Epidural and Spinal Anesthesia

Epidurals and spinals are two types of regional anesthesia for labor and delivery.

When the uterus contracts, pain impulses travel from the uterus to the brain via nerves in the spine. Epidural anesthesia and spinal anesthesia involve placing local anesthetics within the backbone to block these pain impulses.

  • With epidural anesthesia, the local anesthetic medication is injected outside of the sac containing the spinal fluid and spinal cord. The nerves are blocked in this epidural space.
  • With spinal anesthesia, the needle pierces the sac containing spinal fluid and spinal cord, and the local anesthetic medication is injected into the spinal fluid. The nerves are blocked in the spinal space. The spinal needle is introduced into the spinal space below the level of the spinal cord so that the spinal cord is not injured.

Epidural anesthesia and spinal anesthesia are called regional anesthetics because they anesthetize one specific region of the body. These are popular for childbirth because the pain relief is effective and very little medication reaches the baby.

The medications used in these procedures include local anesthetics (novocaine-like medications) and narcotics. This method allows you to be awake and alert for the birth.

Combined Spinal-Epidural (CSE)

Combined spinal-epidural (CSE) techniques can combine the advantages of each technique. Distinct advantages of CSE are:

  • Rapid onset
  • Profound suppression of pain
  • Minimal loss of ability to move legs
  • Negligible amount of medications going to other systems of the body and the baby
  • High satisfaction rate from the expectant mother

In CSE, the epidural space is located with a thin needle, and another needle is passed through it and into the spinal fluid to inject a small amount of medication into the spinal fluid. This results in instantaneous onset of pain relief.

The spinal needle is removed and an epidural catheter is inserted into the epidural space, followed by the removal of the epidural needle. The epidural catheter is secured over your back.

An epidural pump gradually injects medications into the epidural space. The spinal anesthesia of the CSE usually lasts about 90 minutes. As the effect of spinal anesthesia wears off, epidural anesthesia kicks in, bringing you comfortable pain relief. The epidural medications are adjusted to provide optimum pain relief until you deliver your baby.

Walking Epidurals

The "walking epidural" is a result of the CSE techniques. The spinal part offers rapid-onset pain relief without producing weakness of the legs. The epidural part provides flexibility of continuing the analgesia. The technique can be tailored to enable women to walk around the labor floor without feeling pain.

While it is unclear whether walking in labor reduces its duration, it has been suggested that women who walk may not need as much pain relief. In addition, many women appreciate the opportunity to walk even for short periods during labor. At Brigham and Women's Hospital, women who have CSE can walk up until the epidural anesthesia begins.

How an Epidural is Performed

The anesthesiologist will feel bony landmarks in your lower back and will clean your back with an antiseptic solution prior to placing the epidural. A small amount of local anesthetic will be injected to numb your skin prior to insertion of the hollow epidural needle.

After the needle is advanced to the epidural space, a tiny catheter (plastic tube) is inserted through the needle into the epidural space. Occasionally, some women feel a tingling nerve sensation (parasthesia) of their legs when the catheter brushes against the nerves in the epidural space during its passage. However, this is very transient and passes quickly.

Once the catheter is in place, the needle is removed and the catheter is taped onto your back. Initial medication is injected through the catheter. Some women report feeling a cold sensation in their back while medications are being injected. Thereafter, the medication is delivered via an automated pump until your baby is born.

The epidural can take 15 to 20 minutes to place, and the medication works gradually in the epidural space over next 15 to 20 minutes. Initially, many women notice that their pain during contractions is less intense and lasts for a shorter duration, until eventually all they feel is the tightening of the contraction. You may not feel the contractions at all; it differs for every woman.

Under Watchful Eyes

After epidural placement, you will be under the watchful eyes of your labor and delivery nurse and the anesthesiologist. There will be continuous monitoring of your baby's heart rate. Your vital signs will be recorded frequently. The frequency of uterine contractions is also recorded. Although you are resting, or sleeping while your labor progresses, the monitoring and vigilance continues unimpeded.

The nurse and the anesthesiologist will monitor your blood pressure all through epidural anesthesia. Occasionally, the blood pressure can decrease during epidural anesthesia. The anesthesiologist will correct the decreases expeditiously with IV medications to normalize the blood pressure. The transient decreases in blood pressure should pose no problem for the baby, as the baby also is under constant surveillance via fetal heart rate monitor.

Epidural analgesia minimally lengthens labor and does not increase the risk of cesarean delivery but may lengthen labor. Numerous studies have shown that the difference is approximately one hour on an average. But this may be highly variable depending on your labor pattern.