Amniotic fluid embolism: principles of early clinical management

Amniotic fluid embolism: 20-year incidence and case-fatality trends in the United States

OBJECTIVE

To estimate incidence and case-fatality rates of amniotic fluid embolism (AFE) and to examine their temporal trends.

STUDY DESIGN

Population-based retrospective cohort study using the 2000-2019 Health Care Cost and Utilization Project, Nationwide Inpatient Sample (HCUP-NIS). Annual population rates were estimated using HCUP-NIS specific weighting. Descriptive analyses and logistic regression described trends within the cohort.

RESULTS

Over the study period, AFE incidence rate remained stable (mean 4.9 cases/100,000 deliveries) and the case-fatality rate declined (mean 17.7 %,95 % CI 16.40-10.09). Highest AFE incidence rates and fatality rates were in women ≥ 35 years, African-Americans, and in urban-teaching hospitals. AFE mortality rates decreased among Hispanics.

CONCLUSION

AFE rates remained stable and fatality rates declined over time. Highest rates of AFE occurrence and death were in women who typically have greater risk of experiencing adverse obstetrical outcomes. Continued research into early diagnostic methods and effective treatments are needed to further improve AFE incidence and mortality rates.

Amniotic Fluid Embolism Coagulopathy Guided by the Point-of-Care Quantra QStat® Hemostasis System: A Case Report

Amniotic fluid embolism (AFE) is a rare pregnancy complication associated with high maternal mortality that occurs during labor or in the early postpartum period. The diagnosis of AFE is challenging because signs and symptoms are common to other obstetric complications. Early identification and management of profound coagulopathy associated with AFE is essential to improve patient survival. We present a case of a 31-year-old woman with placenta previa and clinical suspicion of AFE after cesarean section. Immediately after delivery, the parturient presented hypotension, hypoxia, coagulopathy, and severe postpartum hemorrhage. We hereby discuss the role of the most recently developed point-of-care viscoelastic testing device, the Quantra QStat® system (Stago Group Company; HemoSonics LLC, Durham, NC), for early detection of acute obstetric coagulopathy and guided hemostatic treatment.

Acute Respiratory Distress Syndrome in Pregnancy: Updates in Principles and Practice

Acute respiratory failure occurs in 0.05% to 0.3% of pregnancies and is precipitated by pulmonary and nonpulmonary insults. Acute respiratory distress syndrome (ARDS) is the rapid onset of hypoxemic respiratory failure associated with bilateral pulmonary opacities on chest imaging attributed to noncardiogenic pulmonary edema. The pathophysiological features of ARDS include hypoxemia, diminished lung volumes, and decreased lung compliance. While there is a paucity of data concerning ARDS in the pregnant individual, management principles do not vary significantly between pregnant and nonpregnant patients. The following review will discuss the diagnosis and management of the pregnant patient with ARDS.

Improving the Quality of Maternity Care: Learning From Malpractice

OBJECTIVE

This study aimed to depict the characteristics, injury outcomes, and payment of obstetric malpractice lawsuits to better understand the medicolegal burden in obstetrics and categorize the causes of obstetric malpractice lawsuits using The National Health Service Litigation Authority coding taxonomy for further quality improvement in maternity care.

METHODS

We reviewed and retrieved key information on court records of legal trials from China Judgment Online between 2013 and 2021.

