Emergency cesarean: Anes options

Advanced, Clinical Subspecialties

Anesthetic options for an emergency cesarean include spinal, epidural, conversion of a labor epidural, a combined spinal-epidural (CSE), general anesthesia and local anesthesia. A neuraxial technique is often the default, preferred technique for anesthesia; however, the decision must be dictated by medical comorbidities, urgency of the cesarean, and the specific risks and benefits of each technique.

A spinal anesthetic provides a consistent, dense neuroblockade of a limited duration. It is technically easier and faster to place than both an epidural and a CSE which can be a factor if fetal condition dictates speed. Small doses of drug are required to obtain adequate blockade nearly eliminating the risk of local anesthetic toxicity and drug transfer to the placenta of any consequence. Disadvantages include the limited duration of blockade with inability to supplement/titrate the blockade with additional neuraxial medication. Additionally, some patients (e.g. patients with cardiac disease) may not tolerate the sudden and significant hypotension that can often accompany a spinal anesthetic. Given that a spinal can take some time to both place and ensure adequate level has been attained, a discussion should be had with the surgeon regarding the urgency of the cesarean as a general anesthetic may be preferred due to its speed.

Epidurals allow for titration/repeat administration of medications in situations where a slower onset of sympatholysis is preferred (e.g. aortic stenosis or other cardiac lesions) or the surgery duration is prolonged. However, the anesthesia from an epidural tends to be less profound than a spinal anesthetic and, while adequate for labor, may be inadequate for surgery. Practically, given the time taken to place an epidural, there is often insufficient time to place a de novo epidural in a patient who needs an emergency cesarean.

A CSE allows for both the dense surgical neuroblockade of a spinal anesthetic with the ability to titrate/supplement the level of an epidural. Again, the time required to utilize this anesthetic option often limits its utility in an emergency setting.

If a patient already has a functioning epidural catheter in place for labor, medication can be bolused through it to provide surgical anesthesia adequate for a cesarean. Typical medications used to achieve adequate surgical anesthesia include 15mL-20mL of a fast acting local anesthetic such at 3% 2-chloroprocaine or alkalinized 2% lidocaine with or without adjuvants such as opioids. If this fails to provide surgical anesthesia (e.g. a “patchy” or a one-sided block), the decision about whether to attempt a spinal afterwards is controversial. There is concern that standard intrathecal doses of local anesthetic for a cesarean may result in a high spinal due to compression of the dural sack from the additional volume in the epidural space.

The final anesthetic option is a general anesthetic. The default preference is to avoid a GA due to concerns regarding airway management, aspiration, minimizing fetal transfer of anesthetic drugs, and a mother’s desire to be awake at the birth of her child. However, a GA can typically be performed faster than many neuraxial techniques necessitating it’s use in many emergency cesarean deliveries. One exception is if a functioning labor epidural is in place as a surgical level can often be obtained through the epidural in a similar amount of time as it would take to induce the patient with a GA. If no epidural is in place, a discussion with the obstetrics team should take place regarding the urgency of the cesarean and if enough time exists to attempt one of the above neuraxial techniques.

Local anesthesia to the surgical site is an option of last resort typically employed only in low resource countries or if anesthesia services are not readily available in an acceptable amount of time. The multiple layers of tissues that need to be injected result in an unacceptably long period of time waiting for the local anesthetics to setup during an emergency. Additionally, there is a very real risk of local anesthetic toxicity given the amount of injectate required to perform a cesarean under local anesthetic only. More commonly, local anesthesia is used as a supplement to a neuraxial technique which may be providing inadequate coverage.

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2019

Year asked

Author
Karl Hillenbrand, MD