For Bier’s block drug of choice is –
**Core Concept**
Bier's block, also known as intravenous regional anesthesia (IVRA), is a technique used to anesthetize a limb by injecting a local anesthetic into a vein within the limb. The drug of choice for Bier's block is a local anesthetic that can effectively block nerve conduction in the affected limb.
**Why the Correct Answer is Right**
The drug of choice for Bier's block is lidocaine, a fast-acting local anesthetic that blocks sodium channels in nerve membranes, preventing the initiation and transmission of nerve impulses. Lidocaine has a rapid onset of action, making it ideal for Bier's block. Additionally, lidocaine has a relatively short duration of action, which reduces the risk of systemic toxicity.
**Why Each Wrong Option is Incorrect**
**Option A:** None - No alternative is listed.
**Option B:** There is no evidence to support the use of ropivacaine in Bier's block.
**Option C:** Mepivacaine is not the preferred choice for Bier's block due to its slower onset of action and longer duration of action.
**Clinical Pearl / High-Yield Fact**
In Bier's block, it is crucial to ensure that the tourniquet is inflated before injecting the local anesthetic to prevent systemic toxicity. If the tourniquet is not inflated, the local anesthetic can enter the systemic circulation, leading to toxicity.
**Correct Answer:** A. Lidocaine.