RESULTS

A total of 3441 obstetric malpractice lawsuits successfully claimed were reviewed in this study, with a total indemnity payment of $139,875,375. After peaking in 2017, the number of obstetric malpractice claims begins to decline. Of the 2424 hospitals that were sued, 8.3% (201/2424) were referred to as "repeat defendant" because they were involved in multiple lawsuits. Death and injury were the outcomes in 53.4% and 46.6% of the cases, respectively. The most common outcome type was neonatal death, which made up 29.8% of all cases. The median indemnity payment for death was higher compared with injury (P < 0.05). In terms of detailed injury outcomes, the major neonatal injury had higher median indemnity payments than neonatal death and fetal death (P < 0.05). The median indemnity payment of the major maternal injury was higher than that of maternal death (P < 0.05). The leading causes of obstetric malpractice were the management of birth complications and adverse events (23.3%), management of labor (14.4%), career decision making (13.7%), fetal surveillance (11.0%), and cesarean section management (9.5%). The cause for 8.7% of cases was high payment (≥$100, 000). As indicated by the results of the multivariate analysis, the hospitals in the midland of China (odds ratio [OR], 0.476; 95% confidence interval [CI], 0.348-0.651), the hospitals in the west of China (OR, 0.523; 95% CI, 0.357-0.767), and the secondary hospitals (OR, 0.587; 95% CI, 0.356-0.967) had lower risks of high payment. Hospitals with ultimate liability (OR, 9.695; 95% CI, 4.072-23.803), full liability (OR, 16.442; 95% CI, 6.231-43.391), major neonatal injury (OR, 12.326; 95% CI, 5.836-26.033), major maternal injury (OR, 20.885; 95% CI, 7.929-55.011), maternal death (OR, 18.783; 95% CI, 8.887-39.697), maternal death with child injury (OR, 54.682; 95% CI, 10.900-274.319), maternal injury with child death (OR, 6.935; 95% CI, 2.773-17.344), and deaths of both mother and child (OR, 12.770; 95% CI, 5.136-31.754) had higher risks of high payment. In the causative domain, only anesthetics had a higher risk of high payment (OR, 5.605; 95% CI, 1.347-23.320), but anesthetic-related lawsuits made up just 1.4% of all cases.

CONCLUSIONS

The healthcare systems had to pay a significant amount as a result of obstetric malpractice lawsuits. Greater efforts are required to minimize serious injury outcomes and improve obstetric quality in the risky domains.

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

The Gerard W. Ostheimer lecture is given annually to members of the Society for Obstetric Anesthesia and Perinatology. This lecture summarizes new and emerging literature that informs the clinical practice of obstetric anesthesiologists. In this review, some of the most influential articles discussed in the 2021 virtual lecture are highlighted. Themes include maternal mortality; disparities and social determinants of health; cognitive function, mental health, and recovery; quality and safety; operations, value, and economics; clinical controversies and dogmas; epidemics and pandemics; fetal-neonatal and child health; general clinical care; basic and translational science; and the future of peripartum anesthetic care. Practice-changing evidence is presented and evaluated. A priority list for clinical updates, systems, and quality improvement initiatives is presented.

Nontrombotic Pulmonary Embolism: Different Etiology, Same Significant Consequences

Nontrombotic pulmonary embolism represents the embolization of different types of materials (cells, organisms, gas, foreign material) into pulmonary circulation. The disease is uncommon, and clinical presentation together with laboratory findings are nonspecific. Its pathology is usually misdiagnosed based on imaging findings as pulmonary thromboembolism, but the correct diagnosis is essential because different therapeutic approaches are required. In this context, knowledge of the risk factors associated with nontrombotic pulmonary embolism and specific clinical symptoms is fundamental. Our objective was to discuss the specific features of the most common etiologies of nontrombotic pulmonary embolism, gas, fat, amniotic fluid, sepsis and tumors, to provide assistance for a rapid and correct diagnosis. Because the most common etiologies are iatrogenic, knowledge of the risk factors could be an important tool for prevention or rapid treatment if the disease develops during different procedures. The diagnosis of nontrombotic pulmonary embolisms represent a laborious challenge, and endeavors should be made to prevent development and increase awareness of this disease.

The Role of Echocardiography in Extracorporeal Membrane Oxygenation

PURPOSE OF REVIEW

Extracorporeal membrane oxygenation (ECMO) is increasingly used to temporarily support patients in severe circulatory and/or respiratory failure. Echocardiography is a core component of successful ECMO deployment. Herein, we review the role of echocardiography at different phases on extracorporeal support including candidate identification, cannulation, maintenance, complication vigilance, and decannulation.

