An epidural is a local (regional) anesthetic delivered through a catheter (small tube) into a vacant space outside the spinal cord called the epidural space.
The drugs commonly used in epidural anesthesia are bupivicaine (Marcaine, Sensorcaine); chloroprocaine (Nesacaine); and lidocaine (Xylocaine). The solutions of anesthetic should be preservative-free.
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 postoperative pain.
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 is preferable to a solution containing dextrose, 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 she has 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 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).
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, provided that the labor is progressing well, or if the mother feels severe pain during early labor.
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 come up 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 by 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 too loose, 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 space to control intra-operative pain. Medications generally used are such narcotics as fentanyl or morphine (Duramorph). Side effects include severe itching, nausea, and vomiting. Treatment of these side effects with the appropriate medication can be helpful. Despite these problems, epidural analgesia is an effective method to relieve pain after cesarean delivery, allowing the woman to move easily and speed recovery.
Local anesthetics are generally safe when administered by the epidural route. There is a low frequency of allergic reaction to the drug. Most often the drug causes a mild skin reaction, but in more severe cases can cause breathing difficulty and an asthma-like reaction. A burning sensation at the site of injection may occur, sometimes with swelling and skin irritation. Other adverse reactions may occur if the epidural anesthetic is not properly administered.
It is important to carefully monitor vital signs after the administration of epidural anesthesia. Hypotension can result in fetal death and can also have grave consequences for the mother. The nurse should monitor the patient constantly and use a continuous blood pressure machine to obtain regular blood pressure readings for 20–30 minutes after each administration of anesthesia. The systolic blood pressure should not fall below 100 mm Hg or be 20 mm Hg less than a baseline systolic blood pressure for a hypertensive patient.
It is important to remind the woman to empty her bladder at least every two hours. With epidural anesthesia, there is loss of sensation of the need to void. Sometimes, an overfull bladder can block the descent of the baby's head. A catheter can be inserted into the bladder to drain the urine. The nurse needs to closely monitor intake and output and assess the bladder for signs of distension.
Side effects and complications are rare, but sometimes the patient will experience a "spinal headache" due to leakage of cerebrospinal fluid (CSF).
When a woman receives epidural anesthesia for labor pains, at times the labor can be prolonged because of excessive relaxation of the muscles. Also, the baby's head may not rotate—especially if it is in the occiput-posterior position (the back of the head is facing toward the woman's back). The woman may not have the sensation that results in the desire to push during contractions when she is fully dilated. These complications may result in an increased incidence of births with the use of vacuum extraction, forceps, or even cesarean deliveries. Administering a Pitocin (oxytocin) drip intravenously can counter this problem. Pitocin is a medication that causes the uterus to contract. Allowing the epidural to wear off in the second stage of labor when the woman is pushing may avoid this problem, but the return of the labor pains may be overwhelming to the woman.
Occasionally, slow absorption of the medication from the epidural space into the circulation can result in toxic reactions evident by decreased level of consciousness, slurred speech, loss of coordination, drowsiness, nervousness, and anxiety. The health-care provider should look out for these signs, and also report any elevation in temperature before a top-up dose is administered.
Epidural anesthesia is a safe and effective method of giving pain relief to women during labor and delivery. It also can be used for cesarean births. It is believed that very little of the anesthetic is absorbed throughout the body (systemically), therefore epidural anesthesia is ideal because it does not pass the medication into the baby's circulation.
Pillitteri, Adele. Maternal & Child Health Nursing, 3rd edition. Philadelphia: Lippincott, 1999.
American Association of Nurse Anesthetists (AANA). 222 S. Prospect Avenue, Park Ridge, IL 60068. (847) 692-7050. http://www.aana.com .
Anesthesia Options for Labor and Delivery: What Every Expectant Mother Should Know. AANA, 2001. http://www.aana.com/patients/options.asp .
Nadine M. Jacobson, RN Samuel D. Uretsky, PharmD