Subarachnoid Anesthesia - Spinal Anesthesia

Spinal anesthesia is a way to eliminate pain during certain procedures or surgeries.

Who is a candidate for the procedure?

This procedure is commonly called "a spinal." It is usually used for procedures below the rib cage. It is an alternative to general anesthesia. In some cases a spinal is better for a major operation if the person is very weak or sick.

How is the procedure performed?

This procedure involves injecting medications around the spinal cord. A needle or special tube is inserted through the skin of the back until it enters the spinal column, or spine. Medication is then injected inside a special sac that surrounds the spinal cord. The medication acts on nerves that come from the spinal cord.

Spinal anesthesia is different from but similar to epidural anesthesia, also known as an epidural. With an epidural, medication is also put inside the spinal column. However, with an epidural the medication is injected just outside the sac that surrounds the spinal cord. A spinal requires less medicine and works faster than an epidural. However, a spinal is more likely to cause a headache or low blood pressure.

Medication for a spinal is usually given as a one-time injection with a special needle. Another method is to put a special tube into the sac around the spinal cord. This tube stays in place. If the surgery lasts a long time or pain medication is needed after surgery, more medication can be given through the tube.

The medicine stops the sensation of pain and paralyzes the muscles, usually only below the rib cage. The amount of medication given and the location of the injection in the back are important. These factors can control where the numbness and paralysis are in the body. People are generally awake during the procedure. Sedatives can be given if people are anxious. During a spinal, people usually breathe on their own without needing an artificial breathing machine, or ventilator.

Careful monitoring is done during the procedure. Oxygen levels in the blood, blood pressure, pulse, and other functions are monitored. Fluids are usually given through an intravenous or IV. An IV is a thin tube that is inserted into a vein in the hand or arm. The fluid is given to prevent dehydration and low blood pressure. If a tube was inserted into the spinal column, it is taken out after the procedure.

What happens right after the procedure?

A person is taken to an area called the surgery recovery room after the procedure. If sedatives were used, people may feel groggy for a few hours. Pain medication can be given if needed. The pain medication can be given through an IV or through the special tube in the spinal column if one was used.

The numbness and paralysis usually go away within a few hours. People are usually asked to lie flat on their back for an hour or more after the procedure. This may help prevent problems with the injection site, and decrease the chance of headache. A short hospital stay may be needed to recover from major operations. If not, a person may be able to go home later the same day in some cases. If sedatives were used, someone must drive the person home. After a spinal, a person must usually be able to urinate before they are allowed to go home. This lets the healthcare provider know that the medication has worn off.

What happens later at home?

A bandage is usually placed over the area on the back where the needle or tube was inserted. This should be left on for at least 24 hours. The area should not be disturbed. Little else needs to be done at home related to the spinal. Further home care may be needed for the surgery performed.

What are the potential complications after the procedure?

The most feared complication of anesthesia is death. This is thought to occur in roughly 1 out of every 10,000 people who have spinal anesthesia. It is not usually possible to predict who will have this type of severe reaction.

The most common problem after a spinal is a headache. This usually goes away within 24 hours. The headache often responds to pain medicine. Some people may need a repeat injection in the back to help the pain. Nausea is also fairly common for a few hours after the procedure.

Blood pressure can get very low during the procedure, but this usually doesn't cause problems. Allergic reactions and irregular heartbeats are rare complications of spinal anesthesia. Though often feared, nerve or spinal cord damage almost never occurs. Bleeding and infection can occur at the site of the needle injection. Other side effects may occur depending on the specific medicines used.

Author:Adam Brochert, MD
Date Written:
Editor:Evans, Gwen, BA
Edit Date:04/29/00
Reviewer:Eileen McLaughlin, RN, BSN
Date Reviewed:05/01/01

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