Trial on the Effects of Ultrasound Probe Position on Ultrasound-guided Nerve Blocks

Double Blinded Randomized Control Trial on the Effects of Ultrasound Probe Position on Ultrasound-guided Nerve Blocks

Ultrasound has been used to guide a needle to inject local anesthetics around nerves. This is usually done in the same plane as the ultrasound beam in America and is known as an in-plane technique. When done correctly, the entire needle is visualized on the ultrasound screen as it approaches the nerves which are also seen on the same screen the entire time. The ultrasound probe can be held perpendicular or parallel to the shoulders of the person performing the in-plane technique. Our hypothesis is that holding the ultrasound probe perpendicular to the shoulder is superior to holding the probe parallel to the shoulder during an in-plane ultrasound guided regional anesthesia technique.

Right handed volunteers with no prior exposure to ultrasound techniques are used in this study. They will be randomly assigned to be shown an instructional video on how to perform an in-plane ultrasound guided needling technique on a realistic simulation target. The two videos are identical with the exception of the probe position. A blinded assessor will time the volunteers performance behind a screen and note the duration in which the needle is not visualized in the ultrasound screen.

Inclusion Criteria:

• Healthy volunteers
• Right handed
• Aged 18 to 55

Exclusion Criteria:

• Any person who has prior knowledge about ultrasound imaging or regional anesthesia
• Any person who has prior experience with laparoscopy or biopsy
• Any person who has problems with depth of field or simple hand eye co-ordination task