the vocal folds, and hence airway obstruction, in patients with bilateral recurrent laryngeal nerve (RLN) paralysis. Previous research has demonstrated the influence of superior laryngeal nerve (SLN) afferents on CT activity. The present study addresses the effects of vagal and RLN afferents. Electromyographic activity of the CT and right posterior cricoarytenoid muscle was monitored in anesthetized cats during tracheotomy breathing and in response to tracheal or upper airway occlusion in the intact animal. This was repeated following left RLN transection, bilateral vagotomy, and bilateral SLN transection. Vagotomy abolished CT response to tracheal occlusion and markedly reduced the response to upper airway occlusion. Vocal fold position following RLN transection appeared to correlate with CT activity; however, observed changes were minor.

scholarly journals Noninvasive estimation of pharyngeal airway resistance and compliance in children based on volume-gated dynamic MRI and computational fluid dynamics

2011 ◽  
Vol 111 (6) ◽  
pp. 1819-1827 ◽  
Author(s):  
Steven C. Persak ◽  
Sanghun Sin ◽  
Joseph M. McDonough ◽  
Raanan Arens ◽  
David M. Wootton
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Rate ◽  
Magnetic Resonance Images ◽  
Cfd Modeling ◽  
Tidal Breathing ◽  
Upper Airways ◽  
Pharyngeal Airway ◽  
Airway Collapse ◽  
Obstructive Sleep

Computational fluid dynamics (CFD) analysis was used to model the effect of collapsing airway geometry on internal pressure and velocity in the pharyngeal airway of three sedated children with obstructive sleep apnea syndrome (OSAS) and three control subjects. Model geometry was reconstructed from volume-gated magnetic resonance images during normal tidal breathing at 10 increments of tidal volume through the respiratory cycle. Each geometry was meshed with an unstructured grid and solved using a low-Reynolds number k-ω turbulence model driven by flow data averaged over 12 consecutive breathing cycles. Combining gated imaging with CFD modeling created a dynamic three-dimensional view of airway anatomy and mechanics, including the evolution of airway collapse and flow resistance and estimates of the local effective compliance. The upper airways of subjects with OSAS were generally much more compliant during tidal breathing. Compliance curves (pressure vs. cross-section area), derived for different locations along the airway, quantified local differences along the pharynx and between OSAS subjects. In one subject, the distal oropharynx was more compliant than the nasopharynx (1.028 vs. 0.450 mm2/Pa) and had a lower theoretical limiting flow rate, confirming the distal oropharynx as the flow-limiting segment of the airway in this subject. Another subject had a more compliant nasopharynx (0.053 mm2/Pa) during inspiration and apparent stiffening of the distal oropharynx (C = 0.0058 mm2/Pa), and the theoretical limiting flow rate indicated the nasopharynx as the flow-limiting segment. This new method may help to differentiate anatomical and functional factors in airway collapse.

Computational Fluid Dynamics Modeling of Upper Airway During Tidal Breathing Using Volume-Gated MRI in OSAS and Control Subjects

2011 ◽  
Author(s):  
Steven C. Persak ◽  
Sanghun Sin ◽  
Raanan Arens ◽  
David M. Wootton
Keyword(s):  
Fluid Dynamic ◽  
Sleep Apnea Syndrome ◽  
Three Dimensional ◽  
Upper Airway ◽  
Magnetic Resonance Images ◽  
Dynamics Modeling ◽  
Tidal Breathing ◽  
Pharyngeal Airway ◽  
Cross Section Area ◽  
Obstructive Sleep

Three-dimensional (3D) computational fluid dynamic (CFD) analysis was used to model the effect of collapsing airway geometry on internal pressure and velocity in the pharyngeal airway of sedated obese children with and without obstructive sleep apnea syndrome (OSAS). Geometry was reconstructed from volume-gated magnetic resonance images during normal tidal breathing of the respiratory cycle and solved using flow data averaged over 12 consecutive breathing cycles. In the OSAS subject, collapse initiated in the proximal nasopharynx and continued downstream into the oropharynx, while the control experienced negligible collapse. Tube laws (pressure vs. cross-section area) derived for the nasopharynx and oropharynx, indicated the oropharynx in the OSAS subject more compliant than the nasopharynx (1.028 mm2/Pa vs. 0.449 mm2/Pa) and had a lower theoretical limiting flow rate, confirming the oropharynx as the flow-limiting segment of the airway in this subject. This new method may help to differentiate anatomical and functional factors in airway collapse.

