Effect of surface tension of mucosal lining liquid on upper airway mechanics in anesthetized humans

2003 ◽  
Vol 95 (1) ◽  
pp. 357-363 ◽  
Author(s):  
Jason P. Kirkness ◽  
Peter R. Eastwood ◽  
Irene Szollosi ◽  
Peter R. Platt ◽  
John R. Wheatley ◽  
...  
Keyword(s):  
Surface Tension ◽  
Human Subjects ◽  
Upper Airway ◽  
Exogenous Surfactant ◽  
Airway Mechanics ◽  
Before And After ◽  
Airway Opening ◽  
Mucosal Lining ◽  
Effect Of Surface

Upper airway (UA) patency may be influenced by surface tension (γ) operating within the (UAL). We examined the role of γ of UAL in the maintenance of UA patency in eight isoflurane-anesthetized supine human subjects breathing via a nasal mask connected to a pneumotachograph attached to a pressure delivery system. We evaluated 1) mask pressure at which the UA closed (Pcrit), 2) UA resistance upstream from the site of UA collapse (RUS), and 3) mask pressure at which the UA reopened (Po). A multiple pressure-transducer catheter was used to identify the site of airway closure (velopharyngeal in all subjects). UAL samples (0.2 μl) were collected, and the γ of UAL was determined by using the “pull-off force” technique. Studies were performed before and after the intrapharyngeal instillation of 5 ml of exogenous surfactant (Exosurf, Glaxo Smith Kline). The γ of UAL decreased from 61.9 ± 4.1 (control) to 50.3 ± 5.0 mN/m (surfactant; P < 0.02). Changes in Po, RUS, and Po - Pcrit (change = control - surfactant) were positively correlated with changes in γ ( r2 > 0.6; P < 0.02) but not with changes in Pcrit ( r2 = 0.4; P > 0.9). In addition, mean peak inspiratory airflow (no flow limitation) significantly increased ( P < 0.04) from 0.31 ± 0.06 (control) to 0.36 ± 0.06 l/s (surfactant). These findings suggest that γ of UAL exerts a force on the UA wall that hinders airway opening. Instillation of exogenous surfactant into the UA lowers the γ of UAL, thus increasing UA patency and augmenting reopening of the collapsed airway.

Effects of pharyngeal lubrication on the opening of obstructed upper airway

1992 ◽  
Vol 72 (6) ◽  
pp. 2311-2316 ◽  
Author(s):  
H. Miki ◽  
W. Hida ◽  
Y. Kikuchi ◽  
T. Chonan ◽  
M. Satoh ◽  
...  
Keyword(s):  
Hypoglossal Nerve ◽  
Muscle Tone ◽  
Upper Airway ◽  
Intraluminal Pressure ◽  
Lower Airway ◽  
Before And After ◽  
Airway Opening ◽  
Cervical Trachea ◽  
Artificial Surfactant ◽  
Stimulation Of

We examined the effect of electrical stimulation of the hypoglossal nerve and pharyngeal lubrication with artificial surfactant (Surfactant T-A) on the opening of obstructed upper airway in nine anesthetized supine dogs. The upper airway was isolated from the lower airway by transecting the cervical trachea. Upper airway obstruction was induced by applying constant negative pressures (5, 10, 20, and 30 cmH2O) on the rostral cut end of the trachea. Peripheral cut ends of the hypoglossal nerves were electrically stimulated by square-wave pulses at various frequencies from 10 to 30 Hz (0.2-ms duration, 5–7 V), and the critical stimulating frequency necessary for opening the obstructed upper airway was measured at each driving pressure before and after pharyngeal lubrication with artificial surfactant. The critical stimulation frequency for upper airway opening significantly increased as upper airway pressure became more negative and significantly decreased with lubrication of the upper airway. These findings suggest that greater muscle tone of the genioglossus is needed to open the occluded upper airway with larger negative intraluminal pressure and that lubrication of the pharyngeal mucosa with artificial surfactant facilitates reopening of the upper airway.

scholarly journals The effect of rapid eye movement (REM) sleep on upper airway mechanics in normal human subjects

1998 ◽  
Vol 510 (3) ◽  
pp. 963-976 ◽  
Author(s):  
James A. Rowley ◽  
Brian R. Zahn ◽  
Mark A. Babcock ◽  
M. Safwan Badr
Keyword(s):  
Eye Movement ◽  
Rem Sleep ◽  
Human Subjects ◽  
Upper Airway ◽  
Rapid Eye Movement ◽  
Airway Mechanics ◽  
Normal Human

scholarly journals Surface Tension of Upper Airway Mucosal Lining Liquid in Obstructive Sleep Apnea/Hypopnea Syndrome

SLEEP ◽  
2005 ◽  
Vol 28 (4) ◽  
pp. 457-463 ◽  
Author(s):  
Jason P. Kirkness ◽  
Melanie Madronio ◽  
Rosie Stavrinou ◽  
John R. Wheatley ◽  
Terence C. Amis
Keyword(s):  
Surface Tension ◽  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Upper Airway ◽  
Obstructive Sleep ◽  
Mucosal Lining ◽  
Hypopnea Syndrome

