Other Considerations When Choosing Epidural Anesthesia

 


Your Participation with an Epidural

Some women choosing epidural anesthesia look forward to turning over the reins of comfort and control to their care providers. However, others may feel hesitant and worry that choosing an epidural will mean that they are purely in the bystander role. Rest assured that choosing an epidural for pain relief is not an all or nothing proposition. You can still actively participate, advocate for yourself, and feel confident that you are birthing your baby.

 

It is important to reflect on your birth value system and decide which type of experience you most desire to give you "birth satisfaction". Women who express the greatest satisfaction are not those who received the least medication or the fewest medical interventions. Rather the essential ingredients for a sense of satisfaction and fulfillment seem to be: your willingness to educate and prepare yourself for birth, care providers who treat mothers patiently, respectfully and kindly; feeling that you are the central figure when "calling the shots" with the help of your care providers, safety and security in your surroundings, and birth attendants who love you and whom you love. All of these ingredients are available to you with or without an epidural.

 

Interested in learning more about labor pain and satisfaction with childbirth?  Two invaluable resources are:

 

Pregnancy, Childbirth, and the Newborn:  The Complete Guide.  Penny Simkin, P.T., Janet Whalley, R.N., B.S.N., and Ann Keppler, R.N., M.N.  2001

 

Ellen Hodnett's upcoming systematic review to be published in mid-May, 2002 in the American Journal of Obstetrics and Gynecology.  Please find it at:

 

Hodnett ED.  Pain and Women's Satisfaction With the Experience of Childbirth:  A Systematic review.  AM J Obstet Gynecol  2002;  186,5:S160-72.

 

 


 

 

Care Provider Philosophy and Epidurals

In a recent study, researchers compared cesarean rates for 200 healthy first-time mothers managed by the resident staff and 400 similar women at the same hospital who had private physicians. 42% of each group had an epidural, but the cesarean rate for lack of progress on the clinic service, which had a long-standing commitment to minimize the number of cesareans, was 1% versus 20% on the private services. The difference in c-section rates in this study was likely attributable to the difference in care provider philosophy. (8)

 

Hospitals, care providers and even nurses have their own, different rates for cesarean sections and other interventions. The care providers who have lower rates of intervention tend to have the following in common: no arbitrary time limits on laboring or pushing, a commitment to using as few interventions as possible, able and willing to give information on alternatives to traditional OB practices ( for example, using maternal positioning vs. pitocin for a slow labor), have very low rates of inducing labor (under 20%), and ask for the woman's partnership and input in managing her pregnancy and labor.

 

If your goal during labor is to use epidural anesthesia with a minimum of side effects, talk to your care provider about your concerns and listen to their answers carefully. Are they enthusiastic and supportive of your choices? Have they supported other patients with similar goals? How successfully were those patients' goals met?

 

All things being equal, the style in which your care provider will manage your labor will greatly determine your birth outcome. Choose wisely.

 

 

Epidurals and increased likelihood of cesarean sections:

One possibility for an increase in cesareans following an epidural, especially in women who choose to have epidurals early in labor (before 5 centimeters), is an increased chance that the descent of the baby's head will be arrested by baby's awkward positioning in the pelvis. When a mother has no anesthesia and has normal muscle tone in her pelvis, she is able to walk and vary positions, allowing the baby to twist and turn and find the way of least resistance down through the pelvis. When an epidural takes effect, her pelvic musculature may relax dramatically and her movement may be restricted. If baby is posterior and the head is not flexed or is awkwardly turned even slightly, the reduced tone and movement in the pelvis may not encourage the baby's head to correct its position. In turn, the contractions will just bang baby's head against the pelvis and arrest progress, causing "failure to progress".

 

Or, the slide towards a cesearn section may look like this: The epidural slows down labor; pitocin is given to get contractions going again; the pitocin-induced contractions are harder and longer and produce fetal-distress patterns on the electronic fetal monitor; and the obstetrician decides on surgery. (9)

 

Posterior Presentations and Epidurals

Think carefully before asking for epidural anesthesia relief for back labor. Being confined in a horizontal position without the freedom to move lessens the chances that baby will move into a better position and increases the likelihood of a forceps or cesarean delivery.(10)  It's important to exhaust all other coping techniques in an attempt to get baby to rotate to an anterior position before using an epidural as a means of comfort.

 

A better choice for back labor is sterile water papule injections. Sterile water is injected under the skin in 4 areas located near your sacrum. The injections will numb the intensity of the back labor without disrupting or slowing your labor. It's thought the pain is blocked by the interruption of the dermatomal pathway by creating a small amount of pain from the injection over the same pathways. Relief lasts up to 90 minutes and you may repeat the procedure or use it in conjunction with a very light dose epidural or CSE.

