Upper airway muscle paralysis reduces reflex upper airway motor response to negative transmural pressure in rat

2003 ◽  
Vol 94 (4) ◽  
pp. 1307-1316 ◽  
Author(s):  
Stephen Ryan ◽  
Walter T. McNicholas ◽  
Ronan G. O'Regan ◽  
Philip Nolan

The reflex upper airway (UA) motor response to UA negative pressure (UANP) is attenuated by neuromuscular blockade. We hypothesized that this is due to a reduction in the sensitivity of laryngeal mechanoreceptors to changes in UA pressure. We examined the effect of neuromuscular blockade on hypoglossal motor responses to UANP and to asphyxia in 15 anesthetized, thoracotomized, artificially ventilated rats. The activity of laryngeal mechanoreceptors is influenced by contractions of laryngeal and tongue muscles, so we studied the effect of selective denervation of these muscle groups on the UA motor response to UANP and to asphyxia, recording from the pharyngeal branch of the glossopharyngeal nerve ( n = 11). We also examined the effect of tongue and laryngeal muscle denervation on superior laryngeal nerve (SLN) afferent activity at different airway transmural pressures ( n = 6). Neuromuscular blockade and denervation of laryngeal and tongue muscles significantly reduced baseline UA motor nerve activity ( P < 0.05), caused a small but significant attenuation of the motor response to asphyxia, and markedly attenuated the response to UANP. Motor denervation of tongue and laryngeal muscles significantly decreased SLN afferent activity and altered the response to UANP. We conclude that skeletal muscle relaxation reduces the reflex UA motor response to UANP, and this may be due to a reduction in the excitability of UA motor systems as well as a decrease of the response of SLN afferents to UANP.

2005 ◽  
Vol 99 (3) ◽  
pp. 1019-1028 ◽  
Author(s):  
Stephen Ryan ◽  
Philip Nolan

Upper airway (UA) muscle activity is stimulated by changes in UA transmural pressure and by asphyxia. These responses are reduced by muscle relaxation. We hypothesized that this is due to a change in afferent feedback in the ansa hypoglossi and/or superior laryngeal nerve (SLN). We examined 1) the glossopharyngeal motor responses to UA transmural pressure and asphyxia and 2) how these responses were changed by muscle relaxation in animals where one or both of these afferent pathways had been sectioned bilaterally. Experiments were performed in 24 anesthetized, thoracotomized, artificially ventilated rats. Baseline glossopharyngeal activity and its response to UA transmural pressure and asphyxia were moderately reduced after bilateral section of the ansa hypoglossi ( P < 0.05). Conversely, bilateral SLN section increased baseline glossopharyngeal activity, augmented the response to asphyxia, and abolished the response to UA transmural pressure. Muscle relaxation reduced resting glossopharyngeal activity and the response to asphyxia ( P < 0.001). This occurred whether or not the ansa hypoglossi, the SLN, or both afferent pathways had been interrupted. We conclude that ansa hypoglossi afferents tonically excite and SLN afferents tonically inhibit UA motor activity. Muscle relaxation depressed UA motor activity after section of the ansa hypoglossi and SLN. This suggests that some or all of the response to muscle relaxation is mediated by alterations in the activity of afferent fibers other than those in the ansa hypoglossi or SLN.


BMJ Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. e043935
Author(s):  
Xuan Wang ◽  
Yingyuan Li ◽  
Chanyan Huang ◽  
Wei Xiong ◽  
Qin Zhou ◽  
...  

IntroductionDespite 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 remains high. Even 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 analysisThis 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 disseminationThe 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 numberChiCTR2000033832.


1999 ◽  
Vol 86 (1) ◽  
pp. 411-417 ◽  
Author(s):  
Samuel T. Kuna ◽  
Christi R. Vanoye

The mechanical effects of pharyngeal constrictor (PC) muscle activation on pharyngeal airway function were determined in 20 decerebrate, tracheotomized cats. In 10 cats, a high-compliance balloon attached to a pressure transducer was partially inflated to just occlude the pharyngeal airway. During progressive hyperoxic hypercapnia, changes in pharyngeal balloon pressure were directly related to phasic expiratory hyopharyngeus (middle PC) activity. In two separate protocols in 10 additional cats, the following measurements were obtained with and without bilateral electrical stimulation (0.2-ms duration, threshold voltage) of the distal cut end of the vagus nerve’s pharyngeal branch supplying PC motor output: 1) pressure-volume relationships in an isolated, sealed upper airway at a stimulation frequency of 30 Hz and 2) rostrally directed axial force over a stimulation frequency range of 0–40 Hz. Airway compliance determined from the pressure-volume relationships decreased with PC stimulation at and below resting airway volume. Compared with the unstimulated condition, PC stimulation increased airway pressure at airway volumes at and above resting volume. This constrictor effect progressively diminished as airway volume was brought below resting volume. At relatively low airway volumes below resting volume, PC stimulation decreased airway pressure compared with that without stimulation. PC stimulation generated a rostrally directed axial force that was directly related to stimulation frequency. The results indicate that PC activation stiffens the pharyngeal airway, exerting both radial and axial effects. The radial effects are dependent on airway volume: constriction of the airway at relatively high airway volumes, and dilation of the airway at relatively low airway volumes. The results imply that, under certain conditions, PC muscle activation may promote pharyngeal airway patency.


