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Obstetric Anesthesiology

What Is New in Obstetric Anesthesia: The 2021 Gerard W. Ostheimer Lecture

Lim, Grace MD, MSc*,†

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Anesthesia & Analgesia: May 07, 2022 - Volume - Issue - 10.1213/ANE.0000000000006051
doi: 10.1213/ANE.0000000000006051


The Gerard W. Ostheimer lecture aims to update Society of Obstetric Anesthesia and Perinatology (SOAP) members on the relevant literature published in the preceding year. It was started in 1975 as the “What’s New in Obstetric Anesthesia” lecture and then renamed in 1995 in honor of Dr Gerard W. Ostheimer in recognition of his contributions to obstetric anesthesia. In this review, articles from the anesthesiology, obstetric, perinatology, neonatology, and health services literature that were published between January 2020 and December 2020 were evaluated and selected based on significance and relevance to obstetric anesthesiology. There were >2000 articles in 90 medical journals that met initial screening criteria for review. Of these, the list of articles was narrowed to approximately 200 articles that were of high quality and relevance. These articles were organized into 10 themes (Table 1). A complete listing of articles and their summaries is included in Supplemental Digital Content 1, Supplemental Material 1, This article highlights a few of the most consequential articles covered in this lecture, with an emphasis on those that have the potential to change clinical anesthesia practice.

Table 1. - Topics Concerning Obstetric Anesthesiologists in 2020 and Beyond
Maternal mortality
Disparities and social determinants
Cognitive function/mental health/recovery
Quality and safety
Operations, value, and economics
Clinical controversies and dogmas
Epidemics and pandemics: COVID-19 and opioids
Fetal-neonatal and child health
General clinical care
Basic and translational science
The future of peripartum anesthesiology
Abbreviation: COVID-19, coronavirus disease 2019.


For more than a decade, temporal increases in maternal mortality rates in the United States have alarmed clinicians, epidemiologists, and public health experts. In January 2020, the Centers for Disease Control and Prevention (CDC) released its first update since 2007 on maternal mortality.1 The report came after 16 years (2003–2018) of implementing the pregnancy checkbox on death certificates across all 50 states, the District of Columbia, and United States territories. The 2020 National Center for Health Statistics (NCHS) report identified 658 maternal deaths nationwide and a maternal mortality rate (MMR) of 17.4 deaths per 100,000 live births for 2018 (previously reported in 2007 by NCHS as 12.1 per 100,000 live births).2 This increase was largely attributable to data collection and reporting changes. The updated data reveal racial and ethnic disparities in maternal mortality, as well as patient-level factors contributing to maternal death. Black women are dying at 2 to 4× the rate of their non-Hispanic White counterparts. Other factors associated with higher risk for death include maternal age (the MMR for women 40 years of age or older was 8× that of women younger than 25) and cardiovascular disease. Cardiomyopathy is the leading cause of death between 42 days and 1 year after delivery.3

In 2020, the US Department of Health and Human Services (HHS) and the surgeon general released 2 reports,4,5 which were a simultaneous action plan and call to action to improve maternal health in the United States. Both reports include detailed lists of actions aimed at improving maternal mortality and morbidity in the United States. The action items are targeted at improving care for racial and ethnic minorities. The HHS action plan focuses on changes within the health care system, while the surgeon general’s report highlights opportunities for action across all stakeholders: payers, employers, innovators, and patients themselves. In the action plan, HHS supplies a roadmap that addresses risk factors before and during pregnancy, improving quality of and access to pregnancy and postpartum care and supporting research to fill evidence gaps. The action plan outlines 3 specific targets to improve the maternal health outcomes in the nation by 2025: (1) reduce the maternal mortality rate by 50%, (2) reduce low-risk cesarean deliveries by 25%, and (3) achieve blood pressure control in 80% of women of reproductive age with hypertension. Altogether, the joint efforts of the HHS and Surgeon General set a clear, yet ambitious agenda for improving maternal health within the next 5 years.


A leading cause of maternal mortality is cardiovascular disease. A review of published literature outlines how hypertensive disorders of pregnancy (HDPs) can predict future cardiovascular health.6 Women with preeclampsia have a higher lifetime risk for stroke, ischemic heart disease, heart failure, and venous thromboembolism. A “dose-response” effect potentially regulates this relationship: severe HDP, early-onset HDP, coexistence of fetal growth disorders, and recurrence of HDP result in worse cardiovascular outcomes.

