
Probe selection
Optimised Imaging: The correct probe selection ensures clear and high-resolution visualisation of target structures, enabling precise identification of anatomical landmarks and nerve pathways.
Enhanced Visual Clarity: Selecting the appropriate frequency and footprint of the probe allows for better focus on specific regions, ensuring the correct identification of fascial planes and nerves.
Procedure-Specific Suitability: Different regional blocks require different probe characteristics; choosing the right probe ensures optimal imaging depth and detail according to the specific block requirements.
Adequate Coverage: Choosing a probe with the right size and footprint allows for adequate scanning of the target area, improving efficiency and reducing the need for multiple probe adjustments.
Enhanced Learning and Skills: Understanding the rationale behind probe selection enhances the practitioner’s ability to choose the correct equipment, promoting skill development in ultrasound-guided regional anaesthesia.
Rectus Sheath Block
Type of Probe: High-Frequency Linear Probe (8-15 MHz)
A high-frequency linear probe is optimal for visualising the superficial structures of the anterior abdominal wall, including the rectus abdominis muscle and the posterior sheath. The high resolution ensures precise identification of the fascial plane where the local anaesthetic is injected.
Probe Size: Small to Medium-sized footprint
A small to medium-sized probe provides adequate coverage of the abdominal wall and is easy to manoeuvre, particularly for targeting the rectus sheath along the midline.
Ultrasound Settings
Frequency: 8-15 MHz
High-frequency settings provide detailed images of the superficial structures of the abdominal wall, including the rectus abdominis muscle and its posterior sheath. This ensures accurate identification of the correct fascial plane for injection.
Depth: 2-4 cm
The rectus sheath lies relatively superficial, so adjusting the depth ensures that the entire thickness of the rectus abdominis muscle and its posterior sheath is clearly visualised.
Gain: Moderate to High
Moderate to high gain enhances the contrast between the hypoechoic rectus abdominis muscle and the hyperechoic posterior rectus sheath, allowing for easy identification of the target fascial plane.
Focus: Focal zone set at the level of the posterior rectus sheath
Position the focal zone at the depth of the posterior rectus sheath to optimise visual clarity, ensuring accurate needle placement for effective block administration.
Dynamic Range: Moderate
A moderate dynamic range setting balances contrast and detail, helping to differentiate the rectus abdominis muscle from the posterior sheath and surrounding structures.