Pressure-volume behavior of the upper airway

1986 ◽  
Vol 61 (3) ◽  
pp. 912-918 ◽  
Author(s):  
J. M. Fouke ◽  
J. P. Teeter ◽  
K. P. Strohl
Keyword(s):  
Peak Pressure ◽  
Force Production ◽  
Upper Airway ◽  
Volume Relationship ◽  
Anesthetized Dogs ◽  
Cervical Trachea ◽  
Force Volume ◽  
Pressure Changes ◽  
Upper Airway Muscles ◽  
The Relationship

The study was performed to investigate the relationship between force generation and upper airway expansion during respiratory efforts by upper airway muscles. In 11 anesthetized dogs we isolated the upper airway (nasal, oral, pharyngeal, and laryngeal regions) by transecting the cervical trachea and sealing the nasal and oral openings. During spontaneous respiratory efforts the pressure within the sealed upper airway, used as an index of dilating force, decreased during inspiration. On alternate breaths the upper airway was opened to a pneumotachograph, and an increase in volume occurred, also during inspiration. Progressive hyperoxic hypercapnia produced by rebreathing increased the magnitude of change in pressure and volume. At any level of drive, peak pressure or volume occurred at the same point during inspiration. At any level of drive, volume and pressure changes increased with end-expiratory occlusion of the trachea. The force-volume relationship determined from measurements during rebreathing was compared with pressure-volume curves performed by passive inflation of the airway while the animal was apneic. The relationship during apnea was 1.06 +/- 0.55 (SD) ml/cmH2O, while the force-volume relationship from rebreathing trials was -1.09 +/- 0.45 ml/cmH2O. We conclude that there is a correspondence between force production and volume expansion in the upper airway during active respiratory efforts.

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.

Effect of Chemoreceptor and Pulmonary Receptor Stimulation on Dilator Nares EMG Activity in the Dog

1983 ◽  
Vol 91 (6) ◽  
pp. 648-652 ◽  
Author(s):  
Daniel J. Blum ◽  
Thomas V. McCaffrey
Keyword(s):  
Upper Airway ◽  
Emg Activity ◽  
Receptor Stimulation ◽  
Lung Inflation ◽  
Anesthetized Dogs ◽  
Inspiratory Activity ◽  
Upper Airway Muscles ◽  
The Relationship ◽  
Pulmonary Stretch Receptor ◽  
Stimulation Of

To define the relationship between central control of upper airway muscles and respiratory muscle function, the electromyographic responses of the dilator nares muscles to stimulation of chemoreceptors and pulmonary receptors were studied in six anesthetized dogs. Only at maximal levels of hypoxia was the inspiratory activity of the dilator nares significantly increased. Hypercapnic stimulation increased the inspiratory activity with each incremental increase in CO2. Pulmonary stretch receptor stimulation produced by lung inflation inhibited dilator nares activity. Pulmonary irritant receptor stimulation by intravenously administered histamine increased dilator nares activity, as did pulmonary J receptor stimulation by the intravenous administration of capsaicin.

scholarly journals Reflex activities of the upper airway muscles during experimental nasal occlusion in anesthetized dogs.

1991 ◽  
Vol 53 (1) ◽  
pp. 93-99 ◽  
Author(s):  
Osamu KAMINUMA ◽  
Hirokazu TSUBONE ◽  
Job Manaet MATIAS ◽  
Ryohei NISHIMURA ◽  
Shigeru SUGANO
Keyword(s):  
Upper Airway ◽  
Anesthetized Dogs ◽  
Upper Airway Muscles

An efferent pathway mediating reflex tracheal dilation in awake dogs

1984 ◽  
Vol 57 (2) ◽  
pp. 413-418 ◽  
Author(s):  
G. Bowes ◽  
E. J. Shakin ◽  
E. A. Phillipson ◽  
N. Zamel
Keyword(s):  
Cuff Pressure ◽  
Upper Airway ◽  
Atropine Sulfate ◽  
Adrenergic Blockade ◽  
Continuous Intravenous Infusion ◽  
Lung Inflation ◽  
Efferent Pathway ◽  
Cervical Trachea ◽  
Pressure Changes ◽  
Parasympathetic Pathway

