Echocardiography findings in amniotic fluid embolism: a systematic review of the literature

PURPOSE

Amniotic fluid embolism (AFE) is a leading cause of obstetrical cardiac arrest and maternal morbidity. The pathogenesis of hemodynamic collapse is thought to be from right ventricular (RV) failure; however, there is a paucity of data documenting echocardiography findings in this population. We undertook a systematic review of the literature to evaluate the echocardiography findings in patients with AFE.

SOURCES

We retrieved all case reports and case series reporting AFE in Embase and MEDLINE from inception to 20 November 2021. Studies reporting AFE diagnosed by fulfilling at least one of three different proposed AFE criteria and echocardiography findings during hospitalization were included. Patient and echocardiographic data were retrieved, and univariate logistic regression analysis was performed for outcomes of interest. Bias was assessed using the Joanna Briggs Institute clinical appraisal tool for case series.

PRINCIPAL FINDINGS

Eighty publications reporting on 84 patients were included in the final review. Fifty-five out of 82 patients with data (67%) showed RV dysfunction, including 11/82 (13%) with biventricular dysfunction; 14/82 (17%) had normal systolic function. No data on RV or left ventricular function were reported for two patients. The presence of RV dysfunction on echocardiography was associated with cardiac arrest (odds ratio [OR], 3.66; 95% confidence interval [CI], 1.39 to 9.67; P = 0.009), and a composite risk of cardiac arrest, maternal death or use of extracorporeal membrane oxygenation (OR, 3.86; 95% CI, 1.43 to 10.4; P = 0.007). A low risk of bias was observed in 15/84 (18%) cases.

CONCLUSIONS

Right ventricular dysfunction on echocardiography is a common finding in AFE and is associated with a high risk of cardiac arrest. The finding of RV dysfunction on echocardiography may help diagnose AFE and help triage the highest risk patients with AFE.

STUDY REGISTRATION

PROSPERO (CRD42021271323); registered 1 September 2021.

The role of echocardiography in amniotic fluid embolism: a case series and review of the literature

PURPOSE

Amniotic fluid embolism (AFE) is a rare, but often fatal condition characterized by sudden hemodynamic instability and coagulopathy occurring during labour or in the early postpartum period. As the mechanisms leading to shock and the cardiovascular effects of AFE are incompletely understood, the purpose of this case series is to describe how AFE presents on echocardiography and review limited reports in the literature.

CLINICAL FEATURES

We describe three cases of AFE at the Jewish General Hospital, a tertiary care centre in Montreal, Canada. All cases met the Clark diagnostic criteria, which comprise 1) sudden cardiorespiratory arrest or both hypotension and respiratory compromise, 2) disseminated intravascular coagulation, 3) clinical onset during labour or within 30 min of delivery of the placenta, and 4) absence of fever. Two patients had a cardiac arrest and the third developed significant hypotension and hypoxia. In all patients, point-of-care echocardiography at the time of shock revealed signs of right ventricular failure including a D-shaped septum, acute pulmonary hypertension, and right ventricular systolic dysfunction.

CONCLUSION

This case series and literature review of AFE emphasizes the importance of echocardiography in elucidating the etiology of maternal shock. The presence of right ventricular failure may be considered an important criterion to diagnose AFE.

Case report of amniotic fluid embolism coagulopathy following abortion; use of viscoelastic point-of-care analysis

BACKGROUND

Amniotic fluid embolism (AFE) is a rare, life threatening obstetric complication, often associated with severe coagulopathy. Induced abortions are extremely safe procedures however complications including AFE can occur.

CASE PRESENTATION

A 29-year-old previously healthy woman, gravida 1 para 0, presented for a scheduled second trimester induced abortion via dilation and evacuation at 22-weeks gestation. The case was complicated by a suspected AFE with associated profound coagulopathy. Viscoelastic point-of-care coagulation analysis was used to successfully and swiftly guide management of her coagulopathy.

