Neuraxial Anesthesia Onset: Combined Spinal Epidural
An alternative to a single-shot spinal or an epidural technique is a combined spinal epidural (CSE) technique. A CSE technique allows the anesthesiologist to place an initial lower dose of local anesthetic in the intrathecal space, because if the intrathecal block is inadequate, then an epidural catheter would be present to dose. Although one study found no difference in CO or the incidence of hypotension regardless of whether 5 or 10 mg intrathecal bupivacaine was administered during a CSE, as discussed earlier, multiple other studies have shown that decreasing doses of intrathecal local anesthetic decreases rates and degrees of spinal hypotension.
A low-dose CSE technique has been described in four high-risk cardiac patients, in which an intrathecal dose of 4–5 mg of heavy bupivacaine, along with 20–25 mcg fentanyl was administered. This was subsequently followed by the slow loading of epidural local anesthetic to achieve a T4 surgical level. The purported benefits of the low-dose CSE technique include a slower-onset of the neuraxial block, which may allow the anesthesiologist to maintain preload and afterload during the onset, while still achieving the greater block reliability of intrathecal local anesthetic administration. Further investigation is needed to determine the hemodynamic benefit of such techniques.
Expert Rev of Obstet Gynecol. 2012;7(1):59-75. © 2012 Expert Reviews Ltd.