Lung inflation is known to produce reflex relaxation of tracheal smooth muscle (TSM) and dilation of the upper airway, but the specific efferent pathway involved has not been established. Therefore we examined TSM tone in four trained awake dogs by measuring pressure changes in the water-filled cuff of an endotracheal tube that was inserted into the lower cervical trachea through a permanent tracheostomy. Under control conditions, sustained lung inflation with 1 liter of air produced apnea (Hering-Breuer inflation reflex) and a decrease in cuff pressure (Pcuff) of 37.4 +/- 12.0 (mean +/- SD) cmH2O. beta-Adrenergic blockade with propranolol had no effect on either the apneic or TSM responses to lung inflation. Efferent parasympathetic blockade with atropine sulfate (1.2–2.4 mg) abolished TSM tone, which was then restored to control levels by a continuous intravenous infusion of serotonin (14–28 micrograms X kg-1 X min-1). Under these conditions, lung inflation still induced reflex apnea but no longer relaxed TSM tone (mean decrease in Pcuff, 2.7 +/- 1.4 cmH2O, P less than 0.001). The findings indicate that reflex tracheal dilation in response to lung inflation is mediated by an efferent cholinergic (parasympathetic) pathway.

Movement of the human upper airway during inspiration with and without inspiratory resistive loading

2011 ◽  
Vol 110 (1) ◽  
pp. 69-75 ◽  
Author(s):  
S. Cheng ◽  
J. E. Butler ◽  
S. C. Gandevia ◽  
L. E. Bilston
Keyword(s):  
Soft Palate ◽  
Soft Tissues ◽  
Upper Airway ◽  
Spatial Modulation ◽  
Emg Activity ◽  
Anterior Border ◽  
Resistive Loading ◽  
Airway Walls ◽  
Upper Airway Muscles ◽  
The Relationship

The electromyographic (EMG) activity of human upper airway muscles, particularly the genioglossus, has been widely measured, but the relationship between EMG activity and physical movement of the airway muscles remains unclear. We aimed to measure the motion of the soft tissues surrounding the airway during normal and loaded inspiration on the basis of the hypothesis that this motion would be affected by the addition of resistance to breathing during inspiration. Tagged MR imaging of seven healthy subjects was performed in a 3-T scanner. Tagged 8.6-mm-spaced grids were used, and complementary spatial modulation of magnetization images were acquired beginning ∼200 ms before inspiratory airflow. Deformation of tag line intersections was measured. The genioglossus moved anteriorly during normal and loaded inspiration, with less movement during loaded inspiration. The motion of tissues at the anterior border of the upper airway was nonuniform, with larger motions inferiorly. At the level of the soft palate, the lateral dimension of the airway decreased significantly during loaded inspiration (−0.15 ± 0.09 and −0.48 ± 0.09 mm during unloaded and loaded inspiration, respectively, P < 0.05). When resistance to inspiratory flow was added, genioglossus motion and lateral dimensions of the airway at the level of the soft palate decreased. Our results suggest that genioglossus motion begins early to dilate the airway prior to airflow and that inspiratory loading reduces the anterior motion of the genioglossus and increases the collapse of the lateral airway walls at the level of the soft palate.

Bronchoconstriction: upper airway dilating muscle and diaphragm activity

1983 ◽  
Vol 55 (6) ◽  
pp. 1837-1843 ◽  
Author(s):  
M. A. Haxhiu ◽  
E. C. Deal ◽  
W. B. Van de Graaff ◽  
E. Van Lunteren ◽  
J. A. Salamone ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Upper Airway ◽  
Pulmonary Resistance ◽  
Cervical Vagotomy ◽  
Anesthetized Dogs ◽  
Posterior Cricoarytenoid ◽  
Upper Airway Muscles ◽  
Spontaneously Breathing ◽  
Different Levels ◽  
Diaphragm Activity

The effect of bronchoconstriction on the activity of the diaphragm and the upper dilating airway muscles were studied by administering graded doses of methacholine to anesthetized dogs spontaneously breathing oxygen. The electrical activity of the genioglossus, posterior cricoarytenoid, and alae nasi was compared with that of the diaphragm at different levels of pulmonary resistance. Induced bronchoconstriction was associated with increases in the electrical activity of all muscles examined. Bilateral cervical vagotomy diminished but did not prevent the bronchoconstrictor effects of methacholine. When greater concentrations of methacholine were administered to produce bronchoconstriction comparable with that produced prevagotomy, both genioglossus and diaphragm activity increased. This study indicates that the upper airway muscles and the diaphragm respond to bronchoconstriction. The activation of the upper airway muscles with bronchoconstriction may decrease upper airway resistance serving to partially offset increases in pulmonary resistance and to modulate airflow patterns during bronchoconstriction.

