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

A Case of Consumptive Coagulopathy Before Cardiopulmonary Failure in Amniotic Fluid Embolism and Review of Literature: A Perspective of the Latent Onset and Progression of Coagulopathy

Amniotic fluid embolism (AFE) induces cardiopulmonary insufficiency with consumptive coagulopathy. Previous studies reported that refractory coagulopathy has already advanced at the onset of maternal cardiovascular and/or respiratory symptoms. However, when the consumption of coagulation factors starts during the clinical course, AFE remains to be elucidated. We report an intrapartum AFE case of consumptive coagulopathy before dyspnea with hypotension developing during urgent cesarean delivery that was revealed by non-reassuring fetal heart rate tracing. The patient, a 42-year-old multiparous parturient, underwent induced labor after a premature rupture of membranes in week 39 of pregnancy. Coagulation screening was initially within the normal range. Fetal heart rate monitoring demonstrated bradycardia coincided with uterine tachysystole after three hours, which required urgent cesarean section with preoperative blood screening. The hemoglobin level was maintained at 129 g/L; however, the fibrinogen value reduced to 1.79 g/L with D-dimer elevation over 60 µg/mL. Ninety minutes later, she developed dyspnea with hypotension at suturing hysterotomy. At the end of surgery, her fibrinogen further decreased to below 0.3 g/L with prolonged prothrombin time. After vigorous intensive care, she was discharged without sequelae. Consumptive coagulopathy may initiate and progress before apparent cardiopulmonary symptoms in some AFE cases. Non-reassuring fetal heart rate tracing concomitant with abrupt uterine tachysystole and/or hypertonus may be an earlier time point for the detection and intervention of AFE-related coagulopathy.

Amniotic fluid embolism: a reappraisal

OBJECTIVES

Using cases from our own experience and from the published literature on amniotic fluid embolism (AFE), we seek to improve on existing criteria for diagnosis and discern associated risk factors. Additionally, we propose a novel theory of pathophysiology.

METHODS

This retrospective case review includes eight cases of AFE from two hospital systems and 21 from the published literature. All cases were evaluated using the modified criteria for research reporting of AFE by Clark et al. in Am J Obstet Gynecol, 2016;215:408-12 as well as our proposed criteria for diagnosis. Additional clinical and demographic characteristics potentially correlated with a risk of AFE were included and analyzed using descriptive analysis.

RESULTS

The incidence of AFE was 2.9 per 100,000 births, with five maternal deaths in 29 cases (17.2 %) in our series. None of the cases met Clark's criteria while all met our criteria. 62.1 % of patients were over the age of 32 years and two out of 29 women (6.9 %) conceived through in-vitro fertilization. 6.5 % of cases were complicated by fetal death. Placenta previa occurred in 13.8 %. 86.2 % of women had cesarean sections of which 52.0 % had no acute maternal indication.

CONCLUSIONS

Our criteria identify more patients with AFE than others with a low likelihood of false positives. Clinical and demographic associations in our review are consistent with those previously reported. A possible relationship between cesarean birth and risk of AFE was identified using our criteria. Additionally, we propose a new hypothesis of pathophysiology.

Neurological Complications in Pregnancy and the Puerperium: Methodology for a Clinical Diagnosis

Neurological complications in pregnancy and the puerperium deserve particular attention from specialists due to the worsening of the clinical picture for both the mother and the fetus. This narrative review of existing data in the literature aims to analyze the most common "red flag symptoms" attributable to neurological complications such as pre-eclampsia (PE), eclampsia, HELLP syndrome, posterior reversible encephalopathy syndrome (PRES), cerebral vasoconstriction syndrome (RCVS), stroke, CVS thrombosis, pituitary apoplexy, amniotic fluid embolism and cerebral aneurysm rupture, with the aim of providing a rapid diagnostic algorithm useful for the early diagnosis and treatment of these complications. The data were derived through the use of PubMed. The results and conclusions of our review are that neurological complications of a vascular nature in pregnancy and the puerperium are conditions that are often difficult to diagnose and manage clinically. For the obstetrics specialist who is faced with these situations, it is always important to have a guide in mind in order to be able to unravel the difficulties of clinical reasoning and promptly arrive at a diagnostic hypothesis.

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.

Maternal collapse in pregnancy

Maternal collapse is a rare life-threatening event that can occur at any stage of pregnancy or up to 6 weeks postpartum. Prompt identification and timely intervention by a multidisciplinary team that includes an obstetrician, midwifery staff and an obstetric anaesthetist are essential to improve maternal and fetal outcomes. Standard adult resuscitation guidelines need to be followed with some modifications, taking into account the maternal-fetal physiology, which clinicians should be familiar with. During cardiac arrest, the emphasis is on advanced airway management, manual uterine displacement to relieve aortocaval compression and performing a resuscitative hysterotomy (peri-mortem caesarean delivery) swiftly in patients who are more than 20 weeks gestation to improve maternal survival. Annual multidisciplinary simulation training is recommended for all professionals involved in maternity care; this can improve teamwork, communication and emergency preparedness during maternal collapse.

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.

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.

Utilization of point-of-care ultrasound and rotational thromboelastometry (ROTEM) in the diagnosis and management of amniotic fluid embolism presenting as post-partum hemorrhage and cardiac arrest

Objectives

To describe the integration of point-of-care ultrasound (POCUS) and rotational thromboelastometry (ROTEM) in the diagnosis and management of cardiac arrest secondary to amniotic fluid embolism (AFE).

Case presentation

A 29-year-old female presented for induction of labor at 39 weeks. Labor was complicated by hemorrhage and subsequent sinus tachycardia pulseless electrical activity (PEA) arrest. Intra-arrest POCUS demonstrated right ventricular dilation and hypokinesis adding to a presumed hemorrhagic arrest etiology. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) was initiated at the bedside following the POCUS findings. ROTEM further clarified the etiology of hemorrhage as disseminated intravascular coagulation (DIC), and in combination with the POCUS findings led to a final diagnosis of amniotic fluid embolism with DIC. The patient was maintained on VA-ECMO without heparin in the setting of DIC. She had a complicated hospital course but was discharged home with her healthy child and no residual physical or neurologic deficits.

Conclusions

In the absence of more specific testing modalities the utilization of rapidly available POCUS in conjunction with ROTEM can impact clinical decision making of cardiovascular resuscitation in patients during labor and delivery by narrowing the differential between pulmonary embolism and AFE.