2020 ◽  
Vol 10 (4) ◽  
Author(s):  
Parviz Amri ◽  
Novin Nikbakhsh ◽  
Seyed Reza Modaress ◽  
Ramin Nosrati

Background: Rigid bronchoscopy is often used to diagnose and treat the location of resection of the tracheal stenosis. It is a selective procedure for the dilatation of tracheal stenosis, especially when accompanied by respiratory distress. Objectives: We introduced patients who were diagnosed with tracheal stenosis and candidate for rigid bronchoscopy dilatation by the upper airway nerve blocks. Methods: This prospective observational study was conducted on 17 patients who underwent dilatation with rigid bronchoscopy in tracheal stenosis at Hospitals affiliated with Babol University of Medical Sciences from 2002 to 2017. The patients were given three nerve blocks, 6 bilateral superior laryngeal nerve block, bilateral glossopharyngeal nerve block, and recurrent laryngeal nerve block (transtracheal) before awake rigid bronchoscopy using 2% lidocaine. We evaluated the demographic data, the cause of tracheal stenosis, the quality of the airway nerve block (Intubation score), patients’ satisfaction from bronchoscopy and thoracic surgeons’ satisfaction. Complications of nerve blocks were recorded. Results: From 2002 to 2017, 17 patients (14 were male and 3 were) female with tracheal stenosis who were candidates for dilatation with bronchoscopy and accepted the upper nerve block were included. The quality of the block was acceptable in 16 (94%) patients. 15 patients received fentanyl, and only two patients did not need to intravenous sedation. The mean age of patients was 29.59 ± 11.59. The average satisfaction of the surgeon was 8.82 ± 1.13 and the satisfaction of patients with anesthesia was 8.89 ± 1.16. There was one serious complication (laryngospasm) in one patient. Conclusions: The upper airway nerve block method is a suitable anesthesia technique for patients with tracheal stenosis who are candidates for the tracheal dilatation with rigid bronoscopy, especially when the patient has respiratory distress and has not been evaluated before surgery.


2009 ◽  
Vol 110 (6) ◽  
pp. 1253-1260 ◽  
Author(s):  
Frank Herbstreit ◽  
Jürgen Peters ◽  
Matthias Eikermann

Background Residual neuromuscular blockade increases the risk to develop postoperative complications. The authors hypothesized that minimal neuromuscular blockade (train-of-four [TOF] ratio 0.5-1) increases upper airway collapsibility and impairs upper airway dilator muscle compensatory responses to negative pharyngeal pressure challenges. Methods Epiglottic and nasal mask pressures, genioglossus electromyogram, respiratory timing, and changes in lung volume were measured in awake healthy volunteers (n = 15) before, during (TOF = 0.5 and 0.8 [steady state]), and after recovery of TOF to unity from rocuronium-induced partial neuromuscular blockade. Passive upper airway closing pressure (negative pressure drops, random order, range +2 to -30 cm H2O) and pressure threshold for flow limitation were determined. Results Upper airway closing pressure increased (was less negative) significantly from baseline by 54 +/- 4.4% (means +/- SEM), 37 +/- 4.2%, and 16 +/- 4.1% at TOF ratios of 0.5, 0.8, and 1.0, respectively (P &lt; 0.01 vs. baseline for any level). Phasic genioglossus activity almost quadrupled in response to negative (-20 cm H2O) pharyngeal pressure at baseline, and this increase was significantly impaired by 57 +/- 44% and 32 +/- 6% at TOF ratios of 0.5 and 0.8, respectively (P &lt; 0.01 vs. baseline). End-expiratory lung volume, respiratory rate, and tidal volume did not change. Conclusion Minimal neuromuscular blockade markedly increases upper airway closing pressure, partly by impairing the genioglossus muscle compensatory response. Increased airway collapsibility despite unaffected values for resting ventilation may predispose patients to postoperative respiratory complications, particularly during airway challenges.


