Ultrasound Regional Anesthesia

Question 1

abc
abc
abc

Answer 1

abc
abc
abc

Question 2

What is the mechanism of action of paravertebral block?

Answer 2

1. Direct effect on the somatic and sympathetic nerves in the PVS
2. Extension into the intercostal space laterally
3. Epidural space medially.

The PVS (paravertebral space) medially communicates with the epidural space via the intervertebral foramen inferiorly and superiorly across the head and neck of the ribs. Consequently, injection of local anesthetic into the PVS space often results in unilateral (sometimes bilateral) epidural anesthesia. The PVS also communicates with the intercostal spaces laterally, resulting in the spread of the local anesthetic into the intercostal sulcus and resultant intercostal block as part of the mechanism of action.

Question 3

Decribe Paravertebral Block Technique Algorithm

Answer 3

Local anesthetic (15–20 mL) is injected slowly in small increments, avoiding forceful high-pressure injection to reduce the risk of bilateral epidural spread.

Hint: – A multiple injection technique with small volumes (3–4 mL) of local anesthetic at several contiguous thoracic levels, is preferable over a single, large-volume injection. This is particularly important when reliable anesthesia over several ipsilateral thoracic dermatomes is desired, such as when a thoracic paravertebral block is used for anesthesia during breast surgery.