Cardio-obstetrics has emerged as an important multidisciplinary discipline that emphasizes a team approach to optimizing cardiovascular disease during and after pregnancy. In 2020, publications on cardio-obstetrics revealed disparities in the effect that cardiovascular disease has on pregnancy and across the lifespan. In a prospective cohort study of >1000 women,7 those with hypertension during hospitalization were provided with blood pressure cuffs on discharge, and remote monitoring of blood pressures occurred weekly for 6 weeks. Black women were found to have a less rapid decrease in blood pressure compared with White women, resulting in higher blood pressure by the end of the 6-week monitoring program. Six weeks postpartum, 68% of Black women and 51% of White women met criteria for stage 1 or 2 hypertension. Considering the number of women with persistent hypertension at the end of the 6-week program, it is important to begin extending ongoing postpartum care beyond the traditional 6 weeks after delivery.

Disparities and Social Determinants of Health

Health disparities not only affect cardiovascular health and outcomes but also influence overall mortality risk. Disparities in racial, ethnic, and social determinants of pregnancy-related morbidity and mortality have persisted since the new millennium. A systematic review of 83 studies found that minority race and ethnicity (58 of 67 studies with positive findings), public or no insurance (21 of 30 studies), and lower education levels (8 of 12 studies) were linked to increased risk for maternal death and severe maternal morbidity.8 However, only 2 of the 83 studies included factors of socioeconomic, political, and cultural contexts (ie, public policy) on these relationships. These limitations hamper the ability to study social determinants of health factors in maternal mortality. Therefore, clinical and research work should now focus on identifying social determinants that increase the risk for maternal mortality and morbidity. Implementation science and health services research will be integral toward evaluating and optimizing policymaking impacts and quality improvement work at local, state, and national levels.

Although few evidence-based interventions exist that reduce peripartum disparities, one intervention that has been shown to improve outcomes for Black women is group prenatal care. In a clinical opinion piece describing a case study of system-level impact,9 the authors point out the importance of addressing institutional, community, and social-cultural contexts in which pregnant women are living. They outlined the cross-disciplinary Elevating Voices, Addressing Depression, Toxic Stress, and Equity in Group Prenatal Care Women’s Collaborative (EleVATE Collaborative) in St Louis, Missouri. EleVATE group perinatal care has achieved improvements in equitable health outcomes. Group care is one of the few interventions that has been shown to improve pregnancy outcomes for Black women, possibly by improving quantity and quality of patient and practitioner time together and community building. Group care fosters cross-cultural exposure and reduces clinician bias. These system-level changes can directly benefit patients and improve perinatal outcomes.

Levels of Maternal Care

The Levels of Maternal Care (LoMC) by the American College of Obstetricians and Gynecologists (ACOG) are intended to address maternal morbidity and mortality by defining appropriate hospital-level assignments based on capabilities, providers, and specialty care needed.10 A national case-control study in France assessed the risk of perihospital maternal death according to hospital characteristics11 between regionalized centers that parallel LoMC structures. All 2007 to 2009 postpartum maternal deaths from the national confidential inquiry (n = 147 cases) and a national sample of parturients (n = 14,639 controls) were examined. After adjusting for referral bias related to prepartum morbidity, the risk of maternal mortality differed by hospital characteristics: the risk of postpartum maternal death from complications occurring during or after delivery was higher for women who delivered in for-profit compared with teaching hospitals (adjusted odds ratio, 2.8; 95% confidence interval [CI], 1.3–6.0; P = .009), and the risk of death from hemorrhage was higher in for-profit versus nonprofit hospitals (adjusted odds ratio, 2.8; 95% CI, 1.2–6.5; P = .019). The risk of postpartum maternal death from hemorrhage was higher for deliveries in hospitals without a 24-hour, 7-day on-site anesthesiologist (adjusted odds ratio, 2.4; 95% CI, 1.003–5.7; P = .049), in level 1 (basic care) hospitals (adjusted odds ratio, 2.4; 95% CI, 1.05–5.6; P = .04), and in for-profit hospitals (adjusted odds ratio, 3.0; 95% CI, 1.3–7.0; P = .01). The findings may reflect differences in practice patterns: in private hospitals, decisions are usually made by individual physicians, whereas teaching hospitals tend to use collegial decision-making and team-based work.12 Regionalization of care through LoMC structures may offer a potentially promising solution to our maternal mortality crisis. However, existing challenges to implementing LoMC include unanticipated emergency needs (eg, hemorrhage, abruption, or amniotic fluid embolism [AFE], etc), transportation for timely access to higher-level care for mothers in rural areas, and other logistical constraints around equipment, staffing, blood bank, and other resources needed to support low-resource centers.


