Effect of three anaesthetic techniques on isometric skeletal muscle strength

Ginz, H. F.; Zorzato, Francesco; Iaizzo, Paul A.; Urwyler, Albert

doi:10.1093/bja/aeh080

Cited by 37 publications

(34 citation statements)

References 24 publications

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“…Although propofol anesthesia was often referred to as "druginduced sleep" (2,5), it may produce more muscle relaxation than sleep, rendering the upper airway more passive and more collapsible (7,21) and lowering neural output to the GG (7), thereby limiting extrapolation of our findings to conditions occurring during sleep. However, propofol does not influence involuntary isometric skeletal muscle strength (8), and the mechanical properties of the pharynx during anesthesia have been shown to be relevant to OSA (6). Also, we found a similar decrease in Pcrit during GG-ES performed with equal stimulation techniques during sleep and propofol anesthesia (18,19).…”

Section: Discussionsupporting

confidence: 64%

Interacting effects of genioglossus stimulation and mandibular advancement in sleep apnea

Oliven¹,

Tov²,

Odeh³

et al. 2009

Journal of Applied Physiology

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Oliven A. Interacting effects of genioglossus stimulation and mandibular advancement in sleep apnea. J Appl Physiol 106: 1668-1673, 2009. First published February 19, 2009 doi:10.1152/japplphysiol.91501.2008 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 Ϯ 2.2 to 0.9 Ϯ 2.5, Ϫ1.4 Ϯ 2.9, and Ϫ4.2 Ϯ 3.3 cmH2O, respectively), without significant change in Rus. ⌬Pcrit during GG stimulation was significantly larger during MA than under baseline conditions (Ϫ2.8 Ϯ 1.4 vs. Ϫ2.0 Ϯ 1.4 cmH 2O, P ϭ 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.

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Section: Discussionsupporting

confidence: 64%

Interacting effects of genioglossus stimulation and mandibular advancement in sleep apnea

Oliven¹,

Tov²,

Odeh³

et al. 2009

Journal of Applied Physiology

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“…Anaesthesia may produce more muscle relaxation than sleep, rendering the upper airway more passive and more collapsible [18]. Drug-induced depression of neural output to the GG could affect its response to ES, although propofol does not influence involuntary isometric skeletal muscle strength [19]. In addition, changes in lung volume are known to affect pharyngeal stability, lung volume may change differently during anaesthesia and sleep, and changes in lung volume were not measured in the present study.…”

Section: Discussionmentioning

confidence: 64%

Effect of genioglossus contraction on pharyngeal lumen and airflow in sleep apnoea patients

Oliven¹,

Tov²,

Geitini³

et al. 2007

Eur Respir J

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The purpose of the present study was to quantify the mechanical effect of genioglossus stimulation on flow mechanics and pharyngeal cross-sectional area in patients with obstructive sleep apnoea, and to identify variables that determine the magnitude of the respiratory effect of tongue protrusion.The pressure/flow and pressure/cross-sectional area relationships of the velo-and oropharynx were assessed in spontaneously breathing propofol-anaesthetised subjects before and during genioglossus stimulation.Genioglossus contraction decreased the critical pressure significantly from 1.2¡3.3 to -0.7¡3.8 cmH 2 O, with individual decreases ranging -0.6-5.9 cmH 2 O. Pharyngeal compliance was not affected by genioglossus contraction. The pharyngeal response to genioglossus stimulation was related to the magnitude of advancement of the posterior side of the tongue, but not to the severity of sleep apnoea, critical pressure, compliance or the shape and other characteristics of the velopharynx.Genioglossus contraction enlarges both the velo-and the oropharynx and lowers the critical pressure without affecting pharyngeal stiffness. The response to genioglossus stimulation depends upon the magnitude of tongue protrusion achieved rather than on inherent characteristics of the patient and their airway.

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“…Although propofol induces a state of coma that can be classified by EEG from minimally conscious state (phase 1) to full coma resembling brain death (phase 4), under mild anaesthesia, motor tone and respiration are preserved [53]. Propofol does not have a direct effect on striated muscle [54,55], but its effect on upper airway dilator muscles has not been specifically evaluated. Spontaneous breathing is the harbinger of recovery from anaesthesia, and integrates both muscular activity and active respiratory control network in the ventral medulla and pons [45].…”

Section: Sleep-related Disorders Y Dotan Et Almentioning

confidence: 99%

Dissociation of electromyogram and mechanical response in sleep apnoea during propofol anaesthesia

et al. 2012

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Pharyngeal collapsibility during sleep is believed to increase due to a decline in dilator muscle activity. However, genioglossus electromyogram (EMG) often increases during apnoeas and hypopnoeas, often without mechanical effect.17 patients with obstructive sleep apnoea were anaesthetised and evaluated from termination of propofol administration to awakening. Genioglossus EMG, flow and pharyngeal area (pharyngoscopy) were monitored. Prolonged hypopnoeas enabled evaluation of the relationships between genioglossus EMG and mechanical events, before and after awakening. Additional dilator muscle EMGs were recorded and compared to the genioglossus. Electrical stimulation of the genioglossus was used to evaluate possible mechanical dysfunction.Prolonged hypopnoeas during inspiration before arousal triggered an increase in genioglossus EMG, reaching mean¡SD 62.2¡32.7% of maximum. This augmented activity failed to increase flow and pharyngeal area. Awakening resulted in fast pharyngeal enlargement and restoration of unobstructed flow, with marked reduction in genioglossus EMG. Electrical stimulation of the genioglossus under propofol anaesthesia increased the inspiratory pharyngeal area (from 25.1¡28 to 66.3¡75.5 mm 2 ; p,0.01) and flow (from 11.5¡6.5 to 18.6¡9.2 L?min -1 ; p,0.001), indicating adequate mechanical response. All additional dilators increased their inspiratory activity during hypopnoeas. During propofol anaesthesia, pharyngeal occlusion persists despite large increases in genioglossus EMG, in the presence of a preserved mechanical response to electrical stimulation.

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Effect of three anaesthetic techniques on isometric skeletal muscle strength

Cited by 37 publications

References 24 publications

Interacting effects of genioglossus stimulation and mandibular advancement in sleep apnea

Interacting effects of genioglossus stimulation and mandibular advancement in sleep apnea

Effect of genioglossus contraction on pharyngeal lumen and airflow in sleep apnoea patients

Dissociation of electromyogram and mechanical response in sleep apnoea during propofol anaesthesia

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