Effects of Depth of Propofol and Sevoflurane Anesthesia on Upper Airway Collapsibility, Respiratory Genioglossus Activation, and Breathing in Healthy Volunteers

Abstract Background Volatile anesthetics and propofol impair upper airway stability and possibly respiratory upper airway dilator muscle activity. The magnitudes of these effects have not been compared at equivalent anesthetic doses. We hypothesized that upper airway closing pressure is less negative and genioglossus activity is lower during deep compared with shallow anesthesia. Methods In a randomized controlled crossover study of 12 volunteers, anesthesia with propofol or sevoflurane was titrated using a pain stimulus to identify the threshold for suppression of motor response to electrical stimulation. Measurements included bispectral index, genioglossus electromyography, ventilation, hypopharyngeal pressure, upper airway closing pressure, and change in end-expiratory lung volume during mask pressure drops. Results A total of 393 attempted breaths during occlusion maneuvers were analyzed. Upper airway closing pressure was significantly less negative at deep versus shallow anesthesia (−10.8 ± 4.5 vs. −11.3 ± 4.4 cm H2O, respectively [mean ± SD]) and correlated with the bispectral index (P < 0.001), indicating a more collapsible airway at deep anesthesia. Respiratory genioglossus activity during airway occlusion was significantly lower at deep compared with light anesthesia (26 ± 21 vs. 35 ± 24% of maximal genioglossus activation, respectively; P < 0.001) and correlated with bispectral index (P < 0.001). Upper airway closing pressure and genioglossus activity during airway occlusion did not differ between sevoflurane and propofol anesthesia. Conclusions Propofol and sevoflurane anesthesia increased upper airway collapsibility in a dose-dependent fashion with no difference at equivalent anesthetic concentrations. These effects can in part be explained by a dose-dependent inhibiting effect of anesthetics on respiratory genioglossus activity.

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

Journal of Applied Physiology ◽

10.1152/japplphysiol.00346.2015 ◽

2015 ◽

Vol 119 (6) ◽

pp. 617-626 ◽

Cited By ~ 15

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.

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Influences of the breathing route on upper airway dynamics properties in normal awake subjects with constant mouth opening

Clinical Science ◽

10.1042/cs20060038 ◽

2006 ◽

Vol 111 (5) ◽

pp. 349-355 ◽

Cited By ~ 4

Author(s):

Wei Wang ◽

Eric Verin ◽

Frédéric Sériès

Keyword(s):

Polynomial Regression ◽

Dynamic Properties ◽

Mouth Opening ◽

Upper Airway ◽

Nasal Breathing ◽

Airway Collapsibility ◽

Flow Pressure ◽

Upper Airway Collapsibility ◽

Male Subjects ◽

Closing Pressure

MB (mouth breathing) promotes the occurrence of sleep-disordered breathing even in non-apnoeic subjects. Considering that MO (mouth opening) contributes to an increase in UA (upper airway) collapsibility independently of MB, the aim of the present study was to assess the influence of breathing route on UA dynamics in the presence of MO. Bilateral anterior magnetic phrenic nerve stimulation was performed 2 s after expiratory onset in 12 healthy male subjects during wakefulness (age, 50±5 years; body mass index, 27.8±2.4 kg/m2) during MB through a mouthpiece and during exclusive NB (nasal breathing) with the same mouthpiece in place. Twitch-induced V̇I (instantaneous flow), Pph and Pes (pharyngeal and oesophageal pressures respectively) were recorded and the corresponding resistances were measured. A polynomial regression model, V̇I=k1Pd+k2Pd2, was used to characterize flow–pressure relationship and to determine the Pd value at which UA collapses. There was no difference in UA dynamic properties between NB and MB when UA collapse occurred above the pharyngeal catheter. For twitches where UA collapse occurred lower in the UA, pharyngeal resistance decreased from NB to MB (2.0±0.3 and 1.5±0.2 cmH2O·l−1·s respectively; P=0.02; values are means±S.D.), whereas closing pressure increased (−25.7±10.1 and −18.0±3.0 cmH2O respectively; P=0.04). We conclude that (i) in the presence of MO the dynamic properties of the proximal UA free of phasic activity do not differ between NB and MB, and (ii) MB decreases the upstream resistance and increases collapsibility of the distal UA.

