Impact of Labor and Delivery on Ultrasound Measured Cricothyroid Membrane Depth and Height

Study Overview
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Brief Summary
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The cricothyroid membrane acts as a route through which the upper airway can be accessed to provide oxygen and ventilation to patients. Anesthesiologists need to deliver oxygen and ventilation to patients under general anesthesia, where patients may lose the ability to breath for themselves. Access through this membrane to provide oxygen and ventilation is critical in emergency situations where other traditional means to access the airway (e.g. through endotracheal ventilation, supraglottic airway devices or face mask ventilation) have failed. It is known, from previous studies, that due to the physiological changes that occur in labour, the upper airway of the body undergoes changes that can make accessing the airway through traditional means more difficult, specifically during the period of labor, delivery, and just after delivery. Ultrasound is becoming increasingly popular due to its ability both to identify the cricothyroid membrane and to improve success in accessing the airway through the cricothyroid membrane. What is not known, and has not been studied to date, is specifically how the anatomy (i.e. its height and its depth) specifically changes during the period of labour, delivery and just after delivery. The aim of this study would be to scan (using ultrasound) pregnant women's necks once at the very start of their labour, and once within 4 hours of delivery of their baby, to identify how the size and depth of the cricothyroid membrane changes. This information would improve the understanding of how to best approach accessing this membrane in laboring pregnant women. The investigators hypothesize that in labouring third trimester patient, that the depth to the cricothyroid membrane will increase, and there will be no change in the cricothyroid membrane height.

Official Title
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Impact of Labor and Delivery on Ultrasound Measured Cricothyroid Membrane Depth and Height

Conditions
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Airway Complication of Anesthesia

Intervention / Treatment
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* Device: Ultrasound


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age >=18 years old Pregnant patients in third trimester (>28/40 weeks) Ability to understand the rationale of the study assessments and to provide signed consent. Exclusion Criteria: Neck arthritis Cervical stenosis Known cervical degenerative disc disease Rheumatoid Arthritis Any restriction of neck movement Upper limb neurology Patient refusal Patients not in established labour. Patients undergoing cesarean section Known distorted airway anatomy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Female

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: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Ultrasound<br>Ultrasound measurements of the cricothyroid membrane. | Device: Ultrasound<br>* Ultrasound scan of the cricothyroid membrane<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cricothyroid membrane position change | Difference between the depth from the skin to the cricothyroid membrane- tracheal interface change ultrasound between the onset of established labor and following delivery of the baby and placenta. | 24 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cricothyroid membrane size change | Difference between the height of the cricothyroid membrane (CTM) at the onset of established labor and the height of CTM following delivery of the baby. | 24 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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cricothyroid membrane, pregnancy, ultrasound