CONCLUSION

AFE can occur in the setting of induced abortion. This case report suggests viscoelastic point-of-care coagulation analyzers may aid in the management of pregnancy-related coagulopathy by providing faster coagulation assessment than laboratory testing, and facilitating timely, targeted management of coagulopathy.

Amniotic fluid embolism: principles of early clinical management

Amniotic fluid embolism is an uncommon, but potentially lethal, complication of pregnancy. Because amniotic fluid embolism usually is seen with cardiac arrest, the initial immediate response should be to provide high-quality cardiopulmonary resuscitation. We describe key features of initial treatment of patients with amniotic fluid embolism. Where available, we recommend performing transthoracic or transesophageal echocardiography as soon as possible because this is an easy and reliable method of identifying a failing right ventricle. If such failure is identified, treatment that is tailored at improving right ventricular performance should be initiated with the use of inotropic agents and pulmonary vasodilators. Blood pressure support with vasopressors is preferred over fluid infusion in the setting of severe right ventricular compromise. Amniotic fluid embolism-related coagulopathy should be managed with hemostatic resuscitation with the use of a 1:1:1 ratio of packed red cells, fresh frozen plasma, and platelets (with cryoprecipitate as needed to maintain a serum fibrinogen of >150-200 mg/dL). In cases that require prolonged cardiopulmonary resuscitation or, after arrest, severe ventricular dysfunction refractory to medical management, consideration for venoarterial extracorporeal membrane oxygenation should be given.

Echocardiographically detected mass "in transit" in early amniotic fluid embolism

BACKGROUND

Amniotic fluid embolism is a catastrophic illness related to the passage of fetal material into the pulmonary circulation causing cardiovascular collapse.

CASE

A 29-year-old female sustained cardiopulmonary arrest during delivery presumably due to amniotic fluid embolism. A right atrial mass "in transit" was detected by echocardiography. It had an appearance and pattern of motion that was suggestive of a gelatinous consistency and is likely to have been an amniotic fluid embolus. There was also evidence of acute right ventricular overload.

CONCLUSION

We recommend that echocardiography be considered early on such conditions to gain more insight into the pathogenesis of this complication.

Massive amniotic fluid embolism: diagnosis aided by emergency transesophageal echocardiography

A 36-year-old woman was hospitalized at term and in labor at 3-cm cervical dilatation. The early labor course was remarkable only for oxytocin augmentation and combined spinal-epidural analgesia. Eight hours after admission, tetanic uterine contractions ensued, followed by persistent fetal bradycardia. An emergency cesarean section was performed and a viable male infant was delivered. Intraoperatively, a placental abruption was identified, and disseminated intravascular coagulation and persistent hypotension developed despite resuscitative efforts. Transesophageal echocardiography revealed normal left ventricular contractility and gross enlargement of the right ventricle and main pulmonary trunk, consistent with acute right ventricular pressure overload and underloading of the left ventricle. Despite resuscitative efforts, the patient died three hours postoperatively. Autopsy showed extensive microvascular plugging of the pulmonary capillaries by fetal cells in all lung fields. This is a rare case of amniotic fluid embolism diagnosed in part and managed pre-mortem with transesophageal echocardiography and confirmed by autopsy findings.

Thrombotic and nonthrombotic pulmonary arterial embolism: spectrum of imaging findings

Along with clinical examination and laboratory tests, imaging plays a key role in the diagnosis of pulmonary embolism. Multi-detector row helical computed tomography (CT) is particularly helpful in the diagnosis of acute pulmonary thromboembolism (PTE) owing to its capacity to directly show emboli as intravascular filling defects. Although parenchymal abnormalities at CT are nonspecific for acute PTE, they may contribute to a correct diagnosis of chronic PTE, the characteristic helical CT features of which are similar to its angiographic features and include webs or bands, intimal irregularities, abrupt narrowing or complete obstruction of the pulmonary arteries, and "pouching defect." Nonthrombotic pulmonary embolism is an uncommon condition but is sometimes associated with specific imaging findings, including discrete nodules with cavitation (septic embolism), widespread homogeneous and heterogeneous areas of increased opacity or attenuation that typically appear 12-24 hours after trauma (fat embolism), and fine miliary nodules that subsequently coalesce into large areas of increased opacity or attenuation (talcosis). Knowledge of appropriate imaging methods and familiarity with the specific imaging features of pulmonary embolism should facilitate prompt, effective diagnosis.