 

Eating and Drinking to Hunger and Thirst with Epidurals

Recently, NPO (nothing by mouth) policies have been challenged by mothers, midwives, obstetricians and even some obstetric anesthesiologists. They argue that prolonged fasting has never been proven to influence aspiration (during cesarean sections using general anesthesia) and that since most maternal anesthetic deaths are now the result of difficult or failed intubation in the hands of inexperienced anesthesiologists, it is illogical to continue to make women fast during labor. Moreover, the metabolic consequences of fasting might even be detrimental to the progress and outcome of labor.

Discuss eating and drinking during labor with your care provider. The narcotic used in CSE epidurals may hamper digestion. Drinking in addition to receiving IV fluids can cause over-hydration (which may lead to a slow-down of labor and respiratory problems for mother and baby). Find out how you can stay appropriately nourished and hydrated during your labor for maximum performance.

 

 

Pitocin and Epidurals

Nearly all women who choose epidural anesthesia will have their labors augmented with Pitocin. Epidural anesthesia tends to dampen the strength of contractions. In the first stage, this can mean slowing or stopping cervical dilation (failure to progress). In the second stage, the less efficient uterine contractions may keep baby from rotating naturally, and the diminished urge to push may keep baby from coming down. To help combat these effects, you may be given Pitocin. However, Pitocin carries its own risks.

 

Your body will produce its own oxytocin on an as-needed basis. With Pitocin augmentation, you'll receive an IV drip through an automatic infusion pump at a steady rate. Because the way the uterus receives its hormonal boost is unnatural, the contractions Pitocin produces are different from the ones the body would produce on its own. Pitocin produced contractions are stronger, longer, and closer together. This different type of contraction can be intolerable for the mother and unsafe for the baby.

 

Consider the effects on the baby. With normal contractions, the uterine muscle briefly constricts the blood vessels carrying oxygenated blood to the placenta, but the blood-rich reservoirs within the placenta continue to deliver oxygen to the baby during these periods of decreased uterine blood flow. With pitocin-produced contractions, however, the increased force of the contraction may decrease uterine blood flow even more, and the time between contractions may be too short to allow the reservoirs in the placenta to refill with blood. Pitocin-produced contractions may, therefore, result in lower delivery of oxygen to the baby. Infact, fetal distress, as detected by electronic fetal monitoring, is more common during pitocin-infusion.(11)

 

Pitocin is also unkind to the mother. Pitocin contractions are more painful, so an epidural is usually requested much earlier in labor.

 

Endorphins and Epidurals

Some mothers who have experienced both unmedicated and medicated childbirths feel that epidurals take away not only the pain of birth but also the pleasure. In unmedicated labors, mothers get natural relief from their own endorphins. And, as contractions become more intense and closer together your body will produce more endorphins. Mothers having epidural anesthesia have been shown to have lower endorphin levels. Once you've blocked the pain of labor with epidural anesthesia, your body doesn't need to make its own endorphins. On the positive side, epidural anesthesia can also lower levels of circulating catecholamines. Too high levels of these hormones can produce dysfunctional uterine contractions and decreased blood flow to the placenta in mothers who are experiencing sever pain. When the catecholamine levels drop after the epidural anesthesia, the uterine contractions may become regular.(12)

 

Your endorphins help your baby, too. At the time of birth in unnmedicated women, endorphins are found 30 times higher than in non-pregnant women, and levels can be 20 times higher in women with prolonged or difficult labors as in uncomplicated labors.(13)  Your endorphins readily reach your baby, helping baby weather the stresses of labor and birth and preparing him for life outside of the womb. Higher levels of endorphins and adrenaline in babies whose mothers didn't receive epidurals may be part of the reason why these babies are generally more alert at birth.

 

Emotionally, mothers having epidural anesthesia report very different birth experiences from mothers who had a unmedicated birth. Mothers choosing epidurals often observe the workings of their bodies much like a bystander. In a unmedicated birth, the mother tends to experience the lowest lows at the most difficult point of labor, and the highest highs as she births her baby. Some mothers with epidurals have reported feeling "muted" emotions or even feeling the birth to be anticlimactic.

