1. Peripheral Nerve Blocks
Diane Williamson
Emergency Medicine Consultant
CUHFT

2. Peripheral Nerve Blocks
Preparation, complications, agents
Digital nerve block
Wrist block
Fascia iliac block
Other nerve blocks
– ankle and face
Local anaesthetic toxicity

3. Right Block Right Patient
Is there a block that will benefit your patient?
Do you know the anatomy and technique?
Have you obtained informed consent?
Have you established?
IV access
Monitoring – ECG, BP SpO2

4. Potential Complications
Block failure
Intravascular injection
Local anaesthetic toxicity – know the signs/symptoms
Nerve damage
Injury secondary to numbness or weakness
Infection

5. Preparation
Infection control – sterile gloves, drape, antiseptic cleaning solution (2% chlorhexidine)
Equipment
Local anaesthetic
Syringe
Needle e.g. 23G (blue), Blunt bevelled, dental
USS
Nerve stimulator

6. Local Anaesthetic Agents
Lidocaine
Onset 5-10 minutes
Duration 1-2 hours
Maximum dose 3mg/kg (with epinephrine 7mg/kg)
Prilocaine
Maximum dose 6mg/kg
Bupivocaine and L-bupivociane (chirocaine)
Onset minutes
Duration 3-12 hours
Maximum dose 2mg/kg

7. Safe Injection Know the anatomy – near, not in the nerve
Aspirate first
Inject incrementally (5ml at a time)
Expect: negative aspiration, painless, easy to inject, spread of LA if using USS
If in doubt - STOP

8. With or without adrenaline?
Adrenaline is a vasoconstrictor – think first

9. Contraindications Patient refusal Anticoagulation
Inflammation or infection over injection site
Allergy to local anaesthetics

10. Digital Nerve Blocks Web-space block Trans-thecal block
Trans-thecal block

11. Anatomy

12. Equipment Sterile field Skin prep antiseptic (2% chlorhexidine)
23G (blue) needle
5ml syringe
Local anaesthetic (e.g. 1% lidocaine)

13. Web-space block Place hand palm down on sterile field
Hold syringe perpendicular to digit
Insert needle into web space 1st distal to MP joint
Aspirate and inject slowly into dorsal aspect
Advance needle to volar aspect of web space
Aspirate and inject

14. Transthecal block Also called flexor tendon sheath block
Place hand palm up on sterile field
Palpate flexor tendon sheath at distal palmar crease
Insert needle at 45deg just distal to crease
Aspirate and inject slowly

15. Anatomy

17. Wrist Block Anatomy 6 nerves supply the wrist/hand Median Ulnar
Anatomy
6 nerves supply the wrist/hand
Median
Ulnar
Dorsal branch of ulnar nerve
Radial
Posterior interosseous
Anterior interosseous

18. Equipment
15ml local anaesthetic (e.g. 1% lidocaine or combined with 0.5% bupivocaine)
10ml syringe
23G (blue) needle
Chlorhexidine 2% skin antiseptic

19. Radial Nerve “Field block”
Inject subcutaneously, 3cm proximal to radial styloid
Aim medially then extend laterally
Up to 5ml local anaesthetic

20. Median Nerve
Insert 2.5cm proximal to wrist crease between tendons of palmaris longus and flexor carpe radialis (proximal to carpal tunnel)
Pierce deep fascia (3.5mm)
3-5ml local anaesthetic

21. Ulnar Nerve
Insert needle under the tendon of flexor carpi ulnaris close to ulnar styloid
Advance 5-10mm
3-5ml local anaesthetic

22. Posterior Interosseus Nerve
Forearm in pronation
Ulnar border of distal radius
3cm proximal to palpable ulnar head
Insert to contact radial cortex and inject into periosteum where nerve lies
2ml local anaesthetic

23. Anterior Interosseus Nerve
“walk off” ulnar border of radius after injecting the posterior interosseus nerve
Between radius and ulna, feel “click” of passing through interosseous membrane
2ml local anaesthetic

24. Fascia Iliaca Block
Innervation of medial, anterior and lateral aspects of thigh L2 to 4
Fascia iliaca compartment contains 3 of 4 major nerves to the leg
Local anaesthetic reliably reaches the femoral and LFCN only

25. Indications Specific Contraindication:
Perioperative analgesia for patients with fractured neck or shaft of the femur
Analgesia for plaster applications in children with femoral fracture
Analgesia for lower leg tourniquet pain during awake surgery
Specific Contraindication:
Previous femoral popliteal bypass graft

26. Equipment Blunted or short-bevelled needle
Skin antiseptic (2% chlorhexidine)
1-2ml 1% lidocaine for skin infiltration
30-40ml bupivocaine (or L-bupivocaine) in the right dose (2mg/kg)

27. Landmarks Anterior superior iliac spine Pubic tubercle
Connecting line divided in thirds
Injection point is 1cm caudal to junction of lateral and middle thirds

28. Procedure
Landmark
Palpate femoral artery pulse (injection point should be 1-2cm lateral to the pulse)
Infiltrate skin with 1% lidocaine
Blunt needle – pierce skin at right angle
Angle to 60deg – point cranially in sagittal plane
Advance through two “pops”
Angle to 30deg, advance 2mm
Aspirate - if negative, inject 5ml and repeat
Anaesthetic should enter freely and without pain
Monitor for 30 minutes post-injection

29. Nerves blocked Femoral and Lateral femoral cutaneous nerve FCN
blockade of the obturator nerve unreliable, despite its location within the same anatomical compartment

30. More Blocks You Should Know
Ankle
Femoral nerve (next year)
Facial
Auricular
Supra-trochlear
Supra-orbital

31. Ankle

32. Auricular LON – lesser occipital nerve ATN – auriculotemporal nerve
GAN – greater auricular nerve

33. Supratrochlear and Supraorbital

34. Infraorbital and Mental

35. Local Anaesthetic Toxicity
Recognition
Immediate Management
Treatment
Follow-up

40. Intralipid

43. ANY QUESTIONS?