Severe maternal morbidity (SMM) affects long-term health. This single-center case-control study found that 315 women in the SMM group had fewer children after index pregnancy, new complications in subsequent pregnancies, and required specialized medical care after delivery compared with women without SMM. The authors suggest that surveillance and follow-up of women with SMM should extend beyond the typical 6 weeks postpartum. However, women deserve much more than to know they are simply going to survive childbirth or emerge from it unscathed.13 Respectful maternity care—including respect for women’s autonomy, dignity, feelings, choices, and preferences, including companionship during maternity care—is also an underrecognized priority and is consistent with 2018 World Health Organization (WHO) recommendations to support human dignity in childbirth.

A successful transition to motherhood includes optimal recovery, mental health, and cognitive health. Cerebrovascular health optimization includes stroke risk reduction. In this context, HDPs have been found to predict future stroke risk. In a Taiwanese National Health Insurance database study of women with and without HDP matched by age, patients with HDP had a 2-fold higher risk of developing stroke than did patients without HDP.14 More evidence is emerging, suggesting that HDPs can be a “stress test” and a window into not only cardiovascular but also future cerebrovascular health.

Depression and Pain

The past few years have seen several investigations on the role that labor pain and epidural analgesia use can potentially have on postpartum depression (PPD). A cohort study of 1500 Scandinavian women investigated the complex links between fear of childbirth, the childbirth experience, epidural analgesia, and PPD.15 Epidural analgesia was not associated with the risk of PPD at 6 weeks after adjusting for age, fear of childbirth, and antenatal depressive symptoms (adjusted odds ratio, 1.22; 95% CI, 0.87–1.72). However, these findings did not preclude a potential link between PPD and childbirth pain or other aspects of epidural analgesia that were not measured in this study.

Mounting evidence is suggesting that epidural analgesia itself may not affect PPD risk, but the pain phenotype may still be a key factor in PPD and recovery. Peripartum pain and depression can also affect postpartum opioid requirements. A retrospective study of 900 women found an association between antepartum major depression and acute pain after cesarean delivery, and increased opioid use.16 Women with major depression reported higher daily and average numeric rating pain scores postpartum versus those without depression (2.4 vs 1.7 average pain scores; P < .001). Women with major depression used more morphine milligram equivalents (MMEs) each day during their postpartum hospitalization, leading to higher total MME use (median, 121 mg [interquartile range, 60.5–214.5] versus median, 75 mg [interquartile range, 28.5–133.5]; P < .001). Similarly, a retrospective study of 615 women after cesarean delivery found that the severity of acute postoperative pain was higher in women with PPD than in those without PPD on postoperative day 3 (P < .02) with independent risk factors for PPD, including preoperative presence of chronic pain (odds ratio, 4.44; 95% CI, 1.82–10.81; P <.001) and a numeric rating score ≥2 on postoperative day 3 (adjusted odds ratio, 4.90; 95% CI, 1.06–22.61; P < .05).17 These links between acute peripartum pain and PPD should continue to be investigated to inform clinical acute care interventions, such as better pain control strategies in susceptible women, which may lead to prevention of PPD.


As the United States grapples with higher maternity care costs and poorer outcomes, including maternal and infant morbidity and mortality, maternity care has now come into focus for value-based care. As a step toward building up high-value services and reducing low-value services, these authors presented a new conceptual model for prenatal care.18 It incorporates both medical as well as social needs into 4 care models: low medical/high support, high medical/high support, low medical/low support, and high medical/low support. The authors use human-centered design methods to describe how to better match patient needs with prenatal services. The result was an innovative model of care, including reduced visit schedules in patients with low medical support needs, pregnancy group care, and connected care models.