Severe maternal respiratory distress due to the amniotic fluid embolism syndrome in a twin pregnancy

A 28-year-old female with a twin pregnancy at 29 6/7 weeks who was having premature uterine contractions developed acute respiratory failure due to sudden pulmonary oedema requiring mechanical ventilation. No evidence for venous thromboembolism, pulmonary infection or myocardial infarction was found. Subsequently a mild coagulopathy and foetal distress developed. Ultrasonography revealed oligohydramnios of one of the foetuses. A Caesarean section was performed and postoperatively mother and babies had an uneventful clinical course. By exclusion of other causes, we diagnosed severe maternal acute respiratory distress due to the amniotic fluid embolism syndrome in a twin pregnancy.

[Amniotic fluid embolism in a 24-year-old female after caesarean section - a case report]

A case of a 24-year-old female with amniotic fluid embolism following an urgent caesarean section is presented. Medical treatment was effective. Prognosis in this condition and differential diagnosis are discussed.

Amniotic fluid embolism causing catastrophic pulmonary vasoconstriction: diagnosis by transesophageal echocardiogram and treatment by cardiopulmonary bypass

BACKGROUND

Amniotic fluid embolism is a rare yet often lethal peripartum complication resulting from rapid cardiovascular collapse. Progress toward a better understanding of this entity has failed to identify either the underlying hemodynamic pathophysiology or an effective evidence-based treatment.

CASE

A 45-year-old woman with a documented placenta previa experienced an amniotic fluid embolism during scheduled cesarean delivery. Transesophageal echocardiogram examination revealed catastrophic pulmonary vasoconstriction. The use of cardiopulmonary bypass, heparin, epinephrine, and high-dose steroids resulted in a successful outcome.

CONCLUSION

Timely placement of transesophageal echocardiogram revealed catastrophic pulmonary vasoconstriction as the cause of circulatory collapse in a patient with amniotic fluid embolism, supporting the use of cardiopulmonary bypass as an effective intervention.

Non-fatal amniotic fluid embolism after cervical suture removal

We describe a case of pulmonary oedema occurring at 37 weeks gestation, following the attempted removal of a cervical suture under general anaesthesia. The use of an ultrasound technique to demonstrate the patient's fluid status is described. Signs of amniotic fluid embolism and how it exerts its influence on the circulation are discussed.

Lung mass due to amniotic fluid embolism--an intrathoracic complication of pregnancy

A 29-year-old woman with right chest pain was admitted for radiographic investigation and found to have a round mass in the right lower zone. This was initially suspected to be a hydatid lung cyst but was confirmed as a cystic mass by computed tomography and duly excised. Histologic examination revealed an amniotic fluid embolism. The patient had had a stillbirth three months earlier.

Radiographic appearance of intrathoracic complications of pregnancy

The authors reviewed all chest radiographs obtained for pregnant women at a university hospital over a 15-year period to determine the intrathoracic complications of pregnancy and diseases occurring during pregnancy. The characteristic physiologic changes seen on chest radiographs during normal pregnancy are reviewed. Examples of intrathoracic diseases that may occur in pregnant patients include pulmonary embolism, amniotic fluid embolism, beriberi, aspiration pneumonia, community-acquired pneumonia, viral pneumonia, asthma, systemic disease, trophoblastic disease and peripartum pulmonary edema. The authors discuss the radiation biology implications of performing chest radiography during pregnancy and conclude that the benefit that the fetus receives from diagnosis and treatment of the mother's disease may be greater than the risk of radiation exposure.