The Supraclavicular Nerve Block is an intermediate skill procedure that you will learn to quickly master if you follow certain landmarks. Although the neck has many structures that you do not want be near to, ultrasound and a posterior approach make this block remarkably safe.
Indications: Shoulder or any upper extremity procedure
External Landmarks: Clavicle, external jugular vein
Local Anesthetic Volume: 20 mls. 12-15 mls in patients with elevated BMI's or respiratory disease
Level of Expertise: Intermediate
The block is performed at the level where the brachial plexus passes, along with thesubclavian artery, beneath the first rib. (You will be seeing these three while you perform the block...) This is after the plexus passes the anterior and middle scalene muscles so although useful, you do not necessarily need to identify the latter to perform this block successfully. Proximity to the pleura (you will see it most of the time with its "comet-tail" look) explains why this block was performed rarely without ultrasound. Risk of pneumothorax with the use of ultrasound is extremely low.
View of Supraclavicular Anatomy with a non-linear array ultrasound
Patient is in 20-30 degrees - semi-sitting position (more for your comfort). You can stand behind the patient, no different than if you are ready to ready to intubate.
- I-Streme Echo
- Nerve stimulator (optional)
- 12-20 mls local anesthetic syringe (use Ropivacaine for further sparing of phrenic nerve)
- 25 gauge needle for local infiltration
- Echogenic needle (optional)
- 15 MHz/5 cm setting (24MHz/3 cm optional)
- Place your probe with the button facing lateral on top of the clavicle, and start your scan at the level of the external jugular vein.
- Your approach with the needle should be behind the external jugular vein. This is a shallow block and you will be able to see the needle better if you come in with it at a flat angle.
- Identify the subclavian artery initially. You will usually see the 1st rib just below it, and the brachial plexus anywhere from 12 to 6 o'clock of the vessel. The number of actual nerves you will see is very variable.
- Have the patient turn his head as far away from the block side and have an assistant pull on the arm to further drop the shoulder if you cannot obtain a good view. This is particularly useful in patients who are obese.
- Inject small amounts of local anesthetic to visualize well where your needle tip is.
- Reposition the needle several times during the block to optimize the spread of the local anesthetic.
- Use smaller amounts in obese patients to limit the exposure of the phrenic nerve to your local anesthetic.
- Intravascular injection into the subclavian artery.
- Post-op respiratory insufficiency (paralyzed diaphragm) especially in obese or debilitated patients).
- Nerve injury.