Influence of intralaryngeal CO2 on the response of laryngeal afferents to upper airway negative pressure

1994 ◽  
Vol 76 (6) ◽  
pp. 2720-2725 ◽  
Author(s):  
T. K. Ghosh ◽  
O. P. Mathew
Keyword(s):  
Negative Pressure ◽  
Superior Laryngeal Nerve ◽  
Upper Airway ◽  
Discharge Frequency ◽  
Airway Patency ◽  
Airway Occlusion ◽  
The Mean ◽  
Adult Cats ◽  
Humidified Air ◽  
Spontaneously Breathing

Effects of intralaryngeal CO2 on the response of superior laryngeal afferents to negative pressure were investigated in 20 anesthetized spontaneously breathing adult cats. Single-fiber action potentials were recorded from the peripheral cut end of the superior laryngeal nerve. The larynx was exposed to negative pressure during inspiration when the animal breathed against an occluded upper airway. Among the 99 receptors evaluated, 54 were respiratory modulated and 45 were nonmodulated endings. The effect of intralaryngeal CO2 on the response of 39 receptors responding to negative pressure was determined by exposure of the larynx to CO2 or air for 1 min followed immediately by upper airway occlusion. The mean discharge frequency of 22 fibers inhibited by negative pressure was 32.4 +/- 2.6 Hz during air trials compared with 29.9 +/- 2.6 Hz during CO2 trials (P < 0.005). During occlusion of the upper airway after the warm humidified air trial, the discharge frequency of these endings decreased to 24.2 +/- 2.3 Hz compared with 17.5 +/- 2.2 Hz after CO2 trial (P < 0.001). The mean discharge frequencies of 17 fibers stimulated by negative pressure were 3.7 +/- 2.6 and 4.4 +/- 1.8 Hz, respectively, during air and CO2 trials. The mean frequencies increased to 14.7 +/- 3.5 Hz (air) and 18.6 +/- 4.0 Hz (CO2) during upper airway occlusions (P < 0.01). We conclude that intralaryngeal CO2 can alter the response of pressure-sensitive laryngeal afferents, thereby having a role in the maintenance of upper airway patency.(ABSTRACT TRUNCATED AT 250 WORDS)

Upper airway negative-pressure effects on respiratory activity of upper airway muscles

1984 ◽  
Vol 56 (2) ◽  
pp. 500-505 ◽  
Author(s):  
O. P. Mathew
Keyword(s):  
Negative Pressure ◽  
Respiratory Activity ◽  
Superior Laryngeal Nerve ◽  
Upper Airway ◽  
Pressure Change ◽  
Pressure Effects ◽  
Rapid Decline ◽  
Airway Patency ◽  
Inspiratory Activity ◽  
Upper Airway Muscles

Influence of upper airway negative-pressure change on the respiratory activity of various upper airway muscles was investigated in 13 anesthetized rabbits. Phasic inspiratory activity increased or appeared during virtually all negative-pressure trials in nasolabial, cricothyroid, and posterior cricoarytenoid muscles. No phasic inspiratory activity was seen in the sternothyroid (ST) and sternohyoid (SH) muscles before negative-pressure applications but appeared during 80% of trials in ST and 62% of trials in SH. During maintained negative pressure, a gradual decline in activity was often observed in the nasolabial and laryngeal muscles, whereas a rapid decline in activity was seen in the cervical strap muscles. Reflex effects of negative pressure was markedly reduced or abolished by sectioning the internal branch of the superior laryngeal nerve bilaterally. Reflex augmentation of upper airway muscle activity reported here may have functional significance in the maintenance of upper airway patency. It could prevent upper airway collapse when negative pressure swings in the upper airway increase or facilitate recovery when large negative pressure swings are produced by obstructed inspiratory efforts.

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.

Does Presurgical Nasoalveolar Molding Have a Long-Term Effect on Nasal and Upper Airway Dimensions?

2020 ◽  
pp. 105566562098023
Author(s):  
Ashwina S. Banari ◽  
Sanjeev Datana ◽  
Shiv Shankar Agarwal ◽  
Sujit Kumar Bhandari
Keyword(s):  
Upper Airway ◽  
P Value ◽  
Airway Patency ◽  
The Mean ◽  
Group 2 ◽  
Acoustic Pharyngometry ◽  
Nasoalveolar Molding ◽  
Area And Volume ◽  
Group 1

