Effect of Mandibular Position on Upper Airway Collapsibility and Resistance

2005 ◽  
Vol 84 (6) ◽  
pp. 554-558 ◽  
Author(s):  
T. Inazawa ◽  
T. Ayuse ◽  
S. Kurata ◽  
I. Okayasu ◽  
E. Sakamoto ◽  
...  
Keyword(s):  
Airway Pressure ◽  
Upper Airway ◽  
Mandibular Advancement ◽  
Neutral Position ◽  
Airway Patency ◽  
Airway Collapsibility ◽  
Critical Closing Pressure ◽  
Mandibular Position ◽  
Upper Airway Collapsibility ◽  
Closing Pressure

It has been proposed that advancement of the mandible is a useful method for decreasing upper airway collapsibility. We carried out this study to test the hypothesis that mandibular advancement induces changes in upper airway patency during midazolam sedation. To explore its effect, we examined upper airway pressure-flow relationships in each of 4 conditions of mouth position in normal, healthy subjects (n = 9). In the neutral position, Pcrit ( i.e., critical closing pressure, an index of upper airway collapsibility) was −4.2 cm H2O, and upstream resistance (Rua) was 21.2 cm H2O/L/sec. In the centric occlusal position, Pcrit was −7.1 cm H2O, and Rua was 16.6 cm H2O/L/sec. In the incisor position, Pcrit was significantly reduced to −10.7 cm H2O, and Rua was significantly reduced to 14.0 cm H2O/L/sec. Mandibular advancement significantly decreased Pcrit to −13.3 cm H2O, but did not significantly influence Rua (22.1 cm H2O/L/sec). We conclude that the mandibular incisors’ position improved airway patency and decreased resistance during midazolam sedation.

Interacting effects of genioglossus stimulation and mandibular advancement in sleep apnea

2009 ◽  
Vol 106 (5) ◽  
pp. 1668-1673 ◽  
Author(s):  
Ron Oliven ◽  
Naveh Tov ◽  
Majed Odeh ◽  
Luis Gaitini ◽  
Uri Steinfeld ◽  
...  
Keyword(s):  
Sleep Apnea ◽  
Airway Pressure ◽  
Upper Airway ◽  
Combined Effect ◽  
Mandibular Advancement ◽  
Cross Sectional ◽  
Airway Patency ◽  
Obstructive Sleep ◽  
Critical Closing Pressure ◽  
Stimulation Of

Both mandibular advancement (MA) and stimulation of the genioglossus (GG) have been shown to improve upper airway patency, but neither one achieves the effect of continuous positive airway pressure (CPAP) treatment. In the present study we assessed the combined effect of MA and GG stimulation on the relaxed pharynx in patients with obstructive sleep apnea (OSA). We evaluated responses of upper airway pressure-flow relationships and endoscopically determined pharyngeal cross-sectional area to MA and electrical stimulation of the GG in 14 propofol-anesthetized OSA patients. Measurements were undertaken at multiple levels of CPAP, enabling calculation of the critical closing pressure (Pcrit), upstream resistance (Rus), and pharyngeal compliance. GG stimulation, MA, and the combination of both shifted the pressure:flow relationships toward higher flow levels, resulting in progressively lower Pcrit (from baseline of 2.9 ± 2.2 to 0.9 ± 2.5, −1.4 ± 2.9, and −4.2 ± 3.3 cmH2O, respectively), without significant change in Rus. ΔPcrit during GG stimulation was significantly larger during MA than under baseline conditions (−2.8 ± 1.4 vs. −2.0 ± 1.4 cmH2O, P = 0.011). Combining the effect of GG stimulation with MA lowered Pcrit below 0 in all patients and restored pharyngeal patency to a level that enabled flow above the hypopnea level in 10/14 of the patients. Velopharyngeal compliance was not affected by either manipulation. We conclude that the combined effect of MA and GG stimulation is additive and may act in synergy, preventing substantial flow limitation of the relaxed pharynx in most OSA patients.

