Epidural Anesthesia

What is Epidural Anesthesia?

Epidural anesthesia uses continuous infusion of a local anesthetic in the epidural space (a very narrow space just outside the sac containing the spinal fluid) to numb the nerves from the uterus and birth passage. A successful epidural gives an almost pain free awake state throughout labour and birth.

How Is It Done?

It is done by an anesthetist. The patient is usually helped onto her side for the procedure. The skin of the lower back is cleaned with an antiseptic solution and a local anesthetic is injected to numb the area. The epidural needle is then introduced into the epidural space. The procedure must be performed delicately and with as little movement as possible from the patient. If the patient's anatomy is normal and she is cooperative, the procedure itself should only take about 15-20 minutes. Occasionally, it may be difficult to locate the epidural space and it may take more than one attempt.

A thin plastic tube (catheter) is threaded through the epidural needle and the needle is removed. The catheter remains in the epidural space and is used to administer the anesthetic drug till delivery. It is then taped to the patient's back, and removed soon after delivery. The anesthetic drug is injected slowly by means of an infusion pump until a satisfactory level of pain relief is achieved. The dose required for each patient varies and can always be adjusted.

The blood pressure of the mother and the baby's heart beats are carefully and continuously monitored. An intravenous drip is set up to prevent sudden fall in blood pressure.

How Long Does It Take?

Initially, there may be some tingling sensation or warmth in the legs which may gradually become numb and weak. The onset of pain relief starts from 10-20 minutes from the time the anesthetic drug is injected into the epidural catheter.

The pain relief will last until the baby is delivered. During the second stage, the patient may feel the pressure of the baby's head descending through the birth canal. Assisted delivery using forceps or vacuum cup is more common as the mother often loses the sensation to push.

After the delivery, the catheter is removed. The effects of the anesthesia usually wear off completely in one or two hours. After the medicine wears off, the patient may have an uncomfortable burning sensation around the birth canal.

Occasionally, the pain relief may be one sided or patchy (i.e. some areas are numb while other areas are not); the anesthetist may have to adjust the catheter or repeat the procedure.

Advantages of Epidural Anesthesia

It eliminates most of the discomfort of labour and delivery without causing giddiness or sleepiness which the inhalation of laughing gas (nitrous oxide) and pain-killer injection (pethidine) may give.

Most women feel that they are fully involved in the labour process and they are able to bond with their baby without being too exhausted. Even if the mother requires an immediate caesarean section, this can be performed with the epidural anesthesia.

Risks of Epidural Anesthesia

• Fall in Blood pressure. This is often prevented by administering an intravenous drip.
• Other side effects include shivering, itching and pain over the site of injection.
• Spinal Headache. Occasionally, the epidural needle may accidentally puncture a hole in the sac containing the spinal fluid. Patient will experience severe headache 1-3 days after the procedure. By using blood patch performed by the anesthetist, the headache will disappear quickly.
• Because the nerve supply of the bladder is also anesthetized, the patient may not be able to pass urine and urinary catheterization (a tube put into the bladder) may be required. Urinary catheterization increases the risk of urinary infection.

Can Epidural Be Done To Every Woman In Labour?

There are some women who may not be suitable for an epidural due to medical conditions, spine problems or surgery, bleeding disorders and certain complications of pregnancy.