What recent studies involve general anesthesia (GA) in obstetric patients?

Recent Studies on General Anesthesia in Obstetric Patients

Current Trends and Practice Patterns

General anesthesia (GA) for cesarean delivery has declined significantly over the past decade, with rates dropping below 5% in high-resource centers, primarily due to increased recognition of maternal and neonatal risks associated with GA compared to neuraxial techniques. 1, 2

Declining Utilization Rates

• A 10-year retrospective review demonstrated that GA rates for cesarean delivery decreased from over 10% in 2014 to less than 5% by 2019, with the most significant reduction occurring after implementation of dedicated obstetric anesthesia teams 2
• In high-volume referral centers, current GA rates for emergency cesarean delivery range from 7.7% to 10%, representing a substantial decrease from historical rates 3, 2
• The formation of specialized obstetric anesthesia teams serving as communication bridges between anesthesiology and obstetrics departments has been associated with significant reductions in GA utilization (P = 0.04) 2

Primary Indications for General Anesthesia

Obstetric Indications

Abnormal fetal heart rate, particularly fetal bradycardia, remains the most common obstetric indication for GA in urgent/emergent cesarean delivery, accounting for 39% of cases. 4

• Cord or fetal prolapse is a strong predictor of GA requirement [OR 14.85 (1.90-115.94)] 4
• Emergency code activation significantly increases GA likelihood [OR 13.55 (1.73-106.40)] 4
• Pregnancy-related illness increases GA odds [OR 8.63 (1.06-70.38)] 4
• Lower gestational age is associated with increased GA use [OR 0.86 (0.81-0.92)] 4

Anesthetic Indications

The most frequent modifiable anesthetic indication for GA is inadequate neuraxial anesthesia, accounting for 17% of GA cases in urgent/emergent cesarean deliveries. 4

• "Limited time due to maternal/fetal compromise" accounts for 56% of GA administration decisions 4
• Maternal contraindication to regional anesthesia represents 25% of GA cases 4
• Regional anesthesia failure rates remain relatively low (4.1%) in high-resource centers with dedicated obstetric anesthesia teams 3

Maternal and Neonatal Outcomes

Maternal Complications

GA for cesarean delivery is associated with significantly higher rates of ICU admission and blood product requirements compared to neuraxial techniques, even when controlling for urgency of delivery. 3

• Unnecessary GA is linked to increased surgical site infections, venous thromboembolic events, and serious anesthesia-related complications 1
• Greater maternal pain and higher rates of postpartum depression requiring hospitalization are associated with GA 1
• Airway-related complications remain the primary driver of GA-associated maternal morbidity despite advances in intubation devices and algorithms 1

Neonatal Outcomes

Newborns delivered under GA demonstrate significantly higher rates of low APGAR scores (< 7 at both 1 and 5 minutes) and increased NICU admission requirements compared to those delivered under neuraxial anesthesia. 3

• The rate of poor neonatal outcomes is elevated in the GA group even after controlling for urgency and maternal condition 3
• Both maternal and perinatal mortality increase when GA is provided, particularly in low-resource settings 1

Time-to-Delivery Analysis

Time from operating room entry to incision (TTI) is shortest when using GA or conversion of labor epidural to surgical anesthesia, with no significant difference between these two approaches. 3

• Despite faster TTI with GA, the improved speed does not translate to better neonatal outcomes and is offset by increased maternal and neonatal complications 3
• Time until delivery (TTD) shows no significant difference between GA and epidural conversion groups 3

Evidence-Based Technical Recommendations

Induction Approach

Rapid sequence induction using propofol and rocuronium should be the standard for GA in obstetric patients, replacing historical thiopental-based approaches. 5

• Short-acting opioids should never be withheld in cases of severe preeclampsia, despite historical concerns 5
• Cricoid pressure requires trained caregivers for accurate application and should be released if intubation appears difficult 5

Airway Management

Endotracheal intubation remains the gold standard for GA during cesarean delivery, particularly in emergency cases involving laboring women. 5

• Supraglottic airway devices may be safely used only in fasted, non-obese patients undergoing elective cesarean section 5
• Equipment for management of airway emergencies must be immediately available in labor and delivery operating suites 6

Maintenance Anesthesia

• Both sevoflurane and propofol are appropriate for maintenance of GA during cesarean section 5
• Awareness remains a major concern in obstetric anesthesia and requires vigilant monitoring 5

Disparities and System-Level Factors

Racial and socioeconomic disparities, along with low-resource settings, are major contributing factors to increased GA utilization, with both maternal and perinatal mortality rising when GA is provided in these contexts. 1

• Higher ASA classification is associated with decreased GA likelihood [OR 0.11 (0.06-0.21)], suggesting that sicker patients may receive more careful anesthetic planning 4
• Institutional practice patterns significantly influence GA rates, with some centers historically choosing GA for placenta previa cases despite lack of evidence supporting this approach 2

Strategies to Minimize Unnecessary GA

Implementation of dedicated obstetric anesthesia teams and strengthened partnerships between anesthesiologists and obstetricians represent the most effective strategy for reducing unnecessary GA, particularly for conditions like placenta previa where neuraxial techniques are equally safe. 2

• Early placement of epidural catheters in laboring patients at risk for cesarean delivery provides a pathway to avoid GA in urgent situations 6
• Raising awareness in identifying situations and patients at risk for unnecessary GA remains crucial for improving outcomes 1