Time of day affects the frequency and duration of breathing events and the critical closing pressure during NREM sleep in participants with sleep apnea

2015 ◽  
Vol 119 (6) ◽  
pp. 617-626 ◽  
Author(s):  
Mohamad El-Chami ◽  
David Shaheen ◽  
Blake Ivers ◽  
Ziauddin Syed ◽  
M. Safwan Badr ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Sleep Apnea ◽  
Upper Airway ◽  
Nrem Sleep ◽  
Time Of Day ◽  
Obstructive Sleep ◽  
Airway Collapsibility ◽  
Critical Closing Pressure ◽  
Upper Airway Collapsibility ◽  
Closing Pressure

We investigated if the number and duration of breathing events coupled to upper airway collapsibility were affected by the time of day. Male participants with obstructive sleep apnea completed a constant routine protocol that consisted of sleep sessions in the evening (10 PM to 1 AM), morning (6 AM to 9 AM), and afternoon (2 PM to 5 PM). On one occasion the number and duration of breathing events was ascertained for each sleep session. On a second occasion the critical closing pressure that demarcated upper airway collapsibility was determined. The duration of breathing events was consistently greater in the morning compared with the evening and afternoon during N1 and N2, while an increase in event frequency was evident during N1. The critical closing pressure was increased in the morning (2.68 ± 0.98 cmH2O) compared with the evening (1.29 ± 0.91 cmH2O; P ≤ 0.02) and afternoon (1.25 ± 0.79; P ≤ 0.01). The increase in the critical closing pressure was correlated to the decrease in the baseline partial pressure of carbon dioxide in the morning compared with the afternoon and evening ( r = −0.73, P ≤ 0.005). Our findings indicate that time of day affects the duration and frequency of events, coupled with alterations in upper airway collapsibility. We propose that increases in airway collapsibility in the morning may be linked to an endogenous modulation of baseline carbon dioxide levels and chemoreflex sensitivity (12), which are independent of the consequences of sleep apnea.

scholarly journals Effect of Head Elevation on Passive Upper Airway Collapsibility in Normal Subjects during Propofol Anesthesia

2011 ◽  
Vol 115 (2) ◽  
pp. 273-281 ◽  
Author(s):  
Masato Kobayashi ◽  
Takao Ayuse ◽  
Yuko Hoshino ◽  
Shinji Kurata ◽  
Shunji Moromugi ◽  
...  
Keyword(s):  
Upper Airway ◽  
Normal Subjects ◽  
Target Concentration ◽  
Airway Patency ◽  
Head Elevation ◽  
Jaw Opening ◽  
Airway Collapsibility ◽  
Upper Airway Collapsibility ◽  
Head Flexion ◽  
Male Subjects

Background Head elevation can restore airway patency during anesthesia, although its effect may be offset by concomitant bite opening or accidental neck flexion. The aim of this study is to examine the effect of head elevation on the passive upper airway collapsibility during propofol anesthesia. Method Twenty male subjects were studied, randomized to one of two experimental groups: fixed-jaw or free-jaw. Propofol infusion was used for induction and to maintain blood at a constant target concentration between 1.5 and 2.0 μg/ml. Nasal mask pressure (PN) was intermittently reduced to evaluate the upper airway collapsibility (passive PCRIT) and upstream resistance (RUS) at each level of head elevation (0, 3, 6, and 9 cm). The authors measured the Frankfort plane (head flexion) and the mandible plane (jaw opening) angles at each level of head elevation. Analysis of variance was used to determine the effect of head elevation on PCRIT, head flexion, and jaw opening within each group. Results In both groups the Frankfort plane and mandible plane angles increased with head elevation (P < 0.05), although the mandible plane angle was smaller in the free-jaw group (i.e., increased jaw opening). In the fixed-jaw group, head elevation decreased upper airway collapsibility (PCRIT ~ -7 cm H₂O at greater than 6 cm elevation) compared with the baseline position (PCRIT ~ -3 cm H₂O at 0 cm elevation; P < 0.05). Conclusion : Elevating the head position by 6 cm while ensuring mouth closure (centric occlusion) produces substantial decreases in upper airway collapsibility and maintains upper airway patency during anesthesia.

scholarly journals Upper airway collapsibility measured using a simple wakefulness test closely relates to the pharyngeal critical closing pressure during sleep in obstructive sleep apnea

SLEEP ◽  
2019 ◽  
Vol 42 (7) ◽  
Author(s):  
Amal M Osman ◽  
Jayne C Carberry ◽  
Peter G R Burke ◽  
Barbara Toson ◽  
Ronald R Grunstein ◽  
...  
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Airway Pressure ◽  
Pressure Sensors ◽  
Upper Airway ◽  
Apnea Hypopnea Index ◽  
Pharyngeal Airway ◽  
Obstructive Sleep ◽  
Airway Collapsibility ◽  
Upper Airway Collapsibility