Neurostimulation for Obstructive Sleep Apnea: Investigations

1993 ◽  
Vol 72 (1) ◽  
pp. 52-57 ◽  
Author(s):  
David W. Fairbanks ◽  
David N.F. Fairbanks
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Sleep Apnea Syndrome ◽  
Upper Airway ◽  
Future Research ◽  
Obstructive Sleep ◽  
Airway Obstructions ◽  
Anesthetized Dogs ◽  
Upper Airway Muscles ◽  
Accessory Muscles

Neurostimulation of the upper airway muscles (accessory muscles of respiration) was accomplished in anesthetized dogs and sleeping humans by electrical stimulation of the hypoglossal nerves. Such stimulations relieved partial airway obstructions in dogs. They also aborted (shortened) obstructive sleep apnea events in humans who suffer with obstructive sleep apnea syndrome. In one subject, stimulations delivered in advance of apneic events (by automatic cycling) prevented apneas. Neurostimulation for obstructive sleep apnea may be an important concept for future research and development.

Motor responses to positive-pressure breathing in the developing opossum

1985 ◽  
Vol 58 (5) ◽  
pp. 1489-1495 ◽  
Author(s):  
J. P. Farber
Keyword(s):  
Airway Resistance ◽  
Upper Airway ◽  
Abdominal Muscle ◽  
Positive Pressure ◽  
Postnatal Life ◽  
Abdominal Muscles ◽  
Upper Airways ◽  
Motor Responses ◽  
Upper Airway Resistance ◽  
Upper Airway Muscles

The suckling opossum exhibits an expiration-phased discharge in abdominal muscles during positive-pressure breathing (PPB); the response becomes apparent, however, only after the 3rd-5th wk of postnatal life. The purpose of this study was to determine whether the early lack of activation represented a deficiency of segmental outflow to abdominal muscles or whether comparable effects were observed in cranial outflows to muscles of the upper airways due to immaturity of afferent and/or supraspinal pathways. Anesthetized suckling opossums between 15 and 50 days of age were exposed to PPB; electromyogram (EMG) responses in diaphragm and abdominal muscles were measured, along with EMG of larynx dilator muscles and/or upper airway resistance. In animals older than approximately 30 days of age, the onset of PPB was associated with a prolonged expiration-phased EMG activation of larynx dilator muscles and/or decreased upper airway resistance, along with expiratory recruitment of the abdominal muscle EMG. These effects persisted as long as the load was maintained. Younger animals showed only those responses related to the upper airway; in fact, activation of upper airway muscles during PPB could be associated with suppression of the abdominal motor outflow. After unilateral vagotomy, abdominal and upper airway motor responses to PPB were reduced. The balance between PPB-induced excitatory and inhibitory or disfacilitory influences from the supraspinal level on abdominal motoneurons and/or spinal processing of information from higher centers may shift toward net excitation as the opossum matures.

Effect of Turf Toe on Foot Contact Pressures in Professional American Football Players

2009 ◽  
Vol 30 (5) ◽  
pp. 405-409 ◽  
Author(s):  
Robert H. Brophy ◽  
Seth C. Gamradt ◽  
Scott J. Ellis ◽  
Ronnie P. Barnes ◽  
Scott A. Rodeo ◽  
...  
Keyword(s):  
Body Mass Index ◽  
National Football League ◽  
Peak Pressure ◽  
American Football ◽  
Football Players ◽  
Plantar Pressures ◽  
History Of ◽  
Turf Toe ◽  
The Relationship ◽  
Contact Pressures

Background: The relationship between turf toe and plantar foot pressures has not been extensively studied. Two hypotheses were tested in a cohort of professional American football players: first, that a history of turf toe is associated with increased peak hallucal and first metatarsophalangeal (MTP) plantar pressures; second, that decreased range of motion (ROM) of the first MTP correlates with increased peak hallucal and first MTP plantar pressures. Materials and Methods: Forty-four athletes from one National Football League (NFL) team were screened for a history of turf toe during preseason training. Dorsal passive MTP ROM and dynamic plantar pressures were measured in both feet of each player. Anatomical masking was used to assess peak pressure at the first MTP and hallux. Results: First MTP dorsiflexion was significantly lower in halluces with a history of turf toe (40.6 ± 15.1 degrees versus 48.4 ± 12.8 degrees, p = 0.04). Peak hallucal pressures were higher in athletes with turf toe (535 ± 288 kPa versus 414 ± 202 kPa, p = 0.05) even after normalizing for athlete body mass index ( p = 0.0003). Peak MTP pressure was not significantly different between the two groups tested. First MTP dorsiflexion did not correlate with peak hallucal or first MTP pressures. Conclusion: This study showed that turf toe is associated with decreased MTP motion. In addition, increased peak hallucal pressures were found. Further study is warranted to determine whether these pressures correlate with the severity of symptoms or progression of turf toe to first MTP arthritis.

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