TAP Block

Considerations & Technical Details

• Considerations:

  • Document a neurovascular exam prior to performing the block.

  • Calculate a maximum safe dose of anesthetic prior to the block to avoid LAST.

• Transducer: High-frequency linear probe (curvilinear if the patient is obese or if performing a posterior approach)

• Needle: 20–22 g, 5–10 cm nerve block needle

• Anesthetic Volume: 15–20 mL

• Target of Anesthetic: Anesthetic deposited between the transversus abdominis (TA) and internal oblique (IO) muscles

Area of anesthesia

Positioning

Position the patient supine. Place the linear probe in a transverse orientation between the inferior costal margin and the iliac crest along the mid-axillary line.

Target Identification

Identify the three muscular layers of the lateral abdominal wall — from superficial to deep: the external oblique (EO), internal oblique (IO), and transversus abdominis (TA). The target plane is the fascial interface between the IO and the TA.

Needle Approach

Advance the needle in-plane from medial to lateral toward the fascial plane between the IO and TA. Confirm correct placement by visualizing hydrodissection of this fascial plane during injection.