The Experts below are selected from a list of 120 Experts worldwide ranked by ideXlab platform
Aidan Bradford - One of the best experts on this subject based on the ideXlab platform.
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effects of chronic episodic hypoxia on rat upper airway Muscle contractile properties and fiber type distribution
Chest, 2002Co-Authors: Michelle Mcguire, M Macdermott, Aidan BradfordAbstract:Objective Contraction of upper airway (UA) Muscles such as the Geniohyoids and sternohyoids dilates and/or stabilizes the UA, thereby maintaining its patency. Obstructive sleep apnea (OSA) is caused by episodes of UA collapse, and this results in chronic episodic hypoxia. Chronic continuous hypoxia affects skeletal Muscle structure and function, but the effects of chronic episodic hypoxia on UA Muscle structure and function are unknown. Design Rats were exposed to alternating periods of hypoxia and normoxia twice per minute for 8 h/d for 5 weeks in order to mimic the intermittent hypoxia of OSA in humans. Isometric contractile properties were determined using strips of isolated Geniohyoid and sternohyoid Muscles in physiologic saline solution at 30°C. Fiber-type distribution was determined using adenosine triphosphatase staining. Results Chronic episodic hypoxia had no significant effect on twitch or tetanic tension, twitch/tetanic tension ratio, contractile kinetics, tension-frequency relationship, or fiber-type distribution for either the sternohyoid or Geniohyoid Muscle. However, chronic episodic hypoxia did significantly increase sternohyoid and Geniohyoid fatigue and reduced recovery from fatigue. Conclusions Chronic episodic hypoxia increases UA Muscle fatigue, an effect that may compromise the maintenance of UA patency.
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effects of upper airway carbon dioxide on upper airway resistance and Muscle activity in young guinea pigs
European Respiratory Journal, 2000Co-Authors: A K Curran, Ken D Ohalloran, Aidan BradfordAbstract:The upper airway (UA) of adult animals is known to contain carbon dioxide-sensitive receptors and UA CO2 reflexly affects breathing, UA dilator Muscle activity and UA resistance. These effects may function in the control of UA patency. There is evidence that some UA reflexes are stronger in young than in adult animals, but it is not known whether CO2-sensitive receptors are present in the UA of young animals, and the effects of UA CO2 on UA resistance and on UA dilator Muscle activity have not been investigated in young animals. The responses of ventilation, UA resistance and Geniohyoid Muscle electromyographic activity to warm air containing 10% CO2 applied to the isolated UA were measured in anaesthetized, vagotomized young guinea-pigs breathing spontaneously through a low-cervical tracheostomy. Upper airway carbon dioxide caused an increase in ventilation (46.7+/-16.3 to 49.9+/-16.8 mL x min(-1) x 100 g body weight(-1)) and upper airway resistance (56.8+/-14.8 to 63.7+/-17.7 cmH2O x L(-1) x s(-1) x kg body weight(-1)). Similar effects were obtained following vagotomy. Geniohyoid activity became apparent following vagotomy and this activity was reduced by upper airway carbon dioxide. These responses were abolished by topical anaesthesia of the upper airway. This suggests that the reflexes seen are due to carbon dioxide-sensitive receptors in the upper airway.
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effect of upper airway cooling and co2 on diaphragm and Geniohyoid Muscle activity in the rat
European Respiratory Journal, 1996Co-Authors: Ken D Ohalloran, A K Curran, Aidan BradfordAbstract:Upper airway (UA) reflexes play an important role in regulating breathing and UA patency, but the effects of UA CO2 and cooling on ventilation and UA Muscle activity are controversial. Diaphragm and Geniohyoid electromyographic activities were recorded in anaesthetized rats, breathing spontaneously through a low-cervical tracheostomy. Warmed, humidified air containing 0 or 10% CO2 and cooled, room humidity air were applied at constant flow to the UA through a high- cervical tracheostomy. Spontaneous tracheal airflow, UA airflow and temperature, blood pressure, and rectal temperature were recorded. In all animals, the Geniohyoid Muscle had phasic inspiratory activity, which slightly preceded diaphragmatic activity. CO2 had no effect on mean peak integrated diaphragmatic activity and variable effects on Geniohyoid activity. The coefficients of variation of these activities were unaffected by CO2. Similar results were obtained following bilateral mid-cervical vagotomy. Cool air decreased respiratory frequency (78+/-8%) (mean+/-SD % of control), peak inspiratory flow (78+/-5%) and diaphragmatic activity (77+/-4%), and increased Geniohyoid activity (149+/-11%). Cutting the superior laryngeal nerves abolished these effects. In conclusion, whilst moderate upper airway cooling inhibits breathing and excites Geniohyoid Muscle activity, upper airway carbon dioxide has minimal effect.
