Local Infiltration

Local infiltration uses injectable agents that are extravascularly injected into the region to be anaesthetised. It acts to desensitise the dermis and subcutaneous tissues.

Agents

Commonly used agents include lidocaine, bupvicaine, and mepvicaine.

Uses

Some minor surgical procedures can use infiltration anaesthesia, avoiding the need to put the patient under a general anaesthetic or use sedation, removing the risk of the patient falling over. It can also be used in conjunction with a general anaesthetic to supply analgesia to the surgical site, or reduce the need for a deep anaesthetic in high risk patients. It can also aid diagnostic procedures. It is commonly used over superficial abscesses or haematomas before a stab incision is made. A continuous infiltration system can be used in some post operative cases to provide post operative analgesia, e.g. total ear canal ablation surgery.

Advantages

• Easy to perform and needs only a hypodermic needle and syringe.
• Easy to define area infiltrated by production of intradermal wheals upon injection of the agent - Used in large animals.
• Most reliable and safest technique.

Disadvantages

• Multiple injections may be required if a large area is to be infiltrated.
• Care needs to be taken in the total dose given as may cause toxicity problems.
• Do not use on inflammed or infected tissues.