Another operational strategy to improve care quality while not increasing cost includes optimizing relationships between high and low maternal levels of care. In one example, the authors describe developing a partnership between a freestanding birth center and a tertiary-care medical center;19 18% of birth center labors were transferred for a hospital birth. Birth center admissions had an overall cesarean delivery rate of 6%, while 6% of infants required neonatal intensive care. This is the type of model that can facilitate expanded options for maternity care in regional perinatal health systems while reducing cesarean delivery rates.

Higher levels of obstetric care are also valuable.20 A tertiary maternity center in Sierra Leone in West Africa opened an obstetric high-dependency unit (HDU) in October 2017, and during the first year of operation, it achieved an 89.5% survival rate (n = 468/523). With this volume of admissions, total cost to operate the HDU was 230 Euros per patient. Assuming survivors would live to the average life expectancy of women in Sierra Leone at the time, the authors calculated that this investment achieved an overall cost per quality-adjusted life year gained (QALY) of 10 Euros, an extremely cost-effective intervention.


The Obstetric Anaesthetists’ Association and National Perinatal Epidemiology Unit collaborative used a Delphi process to identify quality indicators for obstetric anesthesia.21 Participants included obstetricians, anesthesiologists, midwives, managers, and service users. The group found 5 key indicators of anesthesia quality, encompassing point-of-care testing, staffing for emergency deliveries, antenatal anesthesia referral, adequate epidural labor analgesia, and accidental dural puncture rates. These areas can be used to inform quality improvement programs and national benchmarking for quality in obstetric anesthesia care.


A large insurance database study of nearly 150,000 children found an association between maternal use of epidural labor analgesia and increased risk for autism spectrum disorder (ASD) after adjusting for several factors, including birth year, maternal age, income, and pregnancy conditions, such as diabetes and preeclampsia (hazard ratio associated with epidural labor analgesia exposure versus nonexposure, 1.37; 95% CI, 1.23–1.53).22 The subanalyses did not show that the risk for ASD was mediated by intrapartum fever. Limitations of this study included omission of factors such as reasons for labor induction, which influence the use of epidural analgesia, and a lack of plausible biologic mechanism; although the authors presented studies in primates that linked, “standard doses of local anesthetics [to] neurotoxic effects and altered neurobehavioral development,” those studies involved high doses of local anesthetics that do not translate to modern clinical obstetric anesthesia practice. Subsequent research has not provided evidence of an association between epidural labor analgesia and risk for ASD. For example, in a large Canadian health care database study of 123,000 children, after adjusting for maternal sociodemographic and perinatal covariates, epidural labor analgesia was not associated with a risk of ASD in offspring (inverse probability of treatment-weighted hazard ratio, 1.08; 95% CI, 0.97–1.20).23

In addition to questions on the effects of epidural analgesia on childhood outcomes, other long-standing clinical care considerations were challenged in the 2020 literature. One such clinical practice in labor and delivery involves stress-dose steroids. This practice is relevant to perioperative or peridelivery anesthetic management in that either the omission or delivery of stress-dose steroids affects hemodynamics and perioperative glucose control and infection risks. In a “questioning clinical practice” opinion piece, the authors summarize the pathophysiology of adrenal insufficiency that could prompt delivery of stress-dose steroids during a physiologically stressful event, such as childbirth.24 They also review situations in which stress-dose steroids may do more harm than good. It may be worthwhile for anesthesiologists to reconsider stress-dose steroid practices in labor and delivery and engage obstetrician team members in these considerations as necessary.


In 2020, the novel coronavirus disease 2019 (COVID-19) introduced profound strains to health care systems, communities, and humanity. It unmasked the structural and social components that influence disparate health outcomes. SOAP developed the COVID-19 toolkit25 and published a clinical review that functions as a reference for frontline workers.26

The pandemic exacerbated the opioid epidemic.27 Anxiety, depression, substance use disorder, and domestic violence all increased since the pandemic erupted. The pandemic created a perfect storm for increasing drug use in people struggling with addiction. Factors include worsening anxieties related to health, loss of pleasurable activities, loss of social interactions (wherein patients in recovery lose their physical connections with people, which is a critical part of recovery), and fragility of traditional support systems.

