Dependency of upper airway patency on head position: The effect of muscle contraction

doi:10.1016/0034-5687(94)00135-M

Respiration Physiology

Volume 100, Issue 3, June 1995, Pages 239-244

Respiration Physiolo...

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Abstract

In the present study we examined the effect of flexion and extension of the head on upper airway (UAW) patency in anesthetized dogs, and compared the dilatory and stabilizing effects of electrically stimulated UAW muscles at the different head positions. Flexion of the head increased UAW resistance (Ruaw) and reduced maximal flow (V̇max), but had little effect on the negative pressure at which UAW collapse occurred (Pcrit). Extension of the head, on the other hand, resulted in more negative Pcrit values and increased V̇max without significantly affecting Ruaw. Electrically induced UAW muscle contraction affected the pressure — flow curve and Ruaw, as well as Pcrit. Changing head position had a substantial effect on the dilatory and stabilizing effect of the various UAW muscles. However, independent of head position, genioglossus stimulation was most effective in reducing Ruaw and increasing Pcrit. We conclude that in the anesthetized, supine dog, head position affects the mechanical properties of the UAW and the effects of UAW muscle contraction.

References (19)

A.J. Block et al.
Factors influencing upper airway closure
Chest
(1984)
M. Odeh et al.
Effect of upper airway muscle contraction on upper airway resistance and collapsibility
Respir. Physiol.
(1993)
W.A. Conrad
Pressure-flow relationship in collapsible tubes
IEEE Transaction Biomed. Ing.
(1969)
M.J. Decker et al.
Functional electrical stimulation and respiration during sleep
J. Appl. Physiol.
(1993)
L.C. Edmonds et al.
The effects of transcutaneous electrical stimulation during wakefulness and sleep in patients with obstructive sleep apnea
Am. Rev. Respir. Dis.
(1992)
N. Gavriely et al.
Theory and measurements of snores
J. Appl. Physiol.
(1993)
G. Insalaco et al.
Effects of submental electrical stimulation on respiratory disorders in obstructive sleep apnea syndrome
Am. Rev. Respir. Dis.
(1992)
H. Miki et al.
Effects of electrical stimulation of the genioglossus on upper airway resistance in anesthetized dogs
Am. Rev. Respir. Dis.
(1989)
H. Miki et al.
Effects of submental electrical stimulation during sleep on upper airway patency in patients with obstructive sleep apnea
Am. Rev. Respir. Dis.
(1989)

There are more references available in the full text version of this article.

