scholarly journals Effect of inhaled carbon dioxide on laryngeal abduction

2015 ◽  
Vol 118 (4) ◽  
pp. 489-494 ◽  
Author(s):  
Jonathan Cheetham ◽  
Amanda Jones ◽  
Manuel Martin-Flores
Keyword(s):  
Laryngeal Mask Airway ◽  
High Speed ◽  
Upper Airway ◽  
Laryngeal Mask ◽  
Maximal Response ◽  
High Temporal Resolution ◽  
Respiratory Drive ◽  
Laryngeal Function ◽  
Airway Patency ◽  
End Tidal

Hypercapnia produces a profound effect on respiratory drive and upper airway function to maintain airway patency. Previous work has evaluated the effects of hypercapnia on the sole arytenoid abductor, the posterior cricoarytenoid (PCA), using indirect measures of function, such as electromyography and direct nerve recording. Here we describe a novel method to evaluate PCA function in anesthetized animals and use this method to determine the effects of hypercapnia on PCA function. Eight dogs were anesthetized, and a laryngeal mask airway was used, in combination with high-speed videoendoscopy, to evaluate laryngeal function. A stepwise increase in inspired partial pressure of CO2 produced marked arytenoid abduction above 70-mmHg end-tidal CO2 (ETCO2) ( P < 0.001). Glottic length increased above 80-mmHg ETCO2 ( P < 0.02), and this lead to underrepresentation of changes in glottic area, if standard measures of glottic area (normalized glottic gap area) were used. Use of a known scale to determine absolute glottic area demonstrated no plateau with increasing ETCO2 up to 120 mmHg. Ventilatory parameters also continued to increase with no evidence of a maximal response. In a second anesthetic episode, repeated bursts of transient hypercapnia for 60 s with an ETCO2 of 90 mmHg produced a 43–55% increase in glottic area ( P < 0.001) at or shortly after the end of the hypercapnic burst. A laryngeal mask airway can be used in combination with videoendoscopy to precisely determine changes in laryngeal dimensions with high temporal resolution. Absolute glottic area more precisely represents PCA function than normalized glottic gap area at moderate levels of hypercapnia.

scholarly journals Ketamine Activates Breathing and Abolishes the Coupling between Loss of Consciousness and Upper Airway Dilator Muscle Dysfunction

2012 ◽  
Vol 116 (1) ◽  
pp. 35-46 ◽  
Author(s):  
Matthias Eikermann ◽  
Martina Grosse-Sundrup ◽  
Sebastian Zaremba ◽  
Mark E. Henry ◽  
Edward A. Bittner ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Eye Movement ◽  
Upper Airway ◽  
Muscle Dysfunction ◽  
High Dose ◽  
Loss Of Consciousness ◽  
Respiratory Drive ◽  
Airway Patency ◽  
Dilator Muscle ◽  
Ketamine Anesthesia

Background Procedural sedation is frequently performed in spontaneously breathing patients, but hypnotics and opioids decrease respiratory drive and place the upper airway at risk for collapse. Methods In a randomized, controlled, cross-over, pharmaco-physiologic study in 12 rats, we conducted acute experiments to compare breathing and genioglossus electromyogram activity at equianesthetic concentrations of ketamine, a noncompetitive N-methyl-D-aspartate receptor antagonist that combines potent analgesic with hypnotic action effects, versus propofol. In 10 chronically instrumented rats resting in a plethysmograph, we measured these variables as well as electroencephalography during five conditions: quiet wakefulness, nonrapid-eye-movement sleep, rapid eye movement sleep, and low-dose (60 mg/kg intraperitoneally) and high-dose ketamine anesthesia (125 mg/kg intraperitoneally). Results Ketamine anesthesia was associated with markedly increased genioglossus activity (1.5 to fivefold higher values of genioglossus electromyogram) compared with sleep- and propofol-induced unconsciousness. Plethysmography revealed a respiratory stimulating effect: higher values of flow rate, respiratory rate, and duty-cycle (effective inspiratory time, 1.5-to-2-fold higher values). During wakefulness and normal sleep, the δ (f = 6.51, P = 0.04) electroencephalogram power spectrum was an independent predictor of genioglossus activity, indicating an association between electroencephalographic determinants of consciousness and genioglossus activity. Following ketamine administration, electroencephalogram power spectrum and genioglossus electroencephalogram was dissociated (P = 0.9 for the relationship between δ/θ power spectrum and genioglossus electromyogram). Conclusions Ketamine is a respiratory stimulant that abolishes the coupling between loss-of-consciousness and upper airway dilator muscle dysfunction in a wide dose-range. Ketamine compared with propofol might help stabilize airway patency during sedation and anesthesia.