Clinical care innovations also emerged, including regulatory allowances for audio-only telehealth encounters for buprenorphine induction without requiring an in-person evaluation.28 Although there are some positive changes that came with these innovations, work is still needed to overcome structural problems that continue to exacerbate the synergistic effects of COVID-19 and the opioid epidemic.


An update by the American Heart Association to neonatal resuscitation was published in 2020.29 In late preterm and term newborns who need respiratory support at birth, it is reasonable to start with 21% oxygen. Due to risk for harm, 100% oxygen is not recommended. In preterm newborns receiving respiratory support, it is reasonable to begin with 21% to 30% oxygen with titration based on pulse oximetry.

Compelling evidence from twin and sibling studies suggests that short-to-moderate length anesthesia exposure at a young age does not affect neurocognitive outcomes. However, questions remain about prolonged or repeated anesthetic exposures in young children. In one study, investigators reported increased use of attention deficit hyperactivity disorder medications in children who were exposed to general anesthesia at a young age.30 Another exploratory analysis raised the possibility that general anesthesia in the first trimester increases the risk of microcephaly.31 The questions were raised based on the idea that the central nervous system is sensitive to teratogens during early fetal development. Both analyses were limited by unmeasured confounders, and the studies do not change practice around necessary use of anesthetics in pregnancy and children. However, despite the limitations of these studies, research should continue to examine factors influenced by anesthesia care and confounders that influence neonatal outcomes. Clinicians should follow this course to safeguard and improve neurocognitive outcomes in the perioperative period.


Thrombocytopenia and Neuraxial Procedures

Thrombocytopenia in pregnancy affects decision-making around neuraxial labor analgesia and anesthesia. A 2017 study from the Multicenter Perioperative Outcomes Group database found that the risk of epidural hematoma associated with neuraxial techniques in parturients at a platelet count <70,000 × 106/L could not be well defined due to the limited number of observations.32 In 2020, a systematic review and meta-analysis of 4100 articles and more than 7000 neuraxial procedures found that only 33 procedures were associated with spinal epidural hematoma.33 A very low probability of spinal epidural hematoma was found near platelet counts of around 75,000 × 106/L. These findings helped to inform the SOAP consensus statement on neuraxial procedures in obstetric patients with thrombocytopenia.34 In this consensus statement, a decision support algorithm is provided, and the salient recommendations are that for pregnant patients with thrombocytopenia in which the platelet count is ≥70,000 × 106/L and immune, gestational, or unknown etiology is suspected, the risk for spinal epidural hematoma is low, and it may be reasonable to proceed with a neuraxial technique. However, caution continues to be necessary for patients with thrombocytopenia in the presence of HDPs, in which more frequent platelet count assessments may be necessary due to the risk for hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome. Ultimately, the decision of whether to proceed with a neuraxial procedure occurs within a clinical context with decision factors, including comorbidities, obstetric risk factors, airway examination, available airway equipment, risks of general anesthesia, and patient preference.

Postdural Puncture Headache

A prospective observational study followed symptoms of more than 1000 obstetric patients with postdural puncture headache (PDPH) from 24 countries over 3 months.35 Sixty-four percent received an epidural blood patch (EBP). A second EBP was needed in about 20% of patients. At 3 months, persistent backache was the most common symptom after EBP: of 635 patients (407 in the EBP group and 228 in the no-EBP group) queried at 3 months, persistent backache was reported by 14% (17% vs 8.8% in the EBP and no-EBP groups, respectively; P = .004). The results continued to be statistically significant after excluding patients who had chronic backache before delivery (14.6% vs 7.5%; P = .01). A persistent headache score of ≥3 on a 0 to 10 numeric rating scale at 3 months was reported in 6.9% vs 1.7% in the EBP and no-EBP groups, respectively (P < .001). These data suggest that chronic back pain and headache after PDPH may be uncommon but still more likely in patients who need EBP to treat PDPH.

