Anaesthesia: Regional anaesthesia
BMJ 2007; 334 doi: https://doi.org/10.1136/sbmj.0705186 (Published 01 May 2007) Cite this as: BMJ 2007;334:0705186
- Jonathan M Behar, final year medical student1,
- Petrut Gogalniceanu, final year medical student1,
- Lesley Bromley, consultant anaesthetist and director of postgraduate medical education2
- 1Royal Free and University College Medical School, London NW7 3SL
- 2University College London Hospitals NHS Foundation Trust, London W1P 9LL
General anaesthesia is the systemic administration of a central nervous system depressant, which leads to loss of consciousness and complete absence of sensation. The trauma associated with surgery activates nociceptors and the nerve fibres emerging from them. But these are not perceived under the influence of a general anaesthetic-the exact underlying mechanism, however, is unknown.
Regional anaesthesia, by contrast, is a method of providing local analgesia by infiltration of a local anaesthetic into tissues adjacent to regional nerves. Regional anaesthetics can be given to central structures, such as the spinal cord, or peripheral nerves, which emanate from the cord. This varies according to the purpose of the anaesthetic “block” and the area that needs to be anaesthetised.
Why not put all patients to sleep?
Although it may seem easier to fully anaesthetise all patients, regional anaesthesia may be the better option in some of the following cases:
If the patient is not a suitable candidate for general anaesthesia-often because of comorbidities, such as chronic obstructive airways disease and end stage heart failure
If the surgical procedure is amenable to regional anaesthesia, and this presents a lower overall risk to the patient compared with a general anaesthetic-for example, arthroscopic procedures of the knee, diagnostic and therapeutic
Some surgical procedures that require the patient to be awake-for example, births (reduced risk to the baby), carotid endarterectomy (so that any developing stroke as a result of an arterial embolus is immediately obvious to the surgeon)
Minor procedures can often be done with simple sedation and local analgesia-for example, sebaceous cyst and skin tag removals.
Cross section of the spinal cord, its covering membranes, and spaces; spinothalamic tracts encircled. Adapted from www.unm.edu/[sim]jimmy/spinal_notes.htm
Box 1: Important anatomy (fig 1)
The epidural space is bordered by the foramen magnum (cranially), …
Log in
Log in using your username and password
Log in through your institution
Subscribe from £184 *
Subscribe and get access to all BMJ articles, and much more.
* For online subscription
Access this article for 1 day for:
£50 / $60/ €56 (excludes VAT)
You can download a PDF version for your personal record.