AbstractStudy ObjectivesA collapsible or crowded pharyngeal airway is the main cause of obstructive sleep apnea (OSA). However, quantification of airway collapsibility during sleep (Pcrit) is not clinically feasible. The primary aim of this study was to compare upper airway collapsibility using a simple wakefulness test with Pcrit during sleep.MethodsParticipants with OSA were instrumented with a nasal mask, pneumotachograph and two pressure sensors, one at the choanae (PCHO), the other just above the epiglottis (PEPI). Approximately 60 brief (250 ms) pulses of negative airway pressure (~ –12 cmH2O at the mask) were delivered in early inspiration during wakefulness to measure the upper airway collapsibility index (UACI). Transient reductions in the continuous positive airway pressure (CPAP) holding pressure were then performed during sleep to determine Pcrit. In a subset of participants, the optimal number of replicate trials required to calculate the UACI was assessed.ResultsThe UACI (39 ± 24 mean ± SD; range = 0%–87%) and Pcrit (–0.11 ± 2.5; range: –4 to +5 cmH2O) were quantified in 34 middle-aged people (9 female) with varying OSA severity (apnea–hypopnea index range = 5–92 events/h). The UACI at a mask pressure of approximately –12 cmH2O positively correlated with Pcrit (r = 0.8; p < 0.001) and could be quantified reliably with as few as 10 replicate trials. The UACI performed well at discriminating individuals with subatmospheric Pcrit values [receiver operating characteristic curve analysis area under the curve = 0.9 (0.8–1), p < 0.001].ConclusionsThese findings indicate that a simple wakefulness test may be useful to estimate the extent of upper airway anatomical impairment during sleep in people with OSA to direct targeted non-CPAP therapies for OSA.

The effect of diaphragm contraction on upper airway collapsibility

2013 ◽  
Vol 115 (3) ◽  
pp. 337-345 ◽  
Author(s):  
David R. Hillman ◽  
Jennifer H. Walsh ◽  
Kathleen J. Maddison ◽  
Peter R. Platt ◽  
Alan R. Schwartz ◽  
...  
Keyword(s):  
Nerve Stimulation ◽  
Lung Volume ◽  
Phrenic Nerve ◽  
Upper Airway ◽  
Dependent Manner ◽  
Phrenic Nerve Stimulation ◽  
Airway Patency ◽  
Airway Collapsibility ◽  
The Difference ◽  
Upper Airway Collapsibility

Increasing lung volume increases upper airway patency and decreases airway resistance and collapsibility. The role of diaphragm contraction in producing these changes remains unclear. This study was undertaken to determine the effect of selective diaphragm contraction, induced by phrenic nerve stimulation, on upper airway collapsibility and the extent to which any observed change was attributable to lung volume-related changes in pressure gradients or to diaphragm descent-related mediastinal traction. Continuous bilateral transcutaneous cervical phrenic nerve stimulation (30 Hz) was applied to nine supine, anesthetized human subjects during transient decreases in airway pressure to levels sufficient to produce flow limitation when unstimulated. Stimulation was applied at two intensities (low and high) and its effects on lung volume and airflow quantified relative to unstimulated conditions. Lung volume increased by 386 ± 269 ml (means ± SD) and 761 ± 556 ml during low and high stimulation, respectively ( P < 0.05 for the difference between these values), which was associated with peak inspiratory flow increases of 69 ± 57 and 137 ± 108 ml/s, respectively ( P < 0.05 for the difference). Stimulation-induced change in lung volume correlated with change in peak flow ( r = 0.65, P < 0.01). Diaphragm descent-related outward displacement of the abdominal wall produced no change in airflow unless accompanied by lung volume change. We conclude that phrenic nerve stimulation-induced diaphragm contraction increases lung volume and reduces airway collapsibility in a dose-dependent manner. The effect appears primarily mediated by changes in lung volume rather than mediastinal traction from diaphragm descent. The study provides a rationale for use of continuous phrenic stimulation to treat obstructive sleep apnea.

scholarly journals The effect of increased genioglossus activity and end-expiratory lung volume on pharyngeal collapse

2010 ◽  
Vol 109 (2) ◽  
pp. 469-475 ◽  
Author(s):  
Amy S. Jordan ◽  
David P. White ◽  
Robert L. Owens ◽  
Danny J. Eckert ◽  
Shilpa Rahangdale ◽  
...  
Keyword(s):  
Lung Volume ◽  
Nrem Sleep ◽  
Adequate Treatment ◽  
Airway Patency ◽  
Obstructive Sleep ◽  
Airway Collapsibility ◽  
Critical Closing Pressure ◽  
C 50 ◽  
Airway Walls ◽  
Closing Pressure

