Chapter 20. Intravenous Regional Block for Upper and Lower Extremity Surgery
Which of the following statements is not true regarding intravenous regional anesthesia (IVRA) (Bier block)?
A. Produces analgesia by the local anesthetic bathing bare nerve endings in the tissue
B. Produces analgesia by conduction block in the substance of the nerve
C. Produces analgesia by reducing neurogenic inflammation
D. Produces analgesia by vasoconstriction of the vasa nervorum
D is not true, so option D is correct. Bier block does not produce analgesia by vasoconstriction of the vasa nervorum. While the indirect anesthesia described by Bier is thought to occur due to the transport of local anesthetic to the substance of the nerve through the vasa nervorum, there is no evidence that it causes vasoconstriction of the vasa nervorum.
A is true, so option A is incorrect. Cadaver dissections of the upper extremity after injecting methylene blue have shown that direct anesthesia during IVRA occurs as a result of the local anesthetic bathing bare nerve endings in the tissue.
B is true, so option B is incorrect. The indirect (delayed onset) anesthesia is thought to occur due to conduction block in the substance of the nerve as a result of the transport of local anesthetic via the vasa nervorum to the substance of the nerve.
C is true, so option C is incorrect. In cases of complex regional pain syndrome, Bier block has been shown to decrease neurogenic inflammation, especially when mepivacaine is the local anesthetic chosen for the block.
For which of the following conditions is a Bier block not an option for providing analgesia?
A. Excision of a ganglion cyst in the dorsum of the wrist
B. Complex regional pain syndrome affecting the hand
C. Raynaud’s disease affecting the fingertips of the upper extremity
D. Neuroma excision of the big toe
C is correct. Bier block is not an option for providing analgesia in patients with Raynaud’s disease. In patients with severe peripheral vascular disease or preexisting vascular arteriovenous shunts, intravenous regional anesthesia (IVRA) is contraindicated.
A is incorrect. Bier Block is an option for this condition. IVRA is most suited for surgery and manipulation of the extremities requiring anesthesia of up to 1 hour duration, and also for peripheral, soft tissue operations such as ganglionectomies.
B is incorrect. Bier Block is an option for this condition. IVRA is effective as a treatment adjunct for complex regional ...