Determination of the Optimal Size of Oropharyngeal Airway; Correlation With External Body Measurements

Study Overview
=================
Brief Summary
-----------------
There are several studies that have measured various oropharyngeal airway space distances using radiological method. However, direct confirmation of optimal size of oropharyneal airways (OPAs) in individual using fiberoptic bronchoscope (FOB) is lacking as now. The purposes of this study were to directly determinate the proper size of OPA in individual by FOB via different sizes of OPA in adults under general anestheisia. Additionally, we examine the relationships among the size of OPA, straight length from the incisors to the tip of the epiglottis by laryngoscopy, patient height, and external facial measurements.

Conditions
-----------------
Ear,Nose and Throat Surgery

Intervention / Treatment
-----------------
* Device: Guedel type color-coded OPAs


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: ASA class I-II 2. 20-70 years adults Exclusion Criteria: 1. an abnormal airway anatomy in preoperative radiologic study. 2. cervical spine pathology, 3. a history of difficult intubation, 4. neurologic disease or cardiovascular disease, 5. obesity (body mass index ≥ 30 kg m-1), 6. dental problem

Ages Eligible for Study
-----------------
Minimum Age: 20 Years
Maximum Age: 70 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Optimal size of OPAs<br> | Device: Guedel type color-coded OPAs<br>* The OPAs was used four different sizes as No. 8 (80 mm, green), 9 (90 mm, yellow), 10 (100 mm, red), and 11 (110 mm, orange) in regular sequence. The curvilinear distance from the incisors to the tip of the epiglottis was measured by FOB (Olympus LF-GP; Olympus Optical Co., Tokyo, Japan) with tape marking via each size of OPAs. The distance from the distal end of OPA to the tip of the epiglottis was calculated by the difference between measured distance from the incisors to the tip of the epiglottis via each OPA by FOB and typical distance from the flange to distal end of each OPA via inside tube of OPA. When the size of OPAs was longer than distance from the incisors to the tip of the epiglottis, OPAs were partly withdrawn and repositioned the distal end of OPAs is placed just above the tip of epiglottis. Then, the length from the incisors to the flange of OPAs was measured. .<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Optimal size of OPA | Primary Outcome - 기술(Description) The distance from the distal end of OPA to the tip of the epiglottis was calculated by the difference between measured distance from the incisors to the tip of the epiglottis via each OPA by FOB and typical distance from the flange to distal end of each OPA via inside tube of OPA. When the size of OPAs was longer than distance from the incisors to the tip of the epiglottis, OPAs were partly withdrawn and repositioned the distal end of OPAs is placed just above the tip of epiglottis. Then, the length from the incisors to the flange of OPAs was measured. The optimal size of OPAs in individuals was defined that the distal end of OPA is placed the tip of epiglottis as close as possible without impingement on the epiglottis when the flange of OPA contact with the four central incisors. | 1 min after each FOB measurement |