The potential role of the sphenopalatine ganglion (SPG) block in managing PDPH has been questioned. A randomized, blinded, placebo-controlled trial randomized patients with PDPH requiring EBP to SPG with local anesthetic or with placebo.36 Participants received a bilateral SPG block with 1 mL of lidocaine 4% and ropivacaine 0.5% or placebo (saline). The primary outcome was pain in the upright position 30 minutes after the block, measured on a 0- to 100-mm visual analog scale. There were 40 subjects randomized who had a baseline upright median pain intensity of 74 and 84 mm in the local anesthetic and placebo groups, respectively. At 30 minutes after SPG block, the median pain intensity in the upright position was reduced from baseline: 26 mm in the active SPG group versus 37 mm in the placebo SPG group (estimated median difference, 5 mm; 95% CI, −14 to 21; P = .53). In the local anesthetic group, 50% required an EBP compared with 45% in the placebo group (not statistically significantly different); pain was similarly reduced in both active and placebo SPG groups. The study shows that although true SPG and placebo perform similarly in PDPH treatment, both are effective in reducing pain from PDPH but not in reducing the need for EBP. This study highlights a need for additional research on mechanisms behind the effectiveness of SPG blocks, intranasal lidocaine, and placebo analgesia.

Postpartum Hemorrhage

In a retrospective study of 118 patients with postpartum hemorrhage,37 13% of patients had clot lysis at 30 minutes after maximum clot strength (LY30) values >3%, indicating fibrinolysis. However, functional fibrinogen thromboelastography LY30 was 0% in all patients, suggesting that these LY30 values could potentially be due to clot retraction rather than clot lysis. These data expose clinical knowledge gaps on the fibrinolytic system during labor and delivery, including changes that occur during postpartum hemorrhage, and potential limitations in viscoelastic testing in these settings.

A key component of modern postpartum hemorrhage management is point-of-care testing. A study of 120 healthy laboring women at term gestation with uncomplicated pregnancies established reference ranges for rotational thromboelastometry (ROTEM) parameters.38 As expected, ROTEM amplitudes were higher than the manufacturer reference ranges for nonobstetric patients. The accompanying editorial39 emphasized the need for more evidence and pointed out that many postpartum hemorrhage guidelines (including the Royal College of Obstetricians and Gynaecologists, the Obstetric Anaesthetists’ Association, and the Association of Anaesthetists of Great Britain and Ireland) recommend using point-of-care coagulation testing for hemorrhage management. However, the National Institute for Health and Care Excellence indicates that there is insufficient evidence to recommend routine viscoelastomeric testing in management of PPH, primarily because existing data on point-of-care coagulation testing had come from cardiovascular surgery and trauma management. Considering the major coagulation physiology differences between pregnant and nonpregnant populations, clinicians should weigh strengths and limitations of viscoelastic testing in hemorrhage management and continue following the evidence on point-of-care testing as more data become available.

Amniotic Fluid Embolism

An analysis from an international registry on AFE was a combined effort by the National Institute of Child Health and Human Development (NICHD) and the AFE Foundation.40 A total of 129 cases were classified as typical, atypical, non-AFE, or indeterminant using previously published criteria; 66% of women with AFE had a history of atopy, allergy, or placenta previa. Of all cases, only 46% were typical, while the remaining were indeterminant, atypical, or non-AFE. Of the 27 cases misclassified as AFE, the most common, true, alternative diagnosis was hypovolemic shock from hemorrhage. These data highlight the importance of aggressively treating postpartum hemorrhage early to avoid clinical embodiments of hypovolemic shock that could be misdiagnosed as an AFE. A review about AFE by Pacheco et al41 discusses the clinical utility of point-of-care ultrasound (POCUS) in cases of AFE. It gives a helpful review of key examination findings to make timely assessments and management of pulmonary hypertension and cardiac failure. Daily application of POCUS will be helpful not only in everyday clinical care but also in these rare but high-stakes situations in which timely diagnosis and treatment make the difference between life and death.

Enhanced Recovery After Cesarean Delivery

The SOAP enhanced recovery after cesarean delivery (ERAC) consensus statement provides detailed, element-by-element guidance to establish ERAC within each institution, from preoperative to intraoperative to postoperative periods.42 Highlight areas for ERAC guidelines include recommendations around oral intake, limiting fasting intervals, carbohydrate loading, patient education, promoting resting periods, early discharge, early mobilization, intravenous fluid optimization, multimodal analgesia, breastfeeding, and nausea/vomiting prophylaxis.

