Surface anesthesia, along with infiltration anesthesia and regional anesthesia, is one of the local anesthesia procedures. It is used for “superficial” pain anesthesia. Here, mucosal anesthesia is distinguished from topical local anesthesia of the skin. While local anesthetics can be absorbed very well through the mucous membrane, these would not be able to penetrate the body skin. For this purpose, the so-called EMLA cream is used, the use of which will be discussed later.
Indications (areas of application)
- Procedures in the mouth, nose, throat – e.g., anesthesia of the vocal folds.
- Gastroscopy or bronchoscopy and other procedures requiring passage of instruments – to attenuate protective reflexes
- Eye drops containing local anesthetic – e.g., for removal of foreign bodies or for tonometry (measurement of intraocular pressure)
- Use of a local anesthetic-containing lubricant before catheterization of the male urethra (urethra).
- Venipuncture in children (EMLA cream).
- Circumcision (circumcision) (EMLA cream)
Contraindications
- Allergy to the local anesthetic
- Large-area application of topical local anesthetics in pre-damaged skin – Especially in children, this increases the risk of systemic effects of local anesthetics (EMLA cream).
Before surface anesthesia
No special precautions need to be taken before performing infiltration anesthesia. However, an allergy to the local anesthetic used should be ruled out in advance. In addition, when anesthetizing the mouth, nose, and throat, the patient should be advised not to eat or drink afterward because the failure of protective reflexes may persist.
The procedure
The local anesthetic is usually administered as a spray during mucosal anesthesia, and lidocaine is usually used. For example, in anesthesia (numbing) of the vocal folds, the lidocaine solution is sprayed onto the vocal folds under visual control.
The so-called EMLA cream contains 25 mg of lidocaine and 25 mg of prilocaine per gram of ointment. As mentioned earlier, this drug is used for surface anesthesia (surface numbing) prior to venipuncture in young children. The ointment is applied through a patch.
Possible complications
- Allergic reaction to the local anesthetic.
- Aspiration (foreign body entering the respiratory tract) during anesthesia in the oral, nasal, pharyngeal cavity
- Corneal irritation – In contact with the eye (EMLA cream).
