Determining the Depth of Endotracheal Tube Insertion

Study Overview
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Brief Summary
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Airway length from the medial incisor to carina is divided into four segments ; the length from medial incisor to mouth angle, mouth angle to epiglottis, epiglottis to vocal cords and vocal cords to carina. Determining the mean length of each segments with the direct laryngoscope, videolaryngoscope and fiberoptic bronchoscope at the time of endotracheal intubation. Making a new formula to determine the proper individualized depth of intubation on the basis of the length of segments Virtual experiment : comparing the new formula with conventional method of determining the depth of endotracheal intubation

Conditions
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Endotracheal Intubation, Individualized Depth of Endotracheal Intubation

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who are scheduled to take general anesthesia with endotracheal intubation Exclusion Criteria: Patients undergoing general anesthesia with face mask ventilation or laryngeal mask airway

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 90 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Conventional group, Touch and Read group<br> | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of Airway Length Between Male and Female | Airway length is defined the distance from medial incisor to carina. It is divided into four parts. It is medial incisor to mouth angle, mouth angle to epiglottis tip, epiglottis tip to vocal cords and vocal cords to carina. | Endotracheal intubation time | 
| Airway Length vs Height in Male |  | Endotracheal intubation time | 
| Airway Length vs Height in Female |  | Endotracheal intubation time | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison Between Conventional Method and Touch and Read Method for Risk Group of Male | Normal group is defined as the patients whose airway length from medial incisor to carina is below 25cm. Conventional method : depth of intubation is 23cm at the medial incisor for male. Touch and read method : depth of intubation is calculated as follow : length from mouth angle to epiglottis tip plus 12.5cm for male. | Endotracheal intubation time | 
| Comparison Between Conventional Method and Touch and Read Method for Normal Group of Male | Normal group is defined as the patients whose airway length from medial incisor to carina is over 25cm. Conventional method : depth of intubation is 23cm at the medial incisor for male. Touch and read method : depth of intubation is calculated as follow : length from mouth angle to epiglottis tip plus 12.5cm for male. | Endotracheal intubation time | 
| Comparison Between Conventional Method and Touch and Read Method for Risk Group of Female | Risk group is defined as the patients whose airway length from medial incisor to carina is below 23cm. Conventional method : depth of intubation is 21cm at the medial incisor for female. Touch and read method : depth of intubation is calculated as follow : length from mouth angle to epiglottis tip plus 11.5cm for female. | Endotracheal intubation time | 
| Comparison Between Conventional Method and Touch and Read Method for Normal Group of Female | Normal group is defined as the patients whose airway length from medial incisor to carina is over 23cm. Conventional method : depth of intubation is 21cm at the medial incisor for female. Touch and read method : depth of intubation is calculated as follow : length from mouth angle to epiglottis tip plus 11.5cm for female. | Endotracheal intubation time |