Several studies have provided evidence of positive effects of implementing ERAC protocols. In a pre-post single-center impact study, the authors compared hospital opioid requirements and length of stay after ERAC protocol implementation.43 They found significantly lower peak pain scores after ERAC, although mean pain scores were not different. There was a 38% reduction in total postoperative opioid consumption. Length of stay was shorter by nearly half a day after ERAC. More patients (70% of the cohort) were discharged on postpartum day 3 after ERAC was implemented. A systematic review on this topic found a low-grade level of evidence for all outcomes.44 Most ERAC studies show benefit, and no studies show harm. Altogether, ERAC adoption is safe and overall recommended to be adopted at all modern maternity centers.

Peripheral Nerve Blocks for Cesarean Analgesia

Abdominal wall blocks for cesarean analgesia (eg, transversus abdominis plane [TAP], quadratus lumborum [QL], wound catheter [WC], and wound infiltration [WI]) have captured attention, given clinical care considerations around enhanced recovery, opioid use, and the patient experience. In one multicenter, randomized, double-blind, controlled trial, TAP block with liposomal bupivacaine as part of a multimodal analgesia protocol incorporating intrathecal (IT) morphine resulted in reduced opioid consumption after cesarean delivery.45 A systematic review and network meta-analysis found that in the absence of long-acting neuraxial opioid after cesarean delivery, single-dose TAP, WC, and WI are effective opioid-sparing strategies. The network meta-analysis showed no difference in 24-hour opioid consumption among WC, WI, and TAP block groups. However, surface under the cumulative ranking curve (SUCRA) values suggest that the order of effectiveness among techniques is TAP, followed by WC and WI. There were no differences between TAP and WC for pain outcomes at 12 or 24 hours.46 Another systematic review involving 31 trials and 2188 patients found that in the absence of IT morphine, TAP and QL were equivalent, both were superior to control (moderate-quality evidence), and in the presence of neuraxial morphine, there were no differences among control, TAP, and QL (moderate-quality evidence).47 The sum of evidence so far suggests that in the absence of neuraxial morphine, the provision of peripheral wall blocks should be used in multimodal analgesia strategies.

Spinal Anesthesia–Induced Hypotension: Consequences and Treatments

Hypotension is a known consequence of spinal anesthesia induction, and new evidence provides insights into its clinical consequences and management. In a retrospective analysis of 3,150 women undergoing spinal anesthesia for planned cesarean delivery at term, neonatal acidosis was common: neonatal acidosis occurred in in 3.4% cases of sporadic spinal hypotension (ie, at least one episode of systolic blood pressure of <100 mm Hg or <80% of the baseline) with an odds ratio of 1.83 (95% CI, 2.27-2.87). In contrast, neonatal acidosis occurred in 5.8% cases of sustained hypotension (i.e., a calculated index encompassing both the magnitude and the duration of hypotension) with an odds ratio of 3.00 (95% CI, 1.87-4.80). However, severe perinatal consequences (eg, tachypnea, neonatal intensive care admission, or respiratory distress) were rare and not associated with sporadic hypotension. The effects of sustained spinal hypotension and prolonged anesthesia-to-incision and incision-to-delivery intervals were additive.48

Treatment for spinal anesthesia–induced hypotension focuses on prophylactic vasopressor infusions, such as phenylephrine, and there has been growing attention to norepinephrine due to its favorable inotropic properties. However, there are some concerns about the safety of short-term norepinephrine administration through a peripheral venous catheter. A retrospective cohort study using perioperative databases identified 14,385 surgical patients who received peripheral intravenous infusions of norepinephrine 20 µg/mL during general anesthesia for nonobstetric surgery.49 There was no significant association between peripheral intravenous norepinephrine infusions and adverse events. Drug extravasation occurred in 5 patients (5/14,385 = 0.035%; 95% CI for infusion extravasation, 0.011–0.081). All 5 complications were minor and resolved without any medical and surgical intervention or permanent injury. The findings suggest that it may be relatively safe to use short-term peripherally administered norepinephrine for indications such as spinal anesthesia–induced hypotension. In obstetrics, safety of routine norepinephrine for spinal anesthesia-induced hypotension may be further supported, given that: (1) proposed solutions of norepinephrine in obstetrics are more dilute (6 µg/mL), and (2) awake patients under spinal anesthesia for cesarean delivery are capable of reporting intravenous line infiltration early.


