Labor Epidural: Epidural Anesthesia for Labor Pain
If you are pregnant and approaching your due date, you may have been asked whether or not you plan to have an epidural for labor and delivery. This may lead you to search the internet for information on epidurals. There is so much information and misinformation out there that you may be more confused about it than when you started your search. This article is meant to help you start with the basics by answering the question "What exactly is an epidural and how does it work?"
I will not address the controversies surrounding labor epidurals here- that's another hub (or five) for another day. This is just an introduction to the procedure and theory of epidural analgesia for labor.
Also, there is a lot of variability in the technique placement of epidurals. This is one of the basic techniques that many anesthesiologists use.
My disclaimer: I am a board-certified anesthesiologist. I do not, however, believe epidurals are the right answer for every woman who is in labor (although they were for me- I've had two, myself). This hub is for informational purposes and is not necessarily an endorsement of epidurals for labor. It is intended to provide information for those who are curious about how an epidural is placed and how it works.
What is an Epidural?
Epidural anesthesia should really be referred to as "epidural analgesia" when used in laboring patients. This means that it is used for pain relief (analgesia), rather than to completely deaden or numb all sensations (anesthesia). If needed, however, the epidural may be used as full surgical anesthesia during cesarean sections by using more potent medications in it.
WHAT IS THE EPIDURAL SPACE AND WHERE DOES EPIDURAL MEDICINE GO?
The spinal cord originates at the base of the brain and extends down to the lower back. At a point near the top of the hips, the spinal cord splits into long fibers, called the cauda equina. All along the length of the spinal cord, nerves leave the spinal cord and exit the spinal column through openings in the vertebrae.
Surrounding the spinal cord is cerebrospinal fluid (CSF), which is contained within a membrane called the dura. Outside the dura is a space -- the epidural space. This space is a few millimeters thick and occupied by blood vessels, connective tissue, nerve roots and fat. Outside of this space are the bones, ligaments, muscles, fat and skin.
So, when the anesthesiologist places your epidural he or she is using this knowledge of anatomy, the feel of each of these layers and a special technique to find that epidural space.
When the epidural space is located, medicine can be placed into it, to numb the nerves as they exit the subdural (below the spinal covering) space and enter the epidural space (outside the spinal covering). Usually, a thin catheter (flexible tube) is placed into the epidural space so that medicine can be continuously infused or added when needed for the duration of labor.
Ever wonder "What is the Difference between a spinal and an epidural?" This animation explains it.
Anesthesia Consent for Epidural (sample only - actual discussion may include more or less information)
"Epidurals are placed in a space outside of the spinal canal to numb the nerves and relieve some of your pain. There are, of course, risks to the epidural, but most risks are not serious. The biggest risk of an epidural is that it won't be able to be placed for some unforeseen reason, or that it will be placed but will not work as well as we'd like. Epidurals can fail for various reasons, some of which don't seem to be preventable. In addition to the risk of failure of the epidural to work at all is the risk that it will only work partially. It may numb one side of your abdomen and not the other, or may leave one area or patch of the abdomen without numbness. Also epidurals are rarely associated with spinal headaches. This happens when the needle pierces the covering over the spinal fluid and fluid leaks out, causing a headache. Other risks which may occur include bleeding or infection that could cause permanent damage to the spinal cord or nerves and result in paralysis (this is exceedingly rare, however). Rarely, women report back pain or leg numbness that occur after labor with an epidural. It is hard to say if this happens because of the labor itself, the epidural or both. But, it is a risk. Other risks that are even more rare are seizures or cardiac arrest related to the medicine in the epidural. As far as risk to the baby, there is a lot of controversy. It seems possible that epidurals can slow labor for a while. It is not conclusively determined whether or not this leads to a higher likelihood of c-section. Also, your blood pressure may drop. This is occasionally associated with a drop in the baby's heart rate. If this doesn't correct itself, you may be sent for an emergency c-section. Do you understand these risks? Do you have any questions that I didn't already answer?"
NOTE: This sample is not and should not be taken as a required discussion of all issues during consent. In fact, some of these risks are so rare that they do not need to be brought up. This is an EXAMPLE only. In fact, my actual talk gives more info about many of these issues (example- spinal headache and potential treatments, etc).
