Thoracic influence on upper airway patency

1988 ◽  
Vol 65 (5) ◽  
pp. 2124-2131 ◽  
Author(s):  
W. B. Van de Graaff
Keyword(s):  
Muscle Activity ◽  
Upper Airway ◽  
Constant Flow ◽  
Airway Patency ◽  
Anesthetized Dogs ◽  
Measured Resistance ◽  
Flow Through ◽  
Phrenic Nerves ◽  
Tracheostomy Tubes ◽  
Spontaneously Breathing

Patency of the upper airway (UA) is usually considered to be maintained by the activity of muscles in the head and neck. These include cervical muscles that provide caudal traction on the UA. The thorax also applies caudal traction to the UA. To observe whether this thoracic traction can also improve UA patency, we measured resistance of the UA (RUA) during breathing in the presence and absence of UA muscle activity. Fifteen anesthetized dogs breathed through tracheostomy tubes. RUA was calculated from the pressure drop of a constant flow through the isolated UA. RUA decreased 31 +/- 5% (SEM) during inspiration. After hyperventilating seven of these dogs to apnea, we maximally stimulated the phrenic nerves to produce paced diaphragmatic breathing. Despite absence of UA muscle activity, RUA fell 51 +/- 11% during inspiration. Graded changes were produced by reduced stimulation. In six other dogs we denervated all UA muscles. RUA still fell 25 +/- 7% with inspiration in these spontaneously breathing animals. When all caudal ventrolateral cervical structures mechanically linking the thorax to the UA were severed, RUA increased and respiratory fluctuations ceased. These findings indicate that tonic and phasic forces generated by the thorax can improve UA patency. Inspiratory increases in UA patency cannot be attributed solely to activity of UA muscles.

Laryngeal-receptor responses to phasic CO2 in anesthetized cats

1998 ◽  
Vol 85 (3) ◽  
pp. 1135-1141 ◽  
Author(s):  
A. Bradford ◽  
D. McKeogh ◽  
R. G. O’Regan
Keyword(s):  
Negative Pressure ◽  
Muscle Activity ◽  
Upper Airway ◽  
Respiratory Cycle ◽  
Positive Pressure ◽  
Receptor Stimulation ◽  
Airway Patency ◽  
Cold Receptors ◽  
Regulation Of Breathing ◽  
Spontaneously Breathing

We compared the effects of CO2 applied continuously and during expiration on laryngeal-receptor activity in paralyzed, artificially ventilated and nonparalyzed, spontaneously breathing cats by using an isolated larynx, artificially ventilated to approximate a normal respiratory cycle. The majority of quiescent negative-pressure and all cold receptors were excited by 5 and 9% CO2 applied both continuously and during expiration. In general, quiescent positive-pressure, tonic negative-pressure, and tonic positive-pressure receptors were inhibited by 5 and 9% CO2 applied continuously and during expiration. There were no significant differences between responses to 5 and 9% CO2 or to continuous and expired CO2 or between paralyzed and nonparalyzed preparations. In conclusion, laryngeal receptors respond to changes in CO2 concentration occurring during a normal respiratory cycle. Because laryngeal-receptor stimulation exerts reflex effects on ventilation and upper airway muscle activity, these results suggest that airway CO2 plays a role in reflex regulation of breathing and upper airway patency.

Modulation of the extrinsic tongue muscle activity in response to bronchopulmonary C-fiber activation following midcervical contusion in the rat

2020 ◽  
Vol 128 (5) ◽  
pp. 1130-1145
Author(s):  
Hsiao-Sen Chang ◽  
Kun-Ze Lee
Keyword(s):  
Spinal Cord ◽  
Muscle Activity ◽  
Cervical Spinal Cord ◽  
Upper Airway ◽  
Airway Patency ◽  
Tongue Muscle ◽  
Cord Injury ◽  
Burst Amplitude ◽  
C Fiber ◽  
Spinal Cord Contusion

Tongue muscle activity plays an important role in the regulation of upper airway patency. This study aimed to investigate the respiratory activity of the extrinsic tongue muscle in response to capsaicin-induced bronchopulmonary C-fiber activation following cervical spinal cord contusion. Midcervical spinal-contused animals exhibited a greater baseline preinspiratory burst amplitude of the extrinsic tongue muscle and were resistant to inhaled capsaicin-induced reduction of respiratory tongue muscle activity at the acute injured stage. However, inhalation of capsaicin caused a more severe attenuation of preinspiratory activity of the extrinsic tongue muscle at the chronic injured stage. These results suggest that the upper airway may be predisposed to collapse in response to bronchopulmonary C-fiber activation following chronic cervical spinal cord injury.

