Response of laryngeal mechanoreceptors to high-frequency pressure oscillation

1992 ◽  
Vol 73 (1) ◽  
pp. 219-223 ◽  
Author(s):  
S. Zhang ◽  
O. P. Mathew
Keyword(s):  
High Frequency ◽  
Superior Laryngeal Nerve ◽  
Upper Airway ◽  
Pressure Oscillation ◽  
Pressure Change ◽  
Laryngeal Nerve ◽  
Similar Frequency ◽  
Afferent Fibers ◽  
Anesthetized Dogs ◽  
Spontaneously Breathing

High-frequency pressure oscillations (HFPO) in the upper airway induce arousal, activation of genioglossus muscle, and bronchoconstriction. The present study was designed to determine the response of superior laryngeal nerve afferent fibers to HFPO. In 10 anesthetized dogs spontaneously breathing through a tracheal cannula, the upper airway was converted to a closed system. The activity of thin bundles separated from the peripheral cut end of the superior laryngeal nerve was monitored. Of 104 mechanoreceptors identified, 87 were classified as respiratory modulated and 17 as non-respiratory modulated on the basis of their response to transmural pressure change and muscle activity. The responses of these fibers to HFPO of +/- 2.5 cmH2O at 10, 20, and 30 Hz were determined. Among the respiratory-modulated receptors, 86 of 87 increased their activity in response to HFPO. Of the 17 non-respiratory-modulated receptors, 12 receptors showing a random or tonic activity did not respond to HFPO, whereas the 5 that were silent during control condition responded exclusively to HFPO. Our results show that HFPO of similar frequency but much less magnitude than snoring is capable of activating the vast majority of laryngeal mechanoreceptors. Pressure-sensitive respiratory-modulated endings appear to mediate the arousal and genioglossal response, whereas non-respiratory-modulated receptors responding to HFPO presumably mediate the bronchoconstrictive response.

Dilating forces on the upper airway of anesthetized dogs

1985 ◽  
Vol 58 (2) ◽  
pp. 452-458 ◽  
Author(s):  
K. P. Strohl ◽  
J. M. Fouke
Keyword(s):  
Muscle Activation ◽  
Moving Average ◽  
Upper Airway ◽  
Pressure Change ◽  
Emg Activity ◽  
Lung Inflation ◽  
Anesthetized Dogs ◽  
Cervical Trachea ◽  
Pressure Changes ◽  
Spontaneously Breathing

We reasoned that in an isolated sealed upper airway a pressure change would be caused by a change in airway volume. In eight spontaneously breathing anesthetized dogs, we isolated the upper airway by transecting the cervical trachea and sealing it from the lung and from the atmosphere. Pressure changes in this isolated upper airway were studied in relation to respiratory phase as evidenced by alae nasi electromyographic (EMG) activation and tidal volume measured at the distal trachea. A fall in pressure, indicating airway dilation, occurred with each spontaneous respiratory effort. Like the moving average of the alae nasi EMG, the pressure drop reached a peak value early in inspiration, was inhibited by further lung inflation, and was absent during passive mechanical ventilation. End-expiratory tracheal occlusion or vagotomy prolonged and augmented EMG activity and also the inspiratory fall in upper airway pressure. Increased levels of CO2 increased the magnitude of change in pressure during inspiration. An inhibiting effect of lung inflation was present to an equal extent at low and high levels of chemical drive. We show that dilation of the airway is concurrent with upper airway muscle activation during early inspiration, that this dilation increases with increasing chemical drive, and that vagal reflexes during lung inflation inhibit this dilation during the latter half of inspiration.

