Upper airway muscle activity and the thoracic volume dependence of upper airway resistance

1991 ◽  
Vol 70 (1) ◽  
pp. 430-438 ◽  
Author(s):  
R. M. Aronson ◽  
D. W. Carley ◽  
E. Onal ◽  
J. Wilborn ◽  
M. Lopata
Keyword(s):  
Lung Volume ◽  
Airway Resistance ◽  
Linear Regression Analysis ◽  
Control Period ◽  
Upper Airway ◽  
Multiple Linear Regression Analysis ◽  
Respiratory Pattern ◽  
Airway Patency ◽  
Upper Airway Resistance ◽  
Volume Dependence

Although a thoracic volume dependence of upper airway resistance and caliber is known to exist in seated subjects, the mechanisms mediating this phenomenon are unknown. To test the hypothesis that actively altered end-expiratory lung volume (EELV) affects upper airway resistance in the supine position and to explore the mechanisms of any EELV-induced resistance changes, we studied five normal males during wakefulness. Supraglottic upper airway resistance (Ruaw) was calculated at an inspiratory flow of 0.1 l/s. The genioglossal electromyogram was obtained with indwelling wire electrodes and processed as moving time average. End-tidal CO2 was monitored by infrared analyzer. Observations were made during four 20-breath voluntary maneuvers: two at high and two at low EELV in each subject. Each maneuver was preceded by a control period at functional residual capacity. At high lung volume the EELV was increased by 2.23 +/- 0.54 (SD) liters; Ruaw decreased to 67.8 +/- 35.1% of control, while tonic and phasic genioglossal activities declined to 79.0 +/- 23.1 and 72.4 +/- 29.8%, respectively. At low lung volume the EELV was decreased by 0.86 +/- 0.23 liters. Ruaw increased to 178.2 +/- 186.8%, while tonic and phasic genioglossal activities increased to 243.0 +/- 139.3 and 249.1 +/- 146.3%, respectively (P less than 0.0001 for all). The findings were not explained by CO2 perturbations or respiratory pattern. Multiple linear regression analysis indicated that the genioglossal responses blunted the EELV-induced changes in upper airway patency.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of lung volume dependence of upper airway resistance during continuous negative airway pressure

1994 ◽  
Vol 77 (2) ◽  
pp. 840-844 ◽  
Author(s):  
F. Series ◽  
I. Marc
Keyword(s):  
Lung Volume ◽  
Airway Pressure ◽  
Airway Resistance ◽  
Upper Airway ◽  
Random Order ◽  
Pressure Increase ◽  
Nasal Mask ◽  
Upper Airway Resistance ◽  
Volume Dependence ◽  
Negative Airway Pressure

To quantify the contribution of lung volume dependence of upper airway (UA) on continuous negative airway pressure (CNAP)-induced increase in upper airway resistance, we compared the changes in supralaryngeal resistance during an isolated decrease in lung volume and during CNAP in eight normal awake subjects. Inspiratory supralaryngeal resistance was measured at isoflow during four trials, during two CNAP trials where the pressure in a nasal mask was progressively decreased in 3- to 5-cmH2O steps and during two continuous positive extrathoracic pressure (CPEP) trials where the pressure around the chest (in an iron lung) was increased in similar steps. The CNAP and CPEP trials were done in random order. During the CPEP trial, the neck was covered by a rigid collar to prevent compression by the cervical seal of the iron lung. In each subject, resistance progressively increased during the experiments. The increase was linearily correlated with the pressure increase in the iron lung and with the square of the mask pressure during CNAP. There was a highly significant correlation between the rate of rise in resistance between CNAP and CPEP: the steeper the increase in resistance with decreasing lung volume, the steeper the increase in resistance with decreasing airway pressure. Lung volume dependence in UA resistance can account for 61% of the CNAP-induced increase in resistance. We conclude that in normal awake subjects the changes in supralaryngeal resistance induced by CNAP can partly be explained by the lung volume dependence of this resistance.