 

Different Types of Epidurals: Traditional, CSE, and Intrathecal

**Please see the supplemental information on the pharmacology and other related information on epidurals at the bottom of the page.**

 

Traditional, All-Anesthetic Epidural 

The practice of of using only anesthetic is currently out of fashion and it's unlikely that you'll an all-anesthetic epidural.  Epidural catheter may be left in place for continuous or patient controlled pain relief.  Provides the best pain relief over a long period of time. Biggest disadvantages are the numbness in lower extremities and muscle weakness of all muscles below the epidural site, as well as a potential for dangerous drops in blood pressure. 

 

Intrathecal

This is considered spinal anesthesia, and not an epidural. This technique involves placing a small dose of narcotic in the intrathecal space (the fluid-filled space surrounding the spinal cord). Provides almost immediate pain relief and the patient is able to move, and push without any muscle weakness. The risk of hypotension is significantly reduced in comparison to epidurals. However, intrathecal anesthesia provides a lower level of pain control when compared to an all-anesthetic epidural and must be re-administered once it wears off.

 

Combined Spinal Epidural

This is a technique that combines the first two techniques from above. The anesthesiologist will use both an anesthetic in the epidural space to provide long-lasting pain control, as well as a narcotic in the intrathecal space. The addition of the narcotic allows the anesthesiologist to use very little anesthetic and still provide good pain relief. And, by using the narcotic in the intrathecal space, women experience much less muscle weakness and numbness as opposed to an all-anesthetic epidural. Also referred to as a "walking epidural".

 


The following information was gratefully received from Janis Chissikos, RN, FNE, SANE, CBE, and CD.  

 

"Traditional epidurals actually have both anethetic and narcotic analgesic.

 

When combined, lower concentrations of each can be used, shivering is reduced and hypotension is reduced compared to just using an anesthetic.  Epinephrine is also often given to increase the anlgesia but not the duration (It causes the drugs to stay in the eidural space longer so more is absorbed epidurally before entering the bloodstream). 

 

Fentanyl (opiod narcotic) and bupivicaine (anesthetic) are the most common infusion. Morphine can also be given, though. Bupivicaine (generic name) is pcurrently preferred in labor as it has less fetal transfer of all local anesthetics. Systemic absorption leads to fetal depression and maternal hypotension. It also does not transfer well into breastmilk. 

 

Using just bupivicaine (also called Marcaine) requires a higher doage, increases problems with low blood pressure and shivering, causes higher oxygen consumption by mom (shivering increases oxygen consumption 100%. Adding a narcotic decreases bupivicaine dose 10 fold. ) There is a new anesthetic called ropivacaine which has less of a hypotensive effect. 

 

Sufentanil is a preferable narcotic choice due to a more rapid onset, more potent analgesia, less transfer of narcotic to fetus compared to fentanyl, less build up than fentanyl.

 

I attended a conference by Dr. Thomas Hale (associate professor of pediatrics, associate professor of pharmacology, division of clinicalpharmacology, Texas Tech School of Medicine, author of Medications and Mother's Milk now in its 9th edition)for continuing education credits last year. One of the classes I took was called Labor Analgesia and Anesthesia in Breastfeeding Mothers. Here is a little more information from this class.  

 

Ropivacaine is a new local anesthetic that will probably be replacing bupivacaine(Marcaine) in the near future. Ropivacaine is a derivative of bupivacaine but it lacks the cardiotoxic effects of bupivacaine. If an anesthiologist inadvertently injects bupivacaine directly into a vein, severehypotension and cardiotoxicity can occur. The side effect profile of ropivacaine appears similar to bupivacaine and includes hypotenision, nausea, vomiting, bradycardia, and paresthesias,but the new drug is far less cardiotoxic. Ropivacaine is cleared by the FDA for local or regional block for surgery, obstetrical procedures and postoperative pain management. 

 

Ropivacaine is apparently similar to, but less potent than bupivacaine with a slightly slower onset, less intense and shorter duration than produced by equivalent doses of bupivacaine. Interestingly, the addition of epinephrine to the epidural injection does not apparently increase the degree of block, nor the length of block. This is contrary to the anesthetics curretnly in use.Ropivacaine is approximately twice as expensive as bupivacaine. You should watch for Ropivacaine (Naropin-Astra)to emerge in the field of obstetric anesthesia.  

 

Epidural indwelling cannulas are often used today to facilitate repeat dosing for increasing pain control. The common fentanyl/bupivicaine combination can be reinfused later.

 

The CSE is called a needle-through-needle technique. The epidural needle is placed first. Then the spinal needle is place in the intrathecal (subarachnoid) space. Opiod analgesic is injected, usually morphine or fentanyl. Pain control lasts 4-8 hours in early labor and avoids local anesthetic problems. The spinal needle is removed after the injection of mediation and a epidural soft catheter is placed. In late labor, local anesthetic and maybe a little opiod is added for better pain control. This techniques is not available everywhere so make sure to check with the anesthesia service used at your delivery site.

