Pharyngeal Narrowing and Closing Pressures in Patients with Obstructive Sleep Apnea

Morrison, Debra; Launois, Sandrine; Isono, Shiroh; Feroah, Thom R.; Whitelaw, William A.; Remmers, John E.

doi:10.1164/ajrccm/148.3.606

Cited by 223 publications

(132 citation statements)

References 14 publications

Supporting

Mentioning

121

Contrasting

Unclassified

Order By: Relevance

“…Previous studies have confirmed that the velopharynx is the most common site of narrowing in the UA of OSA patients [20][21][22]. Therefore, the fact that mandibular advancement mechanically enlarges and improves velopharyngeal patency seems to be a reasonable concept [4,21].…”

Section: Discussionmentioning

confidence: 99%

Effects of mandibular advancement on airway curvature and obstructive sleep apnoea severity

Tsuiki¹,

Lowe²,

Almeida³

et al. 2004

Eur Respir J

View full text Add to dashboard Cite

In a curved tube, the amount of airflow appears to be influenced by the amount of curvature. The purpose of this study was to investigate changes in obstructive sleep apnoea (OSA) severity and awake velopharyngeal curvature in response to an anteriorly titrated mandibular position in 20 male OSA patients.Baseline supine cephalometry was obtained before the initial insertion of a titratable oral appliance and follow-up supine cephalometry was undertaken after titration of the mandibular position with the appliance in place.The mean apnoea/hypopnea index (AHI) before treatment (31.6¡13.0 events?h -1 ) was significantly reduced (9.8¡7.4 events?h -1 ) after titration of the mandibular position in all 20 patients. There was a significant increase in the anteroposterior calibre and the radius of the curvature of the anterior wall of the velopharynx in 14 good responders who exhibited an AHI reduction to f15. Similar observations were not found in six poor responders.To conclude, an anteriorly titrated mandibular position reduced obstructive sleep apnoea severity, enlarged the velopharynx and diminished the curvature of the anterior velopharyngeal wall in good responders. It is proposed that this change in the upper airway curvature associated with mandibular advancement may effect obstructive sleep apnoea severity through its effect on airflow dynamics. The fluid flow through curved tubes in human organs such as the aortic arch and the coronal arteries are of interest physiologically in the study of cardiovascular systems, since an increase in the curvature induces pressure losses as well as higher resistance in the same region [1,2]. The upper airway (UA) has characteristics similar to those of the curved vessels in the cardiovascular system in that the airstream is curved from the nasal cavity to the hypopharynx at the level of the velopharynx. Nevertheless, an interaction between the curvature of the velopharynx and the pathogenesis of obstructive sleep apnoea (OSA) remains unknown.Recent developments in mandibular advancement oral appliances (OAs) have provided a better quality of life not only for patients with snoring and mild-to-moderate OSA, but also for severe OSA patients who could not tolerate nasal continuous positive airway pressure (nCPAP) [3,4]. An anterior titration of the mandibular position using OAs has been reported to increase the anteroposterior diameter [5] and cross-sectional area [6] of the velopharynx, resulting in a reduction of OSA severity. In addition to such anatomical changes, it was reported that advancement of the mandible decreased nasal resistance and facilitated nasal breathing [7,8]. These reports indicate a close relationship between morphological alteration and improvement of airflow dynamics in response to mandibular protrusion. If the anterior titration of the mandibular position decreased the curvature of the velopharynx, it may assist in improving airflow dynamics.It was hypothesised that an anteriorly titrated mandibular position would diminish the curvature of t...

show abstract

Section: Discussionmentioning

confidence: 99%

Effects of mandibular advancement on airway curvature and obstructive sleep apnoea severity

Tsuiki¹,

Lowe²,

Almeida³

et al. 2004

Eur Respir J

View full text Add to dashboard Cite

show abstract

“…Genioglossus activity has clearly been shown to be decreased during REM sleep (Sauerland & Harper, 1976;Sauerland et al 1981;Wiegand et al 1991) and it is conceivable that REM sleep is characterized by greater collapse in the oropharynx than the nasopharynx. However, this is speculative as all the previous studies on the site of upper airway narrowing in normal subjects and apnoeics have been performed during either NREM sleep or general anaesthesia (Isono et al , 1997Morrison et al 1993). …”