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Evolution of Changes in Upper Airway Collapsibility during Slow Induction of Anesthesia with Propofol

Anesthesiology ◽

10.1097/aln.0b013e3181a7ec68 ◽

2009 ◽

Vol 111 (1) ◽

pp. 63-71 ◽

Cited By ~ 118

Author(s):

David R. Hillman ◽

Jennifer H. Walsh ◽

Kathleen J. Maddison ◽

Peter R. Platt ◽

Jason P. Kirkness ◽

...

Keyword(s):

Bispectral Index ◽

Critical Pressure ◽

Upper Airway ◽

Index Score ◽

Loss Of Consciousness ◽

Electromyographic Activity ◽

Verbal Command ◽

Effect Site ◽

Airway Collapsibility ◽

Upper Airway Collapsibility

Background Upper airway collapsibility is known to increase under anesthesia. This study assessed how this increase in collapsibility evolves during slow Propofol induction and how it relates to anesthesia-induced changes in upper airway muscle activity and conscious state. Methods Nine healthy volunteers were studied. Anesthesia was induced with Propofol in a step-wise manner (effect-site concentration steps of 0.5 microg x ml(-1) from 0 to 3 microg x ml(-1) and thereafter to 4 microg x ml(-1) and 6 microg x ml(-1) [target-controlled infusion]). Airway patency was maintained with continuous positive airway pressure. Pharyngeal collapsibility was assessed at each concentration by measuring critical pressure. Intramuscular genioglossus electromyogram and anesthetic depth (bispectral index score) were monitored throughout. Loss of consciousness was defined as failure to respond to loud verbal command. Results Loss of consciousness occurred at varying Propofol effect-site concentrations between 1.5 and 4.0 microg x ml(-1). Initially genioglossus electromyographic activity was sustained with increases in Propofol concentration, increasing in some individuals. At or approaching loss of consciousness, it decreased, often abruptly, to minimal values with an accompanying increase in critical pressure. In most subjects, bispectral index score decreased alinearly with increasing Propofol concentration with greatest rate of change coinciding with loss of consciousness. Conclusions Slow stepwise induction of Propofol anesthesia is associated with an alinear increase in upper airway collapsibility. Disproportionate decreases in genioglossus electromyogram activity and increases in pharyngeal critical closing pressure were observed proximate to loss of consciousness, suggesting that particular vulnerability exists after transition from conscious to unconscious sedation. Such changes may have parallels with upper airway behavior at sleep onset.

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Dose-dependent effects of mandibular advancement on upper airway collapsibility and muscle function in obstructive sleep apnea

SLEEP ◽

10.1093/sleep/zsz049 ◽

2019 ◽

Vol 42 (6) ◽

Cited By ~ 17

Author(s):

Ahmad A Bamagoos ◽

Peter A Cistulli ◽

Kate Sutherland ◽

Joachim Ngiam ◽

Peter G R Burke ◽

...

Keyword(s):

Obstructive Sleep Apnea ◽

Sleep Apnea ◽

Muscle Function ◽

Upper Airway ◽

Mandibular Advancement ◽

Obstructive Sleep ◽

Airway Collapsibility ◽

Upper Airway Collapsibility ◽

Dose Dependent

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Upper airway collapsibility and patterns of flow limitation at constant end-expiratory lung volume

Journal of Applied Physiology ◽

10.1152/japplphysiol.00091.2012 ◽

2012 ◽

Vol 113 (5) ◽

pp. 691-699 ◽

Cited By ~ 24

Author(s):

Robert L. Owens ◽

Bradley A. Edwards ◽

Scott A. Sands ◽

James P. Butler ◽

Danny J. Eckert ◽

...

Keyword(s):

