Peripheral regional anaesthesia

Peripheral regional anaesthesia is also known as a nerve block or conduction anaesthesia, a form of regional anaesthesia. With this modality local anaesthetic is administered around the nerve supplying the area to be anaesthetised. This may take place some distance from the surgical site, like for example a brachial plexus block for hand surgery. The result is anaesthesia of the area supplied by the nerve distal to the area of injection.

Nerve block

Nerve blocks are often used for anaesthesia of fingers (example) and toes as well (digital nerve block), in which case local anaesthetic is injected to each side of the digit, as close to the nerves passing there as possible. There is one dorsal and one palmar/plantar digital nerve on each side of the digit, and so local anaesthetic should be deposited at four sites across two injections.

Local anaesthesia

Local anaesthesia involves either infiltration anaesthesia or topical anaesthesia.

Infiltration anaesthesia is similar to nerve blocks but differ in that the aim of infiltration anaesthesia is not to anaesthetise the nerve itself, but the nerve endings in a certain area of tissue. Local anaesthetic is injected directly into and around the area to be anaesthetised, from which it will disperse in the tissue. This is simpler than nerve blocks and preferred for most cases, except for toes and fingers. Infiltration anaesthesia is often used for wounds which are to be examined or sutured, or for skin biopsy.

Topical anaesthesia refers to applying local anaesthetic topically to the area to be anesthetised, often as a spray or gel. This is useful for the upper airway before laryngoscopy, endoscopy, or intubation, and before bladder catheterisation. Topical anaesthesia is especially useful in children.

Intravenous regional anaesthesia

Intravenous regional anaesthesia (IVRA) or Bier block involves isolating an exsanguinated limb from the circulation with a tourniquet and injecting the local anaesthetic intravenously. It’s simple, safe, and effective, and especially suitable for short procedures and outpatient surgery.