RECENT FINDINGS

During cannulation, ultrasound is used to confirm intended vascular access and appropriate inflow cannula positioning. While on ECMO, echocardiographic evaluation of ventricular loading conditions and hemodynamics, cannula positioning, and surveillance for intracardiac or aortic thrombi is needed for complication mitigation. Echocardiography is crucial during all phases of ECMO use. Specific echocardiographic queries depend on the ECMO type, V-V, or V-A, and the specific cannula configuration strategy employed.

Association of Pregnancy Characteristics and Maternal Mortality With Amniotic Fluid Embolism

IMPORTANCE

Amniotic fluid embolism (AFE) is an uncommon pregnancy complication but is associated with high maternal mortality. Because of the rarity of AFE, associated risks factors and maternal outcomes have been relatively understudied.

OBJECTIVE

To examine the clinical, pregnancy, and delivery characteristics and the maternal outcomes related to AFE in a recent period in the US.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study examined hospital deliveries from January 1, 2016, to December 31, 2019, from the Healthcare Cost and Utilization Project's National Inpatient Sample.

MAIN OUTCOMES AND MEASURES

The primary outcome was clinical, pregnancy, and delivery characteristics of AFE, assessed with a multivariable binary logistic regression model. The coprimary outcome was failure to rescue, defined as maternal mortality after AFE. Associations with other severe maternal morbidity indicators and failure to rescue per clinical and pregnancy characteristics were also assessed.

RESULTS

A total of 14 684 135 deliveries were examined, with AFE diagnosed in 880 women, corresponding to an incidence rate of 6.0 per 100 000 deliveries. The cohort-level median patient age was 29 years (IQR, 25-33 years). In a multivariable analysis, (1) patient factors of older age, Asian and Black race, Western US region, pregestational hypertension, asthma, illicit substance use, and grand multiparity; (2) pregnancy factors of placental accreta spectrum (PAS), placental abruption, uterine rupture, polyhydramnios, chorioamnionitis, preeclampsia, fetal growth restriction, and fetal demise; and (3) delivery factors of early gestational age, cervical ripening, cesarean delivery, operative delivery, and manual removal were associated with AFE. Among these characteristics, PAS had the largest association with AFE (adjusted odds ratio [aOR], 10.01; 95% CI, 7.03-14.24). When stratified by the PAS subtypes, more severe forms of PAS had a greater association with AFE (aOR for increta and percreta, 17.35; 95% CI, 10.21-28.48; and aOR for accreta, 7.62; 95% CI, 4.83-12.01). Patients who had AFE were more likely to have coagulopathy (aOR, 24.68; 95% CI, 19.38-31.44), cardiac arrest (aOR, 24.56; 95% CI, 17.84-33.81), and adult respiratory distress syndrome (aOR, 10.72; 95% CI, 8.09-14.20). The failure-to-rescue rate after AFE was 17.0% overall. However, the failure-to-rescue rate exceeded 30% when AFE co-occurred with other severe maternal morbidity indicators: 45.8% for AFE, cardiac arrest, and coagulopathy; 43.2% for AFE, shock, and cardiac rhythm conversion; and 38.6% for AFE, cardiac arrest, coagulopathy, and shock. The failure-to-rescue rate after AFE also exceeded 30% when AFE occurred in the setting of placental pathology: 42.9% for AFE and PAS and 31.3% for AFE and placental abruption.

CONCLUSIONS AND RELEVANCE

This contemporaneous, national-level analysis validated previously known risk factors for AFE and confirmed the dismal outcomes of pregnancy complicated by AFE. The association between PAS and AFE, which was not previously reported, warrants further investigation.