Effects of HCl-pepsin laryngeal instillations on upper airway patency-maintaining mechanisms

1998 ◽  
Vol 84 (4) ◽  
pp. 1299-1304 ◽  
Author(s):  
Franca B. Sant’Ambrogio ◽  
Giuseppe Sant’Ambrogio ◽  
Kyungsoon Chung
Keyword(s):  
Gastroesophageal Reflux ◽  
Negative Pressure ◽  
Sensory Feedback ◽  
Upper Airway ◽  
Esophageal Pressure ◽  
Airway Patency ◽  
Laryngeal Mucosa ◽  
Posterior Cricoarytenoid Muscle ◽  
Anesthetized Dogs ◽  
Posterior Cricoarytenoid

Gastroesophageal reflux has been indicated as an etiopathological factor in disorders of the upper airway. Upper airway collapsing pressure stimulates pressure-responsive laryngeal receptors that reflexly increase the activity of upper airway abductor muscles. We studied, in anesthetized dogs, the effects of repeated laryngeal instillations of HCl-pepsin (HCl-P; pH = 2) on the response of laryngeal afferent endings and the posterior cricoarytenoid muscle (PCA) to negative pressure. The effect of negative pressure on receptor discharge or PCA activity was evaluated by comparing their response to upper airway (UAO) and tracheal occlusions (TO). It is only during UAO, but not during TO, that the larynx is subjected to negative transmural pressure. HCl-P instillation decreased the rate of discharge during UAO of the 10 laryngeal receptors studied from 56.4 ± 10.9 (SE) to 38.2 ± 9.2 impulses/s ( P < 0.05). With UAO, the peak PCA moving time average, normalized by dividing it by the peak values of esophageal pressure, decreased after six HCl-P trials from 4.29 ± 0.31 to 2.23 ± 0.18 ( n = 6; P < 0.05). The responses to TO of either receptors or PCA remained unaltered. We conclude that exposure of the laryngeal mucosa to HCl-P solutions, as it may occur with gastroesophageal reflux, impairs the patency-maintaining mechanisms provided by laryngeal sensory feedback. Inflammatory and necrotic alterations of the laryngeal mucosa are likely responsible for these effects.

Anatomic consequences of intrinsic tongue muscle activation

2006 ◽  
Vol 101 (5) ◽  
pp. 1377-1385 ◽  
Author(s):  
E. Fiona Bailey ◽  
Yu-Hsien Huang ◽  
Ralph F. Fregosi
Keyword(s):  
Electrical Stimulation ◽  
Muscle Activation ◽  
Critical Role ◽  
Upper Airway ◽  
Pressure Source ◽  
Airway Patency ◽  
Tongue Muscle ◽  
Airway Pressures ◽  
Tongue Muscles ◽  
Spontaneously Breathing

We recently showed respiratory-related coactivation of both extrinsic and intrinsic tongue muscles in the rat. Here, we test the hypothesis that intrinsic tongue muscles contribute importantly to changes in velopharyngeal airway volume. Spontaneously breathing anesthetized rats were placed in a MRI scanner. A catheter was placed in the hypopharynx and connected to a pressure source. Axial and sagittal images of the velopharyngeal airway were obtained, and the volume of each image was computed at airway pressures ranging from +5.0 to −5.0 cmH2O. We obtained images in the hypoglossal intact animal (i.e., coactivation of intrinsic and extrinsic tongue muscles) and after selective denervation of the intrinsic tongue muscles, with and without electrical stimulation. Denervation of the intrinsic tongue muscles reduced velopharyngeal airway volume at atmospheric and positive airway pressures. Electrical stimulation of the intact hypoglossal nerve increased velopharyngeal airway volume; however, when stimulation was repeated after selective denervation of the intrinsic tongue muscles, the increase in velopharyngeal airway volume was significantly attenuated. These findings support our working hypothesis that intrinsic tongue muscles play a critical role in modulating upper airway patency.