Control of segmental upper airway resistance in patients with obstructive sleep apnea

1993 ◽  
Vol 74 (6) ◽  
pp. 2694-2703 ◽  
Author(s):  
M. J. Wasicko ◽  
J. S. Erlichman ◽  
J. C. Leiter
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Upper Airway ◽  
Normal Subjects ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Resistive Load ◽  
Airway Collapse ◽  
Upper Airway Collapse ◽  
Obstructive Sleep

We sought to determine if the upper airway response to an added inspiratory resistive load (IRL) during wakefulness could be used to predict the site of upper airway collapse in patients with obstructive sleep apnea (OSA). In 10 awake patients with OSA, we investigated the relationship between resistance in three segments of the upper airway (nasal, nasopharyngeal, and oropharyngeal) and three muscles known to influence these segments (alae nasi, tensor veli palatini, and genioglossus) while the patient breathed with or without a small IRL (2 cmH2O.l–1.s). During IRL, patients with OSA exhibited increased nasopharyngeal resistance and no significant increase in either the genioglossus or tensor veli palatini activities. Neither nasal resistance nor alae nasi EMG activity was affected by IRL. We contrasted this to the response of five normal subjects, in whom we found no change in the resistance of either segment of the airway and no change in the genioglossus EMG but a significant activation of the tensor palatini. In six patients with OSA, we used the waking data to predict the site of upper airway collapse during sleep and we had limited success. The most successful index (correct in 4 of 6 patients) incorporated the greatest relative change in segmental resistance during IRL at the lowest electromyographic activity. We conclude, in patients with OSA, IRL narrows the more collapsible segment of the upper airway, in part due to inadequate activation of upper airway muscles. However, it is difficult to predict the site of upper airway collapse based on the waking measurements where upper airway muscle activity masks the passive airway characteristics.

Thyroid cartilage movements during breathing

1995 ◽  
Vol 78 (2) ◽  
pp. 441-448 ◽  
Author(s):  
T. C. Amis ◽  
A. Brancatisano ◽  
A. Tully
Keyword(s):  
Electrical Stimulation ◽  
Recurrent Laryngeal Nerve ◽  
Thyroid Cartilage ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Electromyographic Activity ◽  
Tidal Breathing ◽  
Left And Right ◽  
Posterior Cricoarytenoid ◽  
Stimulation Of

We measured lateral (outward) thyroid cartilage displacement (TCD) of the larynx in six supine anesthetized (intravenous chloralose) dogs. Combined left and right TCDs were measured with linear transducers attached by a thread to the thyroid alae. During tidal breathing via a tracheostomy, phasic inspiratory TCD occurred in all dogs [0.66 +/- 0.2 mm (mean +/- SE)] together with phasic inspiratory electromyographic activity in the cricothyroid (CT) and posterior cricoarytenoid (PCA) muscles. During brief tracheal occlusions, TCD increased significantly to 1.27 +/- 0.2 mm (P = 0.001), accompanied by an increase of 95–115% in the peak CT and PCA electromyograms. Bilateral supramaximal electrical stimulation of the external branches of the superior laryngeal nerve (ExSLN) produced a TCD of 9.9 +/- 0.8 mm; however, similar stimulation of the recurrent laryngeal nerve (RLN) produced a TCD of only 1.33 +/- 0.1 mm (P = 0.0001). Furthermore, bilateral section of the ExSLN in five dogs significantly reduced tidal TCD by 48.7 +/- 24.4% (P < 0.05), and bilateral section of both the ExSLN and RLN resulted in slight phasic inward TCD (-0.06 +/- 0.05 mm). Thus, it appears that the activities of both the CT and RLN-innervated muscles (probably the PCA muscle) contribute to tidal breathing TCD. These findings suggest that inspiratory dilation of the hypopharynx is mediated by contractions of CT and PCA muscles.

Persistence of the Hering-Breuer reflex beyond the neonatal period

1991 ◽  
Vol 71 (2) ◽  
pp. 474-480 ◽  
Author(s):  
P. S. Rabbette ◽  
K. L. Costeloe ◽  
J. Stocks
Keyword(s):  
Spontaneous Breathing ◽  
Neonatal Period ◽  
Tidal Breathing ◽  
Natural Sleep ◽  
Airway Occlusion ◽  
Conflicting Evidence ◽  
Healthy Infants ◽  
Occlusion Technique ◽  
Relative Change ◽  
Stimulation Of

There is conflicting evidence regarding the persistence of the Hering-Breuer reflex (HBR) beyond the 1st wk of life. This study was designed to assess the influence of postnatal age on the HBR. The airway occlusion technique was used to assess changes in respiratory timing during stimulation of the HBR in healthy full-term unsedated infants measured shortly after birth and at 6–8 wk of life. The strength of the HBR was assessed from the relative change in expiratory time (TE) after end-inspiratory occlusion compared with resting TE during spontaneous breathing. Paired studies were performed in 31 infants at approximately 2 days and 6 wk of age. There was a significant increase in TE during each occlusion in every infant irrespective of age at measurement. No maturational changes were observed. The increase in TE after end-inspiratory occlusion was 91.9 +/- 31.6% (SD) (range 38–158%) at approximately 2 days and 89.8 +/- 30.7% (range 44–175%) at approximately 6 wk. We conclude that the activity of the HBR during tidal breathing persists beyond the neonatal period and that there is no statistically significant change in its strength during the first 2 mo life in healthy infants during natural sleep.