Increasing either genioglossus muscle activity (GG) or end-expiratory lung volume (EELV) improves airway patency but not sufficiently for adequate treatment of obstructive sleep apnea (OSA) in most patients. The mechanisms by which these variables alter airway collapsibility likely differ, with increased GG causing airway dilation, whereas increased EELV may stiffen the airway walls through caudal traction. We sought to determine whether the airway stabilizing effect of GG activation is enhanced when EELV is increased. To investigate this aim, 15 continuous positive airway pressure (CPAP)-treated OSA patients were instrumented with an epiglottic catheter, intramuscular GG-EMG electrodes, magnetometers, and a nasal mask/pneumotachograph. Subjects slept supine in a sealed, head-out plastic chamber in which the extra-thoracic pressure could be lowered (to raise EELV) while on nasal CPAP with a variable deadspace to allow CO2 stimulation (and GG activation). The pharyngeal critical closing pressure (PCRIT) was measured by sudden reduction of CPAP for three to five breaths each minute during non-rapid eye movement (NREM) sleep in 4 conditions: a) baseline, b) 500 ml increased EELV, c) 50% increased GG, and d) conditions b and c combined. PCRIT was found to be reduced from 2.2 ± 0.7 cmH2O at baseline to −1.0 ± 0.5 with increased EELV, 0.6 ± 0.7 with increased GG and −1.6 ± 0.7 when both variables were raised ( P < 0.001). The slope of the PCRIT curves remained unchanged in all conditions ( P = 0.05). However, the CPAP level at which flow limitation developed was lower in both increased EELV conditions ( P = 0.001). These findings indicate that while both increased GG and EELV improve airway collapsibility, the combination of both variables has little additional effect over increasing EELV alone.

Mouth-opening Increases Upper-airway Collapsibility without Changing Resistance during Midazolam Sedation

2004 ◽  
Vol 83 (9) ◽  
pp. 718-722 ◽  
Author(s):  
T. Ayuse ◽  
T. Inazawa ◽  
S. Kurata ◽  
I. Okayasu ◽  
E. Sakamoto ◽  
...  
Keyword(s):  
Maxillofacial Surgery ◽  
Mouth Opening ◽  
Upper Airway ◽  
Airflow Limitation ◽  
Airway Patency ◽  
Anesthetic Agents ◽  
Airway Collapsibility ◽  
Maximal Mouth Opening ◽  
Inspiratory Airflow Limitation ◽  
Upper Airway Collapsibility

Sedative doses of anesthetic agents affect upper-airway function. Oral-maxillofacial surgery is frequently performed on sedated patients whose mouths must be as open as possible if the procedures are to be accomplished successfully. We examined upper-airway pressure-flow relationships in closed mouths, mouths opened moderately, and mouths opened maximally to test the hypothesis that mouth-opening compromises upper-airway patency during midazolam sedation. From these relationships, upper-airway critical pressure (Pcrit) and upstream resistance (Rua) were derived. Maximal mouth-opening increased Pcrit to −3.6 ± 2.9 cm H2O compared with −8.7 ± 2.8 (p = 0.002) for closed mouths and −7.2 ± 4.1 (p = 0.038) for mouths opened moderately. In contrast, Rua was similar in all three conditions (18.4 ± 6.6 vs. 17.7 ± 7.6 vs. 21.5 ± 11.6 cm H2O/L/sec). Moreover, maximum mouth-opening produced an inspiratory airflow limitation at atmosphere that was eliminated when nasal pressure was adjusted to 4.3 ± 2.7 cm H2O. We conclude that maximal mouth-opening increases upper-airway collapsibility, which contributes to upper-airway obstruction at atmosphere during midazolam sedation.

Upper airway patency in the human infant: influence of airway pressure and posture

1980 ◽  
Vol 48 (3) ◽  
pp. 500-504 ◽  
Author(s):  
S. L. Wilson ◽  
B. T. Thach ◽  
R. T. Brouillette ◽  
Y. K. Abu-Osba
Keyword(s):  
Airway Pressure ◽  
Upper Airway ◽  
Surface Forces ◽  
Human Infant ◽  
Neck Flexion ◽  
Neck Extension ◽  
Airway Patency ◽  
Obstructive Apnea ◽  
Closing Pressure ◽  
Closed Airway

We have determined the influence of transmural pressure and neck posture on upper airway patency in infants after death. In natural resting postures, the airway was closed at transmural pressures not exceeding those normally seen during peak inspiratory airflow in the living infant, implying that a neuromuscular mechanism is necessary to maintain airway patency during life. Neck flexion raised closing pressure, making the airway more susceptible to collapse, whereas neck extension lowered closing pressure, making the airway more resistant to collapse. When the angle of flexion was kept constant, closing pressure was not significantly altered by turning the head or positioning the infant prone. Pressures above the corresponding closing pressure were required to reopen the closed airway, suggesting that the walls of the closed airway tended to adhere and implying that surface forces can impose an added load to airway-maintaining musculature during obstructive apnea in the living infant.

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