scholarly journals Modulation of laryngeal and respiratory pump muscle activities with upper airway pressure and flow

2001 ◽  
Vol 91 (2) ◽  
pp. 897-904 ◽  
Author(s):  
M. H. Stella ◽  
S. J. England
Keyword(s):  
Negative Pressure ◽  
Muscle Activity ◽  
Upper Airway ◽  
Abdominal Muscle ◽  
Positive Pressure ◽  
Emg Activity ◽  
Posterior Cricoarytenoid ◽  
Spontaneously Breathing ◽  
Respiratory Muscle Activity ◽  
Stimulation Of

The hypothesis that upper airway (UA) pressure and flow modulate respiratory muscle activity in a respiratory phase-specific fashion was assessed in anesthetized, tracheotomized, spontaneously breathing piglets. We generated negative pressure and inspiratory flow in phase with tracheal inspiration or positive pressure and expiratory flow in phase with tracheal expiration in the isolated UA. Stimulation of UA negative pressure receptors with body temperature air resulted in a 10–15% enhancement of phasic moving-time-averaged posterior cricoarytenoid electromyographic (EMG) activity above tonic levels obtained without pressure and flow in the UA (baseline). Stimulation of UA positive pressure receptors increased phasic moving-time-averaged thyroarytenoid EMG activity above tonic levels by 45% from baseline. The same enhancement of posterior cricoarytenoid or thyroarytenoid EMG activity was observed with the addition of flow receptor stimulation with room temperature air. Tidal volume and diaphragmatic and abdominal muscle activity were unaffected by UA flow and/or pressure, whereas respiratory timing was minimally affected. We conclude that laryngeal afferents, mainly from pressure receptors, are important in modulating the respiratory activity of laryngeal muscles.

Upper airway obstruction in the unconscious patient

1959 ◽  
Vol 14 (5) ◽  
pp. 760-764 ◽  
Author(s):  
Peter Safar ◽  
Lourdes A. Escarraga ◽  
Francis Chang
Keyword(s):  
Upper Airway ◽  
Posterior Pharyngeal Wall ◽  
Muscle Relaxants ◽  
The Unconscious ◽  
Pharyngeal Wall ◽  
Airway Patency ◽  
Forward Displacement ◽  
Oropharyngeal Airway ◽  
Spontaneously Breathing ◽  
Head Neck

Airway patency was studied in 80 anesthetized, spontaneously breathing patients, who received no muscle relaxants. With the neck flexed (chin towards chest) the airway was obstructed in all patients, both in the supine and prone positions, with and without an artificial oropharyngeal airway in place. With extension at the atlanto-occipital joint (chin up) in the supine position approximately 50% of the patients had an open airway. The other 50% required, in addition to extension of the neck, forward displacement of the mandible or the insertion of an oropharyngeal airway or both. Roentgenograms demonstrated that the tongue is pushed against the posterior pharyngeal wall when the neck is flexed and the mandible is not held forward. The incidence and degree of obstruction was similar in the prone and supine positions, with comparable positions of the head, neck and mandible. Submitted on December 19, 1958

A threshold lung volume for optimal mechanical effects on upper airway airflow dynamics: studies in an anesthetized rabbit model

2012 ◽  
Vol 112 (7) ◽  
pp. 1197-1205 ◽  
Author(s):  
Kristina Kairaitis ◽  
Manisha Verma ◽  
Jason Amatoury ◽  
John R. Wheatley ◽  
David P. White ◽  
...  
Keyword(s):  
Lung Volume ◽  
Muscle Activity ◽  
Rabbit Model ◽  
Upper Airway ◽  
Flow Limitation ◽  
Volume Increase ◽  
Mechanical Effects ◽  
Pharyngeal Pressure ◽  
Volume Resistance ◽  
Spontaneously Breathing