2021 ◽  
Vol 62 (6) ◽  
Author(s):  
Doan Minh Nhut ◽  
Nguyen Van Chinh

Introduction: In Vietnam, using a muscle accelerator to measure the TOF index to monitor residue neuromuscular blockade has not been performed routinely, extubation is mainly based on subjective clinical assessments. Methods: A cross-sectional study on 96 patients undergoing laparoscopic appendectomy at Nguyen Tri Phuong Hospital, from November 2020 to May 2021. Objectives: The study was conducted with 2 objectives including (1) Determine the progression of TOF index at 7 time points: immediately after arriving in the recovery room, after extubation, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 120 minutes after extubation; (2) Determination of residual muscle relaxant rate of patients undergoing laparoscopic appendectomy at Nguyen Tri Phuong Hospital. Results: The average TOF ≥ 0,9 index after laparoscopic appendectomy at the time of resuscitation was 88.11%, extubation was 90.53% and at 120 minutes after extubation. is 99.88%. Residual muscle relaxation after surgery when TOF index < 0.9. At the time of resuscitation, the highest residual rate of muscle relaxant accounted for 58.33%, followed by the time of extubation 39.58%, 15 minutes after extubation was 21.88%. Until 120 after extubation, there is no case that has residue neuromuscular blockade. Conclusion: Through the study results, it is necessary to monitor patients undergoing laparoscopic appendectomy with quantitative devices to more accurately assess the clinical index of muscle relaxation.


1994 ◽  
Vol 77 (3) ◽  
pp. 1349-1354 ◽  
Author(s):  
M. J. Gdovin ◽  
S. L. Knuth ◽  
D. Bartlett

We monitored spontaneous bladder contractions (SBCs) in decerebrate vagotomized paralyzed ventilated cats while recording respiratory motor nerve activities and intravesical pressure under isovolumetric conditions. Phrenic nerve discharge diminished during SBCs, as did the activities of the hypoglossal nerve, the nasolabial branch of the facial nerve, and inspiratory (posterior cricoarytenoid) and expiratory (thyroarytenoid) branches of the recurrent laryngeal nerve. Hypoglossal activity was most strikingly reduced during SBCs, disappearing completely in some animals. The triangularis sterni nerve exhibited an initial decrease, followed by an increase in activity during SBCs, whereas the cranial iliohypogastric nerve showed increased activity. The changes in nerve activities during SBCs could also be elicited by passive distension of the bladder and were abolished by bilateral section of the pelvic nerves. These findings extend the understanding of reflexes originating from the urinary bladder to include a coordinated respiratory response and suggest that these reflexes may compromise upper airway patency under some conditions.


1989 ◽  
Vol 98 (5) ◽  
pp. 373-378 ◽  
Author(s):  
Gayle E. Woodson

The cricothyroid muscle (CT) appears to be an accessory muscle of respiration. Phasic inspiratory contraction is stimulated by increasing respiratory demand. Reflex activation of the CT may be responsible for the paramedian position of the vocal folds, and hence airway obstruction, in patients with bilateral recurrent laryngeal nerve (RLN) paralysis. Previous research has demonstrated the influence of superior laryngeal nerve (SLN) afferents on CT activity. The present study addresses the effects of vagal and RLN afferents. Electromyographic activity of the CT and right posterior cricoarytenoid muscle was monitored in anesthetized cats during tracheotomy breathing and in response to tracheal or upper airway occlusion in the intact animal. This was repeated following left RLN transection, bilateral vagotomy, and bilateral SLN transection. Vagotomy abolished CT response to tracheal occlusion and markedly reduced the response to upper airway occlusion. Vocal fold position following RLN transection appeared to correlate with CT activity; however, observed changes were minor.


2012 ◽  
Vol 32 (3) ◽  
pp. e1-e10 ◽  
Author(s):  
Jason Wilson ◽  
Angela S. Collins ◽  
Brea O. Rowan

Neuromuscular blockade is a pharmacological adjunct for anesthesia and for surgical interventions. Neuromuscular blockers can facilitate ease of instrumentation and reduce complications associated with intubation. An undesirable sequela of these agents is residual neuromuscular blockade. Residual neuromuscular blockade is linked to aspiration, diminished response to hypoxia, and obstruction of the upper airway that may occur soon after extubation. If an operation is particularly complex or requires a long anesthesia time, residual neuromuscular blockade can contribute to longer stays in the intensive care unit and more hours of mechanical ventilation. Given the risks of this medication class, it is essential to have an understanding of the mechanism of action of, assessment of, and factors affecting blockade and to be able to identify factors that affect pharmacokinetics.


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