Relationship between surface tension of upper airway lining liquid and upper airway collapsibility during sleep in obstructive sleep apnea hypopnea syndrome

2003 ◽  
Vol 95 (5) ◽  
pp. 1761-1766 ◽  
Author(s):  
Jason P. Kirkness ◽  
Melanie Madronio ◽  
Rosie Stavrinou ◽  
John R. Wheatley ◽  
Terence C. Amis
Keyword(s):  
Surface Tension ◽  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Sleep Disordered Breathing ◽  
Upper Airway ◽  
Obstructive Sleep ◽  
Before And After ◽  
Posterior Pharynx ◽  
Hypopnea Syndrome ◽  
Disordered Breathing

Lowering surface tension (γ) of upper airway lining liquid (UAL) reduces upper airway opening (anesthetized humans) and closing (anesthetized rabbits) pressures. We now hypothesize that in sleeping obstructive sleep apnea hypopnea syndrome (OSAHS) patients lowering γ of UAL will enhance upper airway stability and decrease the severity of sleep-disordered breathing. Nine OSAHS patients [respiratory disturbance index (RDI): 49 ± 8 (SE) events/h, diagnostic night] participated in a two-part, one-night, polysomnography study. In the first part, upper airway closing pressures (during non-rapid eye movement sleep, Pcrit) were measured and samples of UAL (awake) were obtained before and after 2.5 ml of surfactant (Exosurf, Glaxo Smith Kline) was instilled into the posterior pharynx. The γ of UAL was determined with the use of the “pull-off” force technique. In the second part, subjects received a second application of 2.5 ml of surfactant and then slept the remainder of the night (205 ± 30 min). Instillation of surfactant decreased the γ of UAL from 60.9 ± 3.1 mN/m (control) to 45.2 ± 2.5 mN/m (surfactant group) ( n = 9, P < 0.001). Pcrit decreased from 1.19 ± 1.14 cmH2O (control) to -0.56 ± 1.15 cmH2O (surfactant group) ( n = 7, P < 0.02). Compared with the second half of diagnostic night, surfactant decreased RDI from 51 ± 8 to 35 ± 8 events/h ( n = 9, P < 0.03). The fall in RDI (ΔRDI) correlated with the fall in γ of UAL (Δγ) (ΔRDI = 1.8 × Δγ, r = 0.68, P = 0.04). Hypopneas decreased ∼50% from 42 ± 8 to 20 ± 5 events/h ( n = 9, P < 0.03, paired t-test). The γ of UAL measured the next morning remained low at 49.5 ± 2.7 mN/m ( n = 9, P < 0.001, ANOVA, compared with control). In conclusion, instillation of surfactant reduced the γ of UAL in OSAHS patients and decreased Pcrit and the occurrence of hypopneas. Therapeutic manipulation of γ of UAL may be beneficial in reducing the severity of sleep-disordered breathing in OSAHS patients.

Upper airway anesthesia delays arousal from airway occlusion induced during human NREM sleep

1992 ◽  
Vol 73 (2) ◽  
pp. 642-648 ◽  
Author(s):  
R. C. Basner ◽  
J. Ringler ◽  
E. Garpestad ◽  
R. M. Schwartzstein ◽  
D. Sparrow ◽  
...  
Keyword(s):  
Upper Airway ◽  
Nrem Sleep ◽  
Face Mask ◽  
Airway Occlusion ◽  
Before And After ◽  
Arousal Response ◽  
End Tidal ◽  
Arterial O2 Saturation ◽  
Stable Stage

Six healthy subjects (5 males and 1 female, 26–40 yr old) were studied during non-rapid-eye-movement (NREM) sleep to assess the role of upper airway (UA) afferents in the arousal response to induced airway occlusion. Subjects wore an airtight face mask attached to a low-resistance one-way valve. A valve in the inspiratory circuit allowed instantaneous inspiratory airway occlusion and release; the expiratory circuit remained unoccluded at all times. Each subject was studied during two nights. On one night, occlusions were created during stable stage 2 NREM sleep before and after application of 4% lidocaine to the oral and nasal mucosa. On the other night, the protocol was duplicated with saline (“sham anesthesia”) rather than lidocaine. The order of nights was randomized. Occlusions were sustained until electroencephalographic arousal. Three to 12 occlusions were performed in each subject for each of the four parts of the protocol (pre- and post-lidocaine, pre- and post-saline). The auditory threshold for arousal (1,500-Hz tone beginning at 30 dB) was also tested before and after UA lidocaine. For the group, arousal time after UA anesthesia was prolonged compared with preanesthesia arousal time (P less than 0.001); arousal time after sham anesthesia did not significantly increase from before sham anesthesia (P = 0.9). The increase in arousal time with UA anesthesia was greater than the increase with sham anesthesia (P less than 0.001). The auditory arousal threshold did not increase after UA anesthesia. Inspiratory mask pressure, arterial O2 saturation of hemoglobin, and end-tidal PCO2 during occlusions were similar before and after UA anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Decreased Surface Tension of Upper Airway Mucosal Lining Liquid Increases Upper Airway Patency in Anaesthetised Rabbits

