Shoulder reduction: low-volume superior trunk block

Question 1Why does a superior trunk block affect the diaphragm less often than an interscalene block?

1. aThe superior trunk lies further from the phrenic nerve than the C5 root
2. bThe superior trunk contains no sensory fibres
3. cThe phrenic nerve runs inside the superior trunk
4. dSuperior trunk blocks always use no local anaesthetic

Question 2How do you find the superior trunk on ultrasound?

1. aLocate the vertebral artery at C7
2. bFollow the C5 and C6 roots down the neck until they join into one oval
3. cScan the axilla for the axillary artery
4. dFind the subclavian artery and inject below it

Question 3Which patient should not have a superior trunk block?

1. aA patient with a known paralysed diaphragm on the other side
2. bA patient with a first anterior dislocation
3. cA patient who wants to avoid sedation
4. dA patient with a normal neurovascular examination

Question 4What did an emergency department study of low-volume superior trunk blocks for shoulder reduction report?

1. aDiaphragm paralysis occurred in every patient
2. bMost patients needed sedation as well
3. cAll reductions succeeded and no clinically relevant respiratory complications were reported, but diaphragm function was not measured
4. dThe block failed in half of the patients

Question 5During injection the patient feels sharp, shooting pain down the arm. What do you do?

1. aIncrease the volume
2. bAsk the patient to hold still and carry on
3. cStop injecting and reposition the needle
4. dInject faster to finish the block