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Amongst these muscles, genioglossus has received extensive investigations. Genioglossus is the primary protrudor muscle of the tongue, and its role in maintaining upper airway patency in humans has been well described in existing work [37,38]. Existing EMG studies demonstrated pre-inspiratory activity in genioglossus and suggested the critical role of this muscle in protecting upper airway patency during inspiration [39].
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Relationship between the activity of the genioglossus, other peri-pharyngeal muscles and flow mechanics during wakefulness and sleep in patients with OSA and healthy subjects
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The present work was undertaken to assess the role of muscles other than the GG in the pathogenesis of pharyngeal collapse during sleep. In contrast to the GG, the main pharyngeal dilator (Odeh et al., 1995), we labelled other peri-pharyngeal muscles that may dilate and/or stabilize the pharynx as accessory dilators (AD). We hypothesised that if pharyngeal collapse in the presence of increased GG activity is due to deficient recruitment of AD, sufficient co-activation of AD during sleep, even occasionally, should prevent or ameliorates flow limitation.
In patients with OSA, substantial increases in genioglossus (GG) activity during hypopneas/apneas usually fail to restore normal airflow. The present study was undertaken to evaluate if this phenomenon can be explained by reduced activation of other peri-pharyngeal muscles.
We recorded EMGs of the GG and four other peri-pharyngeal muscles (accessory dilators, AD), in 8 patients with OSA and 12 healthy subjects, during wakefulness and sleep. Repetitive events of flow limitation were induced during sleep. The events with the highest increases in AD activity were evaluated, to assess if combined activation of both the GG and AD to levels higher than while awake ameliorate airflow reduction during sleep.
Flow limitation triggered large increases in GG-EMG, but only modest augmentation in AD activity. Nevertheless, phasic EMG activity was present in 40 % of the ADs during sleep. In multiple events, increases of both GG and AD activity to levels substantially higher than while awake were not associated with improvement in airflow.
We conclude that sleep-induced reduction in AD response to airway obstruction cannot completely explain the failure of upper airway dilators to maintain pharyngeal patency. We speculate that reduction in dilator muscle efficacy may be due to the alterations in motor units recruitment patterns during sleep.
Effects of modified and conventional facemask therapies with expansion on dynamic measurement of natural head position in Class III patients
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Although a significant flexion of head posture was determined (mean, 6.4°) in the conventional facemask group, no statistically significant changes were found in pharyngeal airway space compared with the untreated control group. Changes in body posture have been shown to elicit activity from muscles that could affect the mandibular rest position.44,45 This circumstance might be the result of relationships between natural head position and mandibular rest position.
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The conventional facemask group comprised 15 patients (8 girls, 7 boys; mean age, 9.6 ± 1.3 years), the modified facemask group comprised 15 patients (7 girls, 8 boys; mean age, 9.5 ± 1.5 years), and the control group comprised 15 subjects (7 girls, 8 boys; mean age, 9.8 ± 1.6 years). Natural head position measurements and cephalometric records were obtained from all subjects before and after treatment or the control period (approximately 1 year). An inclinometer and a portable data logger were used to collect the dynamic natural head position data. For statistical comparisons, paired samples t tests, analysis of variance (ANOVA), and post-hoc Tukey tests were used at the P <0.05 level.
Both treatment groups showed statistically significant changes in the sagittal (pitch) measurements of natural head position and upper pharynx, aerial, and total area of airway measurements during the treatment period. In the control group, the only statistically significant change was an increased upper pharynx measurement (P = 0.020). According to the intergroup comparisons, statistically significant natural head position differences were found in the conventional (6.4° flexion) and the modified (5.7° flexion) facemask groups when compared with the controls. The modified facemask group also showed significant changes in aerial (P = 0.003) and total (P <0.001) areas of the airway measurements compared with the control group. No statistically significant differences were observed between the 2 treatment groups.
These findings suggest that modified and conventional facemask therapy with expansion have significant cranial flexion effects on the dynamic measurements of natural head position. Additionally, the modified facemask procedure showed significant effects on the orofacial airway dimensions compared with the initial values and the values of the untreated controls.
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Pharyngeal obstruction in patients with obstructive sleep apnea (OSA) is thought to result from decreased upper airway muscle tone during sleep. The goal of the present study was to estimate the role of the tongue muscles in maintaining pharyngeal patency during sleep. Using non-invasive, sub-lingual surface electrical stimulation (ES), we measured tongue protrusion force during wakefulness and upper airway resistance during sleep in seven healthy subjects and six patients with OSA. During wakefulness, ES produced similar protrusion forces in healthy subjects and patients with OSA. ES of the anterior sublingual surface, causing preferential contraction of the genioglossus, resulted in smaller effects than combined ES of the anterior and lateral surface, which also stimulated tongue retractors. During sleep, trans-pharyngeal resistance decreased and peak inspiratory flow rate increased from 319±24 to 459±27 and from 58±16 to 270±35 ml/sec for healthy subjects and OSA patients, respectively (P<0.001). However, ES was usually unsuccessful in reopening the upper airway in the presence of complete apneas. We conclude that non-invasive ES of the tongue improves flow dynamics during sleep. Combined activation of tongue protrusors and retractors may have a beneficial mechanical effect. The magnitude of responses observed suggests that in addition to the stimulated muscles, other muscles and/or forces have a substantial impact on pharyngeal patency.
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View full text

Dependency of upper airway patency on head position: The effect of muscle contraction

Abstract

Chest

Respir. Physiol.

Pressure-flow relationship in collapsible tubes

IEEE Transaction Biomed. Ing.

Functional electrical stimulation and respiration during sleep

J. Appl. Physiol.

The effects of transcutaneous electrical stimulation during wakefulness and sleep in patients with obstructive sleep apnea

Am. Rev. Respir. Dis.

Theory and measurements of snores

J. Appl. Physiol.

Effects of submental electrical stimulation on respiratory disorders in obstructive sleep apnea syndrome

Am. Rev. Respir. Dis.

Effects of electrical stimulation of the genioglossus on upper airway resistance in anesthetized dogs

Am. Rev. Respir. Dis.

Effects of submental electrical stimulation during sleep on upper airway patency in patients with obstructive sleep apnea

Am. Rev. Respir. Dis.