Role of upper airway in ventilatory control in awake and sleeping dogs

1987 ◽  
Vol 62 (3) ◽  
pp. 1167-1173 ◽  
Author(s):  
J. R. Stradling ◽  
S. J. England ◽  
R. Harding ◽  
L. F. Kozar ◽  
S. Andrey ◽  
...  
Keyword(s):  
Endotracheal Tube ◽  
Lung Volume ◽  
Airway Resistance ◽  
Upper Airway ◽  
Respiratory Pattern ◽  
Abrupt Increase ◽  
Ventilatory Control ◽  
Laryngeal Muscle ◽  
Upper Airway Resistance

We examined the role of the upper airway in the regulation of the pattern of breathing in six adult dogs during wakefulness and sleep. The dogs breathed through a fenestrated endotracheal tube inserted through a tracheostomy. The tube was modified to allow airflow to be directed either through the nose or through the tracheostomy. When airflow was diverted from nose to tracheostomy there was an abrupt increase in the rate of expiratory airflow, resulting in prolongation of the end-expiratory pause but no change in overall expiratory duration or respiratory frequency. Furthermore, electromyogram recordings from implanted diaphragmatic and laryngeal muscle electrodes did not show any changes that could be interpreted as an attempt to delay expiratory airflow or increase end-expiratory lung volume. The effects of switching from nose to tracheostomy breathing could be reversed by adding a resistance to the endotracheal tube so as to approximate upper airway resistance. The findings indicate that under normal conditions in the adult dog upper airway receptors play little role in regulation of respiratory pattern and that the upper airway exerts little influence on the maintenance of end-expiratory lung volume.

Effect of geniohyoid and sternohyoid muscle contraction on upper airway resistance in the cat

1991 ◽  
Vol 71 (4) ◽  
pp. 1346-1354 ◽  
Author(s):  
D. A. Wiegand ◽  
B. Latz
Keyword(s):  
Electrical Stimulation ◽  
Muscle Contraction ◽  
Airway Resistance ◽  
Upper Airway ◽  
Muscle Stimulation ◽  
Nasal Airflow ◽  
Airway Patency ◽  
Upper Airway Resistance ◽  
Wide Range ◽  
Consistent Change

Previous investigators (van Lunteren et al. J. Appl. Physiol. 62: 582–590, 1987) have suggested that the geniohyoid and sternohyoid muscles may act as upper airway dilators in the cat. To investigate the effect of geniohyoid and sternohyoid contraction on inspiratory upper airway resistance (UAR), we studied five adult male cats anesthetized with ketamine and xylazine during spontaneous room-air breathing. Inspiratory nasal airflow was measured by sealing the lips and constructing a nose mask. Supraglottic pressure was measured using a transpharyngeal catheter placed above the larynx. Mask pressure was measured using a separate catheter. Geniohyoid and sternohyoid lengths were determined by sonomicrometry. Geniohyoid and sternohyoid contraction was stimulated by direct muscle electrical stimulation with implanted wire electrodes. Mean inspiratory UAR was determined for spontaneous breaths under three conditions: 1) baseline (no muscle stimulation), 2) geniohyoid contraction alone, and 3) sternohyoid contraction alone. Geniohyoid contraction alone produced no significant reduction in inspiratory UAR [unstimulated, 17.75 +/- 0.86 (SE) cmH2O.l-1.s; geniohyoid contraction, 19.24 +/- 1.10]. Sternohyoid contraction alone also produced no significant reduction in inspiratory UAR (unstimulated, 15.74 +/- 0.92 cmH2O.l-1.s; sternohyoid contraction, 14.78 +/- 0.78). Simultaneous contraction of the geniohyoid and sternohyoid muscles over a wide range of muscle lengths produced no consistent change in inspiratory UAR. The geniohyoid and sternohyoid muscles do not appear to function consistently as upper airway dilator muscles when UAR is used as an index of upper airway patency in the cat.

Susceptibility to Upper Airway Obstruction during Partial Neuromuscular Block 

1998 ◽  
Vol 88 (2) ◽  
pp. 371-378 ◽  
Author(s):  
Gilles D'Honneur ◽  
Frederic Lofaso ◽  
Gordon B. Drummond ◽  
Jean-Marc Rimaniol ◽  
Jean V. Aubineau ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Airway Obstruction ◽  
Airway Resistance ◽  
Neuromuscular Block ◽  
Work Of Breathing ◽  
Upper Airway ◽  
Residual Effects ◽  
Airway Patency ◽  
Upper Airway Resistance ◽  
Residual Neuromuscular Block

