Background
- FNB (3 in 1) block should be performed under ultrasound guidance [BestBets]
- Used for #NOF, shaft of femur or fractures of the patella
- Obtain IV access before performing this technique (risk of LA toxicity)
Equipment:
- Something to clean the skin
- 1% lignocaine in one syringe, with a 25G needle for skin infiltration
- 0.5% Bupivacaine in another syringe(22G anaesthetic needle for the nerve block)
LA toxicity
- The toxic dose for Lignocaine is 3 mgs per kilo or 20 mls of 1% Lignocaine for an adult
- In a child = 1 ml of 1% plain Lignocaine for each year of the child's age
- Before any regional anaesthesia ensure you are familiar with the signs / management of LA Toxicty
Procedure
- Very gently, slightly abduct the femur on the affected side
- Identify the femoral artery and keep one finger on it
- The nerve lies lateral and deep to the artery (see diagram)
- Clean the skin
- Infiltrate the skin with lignocaine
- Infiltrate around the nerve in a fan-like fashion with Bupivacaine
- Aspirate frequently to avoid intravascular injection
- If you puncture the femoral artery compress it for 5-10 minutes
- If the bleeding stops continue with the block
- Wait 10-20 minutes before manipulating the limb into a splint
- Monitor the patient for local anaesthetic toxicity
Max dose of local anaesthetic Bupivacaine 2 mg/kg ( = 0.4 ml/kg of 0.5% bupivacaine ) .
You can use a mixture of lignocaine and Bupivacaine. If mixture used then maximum dose should be 2mg/kg in total.
Beware
The RCEM have issued an alert re death after a fascia iliaca block. Please ensure you:
- Site, side, dose and time of block
- Frequency of post procedure observations. A minimum would be at 5, 10, 15, 30 mins post procedure
FNB in anticoagulated patients
- Femoral block technique probably safe [ESRA/ASRA statement 2018] especially when balancing risk/benefit for elderly patients with NOF
- Use small regional anaesthesia needles (22G) and ultrasound guidance
- Target the nerve rather than the iliacus plane/muscle
- Avoid vessel puncture (doh!)
Links
- Fasciailiaca block in NOF
- Femoral Nerve Block Technique (youtube)
- FNB (ultrasounspodcast.com)
- IAEM Guideline: Peri-capsular Nerve Group (PENG) Block for the Mx Pain in NoF, Acetabular and Pubic Ramus #s. Dr Niall Owens, 2023
- ESRA/ASRA statement 2018 - Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy: