Obstetrical anesthesia presents unique challenges. Labor begins without warning, and anesthesia may be required within minutes of a full meal. Vomiting with aspiration of gastric contents is a constant threat. The usual physiological adaptations of pregnancy require special consideration, especially with disorders such as preeclampsia, placental abruption, or sepsis.
Obstetrical analgesia and anesthesia have become extraordinarily safe over the past 40 years (Hawkins, 2011). Anesthetic-related maternal mortality rates decreased more than 60 percent during this time, and from 2007 to 2017, only 0.4 percent of 6765 maternal deaths were due to anesthesia complications (Petersen, 2019). Creanga and colleagues (2017) reported the contribution of anesthetics to pregnancy-associated deaths has declined markedly in the United States (Fig. 25-1). Approximately two thirds of deaths associated with general anesthesia were caused by induction problems or intubation failures during cesarean delivery. Deaths associated with regional analgesia were caused by spinal or epidural blocks reaching higher than planned spinal levels—26 percent; respiratory failure—19 percent; and drug reaction—19 percent.
Contribution of anesthetic complications to pregnancy-associated deaths—United States, 1987–2013.
Of factors contributing to improved obstetrical anesthesia safety, the increased use of regional analgesia for labor and delivery is the most significant. For general anesthesia, the improved case-fatality rate is especially notable considering that this method is now used for the highest-risk patients and for emergencies with decision-incision intervals <15 minutes (Bloom, 2005). In addition, the incidence of aspiration, hypoxia, or other respiratory events has declined during the past three decades. This is likely due to use of difficult-airway algorithms, advanced airway equipment, and increased in-house anesthesia staffing (Davies, 2017; Lim, 2018). Despite these encouraging results with general anesthesia, rising complications with regional analgesia techniques are now reported (Davies, 2017).
Obstetrical Anesthesia Services
Every obstetrician should be proficient in local and pudendal analgesia for select circumstances. However, it is preferable for an anesthesiologist or anesthetist to provide rapid and reliable pain relief to allow the obstetrician to focus attention on the laboring woman and her fetus.
The American College of Obstetricians and Gynecologists (2019b) and the American Society of Anesthesiologists (2016) have reaffirmed prior directives that a woman’s request for labor pain relief is sufficient indication for its provision. Identification of any of the risk factors shown in Table 25-1 should prompt consultation and collaboration with anesthesia personnel. The resulting plan should ideally minimize the need for emergency anesthesia in this high-risk group.
TABLE 25-1Maternal Factors That May Prompt Anesthetic Consultation ||Download (.pdf) TABLE 25-1Maternal Factors That May Prompt Anesthetic Consultation
|Anatomical abnormalities of the face, neck, or spine |
|Cardiac, pulmonary, renal, hepatic, or neurological disease |
|Bleeding disorders |
|Prior anesthetic complications...|