Point of care maternal ultrasound in obstetrics

Ultrasound is the hallmark imaging modality traditionally used by obstetricians for fetal diagnosis and surveillance. The COVID-19 pandemic highlighted the role of point of care ultrasound for expeditious assessment of the maternal cardiopulmonary status. The familiarity of obstetricians with ultrasound, coupled with the availability of ultrasound equipment without the need to transport the patient, make point of care ultrasound particularly valuable in the labor and delivery unit. The rising contribution of cardiopulmonary disorders to maternal morbidity and mortality carves out many potential applications for point of care ultrasound during labor and delivery. Obstetricians have access to the technology and the skills to obtain the basic views required to assess for the presence of pulmonary edema, ventricular dysfunction, or intra-abdominal free fluid. Point of care ultrasound can be used routinely for the evaluation of pulmonary complaints or in the assessment of hypotension and may play an essential role in the diagnosis and management of life-threatening emergencies such as shock, an amniotic fluid embolism, or cardiac arrest. We reviewed the currently established point of care ultrasound protocols for the evaluation of cardiopulmonary complaints through the lens of the obstetrician. We call on educators and academic leaders to incorporate maternal point of care ultrasound teachings into existing curricula. Point of care ultrasound is of enormous value for providers with limited access to diagnostic imaging or subspecialty providers. With the growing complexity of the obstetrical population, acquiring the clinical skills to meet these evolving needs is a requisite step in the ongoing efforts to reduce maternal morbidity and mortality.

Obstetric Disorders and Critical Illness

In this article, we discuss some of the more common obstetric-related conditions that can lead to critical illness and require management in an ICU. These include the hypertensive disorders of pregnancy, postpartum hemorrhage, hemolysis, elevated liver enzymes, and low platelet syndrome, acute fatty liver of pregnancy, amniotic fluid embolism, and peripartum cardiomyopathy. We also discuss pulmonary embolism and Covid-19. Despite not being specific to obstetric patients, pulmonary embolism is a common, life-threatening diagnosis in pregnancy with particular risks and management aspects. Covid-19 does not seem to occur with higher frequency in pregnant women, but it leads to higher rates of ICU admissions and mechanical ventilation in pregnant women than in their nonpregnant peers. Its prevalence during our current global pandemic makes it important to discuss in this article. We provide a basis for critical care physicians to be engaged in informed conversations and management in a multidisciplinary manner with other relevant providers in the care of critically ill pregnant and postpartum women.

Pulmonary Embolism and Amniotic Fluid Embolism

Venous thromboembolism (VTE) as well as other embolic events including amniotic fluid embolism (AFE) remain a leading cause of maternal death in the United States and worldwide. The pregnant patient is at a higher risk of developing VTE including pulmonary embolism. In contrast, AFE is a rare, but catastrophic event that remains incompletely understood. Here the authors review the cause of VTE in pregnancy and look at contemporary and evidence-based practices for the evaluation, diagnosis, and management in pregnancy. Then the cause and diagnostic difficulty of AFE as well as what is known regarding the pathogenesis are reviewed.

Procoagulant Activity in Amniotic Fluid Is Associated with Fetal-Derived Extracellular Vesicles

Procoagulant activity in amniotic fluid (AF) is positively correlated with phosphatidylserine (PS) and tissue factor (TF)-expressing(+) extracellular vesicles (EVs). However, it is unknown if pathological fetal conditions may affect the composition, phenotype, and procoagulant potency of EVs in AF. We sought to evaluate EV-dependent procoagulant activity in AF from pregnant people with fetuses with or without diagnosed chromosomal mutations. AF samples were collected by transabdominal amniocentesis and assessed for common karyotype defects (total n = 11, 7 healthy and 4 abnormal karyotypes). The procoagulant activity of AF was tested using a fibrin generation assay with normal pooled plasma and plasmas deficient in factors XII, XI, IX, X, V, and VII. EV number and phenotype were determined by flow cytometry with anti-CD24 and anti-TF antibodies. We report that factor-VII-, X-, or V-deficient plasmas did not form fibrin clots in the presence of AF. Clotting time was significantly attenuated in AF samples with chromosomal mutations. In addition, CD24+, TF+, and CD24+ TF+ EV counts were significantly lower in this group. Finally, we found a significant correlation between EV counts and the clotting time induced by AF. In conclusion, we show that AF samples with chromosomal mutations had fewer fetal-derived CD24-bearing and TF-bearing EVs, which resulted in diminished procoagulant potency. This suggests that fetal-derived EVs are the predominant source of procoagulant activity in AF.