Superior laryngeal and hypoglossal afferents tonically influence upper airway motor excitability in anesthetized rats

2005 ◽  
Vol 99 (3) ◽  
pp. 1019-1028 ◽  
Author(s):  
Stephen Ryan ◽  
Philip Nolan
Keyword(s):  
Motor Activity ◽  
Muscle Relaxation ◽  
Superior Laryngeal Nerve ◽  
Upper Airway ◽  
Transmural Pressure ◽  
Laryngeal Nerve ◽  
Afferent Feedback ◽  
Afferent Pathways ◽  
Afferent Fibers ◽  
Motor Excitability

Upper airway (UA) muscle activity is stimulated by changes in UA transmural pressure and by asphyxia. These responses are reduced by muscle relaxation. We hypothesized that this is due to a change in afferent feedback in the ansa hypoglossi and/or superior laryngeal nerve (SLN). We examined 1) the glossopharyngeal motor responses to UA transmural pressure and asphyxia and 2) how these responses were changed by muscle relaxation in animals where one or both of these afferent pathways had been sectioned bilaterally. Experiments were performed in 24 anesthetized, thoracotomized, artificially ventilated rats. Baseline glossopharyngeal activity and its response to UA transmural pressure and asphyxia were moderately reduced after bilateral section of the ansa hypoglossi ( P < 0.05). Conversely, bilateral SLN section increased baseline glossopharyngeal activity, augmented the response to asphyxia, and abolished the response to UA transmural pressure. Muscle relaxation reduced resting glossopharyngeal activity and the response to asphyxia ( P < 0.001). This occurred whether or not the ansa hypoglossi, the SLN, or both afferent pathways had been interrupted. We conclude that ansa hypoglossi afferents tonically excite and SLN afferents tonically inhibit UA motor activity. Muscle relaxation depressed UA motor activity after section of the ansa hypoglossi and SLN. This suggests that some or all of the response to muscle relaxation is mediated by alterations in the activity of afferent fibers other than those in the ansa hypoglossi or SLN.

scholarly journals Upper Airway Nerve Block for Rigid Bronchoscopy in the Patients with Tracheal Stenosis: A Case Serie

2020 ◽  
Vol 10 (4) ◽  
Author(s):  
Parviz Amri ◽  
Novin Nikbakhsh ◽  
Seyed Reza Modaress ◽  
Ramin Nosrati
Keyword(s):  
Respiratory Distress ◽  
Nerve Block ◽  
Tracheal Stenosis ◽  
Superior Laryngeal Nerve ◽  
Upper Airway ◽  
Rigid Bronchoscopy ◽  
Laryngeal Nerve ◽  
Intravenous Sedation ◽  
Nerve Blocks

Background: Rigid bronchoscopy is often used to diagnose and treat the location of resection of the tracheal stenosis. It is a selective procedure for the dilatation of tracheal stenosis, especially when accompanied by respiratory distress. Objectives: We introduced patients who were diagnosed with tracheal stenosis and candidate for rigid bronchoscopy dilatation by the upper airway nerve blocks. Methods: This prospective observational study was conducted on 17 patients who underwent dilatation with rigid bronchoscopy in tracheal stenosis at Hospitals affiliated with Babol University of Medical Sciences from 2002 to 2017. The patients were given three nerve blocks, 6 bilateral superior laryngeal nerve block, bilateral glossopharyngeal nerve block, and recurrent laryngeal nerve block (transtracheal) before awake rigid bronchoscopy using 2% lidocaine. We evaluated the demographic data, the cause of tracheal stenosis, the quality of the airway nerve block (Intubation score), patients’ satisfaction from bronchoscopy and thoracic surgeons’ satisfaction. Complications of nerve blocks were recorded. Results: From 2002 to 2017, 17 patients (14 were male and 3 were) female with tracheal stenosis who were candidates for dilatation with bronchoscopy and accepted the upper nerve block were included. The quality of the block was acceptable in 16 (94%) patients. 15 patients received fentanyl, and only two patients did not need to intravenous sedation. The mean age of patients was 29.59 ± 11.59. The average satisfaction of the surgeon was 8.82 ± 1.13 and the satisfaction of patients with anesthesia was 8.89 ± 1.16. There was one serious complication (laryngospasm) in one patient. Conclusions: The upper airway nerve block method is a suitable anesthesia technique for patients with tracheal stenosis who are candidates for the tracheal dilatation with rigid bronoscopy, especially when the patient has respiratory distress and has not been evaluated before surgery.

