Pitfalls and Pearls

As with all local anaesthetic blocks, safe injection is ensured by keeping the needle tip visualised throughout and repeated negative aspiration (at least every 5mls) to detect blood and help prevent accidental intravascular injection.
If the patient experiences any paraesthesia the needle should be repositioned.
The deep block may be easier to perform in those in distorted anatomy however there is increased risk of pneumothorax due to the proximity of the pleura.
The block will not provide immediate analgesia and has an approximate onset time of thirty minutes.
If local anaesthetic is used in any other procedure, e.g. for chest drain insertion, beware the total local anaesthetic dose is not a toxic dose.
Knowledge of the management of local anaesthetic toxicity and the location of intralipid is important when performing any block.¹²
The block will only provide temporary analgesia so should trigger a referral for ongoing assessment of pain score and consideration of catheter regional techniques.
A serratus anterior catheter can be inserted whilst performing the block, but this should be performed in a sterile area, for example operating theatres, with a fully sterile approach (gown, gloves, drape, hat, mask, equipment etc.) to reduce the risk of infection.
This is a low risk technique that requires minimal repositioning of the patient, which is evidenced to be effective as part of multimodal analgesia in the management of patients with rib fractures.