Serratus plane block: see the rib, see the pleura, then open the plane

Question 1Why do you aim the needle at the rib rather than between the ribs?

1. aThe rib acts as a backstop and keeps the needle away from the pleura
2. bThe nerves run inside the rib
3. cIt makes the needle easier to see
4. dThe local anaesthetic works only on bone

Question 2What did the SABRE trial find when emergency clinicians added a serratus anterior plane block to rib fracture care?

1. aMore patients had a meaningful fall in pain at 4 hours, and opioid use halved
2. bNo difference in pain
3. cThe block replaced the need for any other analgesia
4. dMore pneumothoraces in the block group

Question 3Why is the local anaesthetic dose the main safety concern in a serratus plane block?

1. aSerratus anterior absorbs no local anaesthetic
2. bLocal anaesthetic is not toxic in the chest wall
3. cThe block is always intravascular
4. dPlane blocks need large volumes, which can approach the maximum safe dose

Question 4How does correct spread look on ultrasound?

1. aA bright swelling within the muscle
2. bFluid between the ribs below the pleura
3. cA dark pool of fluid lifting the muscle away from the rib along the plane
4. dNo visible change

Question 5Which fractures does the serratus anterior plane block cover least reliably?

1. aFractures of the lateral chest wall
2. bFractures close to the spine at the back of the ribs
3. cFractures of the fourth and fifth ribs laterally
4. dFractures in the mid-axillary line