Background Airway obstruction after anesthesia may be caused or exaggerated by residual neuromuscular block, with loss of muscle support for collapsible upper airway structures. Methods Six male volunteers were studied before treatment, during stable partial neuromuscular block with vecuronium at a mean train-of-four (TOF) ratio of 50% (95% CI, 36-61%), and after reversal by neostigmine. Catheter-mounted transducers were placed in the pharynx and esophagus to estimate, respectively, the upper airway resistance, and the work of breathing (calculated as the time integral of the inspiratory pressure developed by the respiratory muscles, esophageal pressure time product) during quiet breathing, during breathing 5% carbon dioxide, and while breathing with an inspiratory resistor. Breathing with pressure at the airway opening held at pressures from -5 to 40 cm H2O were also tested to assess airway collapsibility. Results Although breathing through a resistor increased upper airway resistance from 1.2 (0.67, 1.72) cm H2O x l(-1) x s to 2.5 (1.32, 3.38) cm H2O x l(-1) x s, and carbon dioxide stimulation reduced resistance to 0.8 (0.46, 1.33) cm H2O x l(-1) x s, no effect of partial neuromuscular block (mean TOF ratio, 52%) on upper airway properties could be shown. Conclusions Neuromuscular block with a TOF ratio of 50% can be present yet clinically difficult to detect in patients recovering from anesthesia. This degree of block has no effect on airway patency in volunteers, even during challenge. Airway obstruction during recovery from anesthesia thus is more likely to be caused by residual effects of general anesthetic agents or centrally acting analgesics, either alone or perhaps in concert with residual neuromuscular block.

Responses to negative pressure surrounding the neck in anesthetized animals

1990 ◽  
Vol 68 (1) ◽  
pp. 154-160 ◽  
Author(s):  
A. D. Wolin ◽  
K. P. Strohl ◽  
B. N. Acree ◽  
J. M. Fouke
Keyword(s):  
Negative Pressure ◽  
Airway Resistance ◽  
Upper Airway ◽  
Transmural Pressure ◽  
Positive Pressure ◽  
Respiratory Drive ◽  
Airway Wall ◽  
Airway Patency ◽  
Upper Airway Resistance ◽  
Continuous Positive Pressure

Continuous positive pressure applied at the nose has been shown to cause a decrease in upper airway resistance. The present study was designed to determine whether a similar positive transmural pressure gradient, generated by applying a negative pressure at the body surface around the neck, altered upper airway patency. Studies were performed in nine spontaneously breathing anesthetized supine dogs. Airflow was measured with a pneumotachograph mounted on an airtight muzzle placed over the nose and mouth of each animal. Upper airway pressure was measured as the differential pressure between the extrathoracic trachea and the inside of the muzzle. Upper airway resistance was monitored as an index of airway patency. Negative pressure (-2 to -20 cmH2O) was applied around the neck by using a cuirass extending from the jaw to the thorax. In each animal, increasingly negative pressures were transmitted to the airway wall in a progressive, although not linear, fashion. Decreasing the pressure produced a progressive fall in upper airway resistance, without causing a significant change in respiratory drive or respiratory timing. At -5 cmH2O pressure, there occurred a significant fall in upper airway resistance, comparable with the response of a single, intravenous injection of sodium cyanide (0.5-3.0 mg), a respiratory stimulant that produces substantial increases in respiratory drive. We conclude that upper airway resistance is influenced by the transmural pressure across the airway wall and that such a gradient can be accomplished by making the extraluminal pressure more negative.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

The evaluation of physiologic decannulation readiness according to upper airway resistance measurement

2008 ◽  
Vol 139 (4) ◽  
pp. 535-540 ◽  
Author(s):  
Chunli Gao ◽  
Liang Zhou ◽  
Chunsheng Wei ◽  
Matthew R. Hoffman ◽  
Cai Li ◽  
...  
Keyword(s):  
Airway Resistance ◽  
Operating Characteristic ◽  
Upper Airway ◽  
High Sensitivity ◽  
Deep Breathing ◽  
Clinical Criteria ◽  
Receiver Operating Characteristic Curves ◽  
Upper Airway Resistance ◽  
Laryngeal Disease ◽  
Subglottal Pressure

Objective To measure the upper-airway resistance in patients with tracheostomies and determine the value representing decannulation readiness. Subjects and Methods Fifty-six patients with tracheostomies resultant to laryngeal disease participated in this study. Forty patients met clinical criteria for decannulation; 16 did not. Subglottal pressure was measured with a tube connected to the tracheostomy tube, and airflow was monitored simultaneously using a facemask. Upper-airway resistance measurements were recorded during shallow and deep breathing. Results During both shallow and deep breathing, the inspiratory and expiratory resistances were significantly higher for the group unsuitable for decannulation ( P < .0001). The areas under the receiver operating characteristic curves were 0.938 or greater for the four curves, indicating a high sensitivity and specificity of resistance measures for diagnosis. Conclusions Objective measurement of upper-airway resistance during shallow and deep breathing may be a useful parameter in determining decannulation readiness of tracheostomized patients.

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