Intravenous Regional Anaesthesia

Introduction

Intravenous regional anaesthesia is used commonly for surgeries affecting the distal limb, particularly cattle. It requires the use of a tourniquet to minimise blood flow from the distal limb, so that the anaesthetic agent only affects the tissue distal to the tourniquet. The agent is injected into a small vein, allowing for diffusion of the agent throughout the circulation distal to the tourniquet. Once the procedure has finished, it is imperative the tourniquet is removed slowly to avoid systemic effects of the anaesthetic agents used.

Agents

Lidocaine is most commonly used in these procedures. Bupivicaine should not be used due to the risk of toxicity, which includes cardiovascular collapse and death.

Uses

• Digit removal in cattle
• Digit surgery in dogs unsuitable for general anaesthetics.

Advantages

• Good analgesia.
• Reduces blood flow to the region allowing for clearer visualisation of structures.
• Requires one injection and no detailed anatomy knowledge is required.

Disadvantages

• Possibility of local anaesthetic toxicity if enters systemic circulation, especially if the tourniquet is not removed slowly.
• Limited to areas it can be applied to i.e. only distal extremities.