As in other areas, anesthesia for laser treatment must be appropriate for the particular therapy and ensure safety and minimum discomfort. It must also keep pace with rapidly advancing laser techniques which have newer applications needing a variety of anesthesia. Some of the anesthesia techniques and the methods of administering them are discussed here.

Topical anesthesia

Cryoanesthesia - the use of cold to anesthetize is an old topical treatment. Cold works like local anesthesia, first blocking pain fibers, then thermal fibers and finally tactile fibers. Refrigerant sprays are fast acting but last few seconds. Ice packs are cheaper, easily available and somewhat longer acting.

A local anesthetic or a eutectic mixture local anesthetic cream (EMLA) is preferred in the painful tattoo treatment by those who cannot tolerate it without anesthesia or with ice packs. EMLA is not advised in infants for more than a month, though it can be used successfully in children for treating port wine stains. The effect of EMLA is not uniform. Very few children under 10 tolerate their treatment using EMLA. Its use is now restricted to adults and adolescents. The non-uniform effect of EMLA can be improved by adding local infiltrative anesthesia and the efficacy can be improved by adding an oral sedative.

Infiltrative anesthesia

Infiltrative anesthesia administered intradermally or subcutaneously, is very common way to anesthetize skin. It acts quickly and the effect lasts from 30 to 120 minutes. Being an amide, chances of allergic reactions are less compared with ester anesthetics. Lidocaine is a common and safe anesthetic, if the dosage is not exceeded. For long duration treatments long acting anesthetic like bupivacaine are used.

Nerve blocks

Peripheral nerve blocks can be produced by administering a local anesthetic along a nerve trunk, which has many nerves branching out. This way, large areas of the skin can be anesthetisized by a small amount of anesthetic which, besides, causes less pain and carries less risk of toxicity. Sometimes, when nerve blocks are difficult to produce, local anesthetic is added.

Oral sedation

Oral sedation is helpful in laser treatment for children, who have low pain tolerance. Chloral hydrate and midazolam are commonly used. These sedatives may be used to control the children, but will not provide any relief from pain since they are not analgesia. Some physicians have not found chloral hydrate particularly helpful. Children importantly, need to be monitored for any cardiopulmonary problems, especially with chloral hydrate.

The other ways of administering analgesia and sedatives are the intramuscular, intranasal and rectal routes. Drugs for intra muscular and intranasal routes include midazolam and ketamine. Methohexital is used for the rectal route. Since these drugs are rapidly absorbed by these methods, it is important that an anesthesiologist be present.

Oral diazepam may be given to anxious adults, especially for CO2 resurfacing, which uses EMLA, nerve blocks and local infiltrates as anesthesia. An oral narcotic analgesic may also be given to reduce pain.

Intravenous sedation

Intravenous sedation is employed where the laser treatment is painful. It is also preferred where the size and location of the treatment site is such, that easy anesthetizing is not possible by other methods. The drugs generally used are the narcotic fentanyl and the tranquiliser midazolam. Since these drugs are very potent, their use must be strictly left in the hands of experienced people. In the hands of inexperienced people the result may be lethal. There are reports of several deaths in such and similar cases. Presence of experienced anesthesiologist or anesthetist during the treatment should be mandatory.

General anesthesia

General anesthesia may be the only choice for treating vascular lesions in children. Reasons include location of the lesions on the face, the lesion size, multiple treatment sessions and the immaturity of the patients. As important, is that early treatment gives a good chance to the lesions to clear quickly and completely. Delayed treatment reduces the chances of complete recovery. According to a group of physicians parents preferred this treatment. Normally, general anesthesia is not used on children before they are 6 months old.

As multiple sessions are usually needed, the anesthetic technique should be custom designed for each child and the same treatment repeated. The child should return to normal quickly with least discomfort and side effects. Importantly, the presence of parents helps the child to cope with the treatment. General anesthesia is also used in some cases of full face resurfacing with CO2 laser.

The use of general anesthesia in laser treatment for skin lesions carries the risk of fire, especially in people with dark hair which absorbs more laser energy. Fire risk can be minimized by wetting the hair and preventing leakages of inflammable gases.