Methods for anesthesia
Local anesthesia
The following local anesthetic methods exist:
- Topical anesthesia with EMLA®:
EMLA is a eutactic mix of lidocane and prilocaine mixed 1 to 1. It is available as an ointment as well as a patch (occlusive bandage) and may be used for local anesthesia of small skin or mucosal areas. Application should occur 30 minutes prior to the operation; if the ointment is used, occlusion (e.g. with a plastic bandage) is also recommended.
- Cryoanesthesia:
Typically Chlorethyl spray is used to achieve short-term anesthesia by cooling the affected area. It is especially useful in case of local infection (e.g. incision and drainage of abcesses), as infiltrative local anesthesia is not effective due to acidity of the tissue.
- Infiltrative anesthesia:
A plethora of local anesthetics is used today (those of the ester type: e.g. procaine [Novocaine®] oder tetracaine [Pantocaine®]; or those of the amide type: e.g. lidocane [Xylocain®], prilocaine [Xylonest®] or mepivacaine [Scandicaine®, Maeverine®] with and without adrenalin). Typically, injection is performed immediately before incising into the operating area. Application should be carried out by injecting as withdrawing the needle to avoid multiple punctures into the skin. If necessary, additional injections should be made from the already numbed area.
Tumescent Anesthesia
Principle: In tumescent anesthesia large amounts of a diluted anesthetic with adrenaline added, are injected into the skin and into the subcutis. Typicaly, thel tumescent mix contains: 1000ml NaCl 0,9%, 1000mg lidocaine, 1000µg adrenaline and 12,5mmol sodiumbicarbonate (as buffer). This leads to swelling of the tissue (tumescere = swelling), separation of individual layers of the skin, excellent analgesia of an extensive operating field, as well as a reduced tendency to bleed (due to vasoconstriction by adrenaline). Most commonly, tumescent anesthesia is used for surgery of the veins, liposuction, and wide excisions.
Regional anesthesia
Principal: The base of a nerve is anesthetised by circumferentially injecting the local anesthetic. Side effects are deactivation of autonomous fibers (sympathicolysis), leading to vasodilitation and enhanced propensity for bleeding. Application: This regional anesthesia is typically used to specifically block certain nerves or branches of nerves to then operate in the area of the skin that those nerves innervate. It is especially suited for operations in distal areas such as fingers, toes, nails, the penis, ears, lips, etc.).
