What is local anesthesia?

Date: Sep-05-2013Local anesthesia involves numbing a specific part of the body to prevent any feeling of pain during surgical procedures. An anesthetic drug - which has numbing effects - is applied to a certain part of the patient's body.

It is typically carried out in combination with sedation - which calms the patient and reduces stress levels - so that patients can undergo surgery without experiencing unbearable pain or distress.

In many cases local anesthesia is considered to be safer than general anesthesia (such as in a cesarean section). Although it is not uncommon for anesthetists to combine methods of both local and general anesthesia.

According to The Nemours Foundation, the type of anesthesia used will depend on many factors, including patients' age, weight, allergies they may have, what part of the body is to be operated on, and their current medical condition.

As local anesthesia only lasts for a short time, it is primarily used for minor outpatient procedures, where the patient can leave on the same day of the surgery.

According to Medilexicon's medical dictionary, Local Anesthesia is:

"a general term referring to topical, infiltration, field block, or nerve block anesthesia but usually not to spinal or epidural anesthesia; may also refer to pharmacologic agents used to achieve local anesthesia."

Local anesthesia not used just for surgery

In addition to being used to reduce pain during surgery, local anesthesia is sometimes applied to help diagnose the cause of some chronic conditions, it is also used for pain relief following an operation (postoperative pain relief).

A team of scientists at the Rothman Institute at Jefferson showed that local anesthesia is probably more beneficial than traditional opioids for managing pain after total knee replacement surgery.

Researchers at Uludag University School of Medicine, Bursa, Turkey, reported in the World Journal of Gastroenterology that the use of local anesthetics may ease symptoms of inflammatory bowel disease (IBD).

Local anesthetics may be effective for treating neuropathic pain, researchers from the M.D. Anderson Cancer Center in Houston, Texas, reported in The Cochrane Library. Ivo W. Tremont-Lukats, M.D., wrote "Intravenous lidocaine and oral derivatives relieve pain from damage to the nervous system. ....(these drugs) were safe in controlled clinical trials for neuropathic pain, were better than placebo and were as effective as other analgesics."
Preparing yourself for local anesthesia

A local anesthetic is administered to a child
before tooth extraction.

Your doctor should tell you how to prepare for the surgery. It is vital that you inform your doctor if you are on any medications - especially if they are blood thinning agents, such as aspirin or warfarin.

The doctor may instruct you not to eat anything a few hours before surgery. In addition, it is important to make sure that you do not drink any alcohol 24 hours before you receive the anesthetic.

Minutes after applying a local anesthetic agent to a certain area of the body, it will begin to feel numbed - your doctor won't proceed with the surgery if you do not feel the numbing effect.

Despite the anesthetic preventing any pain from being felt, it is still possible to feel pressure during the operation.

A sedative is usually given too, which will help make you feel calm and less anxious. The kind of sedative depends on what type of surgery is going to be carried out and how anxious you are feeling.

Doctors will monitor the amount of oxygen in your blood using a small device placed on the finger, in rare cases a plastic nasal tube will be used to provide extra oxygen.

Side effects associated with having local anesthesia and sedation are less prevalent than those associated with general anesthesia. However, they include: headache, dizziness, and vomiting.
What are local anesthetics?

Local anesthetics are membrane stabilizing drugs that achieve anesthesia by acting on certain nerve pathways, stopping pain signals being sent by the nerves to the brain.

The structures of synthetically made anesthetics are very similar to cocaine. However, unlike cocaine, these drugs do not have the same abuse potential.

Doctors can determine how long the effects will last depending on the amount and strength of the solutions they use.

Generally, the numbing effects of a local anesthetic last from anywhere between half an hour to four hours.

Adverse effects of local anesthetic agents may include:

depressed CNS syndrome
allergic reaction
cyanosis - the skin becomes bluish, this is caused by either poor circulation or inadequate oxygenation of the blood

Written by Joseph Nordqvist

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