Epidural Therapy Health Article

Definition

An epidural is a local (regional) anesthetic delivered through a small tube into a vacant space outside the spinal cord, the epidural space.

Purpose

The anesthetic agents that are infused through the small catheter block spinal nerve roots in the epidural space and the sympathetic nerve fibers adjacent to them. Epidural anesthesia can block most of the pain of labor and birth for vaginal and surgical deliveries. Epidural analgesia is also used after cesarean sections to help control post-operative pain.

Precautions

The primary problem associated with receiving epidural anesthesia is low blood pressure, otherwise known as hypotension, because of the blocking of sympathetic fibers in the epidural space. The decreased peripheral resistance that results in the circulatory system causes dilation of peripheral blood vessels. Fluid collects in the peripheral vasculature (vessels), simulating a condition that the body interprets as low fluid volume. A simple measure that prevents most hypotension is the infusion of 500-1000 cc of fluid intravenously into the patient prior to the procedure. Ringer's lactate, as opposed to a solution containing dextrose, is preferable because the elevated maternal glucose that accompanies the rapid infusion of solutions containing dextrose can result in hyperglycemia in the newborn with rebound hypoglycemia.

It is important not to place a woman flat on her back after receiving an epidural because the supine position can bring on hypotension. If a woman's blood pressure does drop, then the proper treatment is to turn her on her side, administer oxygen, increase the flow of intravenous fluids and possibly administer a medication such as ephedrine if the hypotension is severe. Very rarely, convulsions can result from severe reactions. Seizure activity would be treated with short-acting barbiturates or diazepam (Valium).

Description

Epidural anesthesia, because it virtually blocks all pain of labor and birth, is particularly helpful to women with such underlying medical problems as pregnancyinduced hypertension, heart disease, and pulmonary disease. Epidural anesthesia for labor is usually initiated at the woman's request, providing the labor is progressing well, or if the mother feels severe pain during early labor.

Preparation

To prepare for the administration of epidural anesthesia, the woman should have the procedure explained fully and sign consent forms if required. An intravenous line is inserted if not already in place. She is positioned on her side or in a sitting position and connected to a blood pressure monitoring device. The nurse/assistant has the following equipment available: oxygen, epidural insertion equipment, fetal monitor, and additional intravenous fluid.

The health care provider cleans the area with an antiseptic solution, injects a local anesthetic to create a small wheal at the L 3-4 area (between the third and fourth lumbar vertebrae) and inserts a needle into the epidural space. Once it is ascertained that the needle is in the correct place, a polyethylene catheter is threaded through the needle. The needle is removed and a test dose of the anesthetic agent is administered. The catheter is taped in place along the patient's back with the end over her shoulder for easy retrieval when further doses are required.

If the patient responds well to the test dose a complete dose is administered. Pain relief should be to the

level of the umbilicus. The epidural anesthesia lasts approximately 40 minutes to two hours, or longer as required. If necessary, additional doses of anesthetic, or top-up, are injected through the catheter or a continuous infusion on a special pump.

Epidural anesthesia can be given in labor in a "segmented" manner. In this instance, the laboring woman receives a small dose of anesthesia so that the perineal muscles do not fully relax. The baby's head is more apt to undergo internal rotation when the perineal muscles are not lax thus facilitating delivery. At the time of delivery, an additional dose can be administered for perineal relief.

Women who have cesarean deliveries may have additional medication injected into the epidural to control intra-operative pain. Medications used generally are narcotics such as fentanyl or morphine (Duramorph). Side effects include severe itching, nausea, and vomiting. Treatment of these side effects with the appropriate medication

KEY TERMS

Analgesia—A medication that decreases the awareness of pain.

Anesthesia—Loss of sensation through the administration of substances that block the transmission of nerve impulses signaling the feeling of pain and pressure.

Regional anesthesia—Blocking of specific nerve pathways through the injection of an anesthetic agent into a specific area of the body.

can be helpful. Despite these problems, epidural analgesia is an effective method to relieve pain after cesarean delivery, allowing the woman to move well, thereby facilitating rapid recovery.