Anesthesia is broken down into three main categories: local, regional, and general, all of which affect the nervous system in some way and can be administered using various methods and different medications.
Here's a basic look at each kind:
- Local anesthesia. An anesthetic drug (which can be given as a shot, spray, or ointment) numbs only a small, specific area of the body (for example, a foot, hand, or patch of skin). With local anesthesia, a person is awake or sedated, depending on what is needed. Local anesthesia lasts for a short period of time and is often used for minor outpatient procedures (when patients come in for surgery and can go home that same day). For someone having outpatient surgery in a clinic or doctor's office (such as the dentist or dermatologist), this is probably the type of anesthetic used. The medicine used can numb the area during the procedure and for a short time afterwards to help control post-surgery discomfort.
- Regional anesthesia. An anesthetic drug is injected near a cluster of nerves, numbing a larger area of the body (such as below the waist, like epidurals given to women in labor). Regional anesthesia is generally used to make a person more comfortable during and after the surgical procedure. Regional and general anesthesia are often combined.
- General anesthesia. The goal is to make and keep a person completely unconscious (or "asleep") during the operation, with no awareness or memory of the surgery. General anesthesia can be given through an IV (which requires sticking a needle into a vein, usually in the arm) or by inhaling gases or vapors by breathing into a mask or tube.
The anesthesiologist will be there before, during, and after the operation to monitor the anesthetic and ensure you constantly receive the right dose. With general anesthesia, the anesthesiologist uses a combination of various medications to do things like:
- relieve anxiety
- keep you asleep
- minimize pain during surgery and relieve pain afterward (using drugs called analgesics)
- relax the muscles, which helps to keep you still
- block out the memory of the surgery
How Does Anesthesia Work?
To better understand how the different types of anesthesia work, it may help to learn a little about the nervous system. If you think of the brain as a central computer that controls all the functions of your body, then the nervous system is like a network that relays messages back and forth from it to different parts of the body. It does this via the spinal cord, which runs from the brain down through the back and contains threadlike nerves that branch out to every organ and body part.
The American Society of Anesthesiologists (ASA) compares the nervous system to an office's telephone system — with the brain as the switchboard, the nerves as the cables, and body parts feeling pain as the phones. Here's how the ASA puts it into perspective:
- With local anesthesia, the phone (the small part of the body being numbed) is "off the hook" and, therefore, can't receive calls (pain signals) from the switchboard (the brain) or the phone cables (the nerves).
- With regional anesthesia, the phone cable (the nerves) is broken, causing all of the area's phones (entire area of the body being numbed) to be out of service.
- With regional anesthesia, the switchboard operator (the brain) is on a break and, therefore, can't connect incoming calls (pain signals).
Will I Get a Needle?
Often, anesthesiologists may give a person a sedative to help them feel sleepy or relaxed before a procedure. Then, people who are getting general anesthesia may be given medication through a special breathing mask or tube first and then given an IV after they're asleep. Why? Because many people are afraid of needles and may have a hard time staying still and calm.
What Type of Anesthesia Will I Get?
The type and amount of anesthesia given to you will be specifically tailored to your needs and will depend on various factors, including:
- the type of surgery
- the location of the surgery
- how long the surgery may take
- your current and previous medical condition
- allergies you may have
- previous reactions to anesthesia (in you or family members)
- medications you are taking
- your age, height, and weight
The anesthesiologist can discuss the options available, and he or she will make the decision based on your individual needs and best interests.
Reviewed by: Judith A. Jones, MD
Date reviewed: April 2009