Epidural Frequently Asked Questions

Epdiural Basic Questions

  1. How does an epidural work?
  2. What are epidurals used for?
  3. Are there medical conditions that prevent epidural use?
  4. What are the side effects of epidural use?
  5. What complications are possible with epidural use?

Epidural Placement Questions

  1. How are epidural placed?
  2. Where do you place an epidural?
  3. Does epidural placement hurt?
  4. How long does it take to place an epidural?
  5. How am I positioned during epidural placement?
  6. How long can epidurals stay in?
  7. How are epidurals secured?

Epidural Drugs

  1. What drugs are used in epidurals?
  2. How long do epidural drugs last?

How does an epidural work?

A: The term epidural generally refers to a medical procedure used to provide pain relief and nerve block through placement of local anesthestics and/or pain medicines in the epidural space of the spine. These drugs, once placed in the epidural space, act on spinal nerves, the spinal cord and the central nervous system to provide pain control and nerve block.

The two main types of drugs are commonly used in epidurals:

  1. Local anesthetics - block nerve information transmission causing “numbnes” (sensory nerve block) and muscle weakness (motor nerve block).  Examples; lidocaine, bupivicaine, ropivicaine, and others.
  2. Opioids - act in the spinal cord and central nervous system to alter pain information transmission and awareness.  Examples; morphine, dilaudid, fentanyl, and others.

What are epidurals used for?

A: Common Epidurals Uses:

  1. Surgical anesthesia – concentrated local anesthetics provide dense numbness to allow for surgical procedures, generally procedures below the diaphram. Often used with sedation to allow patients to “sleep” lightly during the procedure. Common examples: cesarean section, knee replacement.
  2. Postoperative pain control – dilute local anesthetics plus opioids delivered through a continuous epidural catheter to provide pain control in a specific region of the body after surgery. Dilute local anesthestic attempt to block pain nerves more than motor nerves thus preserving muscle strength allowing many patients to walk while getting epidural therapy. Common examples: postop pain control for; lung surgery, abdominal surgery, pelvic surgery.
  3. Pain control during Childbirth “Labor Epidurals” – dilute local anesthetics plus opioids delivered continuously through an epidural catheter to provide “numbness” and pain control causes by labor and delivery.
  4. Epidural steriod injections – steriods injected into the epidural space to backpain.

Are there medical conditions that prevent epidurals use?

A: The following are generally considered contraindications to epidural placement. Rarely, patients with contraindications to epidural may still be candidates for epidural use and in such cases, careful consideration of the risks, benefits and alternatives should be discussed with your anesthesia professional.

Contraindications to epidural placement:

  • Patient refusal
  • Life threatening allergies to planned epidural medicines (anaphylaxis)
  • Severe, untreated systemic infection (sepsis)
  • Severe, untreated hypovolemia (shock, severe blood loss)
  • Increased intracranial pressure (mass effect from intracranial bleed, other)
  • Severe coagulopathy (bleeding disorder) or platelet disorder
  • Significant cutaneous infection at the epidural entry site
  • Neurological disorders (multiple sclerosis, others – controversial)

What are the side effects of epidural use?

A: Common side effects of epidural use are typically secondary to the specific epidural medicines used. Side effects can be grouped into two categories based on the two common classes of epidural medicines; 1) Local anesthetics and 2) Opioids. Side effects tend to be dose dependent and therefore much more prevalent when higher concentrations of epidural drugs are used.

Local Anesthetics – block nerve signal transmission by interference with sodium channels, side effects are related local (intended) and distant (unintended) nerve dysfunction.
Common Side Effects

  • “Numbness” “tingling” “pins and needles”
  • Muscle weakness
  • Hypotension (low blood pressure)
  • Urinary retention

Rare Side Effects

  • Allergic reaction
  • Local anesthetic toxicity
    • ringing in ears
    • oral / lip numbness
    • restlessness
    • seizures
    • coma, death (very rare)

Opioids – control pain by altering pain signal transmission and processing by stimulating a variety of opioid receptors mainly in the spinal cord and brain. Side effects are related to additional responses cased by opioid receptor activation in non-target organs.
Common Side Effects

  • Sedation
  • Itch
  • Nausea / vomiting
  • Urinary retention / constipation
  • Hypotension (low blood pressure)
  • Respiratory depression

Rare Side Effects

  • Allergic reaction
  • Severe respiratory depression, obtundation, death (very rare)

What complications are possible with epidural use?

How are epidurals placed?

A: The epidural space is typically accessed by use of a specially designed epidural needle. The epidural needle is passed through the skin of the back at the level of desired insertion.

Prior to placing an epidural needle, the skin is usually anesthetized with local anesthestic to allow for relatively pain free epidural needle insertion. If a continuous epidural technique is planned, a small epidural catheter (tube) is passed through the epidural needle, the needle removed and the catheter secured to the skin.

To locate the epidural space when passing an epidural needle, one of several “feel” techniques are typically used. Most techniques rely on a “loss of resistence” (”LOR”) that is encountered when entering the epidural space.

The epidural space is located just deep to a very dense, tough membrane (ligamentum flavum), that offers resistence to needle passage and injection. After passing through this membrane, resistence abruptly drops, when you pass into the fat-filled, destendable epidural space. Common LOR techniques use specialized, sensitive syringes to help the proceduralist sense this loss of resistence and epidural space.

Occassionally, epdiural procedures, especially epidural steriod injections, are performed under fluroscopic guidance.

Where are Epidurals Placed?

A: Most epidurals are placed in the epidural space of the lumbar spine or thoracic spine. Epidural anesthetics generally provide “segmental” anesthesia, creating a band of numbness around the body in a targeted region.

Most epidurals are placed in the back (low lumbar spine) providing segmental anesthesia from around the belly button to the knees. Epidurals placed higher in the back provide a higher segmental block, for example, an epidural placed between the mid-thoracic region (bottom of the scapula) provides segmental block from about the mid-chest to the belly button. This segmental quality is more characteristic of epidural local anesthestics compared with epidural opioids which tend to migrate throughout the spinal cord (depending on the specific opioid).

Does Epidural Placement Hurt?

A: Epidurals are typically placed using local anesthetics to anesthetize (numb) the skin and track of epidural needle passage. A very small needle (often 25g.) is used to infiltrate this local anesthestic (typically lidocaine) and is compariable to getting a “shot”. Patients not having an epidural for labor and delivery during pregnancy are typically sedated prior to epidural placement. Women receiving epidurals for labor are generally not sedated as the sedatives can reach the baby.

How Long Does it Take to Place an Epidural?

A: The entire procedure typically takes 10 – 20 minutes. Most of this time is set-up and prep time. Once everything is ready, passage of the epidural needle and catheter typically takes less than 30 seconds.

How am I Positioned During Epidural Placement?

A: Patients are generally sitting or lying on their side for epidural placement. In addition, patients are typically asked to “curve their back” (often called the “mad cat” position) to help open the spaces between the spine and facilitate epidural needle passage between these bones into the epidural space.

How Long Can an Epidural Stay In?

A: Although most labor epidurals are in place for less than 24 hours, epidurals are routinely used for up to 7 days in some applications.

How are Epidurals Secured?

A: Epidurals are typically secured at the skin with medical tape or adhesive dressings.

What Drugs are Used in Epidurals?

A: Two types of drugs are commonly used in epidurals; 1)local anesthestics and 2)opioid pain medicines. Local anesthestic block nerves to provide “numbness” and opioids (morphine-like medicines) alter pain nerve signal transmission and modify perception of pain. Pain medicines (opioids) mixed with local anesthestics provide superior results compared to local anesthestics alone.