 

Morphine and fentanyl depress respiratory effort. the higher the morphine or fentanyl, the lower the respiratory rate. This means there is a maximum dose that can be given even if it does not provide adequate pain relief.

 

When giving local anesthetics epidurally, a small test dose is given first in case the puncture went to far and an intrathecal (spinal) was accidentally given. This is determined by watching the blood pressure.  An intrathecal placement will cause a more dramatic drop in blood pressure and giving the full amount would be dangerous.

 

Types of anesthetics used include: 

 

Adult half life Pediatric half life Duration of Analgesia Onset 

Lidocaine 1.8 hours 3 hours 60 minutes fast to intermediate

Bupivicaine 2.7 hours 8.1 hours 120-240 minutes slow, about 45 min for good anesthesia 

Mepivacaine 1.9 hours 9 hours 60-90 minutes intermediate

Prilocaine 1.6 hours 30-90 minutes fast

 

 

Adult and pediatric kinetics of opiod analgesics:

 

Drug Adult half life Pediatric half life Peak effect epidural duration of epidural analgesia:

morphine 1.5-2 hours 13.9 hours 60 minutes 4-24 hours

meperidine 3.2 hours 6-32 hours 30 minutes 4-6 hours

(demerol) average 10

Normeperidine 14-21 hours 20-63 hours 

(active metabolite of demerol - see below)

Fentanyl 2-4 hours 3-13 hours 20 minutes 1-3 hours

Sufentanil 2-3 hours 13-19 hours 20-30 minutes 2-6 hours

Alfentanil 1-2 hours 5-6 hours 15 minutes 1-2 hours

Nalbuphine 2.3 hours 0.9 hours

 

Demerol is banned in Europe (where it is called pethidine) from obstetric use. It has mainly a sedative effect with very little analgesia when used during labor. Due to its slow elimination, it has long lasting behavioral and neurological effects in the newborn. As a result, breastfeeding is delayed and mother-infant interaction is disturbed. Many drugs are broken down by the liver into inactive metabolites which are later excreted. However, normeperdine (the metabolite of demerol) is 94-95% as active as the original dose of demerol and has a half-life that is measured in days. It takes a baby 7-10 days to remove sufficient quantities although its effects have been shown to persist for several weeks. 

 

Systemic (IV), epidural and intrathecal (spinal) opiod doses

Opiate Systemic (IV) Intrathecal Epidural

Morphine 0.03-0.15mg/kg 0.5-1mg 7.5-10mg

Meperidine 0.2-0.5 mg/kg 10-20 mg 50-100mg

(demerol)

Fentanyl 0.5-1.5 microgram/kg 5-25 microgram 50-200 microgram

(90-100 microgram IV typical) (136 microgram average)

Sufentanil 0.25-30 microgram/kg 3-10 microgram 10-50 microgram

Alfentanil 8-100 microgram/kg 15 microgram/kg

 

A higher epidural dose is needed compared too the IV dose. The majority of the drug is absorbed by the blood vessels in the epidural space and as such, acts systemically as though the mother was given an IV.  Fentanyl can be found in the mother's blood stream about 1 minute after the epidural is administered. This is how it crosses over the placenta into the baby. 

 

Most narcotic opiods will bind to lipids (fat) so are sequestered in the brain. This means the are not detected in the cord blood so women are often told this means they did not cross the placenta. All it actually means is that the narcotic is not in the cord blood at that time since it was already passed over to the baby and stored in its brain. Since babies have much less body fat than he mom, a greater proportion of the narcotic will be sequestered in its brain. In fact, the fentanyl amount is 5 times greater in the newborn's brain than in the mother's.

 

Another interesting quality of fentanyl is its increasing half life related to the duration of infusion. The half-life is the tine it takes to achieve a 50% drop in drug levels in he blood. In almost all drugs, the half-life is a fixed constant and does not change, regardless of dose administered or length of infusion. Fentanyl is different. At about 1 1/2 hours, its half-life starts to sky rocket, ranging from 5 1/4 hours to almost sixteen hours as the infusion continues.

 

Problems of the newborn associated with epidurals include poor sucking, poor latch, sedation, unresponsive for long periods, less alert, poorer muscle tone, poorer orienting behaviors, more tremors and startles at 6 weeks, poorer behavioral outcomes and recovery for first 30 days of life, lower performance on Newborn Behavior Assessment Scale."

 

 

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