Objectives: To compare nasal and upper airway dimensions in patients with cleft lip and palate (CLP) who underwent nasoalveolar molding (NAM) with those without NAM during infancy using acoustic pharyngometry and rhinometry. Materials and Methods: Eccovision acoustic pharyngometry and rhinometry (Sleep Group Solutions) was used for assessment of mean area and volume of nasal and upper airway in patients with complete unilateral CLP (age range 16-21 years) treated with NAM (group 1, n = 19) versus without NAM (group 2, n = 22). Results: The mean nasal cross-sectional areas and volume were higher in group 1 compared to group 2 on both cleft ( P value <.001) and noncleft side ( P value >.05). The mean area and volume of upper airway were also significantly higher in group 1 compared to group 2 ( P value <.05). Conclusions: Nasoalveolar molding being one of the first interventions in chronology of treatment of patients with CLP, its long-term outcome on nasal and upper airway patency needs to be ascertained. The results of the present study show that the patients with CLP who have undergone NAM during infancy have better improvement in nasal and upper airway patency compared with those who had not undergone NAM procedure. The basic advantages of being noninvasive, nonionizing and providing dynamic assessment of nasal and upper airway patency make acoustic pharyngometry and rhinometry a diagnostic tool of choice to be used in patients with CLP.

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.

Mouth and nose resistance in newborn kittens and puppies

1981 ◽  
Vol 51 (3) ◽  
pp. 641-645 ◽  
Author(s):  
J. P. Mortola ◽  
J. T. Fisher
Keyword(s):  
Mechanical Properties ◽  
Airway Obstruction ◽  
Flow Rate ◽  
Muscle Tone ◽  
Upper Airway ◽  
Upper Airway Obstruction ◽  
Upper Airways ◽  
Airway Patency ◽  
The Difference ◽  
Adult Cats

Newborn mammals, including infants, have difficulties in mouth breathing when the nasal passages are occluded. In this study we examined the possibility that differences in the passive mechanical properties of the upper airways could fully explain this behavior. Steady inspiratory flows through the upper airways in anesthetized supine newborn kittens and puppies resulted in upper airway obstruction, even at flows less than those occurring during resting breathing, suggesting that in the unanesthetized condition muscle tone plays an important role in maintaining upper airway patency. Mouth (Rm) and nose (Rn) resistances have been measured during steady expiratory flows with nostrils closed and mouth passively open or nostrils open and mouth closed. In all the newborns, Rn was substantially smaller than Rm. In contrast, the Rn/Rm in adult dogs is greater than unity. In adult cats Rn/Rm is above or below unity depending upon the flow rate, but the ratio is always larger than in newborn kittens. The difference between newborns and adults is entirely due to the small Rn of the newborn, as Rm is not greater in the newborn than in the adult. We conclude that the obligatory nose breathing behavior of newborns is not fully explained by the passive mechanical properties of the upper airways.

Effects of almitrine on genioglossal and diaphragmatic electromyograms

1986 ◽  
Vol 61 (6) ◽  
pp. 2122-2128 ◽  
Author(s):  
D. E. Weese-Mayer ◽  
R. T. Brouillette ◽  
L. M. Klemka ◽  
C. E. Hunt
Keyword(s):  
Slow Wave Sleep ◽  
Minute Ventilation ◽  
Upper Airway ◽  
Respiratory Drive ◽  
Peripheral Chemoreceptor ◽  
Obstructive Sleep ◽  
Adult Cats ◽  
Alpha Chloralose ◽  
Spontaneously Breathing ◽  
Dose Dependent

We previously demonstrated dose-dependent increases in both hypoglossal and phrenic electroneurograms after almitrine in anesthetized, paralyzed, and vagotomized cats. We have now investigated the effect of this peripheral chemoreceptor stimulant on diaphragmatic and genioglossal (GG, an upper airway-maintaining muscle) electromyograms in five unanesthetized, chronically instrumented, spontaneously breathing adult cats during slow-wave sleep. In 12 studies almitrine doses of 1.0–6.0 mg/kg increased inspired minute ventilation (VI), frequency (f), and tidal volume (VT) and decreased expiratory time (TE). However, almitrine doses as high as 6.0 mg/kg failed to augment phasic inspiratory GG activity. To determine why almitrine induced phasic inspiratory upper airway activity in anesthetized, vagotomized cats but not in sleeping cats, additional studies were performed. In four dose-response studies in three pentobarbital-anesthetized cats, almitrine, 1.0–6.0 mg/kg, did not produce phasic inspiratory GG activity. Almitrine did induce phasic inspiratory GG activity in two of three studies in three vagotomized, tracheostomized, alpha-chloralose-urethan-anesthetized cats. These results suggest that almitrine would not be useful in obstructive sleep apnea, yet because almitrine markedly increased VI, f, and VT and decreased TE in unanesthetized sleeping cats the drug may be effective in patients who lack normal central neural respiratory drive, such as the preterm infant.

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.

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.

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)

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