scholarly journals Comparative Study of Propofol Versus Thiopental Sodium with Succinylcholine for Laryngeal Mask Airway (LMA) Insertion

2018 ◽  
Vol 10 (1) ◽  
pp. 11-15
Author(s):  
Chandra Shekhar Karmakar ◽  
Md Afzalur Rahman ◽  
Mohammad Rezaul Karim ◽  
Monirul Islam ◽  
Md Shahidul Islam ◽  
...  
Keyword(s):  
Laryngeal Mask Airway ◽  
Low Dose ◽  
Upper Airway ◽  
Laryngeal Mask ◽  
Airway Reflex ◽  
Haemodynamic Changes ◽  
Thiopental Sodium ◽  
Group 2 ◽  
Insertion Condition ◽  
Group 1

Background: The increasing emphasis on day case anaesthesia has lead to the greater use of the laryngeal mask airway (LMA) as an alternative to intubation. Laryngoscopy and tracheal intubation are noxious stimuli, which cause a reflex increase in both sympathetic and sympathoadrenal activity that may result in tachycardia, hypertension and dysarrhythmias. Insertion of Laryngeal mask airway (LMA) is associated with less haemodynamic changes, minimal increase in intraocular and intracranial pressure and lower incidence of sore throat. Still its insertion requires sufficient depth of anesthesia to prevent airway reflex (gagging, coughing nd spasms). To insert LMA successfully propofol is the most frequently administered medication. But most of all recommend not using propofol singly for LMA insertion. Thiopental can’t suppress the upper airway reflexes as propofol but with low dose succinylcholine upper airway reflexes are attenuated so combination of thiopental sodium with succinylcholine may be another choice of drug.Objectives: This Prospective study was conducted to evaluate the effectiveness of Thiopental sodium and Succinylcholine for insertion of the LMA in comparison with Propofol.Methods: This interventional study was carried out in Sixty patients, aged 3-45 years who were scheduled for elective surgical procedure under general anaesthesia in ShSMCH. Patients were randomly assigned to two groups by odd and even number basis. In Group-1 (N1=30), LMA was inserted after induction with Thiopental sodium (5 mg/kg body weight i.v.) and Succinylcholine (0.5mg/kg i.v); in Group-2 (N2 = 30), the LMA was inserted with Propofol (2.5mg/kg i.v). Jaw relaxation, incidence of coughing- gagging , overall insertion condition and haemodynamic changes were observed.Results: Grade of jaw relaxation in Group-1 was Good in 93.3%, incomplete in 6.7% and 0% poor but in Group-2, 86.7% was good 10% incomplete and 3.3% was poor. Coughing occurred in 33.3% of patients in the Group-2 and there was only 10% in succinyl group (P=0.028) which is significantly higher in Group-2. Overall insertion condition in Group -1 was excellent in 86.7%, Good in 10% cases and poor in only 3.3% cases on the other hand in Group-2 excellent in 53.3%, Good in 33.3% cases and poor in only 13.3% cases (P=0.019).Conclusion: There was statistically significant difference in jaw relaxation in two groups and incidence of Gagging or Coughing is higher in Group-2. Overall insertion condition was significantly better in Group-1. We concluded that Thiopental sodium with low dose Suxamethonium is an effective alternative of Propofol.J Shaheed Suhrawardy Med Coll, June 2018, Vol.10(1); 11-15

Arterial chemoreceptor input to respiratory hypoglossal motoneurons

1990 ◽  
Vol 69 (2) ◽  
pp. 700-709 ◽  
Author(s):  
S. W. Mifflin
Keyword(s):  
Membrane Potential ◽  
Upper Airway ◽  
Excitatory Input ◽  
Airway Patency ◽  
Hypoglossal Motoneurons ◽  
End Tidal ◽  
Carotid Body Chemoreceptors ◽  
Excitatory Drive ◽  
Arterial Chemoreceptor