2003 ◽  
Vol 547 (2) ◽  
pp. 603-611 ◽  
Author(s):  
Jason P. Kirkness ◽  
Hugo K. Christenson ◽  
Sarah R. Garlick ◽  
Radha Parikh ◽  
Kristina Kairaitis ◽  
...  
Keyword(s):  
Surface Tension ◽  
Upper Airway ◽  
Airway Patency ◽  
Mucosal Lining

Influence of upper airway sensory receptors on respiratory muscle activation in humans

1987 ◽  
Vol 63 (1) ◽  
pp. 368-374 ◽  
Author(s):  
S. Redline ◽  
K. P. Strohl
Keyword(s):  
Respiratory Muscle ◽  
Muscle Activation ◽  
Human Subjects ◽  
Upper Airway ◽  
Normal Subjects ◽  
Emg Activity ◽  
Sensory Receptors ◽  
Upper Airways ◽  
Before And After ◽  
Thoracic Muscles

We reasoned that neural information from upper airway (UA) sensory receptors could influence the relationship between UA and diaphragmatic neuromuscular responses to hypercapnia. In this study, the electromyographic (EMG) activities of the alae nasi (AN), genioglossus (GG), and chest wall (CW) or diaphragm (Di) to ventilatory loading were assessed in six laryngectomized, tracheostomized human subjects and in six subjects breathing with an intact UA before and after topical UA anesthesia. The EMG activities of the UA and thoracic muscles increased at similar rates with increasing hypercapnia in normal subjects, in subjects whose upper airways were anesthetized, and in laryngectomized subjects breathing with a cervical tracheostomy. Furthermore, in the laryngectomized subjects, respiratory muscle EMG activation increased with resistive inspiratory loading (15 cmH2O X l–1 X s) applied at the level of a cervical tracheostomy. At an average expired CO2 fraction of 7.0%, resistive loading resulted in a 93 +/- 26.3% (SE) increase in peak AN EMG activity, a 39 +/- 2.0% increase in peak GG EMG activity, and a 43.2 +/- 16.5% increase in peak CW (Di) EMG activity compared with control values. We conclude that the ventilatory responses of the UA and thoracic muscles to ventilatory loading are not substantially influenced by laryngectomy or UA anesthesia.

The Role of the Renin—Angiotensin—Aldosterone System in Cardiovascular Homeostasis in Normal Man

1974 ◽  
Vol 48 (s2) ◽  
pp. 49s-52s ◽  
Author(s):  
E. Haber ◽  
J. Sancho ◽  
R. Re ◽  
J. Burton ◽  
A. C. Barger
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Enzyme Inhibitor ◽  
Human Subjects ◽  
Plasma Renin ◽  
Pressure Control ◽  
Sodium Depletion ◽  
Aldosterone Secretion ◽  
Before And After

1. To examine the role of angiotensin II in the maintenance of blood pressure and control of aldosterone secretion, eight normal human subjects were studied on a tilt table in sodium-replete and sodium-depleted states, before and after the administration of an angiotensin converting-enzyme inhibitor (CEI). 2. Administration of CEI was followed by a marked fall in blood pressure on tilting in sodium-depleted, but not in sodium-replete, subjects. CEI administration also resulted in a rise in plasma renin activity in the supine position, in the absence of haemodynamic change. The rise in plasma aldosterone observed both in response to tilting and sodium depletion did not occur after CEI, even though plasma renin activities were higher. 3. These results indicate that: (a) angiotensin II is essential for blood pressure control in the sodium-depleted individual; (b) angiotensin II exerts direct feedback control on renin secretion; (c) angiotensin II is the primary stimulus to aldosterone secretion in response to both sodium depletion and posture.

Harmonic holes with surface tension in an elastic plane under uniform remote loading

2016 ◽  
Vol 22 (9) ◽  
pp. 1806-1812 ◽  
Author(s):  
Ming Dai ◽  
Peter Schiavone ◽  
Cun-Fa Gao
Keyword(s):  
Surface Tension ◽  
Conformal Mapping ◽  
Linear Equations ◽  
Elastic Plane ◽  
Mean Stress ◽  
Remote Loading ◽  
The Mean ◽  
Non Linear Equations ◽  
Effect Of Surface

Harmonic holes are designed to leave undisturbed the mean stress in an uncut body subjected to a system of prescribed remote loadings. The role of residual surface tension in the design of harmonic holes is an important consideration, which is usually neglected at the macroscale but remains a significant factor in the design of such holes at the nanoscale. We consider the identification of the geometry of a single harmonic hole in an elastic plane subjected to uniform remote loading when residual surface tension is incorporated into the model of deformation. The geometry of the hole is defined by a conformal mapping with certain unknown coefficients determined from a system of non-linear equations. We illustrate our results with several examples. In particular, we show that for a given remote loading and surface tension, the shapes obtained exhibit strong size-dependency. Moreover, we find that the incorporation of the effect of surface tension greatly extends the range of admissible uniform remote loadings that guarantee the existence of harmonic holes.

Sign in / Sign up

Export Citation Format

Share Document