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 Intensity and frequency dependence of laryngeal afferent inputs to respiratory hypoglossal motoneurons

1997 ◽  
Vol 83 (6) ◽  
pp. 1890-1899 ◽  
Author(s):  
Steven W. Mifflin
Keyword(s):  
Frequency Dependence ◽  
Stimulus Frequency ◽  
Superior Laryngeal Nerve ◽  
Upper Airway ◽  
Airway Patency ◽  
Hypoglossal Motoneurons ◽  
Afferent Fibers ◽  
Complex Motor ◽  
Afferent Inputs ◽  
Motor Acts

Mifflin, Steven W. Intensity and frequency dependence of laryngeal afferent inputs to respiratory hypoglossal motoneurons. J. Appl. Physiol. 83(6): 1890–1899, 1997.—Inspiratory hypoglossal motoneurons (IHMs) mediate contraction of the genioglossus muscle and contribute to the regulation of upper airway patency. Intracellular recordings were obtained from antidromically identified IHMs in anesthetized, vagotomized cats, and IHM responses to electrical activation of superior laryngeal nerve (SLN) afferent fibers at various frequencies and intensities were examined. SLN stimulus frequencies <2 Hz evoked an excitatory-inhibitory postsynaptic potential (EPSP-IPSP) sequence or only an IPSP in most IHMs that did not change in amplitude as the stimulus was maintained. During sustained stimulus frequencies of 5–10 Hz, there was a reduction in the amplitude of SLN-evoked IPSPs with time with variable changes in the EPSP. At stimulus frequencies >25 Hz, the amplitude of EPSPs and IPSPs was reduced over time. At a given stimulus frequency, increasing stimulus intensity enhanced the decay of the SLN-evoked postsynaptic potentials (PSPs). Frequency-dependent attenuation of SLN inputs to IHMs also occurred in newborn kittens. These results suggest that activation of SLN afferents evokes different PSP responses in IHMs depending on the stimulus frequency. At intermediate frequencies, inhibitory inputs are selectively filtered so that excitatory inputs predominate. At higher frequencies there was no discernible SLN-evoked PSP temporally locked to the SLN stimuli. Alterations in SLN-evoked PSPs could play a role in the coordination of genioglossal contraction during respiration, swallowing, and other complex motor acts where laryngeal afferents are activated.

Nasal and laryngeal reflex responses to negative upper airway pressure

1984 ◽  
Vol 56 (3) ◽  
pp. 746-752 ◽  
Author(s):  
E. van Lunteren ◽  
W. B. Van de Graaff ◽  
D. M. Parker ◽  
J. Mitra ◽  
M. A. Haxhiu ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Muscle Activity ◽  
Moving Average ◽  
Superior Laryngeal Nerve ◽  
Upper Airway ◽  
Laryngeal Nerve ◽  
Topical Anesthesia ◽  
Inspiratory Activity ◽  
Posterior Cricoarytenoid ◽  
Upper Airway Muscles

The effects of negative pressure applied to just the upper airway on nasal and laryngeal muscle activity were studied in 14 spontaneously breathing anesthetized dogs. Moving average electromyograms were recorded from the alae nasi (AN) and posterior cricoarytenoid (PCA) muscles and compared with those of the genioglossus (GG) and diaphragm. The duration of inspiration and the length of inspiratory activity of all upper airway muscles was increased in a graded manner proportional to the amount of negative pressure applied. Phasic activation of upper airway muscles preceded inspiratory activity of the diaphragm under control conditions; upper airway negative pressure increased this amount of preactivation. Peak diaphragm activity was unchanged with negative pressure, although the rate of rise of muscle activity decreased. The average increases in peak upper airway muscle activity in response to all levels of negative pressure were 18 +/- 4% for the AN, 27 +/- 7% for the PCA, and 122 +/- 31% for the GG (P less than 0.001). Rates of rise of AN and PCA electrical activity increased at higher levels of negative pressure. Nasal negative pressure affected the AN more than the PCA, while laryngeal negative pressure had the opposite effect. The effects of nasal negative pressure could be abolished by topical anesthesia of the nasal passages, while the effects of laryngeal negative pressure could be abolished by either topical anesthesia of the larynx or section of the superior laryngeal nerve. Electrical stimulation of the superior laryngeal nerve caused depression of AN and PCA activity, and hence does not reproduce the effects of negative pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Sign in / Sign up

Export Citation Format

Share Document