To better understand the role of the arterial chemoreceptors in the regulation of upper airway patency at the level of the oropharynx, intracellular recordings were obtained from inspiratory hypoglossal motoneurons (IHMs), and the responses to selective activation of the carotid body chemoreceptors were examined. In pentobarbital-anesthetized, vagotomized, paralyzed, and artificially ventilated cats, chemoreceptor activation enhanced the inspiratory depolarization of membrane potential in 32 of 36 IHMs. This was manifested as an increase in either the amplitude (n = 13) or duration (n = 3) or an increase in both amplitude and duration (n = 16) of the inspiratory membrane potential depolarization. The amplitude and duration of the inspiratory membrane potential depolarization increased 98 +/- 15% (n = 29) and 78 +/- 13% (n = 19), respectively. Similar patterns of enhanced activity (increased duration and/or amplitude of membrane depolarization) were observed in five expiratory hypoglossal motoneurons (EHMs) after chemoreceptor activation. In 16 of the 32 IHMs, chemoreceptor activation also evoked changes in IHM membrane potential during expiration: enhanced post-inspiratory discharge (n = 6), expiratory depolarization/discharge (n = 6), and tonic depolarization/discharge, which persisted for several respiratory cycles (n = 4). The arterial chemoreceptors provide a powerful excitatory input to IHMs during both inspiration and expiration. This excitatory drive to IHMs and EHMs will aid in the maintenance of upper airway patency throughout the respiratory cycle during increases in end-tidal CO2.

Various Uses of Laryngeal Mask Airway during Tracheal Surgery

2021 ◽  
Author(s):  
Ali Celik ◽  
Muhammet Sayan ◽  
Aykut Kankoc ◽  
Ismail Tombul ◽  
Ismail Cüneyt Kurul ◽  
...  
Keyword(s):  
Postoperative Complications ◽  
Laryngeal Mask Airway ◽  
Tracheal Stenosis ◽  
Laryngeal Mask ◽  
Tracheal Resection ◽  
Tracheal Surgery ◽  
The Mean ◽  
End Tidal ◽  
End Tidal Co2

Abstract Background The use of laryngeal mask airway (LMA) ventilation in surgeries to be performed in upper tracheal stenosis has been reported in the case series. However, there is no generally accepted standardized approach for the use of LMA. In this study, LMA usage areas and advantages of trachea surgery were examined. Methods The records of 21 patients who underwent tracheal surgery using LMA ventilation between March 2016 and May 2020 were evaluated retrospectively. The patient data were analyzed according to age, gender, mean follow-up time, surgical indication, mean tracheal resection length, anastomosis duration, mean oxygen saturation, mean end-tidal CO2 levels, and postoperative complications. Results Four patients were female and 17 were male, their median age was 43 (11–72 range) and the mean follow-up time was 17.6 months. The most common surgical indication was postintubation tracheal stenosis. The mean tracheal resection length was 26.6 mm and the mean anastomosis duration was 11.3 minutes. The mean pulse oximetry and mean end-tidal CO2 during laryngeal mask ventilation was 97.6% ± 2.1 and 38.1 ± 2.8 mm Hg, respectively. Postoperative complications were higher in patients with comorbidities. Conclusion LMA-assisted tracheal surgery is a method that can be used safely as a standard technique in the surgery of benign and malignant diseases of both the upper and lower airway performed on pediatric patients, patients with tracheostomy, and suitable patients with tracheoesophageal fistula.

Comparison of End-Tidal and Arterial Carbon Dioxide in Infants Using Laryngeal Mask Airway and Endotracheal Tube

1997 ◽  
Vol 84 (1) ◽  
pp. 51-53 ◽  
Author(s):  
Ashwani K. Chhibber ◽  
Kenneth Fickling ◽  
Jeffrey W. Kolano ◽  
William A. Roberts
Keyword(s):  
Carbon Dioxide ◽  
Laryngeal Mask Airway ◽  
Endotracheal Tube ◽  
Laryngeal Mask ◽  
Arterial Carbon Dioxide ◽  
End Tidal
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