Pressure Drop ◽

Lung Volume ◽

Upper Airway ◽

Inspiratory Pressure ◽

Flow Limitation ◽

Pressure Drops ◽

Obstructive Sleep ◽

Airway Collapsibility ◽

Measure Change ◽

Upper Airway Collapsibility

The passive pharyngeal critical closing pressure (Pcrit) is measured using a series of pressure drops. However, pressure drops also lower end-expiratory lung volume (EELV), which independently affects Pcrit. We describe a technique to measure Pcrit at a constant EELV. Continuous positive airway pressure (CPAP)-treated obstructive sleep apnea (OSA) patients and controls were instrumented with an epiglottic catheter, magnetometers (to measure change in EELV), and nasal mask/pneumotachograph and slept supine on nasal CPAP. Pcrit was measured in standard fashion and using our novel “biphasic technique” in which expiratory pressure only was lowered for 1 min before the inspiratory pressure was dropped; this allowed EELV to decrease to the drop level before performing the pressure drop. Seven OSA and three controls were studied. The biphasic technique successfully lowered EELV before the inspiratory pressure drop. Pcrit was similar between the standard and biphasic techniques (−0.4 ± 2.6 vs. −0.6 ± 2.3 cmH2O, respectively, P = 0.84). Interestingly, we noted three different patterns of flow limitation: 1) classic Starling resistor type: flow fixed and independent of downstream pressure; 2) negative effort dependence within breaths: substantial decrease in flow, sometimes with complete collapse, as downstream pressure decreased; and 3) and negative effort dependence across breaths: progressive reductions in peak flow as respiratory effort on successive breaths increased. Overall, EELV changes do not influence standard passive Pcrit measurements if breaths 3–5 of pressure drops are used. These results also highlight the importance of inspiratory collapse in OSA pathogenesis. The cause of negative effort dependence within and across breaths is not known and requires further study.

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Effect of Mandibular Position on Upper Airway Collapsibility and Resistance

Journal of Dental Research ◽

10.1177/154405910508400613 ◽

2005 ◽

Vol 84 (6) ◽

pp. 554-558 ◽

Cited By ~ 30

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.

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Supplemental Carbon Dioxide Stabilizes the Upper Airway in Volunteers Anesthetized with Propofol

Anesthesiology ◽

10.1097/aln.0000000000002239 ◽

2018 ◽

Vol 129 (1) ◽

pp. 37-46 ◽

Cited By ~ 2

Author(s):

Katarina Jennifer Ruscic ◽

Janne Bøgh Stokholm ◽

Johann Patlak ◽

Hao Deng ◽

Jeroen Cedric Peter Simons ◽

...

Keyword(s):

Carbon Dioxide ◽

Deep Level ◽

Muscle Tone ◽

Secondary Analysis ◽

Upper Airway ◽

Dependent Manner ◽

Genioglossus Muscle ◽

Airway Collapsibility ◽

Upper Airway Collapsibility ◽

Closing Pressure

Abstract Background Propofol impairs upper airway dilator muscle tone and increases upper airway collapsibility. Preclinical studies show that carbon dioxide decreases propofol-mediated respiratory depression. We studied whether elevation of end-tidal carbon dioxide (Petco2) via carbon dioxide insufflation reverses the airway collapsibility (primary hypothesis) and impaired genioglossus muscle electromyogram that accompany propofol anesthesia. Methods We present a prespecified, secondary analysis of previously published experiments in 12 volunteers breathing via a high-flow respiratory circuit used to control upper airway pressure under propofol anesthesia at two levels, with the deep level titrated to suppression of motor response. Ventilation, mask pressure, negative pharyngeal pressure, upper airway closing pressure, genioglossus electromyogram, bispectral index, and change in end-expiratory lung volume were measured as a function of elevation of Petco2 above baseline and depth of propofol anesthesia. Results Petco2 augmentation dose-dependently lowered upper airway closing pressure with a decrease of 3.1 cm H2O (95% CI, 2.2 to 3.9; P < 0.001) under deep anesthesia, indicating improved upper airway stability. In parallel, the phasic genioglossus electromyogram increased by 28% (23 to 34; P < 0.001). We found that genioglossus electromyogram activity was a significant modifier of the effect of Petco2 elevation on closing pressure (P = 0.005 for interaction term). Conclusions Upper airway collapsibility induced by propofol anesthesia can be reversed in a dose-dependent manner by insufflation of supplemental carbon dioxide. This effect is at least partly mediated by increased genioglossus muscle activity.

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Faculty Opinions recommendation of The effect of diaphragm contraction on upper airway collapsibility.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.718112874.793483877 ◽

2013 ◽

Author(s):

William Sheel

Keyword(s):

Upper Airway ◽

Airway Collapsibility ◽

Upper Airway Collapsibility

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

Anesthesiology ◽

10.1097/aln.0b013e318223ba6d ◽

2011 ◽

Vol 115 (2) ◽

pp. 273-281 ◽

Cited By ~ 16

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.

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