**Question:** Concentration of adrenaline used with lignocaine

**Core Concept:** Adrenaline (epinephrine) is a catecholamine hormone and a sympathomimetic amine that has both cardiovascular and vasoconstrictor effects. When used as an additive to local anaesthetic solutions like lignocaine, adrenaline helps to prolong the duration of action, reduce the total dose required, and minimize post-operative bleeding.

**Why the Correct Answer is Right:**
Adrenaline is typically used at a concentration of 1:100,000 in local anaesthetic solutions. This concentration is chosen due to its ability to reduce bleeding without significantly impairing the anesthetic effect.

**Why Each Wrong Option is Incorrect:**
A. 1:1000 (Option A): This concentration is too high, increasing the risk of systemic toxicity and cardiovascular side effects.
B. 1:2000 (Option B): This concentration is slightly better than A, but still higher than the recommended 1:100,000 concentration.
C. 1:10000 (Option C): This is too low, resulting in inadequate vasoconstriction and potentially increased bleeding.
D. 1:100000 (Option D): This is even lower than option C, leading to insufficient vasoconstriction and possible increased bleeding.

**Clinical Pearl:**
Using the correct concentration of adrenaline (1:100,000) in local anaesthetic solutions helps to optimize the balance between bleeding control and local anaesthetic efficacy, ensuring safe and effective surgical procedures with minimal complications.

**Correct Answer:**
Correct Answer: 1:100,000

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**Core Concept:** Lignocaine is a local anaesthetic drug used for peripheral nerve blockades and general anesthesia. When combined with adrenaline, it enhances the vasoconstrictive effect, reducing bleeding during surgical procedures and prolonging the duration of action.

Adrenaline, a sympathomimetic amine, exerts its action by binding to alpha-adrenergic receptors in the vasculature, causing vasoconstriction. In this context, the correct adrenaline concentration to be used with lignocaine is crucial for ensuring optimal balance between bleeding control and local anaesthetic effectiveness.

**Why the Correct Answer is Right:**
1:100,000 is the appropriate concentration of adrenaline to be used with lignocaine as it provides effective vasoconstriction while maintaining a reasonable anesthetic effect. This concentration ensures minimal bleeding during surgical procedures and reduces the total dose of lignocaine needed, thereby decreasing the risk of local anesthetic toxicity.

**Why Each Wrong Option is Incorrect:**

A. 1:1000: A higher adrenaline concentration (1:1000) is too high and can lead to systemic toxicity due to increased systemic absorption and uptake.
B. 1:2000: Similar to option A, a higher adrenaline concentration (1:2000) can