Combined spinal-epidural blockade

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CHAPTER 124

Combined spinal-epidural blockade

Katherine W. Arendt, MD

Combined spinal-epidural (CSE) blockade was first described in 1937 but was not commonly used until the early 1980s. Combining the advantages of each of its component techniques, CSE blockade combines the rapid onset, reliability, and minimal drug toxicity associated with subarachnoid blocks with the flexibility of the dosing, duration, and analgesic-level control of an indwelling epidural catheter. CSE block is used primarily for obstetric analgesia and anesthesia, but its use has been described for a variety of applications, including general surgery, orthopedic and trauma surgery of the lower limb, urologic surgery, and gynecologic surgery.

Applied anatomy

The essence of a CSE block is single-shot administration of intrathecal anesthetic or analgesic agents along with placement of a catheter into the epidural space. The applied anatomy of a CSE block is the same as that for subarachnoid and epidural blockade (see Chapter 123, Epidural Anesthesia, Figure 123-1).

Indications

CSE blockade can be utilized in patients in whom a neuraxial technique is indicated and for whom it is necessary to combine the rapid onset of analgesia or anesthesia achieved with spinal anesthesia with the ability to provide prolonged analgesia, as is usually done with a continuous infusion of medication through an epidural catheter.

Absolute	Relative
Patient refusal Bacteremia/sepsis Increased intracranial pressure Infection at needle insertion site Shock or severe hypovolemia Coagulopathy or therapeutic anticoagulation*	Preexisting neurologic disease Severe psychiatric disease or dementia Aortic stenosis Left ventricular outflow tract obstruction Various congenital heart conditions (absolute contraindication if severe) Deformities or previous surgery of the spinal column

Advantages

A systematic review comparing CSE and epidural labor analgesia found no evidence for differences in maternal satisfaction, mode of delivery, incidence of hypotension, or the ability to ambulate. However, the advantages of using a CSE technique (as opposed to an epidural technique alone) do exist and may include the following:

The onset of anesthesia or analgesia is faster.

The total dose of local anesthetic agent required to achieve analgesia/anesthesia is smaller than the dose necessary with an epidural-only technique, thus reducing the risk of local anesthetic toxicity. This may ultimately result in lower systemic and fetal (if used for labor and delivery) concentrations of local anesthetic agents.

For obstetric cases, intrathecal opioids can be administered as the sole agent, without the addition of local anesthetic drugs, providing analgesia for the first stage of labor with no motor block.

Epidural catheters placed during a CSE technique are less likely to fail than are epidural catheters placed during an epidural-only technique. This is likely because the epidural space is verified by the return of cerebrospinal fluid through the spinal needle.

Subsequent epidural dosing may provide greater sacral nerve root coverage when a prior dural hole has been made during a CSE technique. This likely occurs from translocation of epidural drugs into the intrathecal space. In obstetric anesthesia, this may decrease the incidence of sacral sparing during the second stage of labor even if the dose of the intrathecally administered local anesthetic agent has worn off before the onset of the second stage of labor.

During labor, more rapid cervical dilation may be associated with the use of a CSE block.

In anesthesia for cesarean delivery, a CSE (with a full surgical intrathecal dose) results in less intraoperative discomfort, better muscle relaxation, less shivering, and less vomiting than with an epidural-only technique and, if the epidural catheter is left in place, an option for providing continued postoperative analgesia.

Disadvantages

Possible disadvantages of using a CSE technique, in comparison with an epidural technique, include the following:

Determining the adequacy of the epidural catheter for surgical anesthesia may be delayed.

Intrathecally administered opioids can cause pruritus.

Theoretically, the risk of infection may be increased because the subarachnoid space is accessed.

When used for labor analgesia, intrathecally administered opioid medications may increase the incidence of post analgesia fetal heart rate decelerations; however, this disadvantage is controversial, and the complex discussion is beyond the scope of this chapter.

CSE blockades are typically performed via a needle-through-needle technique with traditional epidural and spinal needles (Figure 124-1). When the needle-through-needle technique is performed, a sterile field is created at the procedure site, the skin and subcutaneous tissue are infiltrated with a local anesthetic agent, and an epidural needle is inserted into the ligamentum flavum. Loss of resistance with air or saline is used to identify the epidural space. A spinal needle is then advanced through the epidural needle into the subarachnoid space. The spinal needle must be longer than the epidural needle to allow dural puncture, projecting 13 to 17 mm beyond the tip of the epidural needle. Following the appearance of cerebrospinal fluid, the intrathecal anesthetic or analgesic agent is injected, and the spinal needle is removed. Finally, a catheter is advanced through the epidural needle into the epidural space, and the epidural needle is removed.