Anesthesia, Local Health Article

Local anesthesia

INJECTABLE LOCAL ANESTHETICS. Injectable local anesthetics provide pain relief for some part of the body during surgery, dental procedures or other medical procedures. They are given only by a trained health care professional and only in a doctor's office or a hospital. Some commonly used injectable local anesthetics are lidocaine (Xylocaine), bupivacaine (Marcaine), and mepivacaine (Carbocaine).

TOPICAL ANESTHETICS. Topical anesthetics, such as benzocaine, lidocaine (in smaller quantities or doses), dibucaine and tetracaine, relieve pain and itching by blocking the sensory nerve endings in the skin. They are ingredients in a variety of nonprescription products that are applied to the skin to relieve the discomfort of sunburn, insect bites or stings, poison ivy, and minor cuts, scratches, and burns. These products are sold as creams, ointments, sprays, lotions, and gels.

Topical dental anesthetics are intended for pain relief in the mouth or throat. They may be used to relieve throat pain, teething pain, painful canker sores, toothaches, or discomfort from dentures, braces or bridgework. Some dental anesthetics are available only with a doctor's prescription. Others may be purchased over the counter, including products such as Num-Zit, Orajel, Chloraseptic lozenges, and Xylocaine.

Ophthalmic anesthetics are designed for use in the eye. Lidocaine and tetracaine are used to numb the eye before certain eye examinations. Eye doctors may also use these medicines before measuring eye pressure or removing stitches or foreign objects from the eye. These drugs are to be given only by a trained health care professional.

The recommended dosage of a topical anesthetic depends on the type of local anesthetic and the purpose for which it is being used. When using a nonprescription local anesthetic, follow the directions on the package. Questions concerning how to use a product should be referred to a doctor, dentist or pharmacist.

Aftercare

Most patients can return home immediately after a local anesthetic, but some patients might require limited observation. The degree of aftercare needed depends on where the anesthetic was given, how much was given, and other individual circumstances. Patients who have had their eyes numbed should wear a patch after surgery or treatment until the full feeling of the eye area has returned. If the throat was anesthetized, the patient cannot drink until the gag reflex returns. If a major extremity was anesthetized, one may have to wait until function returns before the patient goes home. Some local anesthetics can cause cardiac arrhythmias and therefore require monitoring for a time with an EKG. Patients who have had regional anesthesia or larger amounts of local anesthesia usually recover in a post-anesthesia care unit before being discharged. There, medical personnel watch for immediate postoperative problems. These patients need to be driven home after discharge.

Complications

Side effects of regional or local anesthetics vary depending on the type of anesthetic used and the way it is administered. Any unusual symptoms following the use of an anesthetic requires the immediate attention of a doctor.

Paralysis after a regional anesthetic such as an epidural, spinal or ganglionic blockade is extremely rare, but can occur. Paralysis reportedly occurs even less frequently than deaths due to general anesthesia.

There is also a small risk of developing a severe headache called a spinal headache following a spinal or epidural block. This headache is severe when the patient is upright, even when only elevated 30 degrees, and is hardly felt when the patient lies down. It is treated by increasing fluids to help clear the anesthetic and enhance the flow of spinal fluid.

Finally, blood clots or abscess can form at the site where an anesthetic is injected. Although they can usually be treated, antibiotic resistance is becoming increasingly common. Such infections must be regarded as potentially dangerous, particularly if they develop at the site of a spinal injection.

A physician should be notified immediately if any of the following occur:

• symptoms of an allergic reaction, such as hives (urticaria), which are itchy swellings on the skin, or swelling in the mouth or throat
• severe headache
• blurred or double vision or photophobia (sensitivity to light)
• dizziness or lightheadedness
• drowsiness
• confusion
• an irregular, too slow, or rapid heartbeat
• anxiety, excitement, nervousness, or restlessness
• convulsions (seizures)
• feeling hot, cold, or numb anywhere other than the anesthetized area
• ringing or buzzing in the ears
• shivering or trembling• sweating
• pale skin
• breathing problems
• unusual weakness or tiredness

Results

Local and regional anesthetics help to make many conditions and procedures more comfortable and tolerable for patients.