Thrombotic pulmonary embolism of inferior vena cava during caesarean section: A case report and review of the literature

BACKGROUND

Thrombotic pulmonary embolism (TPE) is one of the most critical diseases in obstetrics but is rarely reported in caesarean section (CS) because TPE patients in CS have a high risk of death and are difficult to diagnose. This case report of TPE during CS was recorded by transthoracic echocardiography (TTE) and can provide a reference for the differential diagnosis of critical illnesses in CS.

CASE SUMMARY

A 37-year-old pregnant woman with rheumatic heart disease (RHD), gravida 5 and para 1 (G5P1), presented for emergency CS at 33 wk and 3 d of gestation under general anesthesia because of acute heart failure, pulmonary hypertension and arrhythmia. After placental removal during CS, TTE revealed a nascent thrombus in the inferior vena cava (IVC) that elongated, detached and fragmented leading to acute thromboembolic events and acute TPE. This report presents the whole process and details of TPE during CS and successful rescue without any sequelae in the patient. This case gives us new ideas for the diagnosis of death or cardiovascular accidents during CS in pregnant women with heart disease and the detailed presentation of the rapid development of TPE may also elucidate new ideas for treatment. This case also highlighted the importance of prophylactic anticoagulation in the management of heart disease during pregnancy.

CONCLUSION

Pregnancy with heart failure could trigger inferior vena cava (IVC)-origin TPE during CS. Detection and timely treatment can avoid serious consequences.

Post-authorization surveillance of adverse events following COVID-19 vaccines in pregnant persons in the Vaccine Adverse Event Reporting System (VAERS), December 2020 – October 2021

Background

Objective

Methods

Results

Conclusions

A Detailed Review of Critical Care Considerations for the Pregnant Cardiac Patient

Maternal cardiovascular disease is a leading cause of maternal death worldwide and recently, maternal mortality has increased secondary to cardiovascular causes. Maternal admissions to critical care encompass 1%-2% of all critical care admissions, and although not common, the management of the critically ill pregnant patient is complex. Caring for the critically ill pregnant cardiac patient requires integration of pregnancy-associated physiologic changes, understanding pathophysiologic disease states unique to pregnancy, and a multidisciplinary approach to timing around delivery as well as antenatal and postpartum care. Herein we describe cardiorespiratory changes that occur during pregnancy and the differential diagnosis for cardiorespiratory failure in pregnancy. Cardiorespiratory diseases that are either associated or exacerbated by pregnancy are highlighted with emphasis on perturbations secondary to pregnancy and appropriate management strategies. Finally, we describe general management of the pregnant cardiac patient admitted to critical care.

Venoarterial extracorporeal membrane oxygenation as an early treatment for amniotic fluid embolism with cardiac arrest: A case report

Amniotic fluid embolism (AFE) is a rare but fatal obstetric complication, characterized by sudden cardiovascular collapse, respiratory failure, and disseminated intravascular coagulation. Maternal mortality associated with AFE is high, making early recognition and prompt treatment important. In AFE with cardiac arrest, survival following acute cardiopulmonary dysfunction is crucial. In recent years, venoarterial extracorporeal membrane oxygenation (VA-ECMO) has attracted attention as an aggressive treatment for AFE with cardiac arrest. A 40-year-old woman experienced sudden cardiac arrest due to AFE during cesarean section. Cardiopulmonary resuscitation and VA-ECMO (also called percutaneous cardiopulmonary support) were initiated early. Finally, she recovered without any complications. VA-ECMO can provide temporary respiratory and hemodynamic support until cardiopulmonary function improves after a few days in intensive care. VA-ECMO should be considered as an early treatment for AFE with cardiac arrest.

