Effect of Paratracheal Esophagus Pressure on the Insertion of Laryngeal Mask Airway

Study Overview
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Brief Summary
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Laryngeal mask airway is inserted into the oral cavity and seals the upper esophagus and the surrounding tissue, effectively securing airway. Laryngeal mask airway has been widely adopted in the clinical practice. On the other hand, cricoid pressure has been used to reduce the risk of pulmonary aspiration of gastric contents during induction of general anesthesia. However, cricoid pressure might impede placement of the laryngeal mask airway, thereby preventing effective ventilation. Recently, left paratracheal pressure was introduced as an alternative to cricoid pressure and reported to be more effective than cricoid pressure in the prevention of gastric air insufflation during positive-pressure ventilation by facemask. Since this method compresses low left paratracheal level, it may affect the successful insertion of laryngeal mask airway. In this study, the investigators aimed to evaluate the effect of paratracheal esophagus pressure on the insertion of laryngeal mask airway compare to conventional cricoid pressure.

Official Title
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Effect of Pressure to Left Paratracheal Esophagus During the Insertion of Laryngeal Mask Airway

Conditions
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General Anesthesia, Pulmonary Aspiration

Intervention / Treatment
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* Procedure: Paratracheal pressure
* Procedure: Cricoid pressure


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who are undergoing surgery under general anesthesia where supraglottic airway management will be appropriate American Society of Anesthesiologists Classification 1-2 Exclusion Criteria: Body mass index > 35 kg/m2 High risk of regurgitation (hiatus hernia, gastro-esophageal reflux disease, non-fasting status) Criteria for difficult airway (limitation of mouth opening/neck extension, Mallampati class IV),

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Randomized double blinded clinical trial
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: PP group<br>During the induction of anesthesia, left paratracheal pressure is applied by 30N force with thumb after confirmation of the location of the esophagus using ultrasound. | Procedure: Paratracheal pressure<br>* To apply paratracheal pressure, the thumb was placed over the left side of the trachea cephalad to the clavicle and medial to the sternocleidomastoid muscle.<br>|
| Active Comparator: CP group<br>During the induction of anesthesia, cricoid pressure is applied by 30N force with three finger. | Procedure: Cricoid pressure<br>* To apply cricoid pressure, the cricoid cartilage is compressed by 30N force with a single-handed three finger maneuvre towards the vertebral bodies.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The success rate of device insertion | Successful insertion of laryngeal mask airway in a maximum of three attempts | During induction of anesthesia, an average of 60 seconds | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The grade of fiberoptic bronchoscopic view | The fiberoptic bronchoscopic view is defined as Grade 1, larynx only seen; Grade 2, larynx and epiglottis posterior surface seen; Grade 3, larynx, and epiglottis tip or anterior surface seen-visual obstruction of epiglottis to larynx: < 50%; Grade 4, epiglottis down-folded, and its anterior surface seen-visual obstruction of epiglottis to larynx: > 50%; Grade 5, epiglottis downfolded and larynx cannot be seen directly. | During induction of anesthesia, an average of 5 minutes | 
| The time for successful insertion of the device | The total time is measured from the removal of the face mask until bilateral chest rise with the first capnogram upstroke. | : During induction of anesthesia, an average of 60 seconds | 
| Peak inspiratory pressure | Peak inspiratory pressure is recorded from mechanical ventilator. | At 5 minute after insertion of laryngeal mask airway | 
| The ease of insertion of device | The ease of placement was assessed using a subjective scale of 1-4 (1= no resistance, 2 = moderate resistance, 3 = high resistance, 4 = inability to place the device | During induction of anesthesia, an average of 60 seconds | 
| The number of attempts at insertion of device | The number of attempts for successful insertion of laryngeal mask airway | During induction of anesthesia, an average of 60 seconds | 
| Success rate in first attempt | Successful insertion of laryngeal mask airway in a first attempt | : During induction of anesthesia, an average of 60 seconds | 
| Incidence of intraoperative complications | Intraoperative complications including coughing, laryngospasm, bronchospasm, hypoxia (SpO2 < 90%), regurgitation, aspiration, blood staining of the device. | During the surgery, an average of 2 hours after anesthesia induction | 
| Incidence of postoperative complications | Postoperative complications including sore throat, hoarseness/dysphonia, jaw, neck or ear pain, persistent cough, tachypnea, stridor, hypoxia (SpO2 < 90%), nausea and vomiting. | An average of 2 hours after extubation | 
| The presence of gastric air insufflation after induction of anesthesia | The presence of gastric air insufflation is defined as an increase in antral cross-sectional area and/or presence of air artifacts in the antrum (comet tail, posterior acoustic shadow) confirmed by ultrasound. | During induction of anesthesia, an average of 5 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Laryngeal mask airway, Paratracheal esophageal pressure, Cricoid pressure