Linking genetics and cell biology to clinical pain and analgesia phenotypes could be considered a holy grail for translational medicine in anesthesiology. In a human-animal translational study, healthy women who did not request analgesia during their first delivery were enrolled. The investigators found that a potassium channel Kv6 variant (K[V]6.4-Met419) affected experimental cold and pressure sensation in women who did not use epidural labor analgesia for their first labor.50 The study then back-translated this finding to physiology and mouse dorsal root ganglion cell biology: for neurons overexpressing K(V)6.4-Met419, the voltage dependence of inactivation for K(V)2.1 was more depolarized compared with neurons overexpressing K(V)6.4. This variant may affect central nervous system processes that can impact previous pain experiences, pain modulation, and pain expectations. Such factors could inform choices surrounding pain, such as the choice to use labor analgesia. This study imagines the possibility of tailoring labor analgesia based, in part, on individual biological factors such as genotypes and gene expression.


Artificial intelligence (AI) is projected to disrupt health care delivery in our lifetime. In anesthesiology and obstetrics, AI is being developed for decision support, risk stratification, and event prediction. One study aimed to develop risk prediction models for intrapartum stillbirth and neonatal death.51 Data were used from the NICHD global registry, which included clinical sites in India, Pakistan, Africa, and Latin America. More than 500,000 pregnancies were prospectively registered and followed. The data used conventional and advanced machine learning models to assess predictive abilities for intrapartum stillbirth and neonatal mortality. Adding delivery variables improved predictive model performance compared with using just prenatal information alone. Prediction accuracy for neonatal death can be improved by including postdelivery variables. These methods are exciting because they can improve identification of neonates at the highest risk for mortality who may need specialized care.

Several studies published in 2020 used electronic systems and AI to predict severe outcomes like hemorrhage and patient deterioration in hospital settings. In one study, an automated surveillance system and the maternal early warning criteria (MEWC) were used to detect severely morbid postpartum hemorrhage.52 The automated system was able to identify 10 severe postpartum hemorrhage cases that were not identified by MEWC alone. In another study, a deep learning AI-based early warning system was used in a hospital ward for events of cardiac arrest and unexpected intensive care unit admission.53 AI-based systems had 257% higher sensitivity than conventional methods for predicting patient deterioration. These kinds of systems are encouraging for transforming clinical care with precise prediction and guided decision-making.


Table 2 summarizes some key takeaway points to implement into clinical practice. A few highlights include the following: use the SOAP COVID-19 toolkit to prepare systems and practices in this ongoing pandemic; ERAC protocols should be implemented locally to improve post-cesarean delivery health outcomes; individual clinicians and practice leaders alike should engage in quality improvement efforts, both within and outside of the birth center; SPG blocks can be added to conservative treatment strategies for PDPH but do not replace EBP; and finally, achieving proficiency in POCUS is imperative to provide modern clinical obstetric anesthesia care. E

Table 2. - Implementation Priorities: Clinical Pearls From 2020 Obstetric Anesthesia Articles
Implement ERAC protocols in group practice.
Develop quality improvement metrics in your birth unit; get involved in system improvement efforts.
Use the SOAP COVID-19 toolkit to prepare units and to care for pregnant patients with this illness.
Adopt SOAP consensus statement on neuraxial procedures in patients with thrombocytopenia.
Add SPG blocks to conservative treatment strategies for PDPH; but they do not replace EBP.
Address limitations of point-of-care viscoelastic testing in postpartum hemorrhage management.
Achieve proficiency in point-of-care ultrasound.
Abbreviations: COVID-19, coronavirus disease 2019; EBP, epidural blood patch; ERAC, enhanced recovery after cesarean delivery; PDPH, postdural puncture headache; SOAP, Society for Obstetric Anesthesia and Perinatology; SPG, sphenopalatine ganglion.


I am indebted and deeply grateful to Emma Nowakowski, Carol Hunn, Madison Morgan, and Amy Monroe for their assistance in preparation of this lecture and manuscript.


Name: Grace Lim, MD, MSc.

Contribution: This author wrote and approved the final manuscript.

This manuscript was handled by: Jill M. Mhyre, MD.


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