The Comparison of Two Different Methods of Partial Inflation of Cuff for Facile Insertion of Laryngeal Mask Airway in Adult Patients

Study Overview
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Brief Summary
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Partial cuff inflation before insertion is generally used for laryngeal mask airway insertion in adult patients. However, it is not proven how much the cuff should be inflated. The aim of this study is to compare efficacy between the method using the resting volume and the method using half the maximum volume for partial cuff inflation.

Official Title
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The Comparison of Two Different Methods of Partial Inflation of Cuff for Facile Insertion of Laryngeal Mask Airway in Adult Patients

Conditions
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General Anesthesia

Intervention / Treatment
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* Procedure: The cuff inflation by the resting volume
* Procedure: The cuff inflation by half the maximum volume


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: adult patients (20-70 years of age) scheduled for elective surgery undergoing general anesthesia using LMA-classic size 3-5 Exclusion Criteria: patients with an abnormal airway, patients with reactive airway disease, patients with gastroesophageal reflux disease, patients with chronic respiratory disease, or a history of an upper respiratory tract infection

Ages Eligible for Study
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Minimum Age: 20 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

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: resting volume group<br> | Procedure: The cuff inflation by the resting volume<br>* 80 patients are randomly allocated into two groups : resting volume group (n=40), half the maximum volume group (n=40). In the resting volume group, the pilot balloon valve is connected to syringe without piston for keeping the valve open to the atmosphere and allowing the pressure within the cuff of LMA to equalize with atmospheric pressure. In the half the maximum volume group, the cuff of LMA is completely emptied and then the cuff is filled with the half the maximum volume.<br>|
| Active Comparator: half the maximum volume group<br> | Procedure: The cuff inflation by half the maximum volume<br>* 80 patients are randomly allocated into two groups : resting volume group (n=40), half the maximum volume group (n=40). In the resting volume group, the pilot balloon valve is connected to syringe without piston for keeping the valve open to the atmosphere and allowing the pressure within the cuff of LMA to equalize with atmospheric pressure. In the half the maximum volume group, the cuff of LMA is completely emptied and then the cuff is filled with the half the maximum volume.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The intra-cuff pressure | After insertion of LMA, we confirm adequate ventilation. And then we measure intra-cuff pressure using cuff pressure manometer. | approximately 5 to 10 minutes after insertion of LMA. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| leak volume | After confirming adequate ventilation, tidal volumes are measured using spirometer sensor attached anesthesia machine. Five corresponding inspiratory and expiratory tidal volumes are recorded and the difference between these is calculated as the leak volume. | approximately 5 to 10 minutes after insertion of LMA. |