Society for Maternal-Fetal Medicine Special Statement: Checklist for initial management of amniotic fluid embolism

Amniotic fluid embolism is a rare syndrome characterized by sudden cardiorespiratory collapse during labor or soon after delivery. Because of its rarity, many obstetrical providers have no experience in managing amniotic fluid embolism and may therefore benefit from a cognitive aid such as a checklist. We present a sample checklist for the initial management of amniotic fluid embolism based on standard management guidelines. We also suggest steps that each facility can take to implement the checklist effectively.

Obstetric Hemorrhage

Peripartum hemorrhage is a leading cause of maternal morbidity and mortality. Anesthesiologists must be familiar with conditions associated with hemorrhage that are unique to labor and delivery and not seen elsewhere in their practice. Regardless of etiology, early recognition and timely treatment of obstetric hemorrhage is necessary to prevent significant blood loss. Massive transfusion protocols are crucial to successful resuscitation, and providers should also consider use of cell salvage, uterine artery embolization, and anti-fibrinolytics. Because more than half the deaths due to hemorrhage are preventable, multidisciplinary care bundles should be used on every labor and delivery unit.

[Maternal Deaths due to Amniotic Fluid Embolism in France 2013-2015]

Amniotic fluid embolism remains the 3rd cause of maternal death in France, with a stable rate and 28 deaths in this triennium, representing 10.7% of maternal deaths and a maternal mortality ratio of 1.2/100,000 live births. Cases are characterized by the suddenness of symptoms: the median delay between symptoms and death was 4h [0.75-696] with 20/28 patients did not reach the intensive care unit. Initial circulatory failure or cataclysmic haemorrhage was the two modes of presentation. Prodromes were reported in 17 (63%) cases and induction of labour was present in 12/27 (44%). One or more factors of sub-optimal care were present in 72% of the cases, and 52% of deaths were considered possibly or probably preventable. This preventability most often concerned the content of care but also the organisation of care (including human resources, communication, sites of care and referrals). The delay in establishing a well-conducted cardio-circulatory resuscitation or the delay in setting up an optimal transfusion strategy were the most frequent elements of substandard care. Absence or delay at hysterectomy during haemorrhagic situations was reported in 15/20 cases. The experts suggest being on the alert to diagnose amniotic embolism at an early stage, initiating intense resuscitation "outside the walls", envisaging a hysterectomy without delay if the haemorrhage is intense. On an organisational level, a "vital emergency maternity care" plan, specific to each establishment could be proposed.

Resuscitating the Crashing Pregnant Patient

Care of the critically ill pregnant patient is anxiety-provoking for those unprepared, as the emergency physician must consider not only the welfare of the immediate patient, but of the fetus as well. Familiarity with the physiologic changes of pregnancy and how they affect clinical presentation and management is key. Although some medications may be safer in pregnancy than others, stabilizing the pregnant patient is paramount. Emergency physicians should target pregnancy-specific oxygen and ventilation goals and hemodynamics and should be prepared to perform a perimortem cesarean section, should the mother lose pulses, to increase chances for maternal and fetal survival.

Maternal mortality in the United States: research gaps, opportunities, and priorities

Maternal mortality and severe maternal morbidity are urgent issues in the United States. It is important to establish priority areas to address these public health crises. On April 8, 2019, and May 2 to 3, 2019, the Eunice Kennedy Shriver National Institute of Child Health and Human Development organized and invited experts with varied perspectives to 2 meetings, a community engagement forum and a scientific workshop, to discuss underlying themes involved in the rising incidence of maternal mortality in the United States. Experts from diverse disciplines reviewed current data, ongoing activities, and identified research gaps focused on data measurement and reporting, obstetrical and health system factors, social determinants and disparities, and the community perspective and engagement. Key scientific opportunities to reduce maternal mortality and severe maternal morbidity include improved data quality and measurement, understanding the populations affected as well as the numerous etiologies, clinical research to confirm preventive and interventional strategies, and engagement of community participation in research that will lead to the reduction of maternal mortality in the United States. This article provides a summary of the workshop presentations and discussions.

Extracorporeal Membrane Oxygenation for Amniotic Fluid Embolism-Induced Cardiac Arrest in the First Trimester of Pregnancy: A Case Report

Supplemental Digital Content is available in the text.