T. Kuroda - One of the best experts on this subject based on the ideXlab platform.
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Breathing modes, body positions, and suprahyoid Muscle activity.
Journal of Orthodontics, 2002Co-Authors: S. Takahashi, T. Ono, Y. Ishiwata, T. KurodaAbstract:Method: Ten normal subjects participated in the study. Electromyographic activities of both the genioglossus and Geniohyoid Muscles were recorded during nasal and oral breathing, while the subject was in the upright and supine positions. The electromyographic activities of the genioglossus and Geniohyoid Muscles were compared during jaw opening, swallowing, mandibular advancement, and tongue protrusion. Results: The Geniohyoid Muscle showed greater electromyographic activity than the genioglossus Muscle during maximal jaw opening. In addition, the Geniohyoid Muscle showed a shorter (P � 0.05) latency compared with the genioglossus Muscle. Moreover, the genioglossus Muscle activity showed a significant difference among different breathing modes and body positions, while there were no significant differences in the Geniohyoid Muscle activity. Conclusion: Electromyographic activities from the genioglossus and Geniohyoid Muscles are successfully differentiated. In addition, it appears that changes in the breathing mode and body position significantly affect the genioglossus Muscle activity, but do not affect the Geniohyoid Muscle activity.
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Breathing modes, body positions, and suprahyoid Muscle activity
2002Co-Authors: S. Takahashi, T. Ono, Y. Ishiwata, T. KurodaAbstract:Aim: To determine (1) how electromyographic activities of the genioglossus and Geniohyoid Muscles can be differentiated, and (2) whether changes in breathing modes and body positions have effects on the genioglossus and Geniohyoid Muscle activities. Method: Ten normal subjects participated in the study. Electromyographic activities of both the genioglossus and Geniohyoid Muscles were recorded during nasal and oral breathing, while the subject was in the upright and supine positions. The electromyographic activities of the genioglossus and Geniohyoid Muscles were compared during jaw opening, swallowing, mandib-ular advancement, and tongue protrusion. Results: The Geniohyoid Muscle showed greater electromyographic activity than the genio-glossus Muscle during maximal jaw opening. In addition, the Geniohyoid Muscle showed a shorter (P 0.05) latency compared with the genioglossus Muscle. Moreover, the genioglossus Muscle activity showed a significant difference among different breathing modes and body positions, while there were no significant differences in the Geniohyoid Muscle activity. Conclusion: Electromyographic activities from the genioglossus and Geniohyoid Muscles are successfully differentiated. In addition, it appears that changes in the breathing mode and body position significantly affect the genioglossus Muscle activity, but do not affect the Geniohyoid Muscle activity
P Duvaldestin - One of the best experts on this subject based on the ideXlab platform.