Section: Discussionmentioning

confidence: 99%

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

Rowley

Zahn

Babcock

et al. 1998

The Journal of Physiology

View full text Add to dashboard Cite

It has been proposed that the upper airway is more compliant during rapid eye movement (REM) sleep than during non‐rapid eye movement (NREM) sleep. The purpose of this study was to test this hypothesis in a group of subjects without sleep‐disordered breathing. On the first night, the effect of sleep stage on the relationship of retropalatal cross‐sectional area (CSA; visualized with a fibre‐optic scope) to pharyngeal pressure (PPH) measured at the soft palate during eupnoeic breathing was studied. Breaths during REM sleep were divided into phasic (associated with eye movements) and tonic (not associated with eye movements). There was a significant decrease in pharyngeal CSA during NREM sleep compared with wakefulness. There was no further decrease observed during either tonic or phasic REM sleep. Pharyngeal compliance, defined as the slope of the regression CSA versus PPH, was significantly increased during NREM sleep compared with wakefulness and REM sleep, with the compliance during both tonic and phasic REM sleep being similar to that observed in wakefulness. On the second night, the effect of sleep stage on pressure‐flow relationships of the upper airway was investigated. There was a trend towards the upper airway resistance being highest in NREM sleep compared with wakefulness and REM sleep. We conclude that the upper airway is stiffer and less compliant during REM sleep than during NREM sleep. We postulate that this difference is secondary to differences in upper airway vascular perfusion between REM and NREM sleep.

show abstract

“…13,14,33 However, the use of a mouthpiece excludes the retropalatal region that is a common site of obstruction during sleep in patients with OSA. 34 In addition, a partial opening of the mouth is necessary for mouthpiece use. Mouth opening has been shown to increase upper airway collapsibility.…”

Section: Discussionmentioning

confidence: 99%

Upper Airway Collapsibility Assessed by Negative Expiratory Pressure while Awake is Associated with Upper Airway Anatomy

Hirata

Schorr

Kayamori

et al. 2016

Journal of Clinical Sleep Medicine

View full text Add to dashboard Cite

Study Objectives:There is a growing interest to develop a simple method to characterize the mechanisms leading to upper airway collapse in order to guide treatment options in patients with obstructive sleep apnea (OSA). Critical closing pressure (Pcrit) during sleep is able to predict the anatomical component of OSA. However, Pcrit is a laborious method that is only used for research purposes. The application of negative expiratory pressure (NEP) is a simple method to assess upper airway collapsibility that can be easily performed during wakefulness. We hypothesized that NEP will be, similarly to Pcrit, associated with upper airway anatomy assessed by computed tomography (CT) scan. Methods: Patients under investigation for OSA underwent polysomnography, CT of the upper airway, NEP while awake, and Pcrit during sleep. NEP was performed with −5 cm H 2 O in supine position using a nasal mask. Pcrit was measured during sleep induced by low doses of midazolam. Results: Twenty-eight male subjects were studied (age 45 ± 13 y, body mass index 29.4 ± 4.9 kg/m 2 , apnea-hypopnea index (AHI) 30 ± 26, range 2 to 86 events/h). NEP and Pcrit were similarly associated with tongue area (r = 0.646 and r = 0.585), tongue volume (r = 0.565 and r = 0.613) and pharyngeal length (r = 0.580 and r = 0.611), respectively (p < 0.05 for all comparisons). NEP and Pcrit were also significantly correlated with AHI (r = 0.490 and r = 0.531). NEP and Pcrit were significantly higher in patients with severe OSA than the remaining population. Conclusions: NEP is a simple and promising method that is associated with the anatomical component of upper airway collapsibility. NEP may be valuable to select patients for noncontinuous positive airway pressure alternative therapies for OSA.

show abstract

Pharyngeal Narrowing and Closing Pressures in Patients with Obstructive Sleep Apnea

Cited by 223 publications

References 14 publications

Effects of mandibular advancement on airway curvature and obstructive sleep apnoea severity

Effects of mandibular advancement on airway curvature and obstructive sleep apnoea severity

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

Upper Airway Collapsibility Assessed by Negative Expiratory Pressure while Awake is Associated with Upper Airway Anatomy

Contact Info

Product

Resources

About