Regional Anesthesia Flashcards
How would you perform a superficial cervical plexus block?
- With the patient’s head turned to the side I would identify the mastoid process, Chassiagnac’s tubercle of C6 and the clavicular head of the sternocleidomastoid muscle. I would then draw a line from C6 to the mastoid and would insert my needle at the midpoint. This line should be along the posterior border of the sterncleidomastoid muscle.
I would inject 10 - 15 cc of local anesthetic in a fan-like distribution posteriorly to superiorly subcutaneously posterior to the sternocleidomastoid with careful and frequent aspiration.
After performing a superficial cervical plexus block, the patient complains of numbness on the contralateral side. What do you do?
I would reassure the patient that this is a normal finding as cross-coverage from the cervical plexus branches from the opposite side is a normal occurrence.
If a patient is undergoing CEA awake with cervical plexus nerve blockade but complains of pain from the surgical skin retractors, how might this have been avoided?
A subcutaneous midline injection of the local anesthetic extending from the thyroid cartilage distally to the suprasternal notch will block the branches crossing from the opposite side. This injection can be considered as a “field” block. It is very useful for preventing pain from surgical skin retractors on the medial aspect of the neck.
What are the risks of a cervical plexus block?
Phrenic nerve blockade (100%)
Local anesthetic toxicity
Nerve injury
Spinal anesthesia
How might a superficial cervical plexus block result in inadvertent spinal anesthesia?
- This complication may occur with injection of larger volume of local anesthetic inside the dural sleeve that accompanies the nerves of the cervical plexus
- It should be noted that a negative aspiration test for CSF does not rule out the possibility of intrathecal spread of local anesthetic.
- Avoidance of high volume and pressure during injection are the best measures to avoid this complication
What are the major nerves of the cervical plexus?
The superficial cervical plexus supplies innervation to the skin of the anterolateral neck through anterior primary rami of C2 through C4. There are four: Lesser occipital greater auricular transverse cervical supraclavicular nerve
What block needs to be done for CEA in addition to cervical plexus blockade?
Glossopharyngeal nerve block which can be done by the surgeon by injecting into the carotid sheath.
What is another way to characterize a deep cervical plexus block?
Paravertebral block of C2, C3, and C4
What current intensity indicates intimate needle-nerve placement?
0.2 - 0.5 mA - a response in this range is probably safe for injection
What current intensity may be associated with intraneural needle placement?
< 0.2mA
Would intraneural placement result in motor response of a motor nerve?
Not always.
What should you do if injection of local anesthetic for a PNB proves difficult?
Abort and the needle flashed to assure patency before trying to reinject because the resistance could have been due to intraneural placement
Where is the stellate ganglion located?
Level of C7, anterior to the transverse process of C7, anterior to the neck of the first rib, and just below the subclavian artery.
Describe the vascular structures about the stellate ganglion.
The vertebral artery which runs anteriorly at C7 before it enters the foramen of the C6 transverse process in about 90% of cases. It enters at C5 or higher in the remainder of cases.
The inferior thyroid vessels - a major source of retropharyngeal hematoma
Carotid artery
What is a sign of successful stellate ganglion block?
Horners syndrome
