Anaesthesiology is the medical speciality that encompasses study and use of anaesthesia; general, regional and local.
Historically surgery was performed without adequate pain relief, usually following the administration of alcohol, which was ineffective as an analgesic. In the mid 19th Century the discovery of the pain relieving properties of nitrous oxide by Horace Wells, and ether by William Morton, led to the birth of modern anaesthesia. The main benefit of ether was that, in a vaporised form, it did not cause respiratory depression and allowed the airway to be kept open by inexperienced anaesthetists.1
General anaesthesia uses chemicals to produce an unconscious state in which a patient has no perception of pain and will have no memory of the procedure upon regaining consciousness.2 This is used primarily during major surgery, however there are more dangers with this type of anaesthesia; namely reduced respiratory and heart rate, blood pressure and body temperature.3
Regional and local anaesthesia are used in minor surgery to block the perception of pain without causing loss of consciousness. This has the benefit of allowing some outpatient procedures which have lower waiting times4, require shorter hospital stays and have shorter recovery periods.5 Regional anaesthetics are used to block the sodium gated channels of specific nerves to inhibit the production of an action potential.6 Nerve blocking can be used in both the central nervous system and peripheral nervous system and causes the numbing of regions of the body. Epidural anaesthesia is often used for surgeries of the lower body (bladder, leg, gynaecological and prostate).3 Local anaesthetics are injected into the specific area where the incision will occur. This has the benefit of faster recovery and reduced risk of anaesthetic complications.
1. Jacob A. et al. The History of Anesthesia. Clinical Anesthesia Sixth Edition. Lippincott Williams and Wilkin. 2009 : 3-7.
2. Alkire M. General Anesthesia. Encyclopedia of Consciousness. Elsevier Inc. 2009 : 295-313.
3. Beers M.H. et al. The Merck Manual of Medical Information. Merck research laboratories. Second home edition. 2003 : 1699-1700.
4. Trentmen T. et al. Outpatient Surgery Performed in an Ambulatory Surgery Center Versus a Hospital: Comparison of Perioperative Time Intervals. The American Journal of Surgery. 2010 ; 200 (1) : 64-67.
5. Rueben S. A Comparison of Local Intraarticular Anesthesia Versus General Anesthesia For Ambulatory Arthroscopic Knee Surgery. Ambulatory Surgery. 2005 ; 12 (1) : 39-44.
6. Liu S. et al. Local Anesthetics. Clinical Anesthesia Sixth Edition. Lippincott Williams and Wilkin. 2009 : 531.