Effects of Depth of Propofol and Sevoflurane Anesthesia on Upper Airway Collapsibility, Respiratory Genioglossus Activation, and Breathing in Healthy Volunteers

2016 ◽  
Vol 125 (3) ◽  
pp. 525-534 ◽  
Author(s):  
Jeroen C. P. Simons ◽  
Eric Pierce ◽  
Daniel Diaz-Gil ◽  
Sanjana A. Malviya ◽  
Matthew J. Meyer ◽  
...  
Keyword(s):  
Bispectral Index ◽  
Upper Airway ◽  
Sevoflurane Anesthesia ◽  
Pressure Drops ◽  
Airway Occlusion ◽  
Airway Collapsibility ◽  
Dose Dependent Fashion ◽  
Upper Airway Collapsibility ◽  
Dose Dependent ◽  
Closing Pressure

Abstract Background Volatile anesthetics and propofol impair upper airway stability and possibly respiratory upper airway dilator muscle activity. The magnitudes of these effects have not been compared at equivalent anesthetic doses. We hypothesized that upper airway closing pressure is less negative and genioglossus activity is lower during deep compared with shallow anesthesia. Methods In a randomized controlled crossover study of 12 volunteers, anesthesia with propofol or sevoflurane was titrated using a pain stimulus to identify the threshold for suppression of motor response to electrical stimulation. Measurements included bispectral index, genioglossus electromyography, ventilation, hypopharyngeal pressure, upper airway closing pressure, and change in end-expiratory lung volume during mask pressure drops. Results A total of 393 attempted breaths during occlusion maneuvers were analyzed. Upper airway closing pressure was significantly less negative at deep versus shallow anesthesia (−10.8 ± 4.5 vs. −11.3 ± 4.4 cm H2O, respectively [mean ± SD]) and correlated with the bispectral index (P &lt; 0.001), indicating a more collapsible airway at deep anesthesia. Respiratory genioglossus activity during airway occlusion was significantly lower at deep compared with light anesthesia (26 ± 21 vs. 35 ± 24% of maximal genioglossus activation, respectively; P &lt; 0.001) and correlated with bispectral index (P &lt; 0.001). Upper airway closing pressure and genioglossus activity during airway occlusion did not differ between sevoflurane and propofol anesthesia. Conclusions Propofol and sevoflurane anesthesia increased upper airway collapsibility in a dose-dependent fashion with no difference at equivalent anesthetic concentrations. These effects can in part be explained by a dose-dependent inhibiting effect of anesthetics on respiratory genioglossus activity.

Respiratory function of hyoid muscles and hyoid arch

1984 ◽  
Vol 57 (1) ◽  
pp. 197-204 ◽  
Author(s):  
W. B. Van de Graaff ◽  
S. B. Gottfried ◽  
J. Mitra ◽  
E. van Lunteren ◽  
N. S. Cherniack ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Respiratory Function ◽  
Flow Resistance ◽  
Respiratory Activity ◽  
Upper Airway ◽  
Hyoid Arch ◽  
Airway Occlusion ◽  
Anesthetized Dogs ◽  
Inspiratory Activity ◽  
Stimulation Of

The position of the hyoid arch suggests that it supports soft tissue surrounding the upper airway (UA) and can act to maintain UA patency. We also suspected that muscles inserting on the hyoid arch might show respiratory patterns of activity that could be affected by respiratory stimuli. To test these possibilities, we moved the hyoid arch ventrally in six anesthetized dogs either by traction on it or by stimulation of hyoid muscles. UA resistance was decreased 73 +/- (SE) 6% and 72 +/- 6% by traction and stimulation during expiration and 57 +/- 15% and 52 +/- 8% during inspiration. Moving averages of the geniohyoid (GH) and thyrohyoid (TH) obtained in six other dogs breathing 100% O2 showed phasic respiratory activity while the sternohyoid (SH) showed phasic respiratory activity in only two of these animals and no activity in four. With progressive hypercapnia, GH and TH increased as did SH when activity was already present. Airway occlusion at end expiration augmented and prolonged inspiratory activity in the hyoid muscles but did not elicit SH activity if not already present. Occlusion at end inspiration suppressed phasic activity in hyoid muscles for as long as in the diaphragm. After vagotomy activity increased and became almost exclusively inspiratory. Activity appeared in SH when not previously present. Duration and amplitude of hyoid muscle activity were increased with negative UA pressure and augmented breaths. We conclude that the hyoid arch and muscles can strongly affect UA flow resistance. Hyoid muscles show responses to chemical, vagal, and negative pressure stimuli similar to other UA muscles.

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