Three-Dimensional Ultrasound (3D US) in Parturients

Study Overview
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Brief Summary
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The purpose of this study is to compare accuracy of a new three-dimensional ultrasound (3D US) technique with the traditional palpation method for identification of the needle insertion site on patients' skin before epidural needle placement in pregnant women. The investigators hypothesize that the needle puncture site identified by 3D US is located within a 5 mm radius from the puncture site identified by palpation.

Detailed Description
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Traditionally, the manual palpation of lower back is used to identify the skin insertion point for the epidural needle placement in obstetric patients. Recently, two-dimensional ultrasound (2D US) scanning before the epidural needle insertion proved to improve an accurate determination of inter-vertebral levels and spine midline. 2D US is also useful in determining the depth to the epidural space and needle insertion angle. A three-dimensional ultrasound (3D US) technique is a new advancement in the ultrasound technology. 3D US allows for a real-time, visual guidance of the epidural needle insertion. This study will assess weather 3D US, compared to palpation, can accurately identify the skin needle insertion site for the epidural needle placement.

Official Title
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Three-Dimensional Ultrasound (3D US) for Epidural Needle Insertion in Parturients

Conditions
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Pregnancy

Intervention / Treatment
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* Device: Lumbar 3D ultrasound scanning and palpation (Ultrasonix )


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA I or II Greater than or equal to 19 years old Term pregnancy (greater than or equal to 38 weeks gestation age) Ability to read English in order to understand the consent form Exclusion Criteria: BMI greater than or equal to 40 Scoliosis Previous difficult regional anesthesia/analgesia Previous lower back surgery Active labour Allergy to epidural tape, surgical paper tape, or felt pen

Ages Eligible for Study
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Minimum Age: 19 Years

Sexes Eligible for Study
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Female

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 |
| --- | --- |
| Scanned and palpated<br>Healthy, pregnant, term women delivering at BC Women's Hospital and expecting to have neuraxial anesthesia. | Device: Lumbar 3D ultrasound scanning and palpation (Ultrasonix )<br>* Paramedian ultrasound scanning of L2-3 and L3-4 lumbar interspaces to visualize ligamentum flavum. Palpation of the same intervertebral spaces to identify spine midline and needle insertion point.<br>* Other names: Ultrasonix US machine (model Sonix Touch);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Distance between two needle insertion points | To measure the distance between the needle puncture site identified by the 3D US transducer to the needle puncture site identified by palpation, measured on a transparency film. | 20 minutes of testing prior to delivery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Distance between needle insertion point and spine midline | To measure the perpendicular distance between the needle puncture site identified by the 3D US transducer to the midline identified by manual palpation (to the P-line), measured on a transparency film. | 20 minutes of testing prior to delivery | 
| assess quality of 3D US images | To obtain US images of the epidural anatomy with various settings of the image-processing system to determine the optimal 3D US parameters that give the clearest images. An experienced sonographer will analyze the US images in the UBC laboratory using a qualitative measure of clarity (scale of 1 to 5) of the depiction of the ligamentum flavum and laminae. This quality measure will be correlated to the image acquisition parameters to determine the optimal set of parameters. | one year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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3D ultrasonography, epidural, neuraxial anesthesia, neuraxial analgesia, pregnant woman, parturients