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comparison of the effects of mivacurium on the diaphragm and Geniohyoid Muscles
BJA: British Journal of Anaesthesia, 1996Co-Authors: G Dhonneur, V Slavov, J C Merle, K Kirov, J M Rimaniol, L Sperry, P DuvaldestinAbstract:Although subjects often report difficulty with swallowing shortly after receiving neuromuscular blocking agents, difficulty with swallowing during recovery from neuromuscular blocking agents appears to be infrequent. We have used electromyography to compare onset and recovery at the diaphragm and Geniohyoid airway Muscles after an intubating dose of mivacurium (0.2 mg kg-1) to determine if the Geniohyoid Muscles were particularly sensitive to neuromuscular blocking agents. Twelve adults undergoing elective surgery were anaesthetized with propofol and fentanyl and the trachea intubated without neuromuscular blocking agents. The left hypoglossal and right phrenic nerves were stimulated with percutaneous needle electrodes and the electromyogram recorded with surface electrodes. EMG responses were measured after a bolus dose of mivacurium 0.2 mg kg-1. Recordings were also made of the mechanical response of the adductor pollicis to supramaximal ulnar nerve stimulation. There was no difference in the rate of onset of block for Geniohyoid Muscles and the diaphragm, but recovery to 25% and 90% of the control response was shorter at the diaphragm (median 14.5 (95% confidence limits 12.9-15.3) min and 23.8 (21.7-26) min) than at the Geniohyoid Muscle (19.4 (15.6-20.1) min and 29.2 (26.3-31.4) min), respectively (P
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comparison of the neuromuscular blocking effect of atracurium and vecuronium on the adductor pollicis and the Geniohyoid Muscle in humans
Anesthesiology, 1995Co-Authors: G Dhonneur, B Guignard, V Slavov, R Ruggler, P DuvaldestinAbstract:Background: Residual paralysis of suprahyoid Muscles may occur when the adductor pollicis response has completely recovered after the administration of a neuromuscular blocking agent. The response of the Geniohyoid Muscle to intubating doses of Muscle relaxants is evaluated and compared to that of adductor pollicis. Methods: Sixteen patients undergoing elective surgery under general anesthesia were given 5-7 mg.kg -1 thiopental and 2 kg.kg -1 fentanyl intravenously for induction of anesthesia. Eight (half) patients then received 0.5 mg.kg -1 atracurium, and the other eight received 0.1 mg.kg -1 vecuronium. The evoked response (twitch height, TH) of the adductor pollicis was monitored by measuring the integrated electromyographic response (AP EMG) on one limb and the mechanical response, using a force transducer (AP force), on the other. The activity of Geniohyoid Muscle (GH EMG) was measured using submental percutaneous electrodes. The following variables were measured: maximal TH depression; onset time for neuromuscular blockade to 50%, 90%, and maximal TH depression (OT50, OT90, and OTmax); times between administration of neuromuscular blocking agent and TH recovery to 10%, 25%, 50%, 75%, and EON of control; and time for return of train-of-four ratio to return to 0.7. Results: The principal findings were (1) OTmax was significantly (P<0.01) shorter for Geniohyoid than for adductor pollicis after either atracurium or vecuronium (OTmax was 216, 256, and 175 s for AP force, AP EMG, and GH EMG, with atracurium and 181, IEE, and 144 s with vecuronium, respectively), and (2) the evoked EMG of Geniohyoid recovered at the same speed as the EMG of adductor pollicis after an intubating dose of atracurium or vecuronium (recovery of TH to 75% of control at 50, 48, 42 min with AP force, AP EMG, and GH EMG with atracurium and 46, 45, and 42 min with vecuronium, respectively). Conclusions: Once the adductor pollicis response has returned to normal values after a single intubating dose of atracurium or vecuronium, the risk of residual depression of the TH of the Geniohyoid Muscle, one of the principal Muscles contributing to airway patency, appears unlikely
S. Takahashi - One of the best experts on this subject based on the ideXlab platform.
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Breathing modes, body positions, and suprahyoid Muscle activity.
Journal of Orthodontics, 2002Co-Authors: S. Takahashi, T. Ono, Y. Ishiwata, T. KurodaAbstract:Method: Ten normal subjects participated in the study. Electromyographic activities of both the genioglossus and Geniohyoid Muscles were recorded during nasal and oral breathing, while the subject was in the upright and supine positions. The electromyographic activities of the genioglossus and Geniohyoid Muscles were compared during jaw opening, swallowing, mandibular advancement, and tongue protrusion. Results: The Geniohyoid Muscle showed greater electromyographic activity than the genioglossus Muscle during maximal jaw opening. In addition, the Geniohyoid Muscle showed a shorter (P � 0.05) latency compared with the genioglossus Muscle. Moreover, the genioglossus Muscle activity showed a significant difference among different breathing modes and body positions, while there were no significant differences in the Geniohyoid Muscle activity. Conclusion: Electromyographic activities from the genioglossus and Geniohyoid Muscles are successfully differentiated. In addition, it appears that changes in the breathing mode and body position significantly affect the genioglossus Muscle activity, but do not affect the Geniohyoid Muscle activity.