Increasing lung volume improves upper airway airflow dynamics via passive mechanisms such as reducing upper airway extraluminal tissue pressures (ETP) and increasing longitudinal tension via tracheal displacement. We hypothesized a threshold lung volume for optimal mechanical effects on upper airway airflow dynamics. Seven supine, anesthetized, spontaneously breathing New Zealand White rabbits were studied. Extrathoracic pressure was altered, and lung volume change, airflow, pharyngeal pressure, ETP laterally (ETPlat) and anteriorly (ETPant), tracheal displacement, and sternohyoid muscle activity (EMG%max) monitored. Airflow dynamics were quantified via peak inspiratory airflow, flow limitation upper airway resistance, and conductance. Every 10-ml lung volume increase resulted in caudal tracheal displacement of 2.1 ± 0.4 mm (mean ± SE), decreased ETPlat by 0.7 ± 0.3 cmH2O, increased peak inspiratory airflow of 22.8 ± 2.6% baseline (all P < 0.02), and no significant change in ETPant or EMG%max. Flow limitation was present in most rabbits at baseline, and abolished 15.7 ± 10.5 ml above baseline. Every 10-ml lung volume decrease resulted in cranial tracheal displacement of 2.6 ± 0.4 mm, increased ETPant by 0.9 ± 0.2 cmH2O, ETPlat was unchanged, increased EMG%max of 11.1 ± 0.3%, and a reduction in peak inspiratory airflow of 10.8 ± 1.0%baseline (all P < 0.01). Lung volume, resistance, and conductance relationships were described by exponential functions. In conclusion, increasing lung volume displaced the trachea caudally, reduced ETP, abolished flow limitation, but had little effect on resistance or conductance, whereas decreasing lung volume resulted in cranial tracheal displacement, increased ETP and increased resistance, and reduced conductance, and flow limitation persisted despite increased muscle activity. We conclude that there is a threshold for lung volume influences on upper airway airflow dynamics.

Laryngeal influences on breathing pattern and posterior cricoarytenoid muscle activity

1985 ◽  
Vol 58 (4) ◽  
pp. 1298-1304 ◽  
Author(s):  
F. B. Sant'Ambrogio ◽  
O. P. Mathew ◽  
W. D. Clark ◽  
G. Sant'Ambrogio
Keyword(s):  
Breathing Pattern ◽  
Upper Airway ◽  
Airway Patency ◽  
Airway Occlusion ◽  
Laryngeal Nerves ◽  
Relative Contribution ◽  
Posterior Cricoarytenoid Muscle ◽  
Regulation Of Breathing ◽  
Anesthetized Dogs ◽  
Posterior Cricoarytenoid

Receptors responding to transmural pressure, airflow, and contraction of laryngeal muscles have been previously identified in the larynx. To assess the relative contribution of these three types of receptors to the reflex changes in breathing pattern and upper airway patency, we studied diaphragmatic (DIA) and posterior cricoarytenoid muscle (PCA) activity in anesthetized dogs during spontaneous breathing and occluded efforts with and without bypassing the larynx. Inspiratory duration (TI) was longer, mean inspiratory slope (peak DIA/TI) was lower, and PCA activity was greater with upper airway occlusion than with tracheal occlusion (larynx bypassed). Bilateral section of the superior laryngeal nerves eliminated these differences. When respiratory airflow was diverted from the tracheostomy to the upper airway the only change attributable to laryngeal afferents was an increase in PCA activity. These results confirm the importance of the superior laryngeal nerves in the regulation of breathing pattern and upper airway patency and suggest a prevalent role for laryngeal negative pressure receptors.

Assessment of upper airway patency in spontaneously breathing non-intubated neonates and infants undergoing conventional MRI of head and neck

2015 ◽  
Vol 31 (9) ◽  
pp. 1521-1525 ◽  
Author(s):  
Thangamadhan Bosemani ◽  
Malvi Hemani ◽  
Angelo Cruz ◽  
Meehir Shah ◽  
Barbara Kim ◽  
...  
Keyword(s):  
Head And Neck ◽  
Upper Airway ◽  
Airway Patency ◽  
Conventional Mri ◽  
Neonates And Infants ◽  
Spontaneously Breathing
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