How is an Epidural Done?
- The anesthesiologist will discuss the potential benefits and risks of the epidural with you. They cannot possibly discuss every detail of every study ever done. Ask any questions about anything that he or she did not explain satisfactorily in their discussion.
- You will be asked to sit or lay on your side curled up in the fetal position. I do most of my epidurals with the patient sitting. The most important thing is that you curl like the anesthesiologist asks you to. This opens up the space between the bones in the back and really facilitates placement of the epidural. Remember, the anesthesia doc is trying to find a space that is only a few millimeters wide. Positioning really helps this process.
- The doc (or nurse anesthetist) will feel your back and probably the position of the top of your hips. This tickles, actually and they won't fault you if you squirm a little at this point. Sometimes, they use a fingernail to mark the space they want to prep.
- Next, a drape or towel may be placed under your bottom before your back is cleaned off with sterilizing soap. This may feel cold and scratchy. Do not reach behind you at this point as your back is now part of the 'sterile field'.
- Numbing medicine will be injected with a small, fine needle to numb the skin and tissues right under the skin.
- The epidural needle will be placed into the skin and advanced to between two vertebrae (backbones that you feel). Because your skin is numb, this may feel like someone pushing on your back with their finger. The epidural needle is a hollow needle, often referred to as a "tuohy needle". It is slowly advanced until the anesthesiologist feels it enter the thick ligament over the epidural space. Then a syringe full of saline is placed onto the end of the needle. At this point you will be reminded to hold very still. The needle is now advanced VERY slowly and carefully as a little pressure is pushed on the end of the syringe attached to the needle. While in the ligament, the anesthesiologist feels resistance when pushing on the plunger of the syringe. When the needle enters the epidural space, loss of resistance is encountered and the saline can easily be injected into the epidural space. Now the syringe is removed from the needle.
This photo shows the thin, flexible epidural catheter in place. The needle has been removed.
- Because the needle is hollow, a thin catheter can be threaded through the needle. The catheter is advanced while the needle is withdrawn. The catheter is left in the epidural space so medicine can be put in, and the needle is completely removed.
- Test medication and then numbing medicine will be placed into the epidural space through the catheter while your vitals signs, and your baby's heart rate and pattern, are watched carefully. You will be asked about any side effects at this point.
- The catheter is taped in place to prevent it from becoming dislodged. A connector hub is attached to the end. Then a filter is placed inline. This can now be connected to a pump that infuses medication through the catheter into the epidural space.
What Happens after the Epidural is in?
After the epidural is placed, you, most likely, will not be allowed to walk or get up out of bed by yourself. A few years ago, the "walking epidural" was very popular. The epidural (or a combined spinal/epidural) was put in. Low potency medicine was used so that the laboring woman would still be able to walk around. The pain relief wasn't always satisfactory and these seem to have fallen out of favor a bit.
At some point, you will likely have a catheter placed into your bladder to empty your urine. Once you get numb, you may not be able to tell when your bladder is full and will not be able to control emptying it reliably.
You will be asked to change position from time to time. You cannot lay flat on your back and should alternate laying on each side. This helps the medicine spread evenly.
If your legs get so numb that you cannot move them, you should let your nurse know. The infusion of medicine may be too strong for you and the rate can be turned down. If your epidural is too dense, you will not be able to push effectively when the time comes.
Likewise, if you are not comfortable enough to rest, you may need to have the rate turned up or a "top off" given. The ideal is for you to have enough pain relief to rest, but still be able to tell when you have a contraction and be able to move your own legs. You should have enough strength to push when it's time to have your baby.
Are You Curious?
The CDC compiled data regarding epidural use from 27 reporting states. This article is quite interesting. It provides information about the demographics of epidural use. For example, epidural use varies according to geographic location, age, race and other traits of the mother.
In 2008, 27 states reported data to the CDC regarding rates of epidural use during labor. Can you guess (without peeking at the map)....
view quiz statistics
Four of the reporting 27 states had an epidural rate of less than 50%
New Mexico had an epidural rate of 21.9%
Californians used epidurals in 42.5% of their deliveries.
46.6% in New Hampshire
In Vermont, the rate was 47.3%