What is Anesthesia?
Anesthesia is a state in which the patient feels no pain. This may range from blocking the sensation of one small part of the body to total unconsciousness. Whenever you have surgery, you usually have some kind of anesthesia. The anesthesia allows the surgeon to perform the surgery painlessly. Your anesthesiologist will help you decide which type of anesthesia is best suited for you based on your history and the type of surgery you are having.

What Are the Different Types of Anesthesia?

• General Anesthesia:
  General Anesthesia is a technique during which the patient is rendered unconscious. General Anesthesia provides analgesia (you have no pain), amnesia (you are unaware and have no memory), and relaxation (your muscles are relaxed to give the surgeon better operating conditions). General Anesthesia is usually started and maintained by giving the patient an intravenous drug (into a vein), an inhalation drug (a gas which you breathe), or a combination of both. The anesthesia provider will monitor the progress of the surgery and the depth of your anesthesia. The depth of anesthesia can be changed by increasing or decreasing the amount of drug given. As the surgeon finishes the procedure, the anesthesia provider reduces the depth of anesthesia so the patient will awaken at the end of the procedure or shortly thereafter.
  
  

• Spinal Anesthesia:
  Spinal anesthesia is a technique in which the patient is given an injection in the lower back that blocks the nerves that supply feeling to the lower half of the body. The medication is injected into a sac of fluid in your lower back (the subarachnoid space) which contains the spinal nerves. The medication blocks the nerves in the lower half of the body. The loss of feeling is temporary and should last from 1 to 4 hours depending on the medication given and other factors.
  
  

• Epidural Anesthesia:
  Epidural anesthesia involves inserting a tiny plastic tube into the epidural space. The spinal nerves (which carry the sensations from your body) pass through the epidural space. Medicine is injected through this tiny plastic tube (or epidural catheter) into the epidural space. This medicine blocks the messages of sensation that tell the brain what your body is feeling. The epidural catheter is usually placed in the lower back for procedures below the umbilicus (belly button). The catheter may be placed higher in the back for procedures of the chest or upper abdomen. For example, for knee or hip surgery, the epidural catheter is placed in the lower back. This allows the medicine to anesthetize or block the feelings in the lower half of your body. After surgery, the medicine can be changed to control your pain or discomfort after surgery. This anesthesia is similar to a Spinal Anesthetic. The Spinal Anesthetic is a single shot of medication which may last from 1 to 4 hours. The epidural catheter, however, allows repeated injections of the medication. This may permit many hours of anesthesia. In addition, the epidural catheter may be used after surgery for pain control.
  
  How is the catheter put in the epidural space?
  For epidural anesthesia, the placement of the epidural catheter is done with the patient in either the holding room (the room where patients are prepared for surgery) or in the operating room. Prior to placement of the epidural catheter, an intravenous line will be started and you may be given sedation. At the appropriate time, the anesthesiologist will begin the procedure to insert the epidural catheter. You will be asked to sit up or lie on your side. The anesthesiologist will wash off your lower back with an antiseptic solution and then place a paper drape over the area. After numbing the skin with a local anesthetic, he will insert a needle into the epidural space. The patient may feel a slight burning sensation with the local anesthetic, but should rarely feel more than a pressure sensation with the epidural needle. The catheter is inserted through the needle and the needle is removed. The catheter is then taped to the patient's back. You should be able to lie on back with no discomfort. You should not feel the catheter except for the tape on your back. You may feel a cold sensation down your back as the medicine is injected through the catheter.
  
  

• Regional Anesthesia:
  Regional Anesthesia involves blocking sensations to one part of the body. By injecting local anesthetic (or numbing medicine) around a group of nerves, the anesthesia provider can block the sensation from one part of the body, such as the arm, the hand, or the foot. Most of the time the patient is given sedation before and during the procedure. A regional block can often give the patient several hours of pain relief after surgery. Regional anesthesia can be given alone, with sedation, or in combination with General Anesthesia. Your anesthesia provider may use this technique to provide anesthesia for your surgery or simply to provide pain relief after your surgery. Use of this technique will depend on the type and length of your surgery, your medical history, and your anesthesiologist and surgeon's preference. The following will list some of the most common blocks.
  

  1. Axillary Block:
     This block is used for procedures of the hand, forearm, and elbow. An injection is given in the patient's axilla (armpit) into a space that surrounds a bundle of nerves that supply feeling to the lower arm. This is usually done with the patient awake with sedation, but can be done with the patient under General Anesthesia.
     
     
  2. Interscalene Block:
     This block is used for procedures on the arm and shoulder. An injection is given into a space around a group of nerves on the side of the patient's neck. These nerves supply feeling to the shoulder and arm. This block can be done with the patient sedated prior to surgery or after General Anesthesia.
     
     
  3. Ankle Block:
     This block is done for procedures on the foot. The block is usually done prior to surgery. Three or four injections of local anesthetic are given around the ankle to block the nerves that supply feeling to the foot.
     
     

• Local Anesthesia:
  A local anesthetic (medication which blocks nerves) is injected around the area of the surgical site. This may be called a "field block" The area blocked is a smaller area than with a regional block. This block is usually saved for small, superficial surgeries, such as breast biopsy, removal of skin lesions, and placement of long term implantable intravenous lines. Occasionally, the surgeon will give local anesthesia even after general anesthesia to reduce the discomfort at the surgical site after surgery.
  
  

• Monitored Anesthesia Care:
  Occasionally you may hear the term M.A.C. or Monitored Anesthesia Care. M.A.C. refers to sedation while under the care of the anesthesia provider. This sedation may range from mild sedation to a state of unconsciousness. Throughout this sedation, the patient's heart, blood pressure, and breathing are monitored closely by the Anesthesia provider. Additional oxygen or breathing assistance may be given if necessary. M.A.C. is usually given in addition to Local or regional anesthesia.