Study Assessing the Position of Cricothyroid Membrane in Relation to Movement of Neck From Neutral to Extended Position

Study Overview
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Brief Summary
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Ability to provide oxygen to patients undergoing general anaesthesia is crucial. This is traditionally provided using face mask, supraglottic airway (breathing tube above voice box) or endotracheal tube (breathing tube in wind pipe). However in some patients it may be impossible to provide oxygen through any of these above means which can be life threatening and lead to permanent brain damage/death. One of the ideal ways of managing this emergency situation is to pass a breathing tube through a membrane in the front of the neck called cricothyroid membrane with the neck in extension position where permitted. Many studies have recommended identifying the cricothyroid membrane before general anaesthesia in high risk patients but with their head in neutral position. This study will be a pilot study to check if the cricothyroid membrane remains in the same place in neutral and extended positions.

Detailed Description
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This is a non-randomised observational pilot study. The results of the study will be used to determine the size of the sample required for a planned randomised controlled trial in the future. All the volunteers will be asked to lie on a trolley with the head in neutral position- Defined as alignment of external auditory meatus (outer ear canal) to the sternal angle (prominent portion of breast bone) is horizontal. A radiologist trained in ultrasound of the neck will identify the position of upper and lower border of the cricothyroid membrane using ultrasound and then mark these borders and the centre point with a black surgical marker pen. Then the volunteer will be asked to extend the neck and the same steps will be repeated using a red surgical marker pen. The distance between the two centre points will then be measured using a calliper/ measuring scale.

Official Title
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An Observational Study Assessing the Position of Cricothyroid Membrane in Relation to Movement of Neck From Neutral to Extended Position

Conditions
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Difficult Intubation

Intervention / Treatment
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* Procedure: ultrasound


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participant is willing and able to give informed consent for participation in the study. Aged 18 years or above. Exclusion Criteria: Age <18 years Inability to communicate or refuses consent History of problems with neck movement Arthritis of the neck Upper limb neurology

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Interventional Model Description: Healthy volunteers
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: cricothyroid membrane<br>ultrasound of the neck will identify the position of the upper and lower border of the cricothyroid membrane in extended position. | Procedure: ultrasound<br>* ultrasound of the neck to identify the position of upper and lower border of the cricothyroid membrane.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ultrasound measurement | The distance between the two centre points of the cricothyroid membrane when the head is kept in the neutral and extension position which is measured using the calliper or measuring device. | 20 minutes |