The US technique

The US technique - 1

It is assumed that you will attend some form of formal training prior to performing this block under US control.

When performing this technique:

An in-plane or out-of-plane technique is appropriate
Everything should be prepared prior to beginning the block
The patient is supine and the US machine and anaesthetist should be positioned ergonomically
A 40-50 mm short bevelled regional anaesthetic needle with extension tubing is preferred
LA (e.g. levobupivacaine) is drawn up and the needle flushed to remove any air
A minimum of 0.075ml/kg is required for success (note the nerve structures must be surrounded) . The maximum dose must not be exceeded
The US machine should be set for ‘small parts’ or ‘nerve’
The highest possible frequency for the assumed depth of the target nerve is chosen. This will usually be >10 MHz

For infants, a probe with a small footprint (hockey stick) is chosen as larger probes are cumbersome.

Sterility is essential for all procedures. When perfoming single shot blocks the probe must be sterilized between cases. Then, either a no-touch technique (between needle and probe) or an occlusive dressing placed over the head of the probe is mandatory.

Question: Why is the highest US frequency preferable?

Click here for the answer.

It is assumed that you will attend some form of formal training prior to performing this block under US control.

When performing this technique:

An in-plane or out-of-plane technique is appropriate
Everything should be prepared prior to beginning the block
The patient is supine and the US machine and anaesthetist should be positioned ergonomically
A 40-50 mm short bevelled regional anaesthetic needle with extension tubing is preferred
LA (e.g. levobupivacaine) is drawn up and the needle flushed to remove any air
A minimum of 0.075ml/kg is required for success (note the nerve structures must be surrounded) . The maximum dose must not be exceeded
The US machine should be set for ‘small parts’ or ‘nerve’
The highest possible frequency for the assumed depth of the target nerve is chosen. This will usually be >10 MHz

For infants, a probe with a small footprint (hockey stick) is chosen as larger probes are cumbersome.

Question: Why is the highest US frequency preferable?

Answer: The highest US frequency is preferred as higher frequencies produce greater resolution images. In addition, the beam is easily attenuated and so depth of penetration is diminished.

The probe should be placed with one end resting on the ASIS and the other end pointing at the umbilicus. The probe can then be arced around the point of the ASIS to define the anatomy.

The next page provides further information about, and a demonstration of, the US technique for creating an ilioinguinal nerve block.