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Breathing modes, body positions, and suprahyoid Muscle activity
2002Co-Authors: S. Takahashi, T. Ono, Y. Ishiwata, T. KurodaAbstract:Aim: To determine (1) how electromyographic activities of the genioglossus and Geniohyoid Muscles can be differentiated, and (2) whether changes in breathing modes and body positions have effects on the genioglossus and Geniohyoid Muscle activities. Method: Ten normal subjects participated in the study. Electromyographic activities of both the genioglossus and Geniohyoid Muscles were recorded during nasal and oral breathing, while the subject was in the upright and supine positions. The electromyographic activities of the genioglossus and Geniohyoid Muscles were compared during jaw opening, swallowing, mandib-ular advancement, and tongue protrusion. Results: The Geniohyoid Muscle showed greater electromyographic activity than the genio-glossus Muscle during maximal jaw opening. In addition, the Geniohyoid Muscle showed a shorter (P 0.05) latency compared with the genioglossus Muscle. Moreover, the genioglossus Muscle activity showed a significant difference among different breathing modes and body positions, while there were no significant differences in the Geniohyoid Muscle activity. Conclusion: Electromyographic activities from the genioglossus and Geniohyoid Muscles are successfully differentiated. In addition, it appears that changes in the breathing mode and body position significantly affect the genioglossus Muscle activity, but do not affect the Geniohyoid Muscle activity
Ying Xiao - One of the best experts on this subject based on the ideXlab platform.
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recovery of early postoperative Muscle strength after deep neuromuscular block by means of ultrasonography with comparison of neostigmine versus sugammadex as reversal drugs study protocol for a randomised controlled trial
BMJ Open, 2021Co-Authors: Xuan Wang, Chanyan Huang, Wei Xiong, Lijun Niu, Qin Zhou, Ying XiaoAbstract:Introduction Despite the use of quantitative neuromuscular monitoring together with the administration of reversal drugs (neostigmine or sugammadex), the incidence of residual neuromuscular blockade defined as a train-of-four ratio (TOFr) 0.9 cannot ensure adequate recovery of neuromuscular function when T1 height is not recovered completely. Thus, a mathematical correction of TOFr needs to be applied because the return of a normal TOFr can precede the return of a normal T1 twitch height. On the other hand, different Muscles have different sensitivities to neuromuscular blockade agents; thus, complete recovery of one specific Muscle group does not represent complete recovery of all other Muscles. Therefore, our study aims to assess the Muscle strength recovery of respiratory-related Muscle groups by ultrasound and evaluate global strength using handgrip dynamometry in the early postoperative period when TOFr=0.9 and corrected TOFr (cTOFr)=0.9 with comparison of neostigmine versus sugammadex as reversal drugs. Methods and analysis This study will be a prospective, single-blinded, randomised controlled trial involving 60 patients with American Society of Anesthesiologists physical status I-II and aged between 18 and 65 years, who will undergo microlaryngeal surgery. We will assess Geniohyoid Muscle, parasternal intercostal Muscle, diaphragm, abdominal wall Muscle and handgrip strength at four time points: before anaesthesia, TOFr=0.9, cTOFr=0.9 and 30 min after admission to the post anaesthesia care unit. Our primary objective will be to compare the effects of neostigmine and sugammadex on the recovery of Muscle strength of different Muscle groups in the early postoperative period when TOFr=0.9 and cTOFr=0.9. The secondary objective will be to observe the difference of Muscle strength between the time points of TOFr=0.9 and cTOFr=0.9 to find out the clinical significance of cTOFr >0.9. Ethics and dissemination The protocol was reviewed and approved by the Ethics Committee of The First Affiliated Hospital, Sun Yat-sen University. The findings will be disseminated to the public through peer-reviewed scientific journals. Trial registration number ChiCTR2000033832.