Amniotic fluid embolism is a rare obstetric emergency that can be accompanied by profound hypoxemia, coagulopathy, hemorrhage, and cardiogenic shock. Extracorporeal membrane oxygenation may provide a rescue strategy in amniotic fluid embolism with cardiopulmonary collapse. Approaches to anticoagulation must be balanced against the risk of hemorrhage with concomitant coagulopathy. Although extracorporeal membrane oxygenation has been described for cardiopulmonary collapse in the setting of amniotic fluid embolism, its initiation as a bridge to hemostasis and cardiopulmonary recovery in amniotic fluid embolism–induced hemorrhagic and cardiogenic shock remains a novel resuscitation strategy.

Amniotic fluid embolism syndrome: analysis of the Unites States International Registry

BACKGROUND

Incidence, risk factors, and perinatal morbidity and mortality rates related to amniotic fluid embolism remain a challenge to evaluate, given the presence of differing international diagnostic criteria, the lack of a gold standard diagnostic test, and a significant overlap with other causes of obstetric morbidity and mortality.

OBJECTIVE

The aims of this study were (1) to analyze the clinical features and outcomes of women using the largest United States-based contemporary international amniotic fluid embolism registry, and (2) to investigate differences in demographic and obstetric variables, clinical presentation, and outcomes between women with typical versus atypical amniotic fluid embolism, using previously published and validated criteria for the research reporting of amniotic fluid embolism.

MATERIALS AND METHODS

The AFE Registry is an international database established at Baylor College of Medicine (Houston, TX) in partnership with the Amniotic Fluid Embolism Foundation (Vista, CA) and the Perinatology Research Branch of the Division of Intramural Research of the NICHD/NIH/DHHS (Detroit, MI). Charts submitted to the registry between August 2013 and September 2017 were reviewed, and cases were categorized into typical, atypical, non-amniotic fluid embolism, and indeterminate, using the previously published and validated criteria for the research reporting of AFE. Demographic and clinical variables, as well as outcomes for patients with typical and atypical AFE, were recorded and compared. Student t tests, χ2 tests, and analysis of variance tables were used to compare the groups, as appropriate, using SAS/STAT software, version 9.4.

RESULTS

A total of 129 charts were available for review. Of these, 46% (59/129) represented typical amniotic fluid embolism and 12% (15/129) atypical amniotic fluid embolism, 21% (27/129) were non-amniotic fluid embolism cases with a clear alternative diagnosis, and 22% (28/129) had an uncertain diagnosis. Of the 27 women misclassified as an amniotic fluid embolism with an alternative diagnosis, the most common actual diagnosis was hypovolemic shock secondary to postpartum hemorrhage. Ten percent (6/59) of the women with typical amniotic fluid embolism had a pregnancy complicated by placenta previa, and 8% (5/61) had undergone in vitro fertilization to achieve pregnancy. In all, 66% (49/74) of the women with amniotic fluid embolism reported a history of atopy or latex, medication, or food allergy, compared to 34% of the obstetric population delivered at our hospital over the study period (P < .05).

CONCLUSION

Our data represent a series of women with amniotic fluid embolism whose diagnosis has been validated by detailed chart review, using recently published and validated criteria for research reporting of amniotic fluid embolism. Although no definitive risk factors were identified, a high rate of placenta previa, reported allergy, and conceptions achieved through in vitro fertilization was observed.

Extracorporeal Membrane Oxygenation During Adult Noncardiac Surgery and Perioperative Emergencies: A Narrative Review

Over the last decade, the use of extracorporeal membrane oxygenation (ECMO) has increased significantly. In some centers, ECMO has been deployed to manage perioperative emergencies and plays a role in facilitating high-risk thoracic, airway, and trauma surgery, which may not be feasible without ECMO support. General anesthesiologists who usually manage these cases may not be familiar with the initiation and management of patients on ECMO. This review discusses the use of ECMO in the operating room for thoracic, airway, and trauma surgery, as well as obstetric and perioperative emergencies.