9: Anesthesia for Cesarean Section and Postoperative Analgesia

INTRODUCTION

The increase in the cesarean delivery rate in the United States has reached near epidemic proportions. As of 2010, approximately 30% of all births in the United States occurred via cesarean delivery, and projections estimate a continued increase over time. Therefore, attention to the anesthetic management of these patients will continue to be of increasing importance.

The typical sequence of events for providing anesthesia for cesarean delivery is as follows:

1. Preoperative assessment and consent

2. Aspiration prophylaxis

3. Placement of monitors

4. Administration of antibiotics

5. Patient positioning

6. Administration of surgical anesthesia

7. Fluid coloading

8. Management of hypotension

9. Administration of uterotonics

10. Postoperative analgesia planning

Each of the components will be discussed in the following sections.

PREOPERATIVE ASSESSMENT AND CONSENT

Assessment

Prior to initiation of anesthesia, a thorough preoperative assessment should be completed. In addition to regular components of the history in obstetric patients, specific attention should also be given to relevant obstetric issues such as medical conditions that may complicate surgery (ie, obesity, hypertensive disorders of pregnancy, gestational diabetes) and number of previous cesarean deliveries.¹

Physical examination should include an examination of the back if neuraxial anesthesia is planned.¹ An airway examination should be timed close to surgery because evidence has shown that there may be changes in the Mallampati classification of the airway with pregnancy/labor.²

Routine laboratory tests may not be necessary for all women prior to cesarean delivery. However, there is controversy among practicing anesthesiologists regarding whether a routine platelet count should be obtained prior to regional anesthesia. Certainly, in high-risk patients, such as parturients with severe preeclampsia, gestational thrombocytopenia, or history of coagulation disorders, a platelet count and/or coagulation studies may be necessary. A sample of the patient’s blood should be sent to the blood bank for all cesarean deliveries. The decision to type and screen or type and cross-match blood should be made based on the likelihood of requiring a blood transfusion.

Consent

During the consent process, the patient should be informed of the risks and benefits of the anesthetic planned for the procedure. Although there are many potential risks with neuraxial and general anesthesia, generally the most common risks should be discussed. For neuraxial anesthesia, these should include infection, bleeding, risk of postdural puncture headache, hypotension, and patchy/failed block requiring a repeat puncture or conversion to general anesthesia.

ASPIRATION PROPHYLAXIS

The estimated incidence of pulmonary aspiration in women undergoing cesarean delivery is 1 in 661 and appears to be decreasing. The decline is likely to be multifactorial, is related to the increased use of neuraxial anesthesia and decreased use of general anesthesia, adherence to fasting guidelines in obstetric practice, and routine use of antacid prophylaxis.

The American Society of Anesthesiologists (ASA) ...