Massive amniotic fluid embolism: diagnosis aided by emergency transesophageal echocardiography

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.

Sudden maternal hypoxemia during elective cesarean section in a woman with placenta previa

There have been no reports regarding imaging‐documented bronchospasm in patients with amniotic fluid embolism (AFE). In a woman with scheduled cesarean section for placenta previa, transient bronchospasm and pulmonary hypertension were documented explaining a sudden drop in SpO₂. Mild AFE was the most likely diagnosis in this patient.

Amniotic fluid embolism

Amniotic fluid embolism (AFE) is an unpredictable and as-of-yet unpreventable complication of maternity. With its low incidence it is unlikely that any given practitioner will be confronted with a case of AFE. However, this rare occurrence carries a high probability of serious sequelae including cardiac arrest, ARDS, coagulopathy with massive hemorrhage, encephalopathy, seizures, and both maternal and infant mortality. In this review the current state of medical knowledge about AFE is outlined including its incidence, risk factors, diagnosis, pathophysiology, and clinical manifestations. Special attention is paid to the modern aggressive supportive care that resulted in an overall reduction in the still alarmingly high mortality rate of this devastating entity. The key factors for successful management and resolution of this disease process continue to be sharp vigilance, a high level of clinical suspicion, and rapid all-out resuscitative efforts on the part of all clinicians involved in the medical care of the parturient.

[Amniotic fluid embolism: report of the successful outcome of a case with inaugural cardiac arrest and early DIVC complicated by hemoperitoneum of iatrogen origin and bleeding of an hepatic adenoma]

Amniotic fluid embolism is a relatively rare clinical entity and with difficult medical recognition. However, it is the second leading cause of maternal mortality. We report here the case of a 32-year-old patient who underwent elective caesarean section complicated by an amniotic fluid embolism with cardiac arrest. The presence of a major disseminated intravascular coagulation favored the occurrence of a retroperitoneal hematoma of iatrogenic origin on attempt of femoral venous catheterization and that of hemoperitoneum on bleeding of an hepatic adenoma. The diagnostic of amniotic fluid embolism was confirmed by the presence of amniotic cells in the bronchoalveolar lavage. The patient survived without sequelae.

Aortic compression and cross clamping in a case of placenta percreta and amniotic fluid embolism: a case report

Amniotic fluid embolism (AFE, also known as anaphylactoid syndrome of pregnancy) at the time of surgery for placenta percreta has been previously reported. We report here a case in which AFE and associated cardiac arrest occurred following a hysterectomy for placenta percreta. In this case, subhepatic manual aortic compression during the cardiac arrest and chest compressions followed by infrarenal aortic cross-clamping during volume infusion and reversal of the coagulopathy were associated with a successful resuscitation and good maternal outcome.

Amniotic fluid embolism: A diagnostic dilemma

Amniotic fluid embolism (AFE) is a rare obstetric catastrophe with an incidence of 7.7 per 100 000 deliveries and mortality as high as 60% to 80%. We describe a case of perioperative cardiac arrest in a young parturient undergoing an emergent cesarean section. Just after delivery of live healthy male baby, patient developed disseminated intravascular coagulation not responding to resuscitation with fluids and blood products. Her autopsy revealed edematous lungs with amniotic fluid debris within pulmonary vessels thus establishing the diagnosis of AFE. Amniotic fluid embolism is life threatening and difficult to predict or prevent condition, which should be always be kept in mind in a parturient with sudden cardiovascular collapse, so that resuscitation commences immediately, as early intervention is essential for a positive outcome.

Maternal death following cardiopulmonary collapse after delivery: amniotic fluid embolism or septic shock due to intrauterine infection?

PROBLEM

The amniotic fluid embolism (AFE) syndrome is a catastrophic complication of pregnancy frequently associated with maternal death. The causes and mechanisms of disease responsible for this syndrome remain elusive.

METHOD OF STUDY

We report two cases of maternal deaths attributed to AFE: (1) one woman presented with spontaneous labor at term, developed intrapartum fever, and after delivery had sudden cardiovascular collapse and disseminated intravascular coagulation (DIC), leading to death; (2) another woman presented with preterm labor and foul-smelling amniotic fluid, underwent a Cesarean section for fetal distress, and also had postpartum cardiovascular collapse and DIC, leading to death.

RESULTS

Of major importance is that in both cases, the maternal plasma concentration of tumor necrosis factor-alpha at the time of admission to the hospital and when patients had no clinical evidence of infection was in the lethal range (a lethal range is considered to be above 0.1 ng/mL).

CONCLUSION

We propose that subclinical intraamniotic infection may be a cause of postpartum cardiovascular collapse and DIC and resemble AFE. Thus, some patients with the clinical diagnosis of AFE may have infection/systemic inflammation as a mechanism of disease. These observations have implications for the understanding of the mechanisms of disease of patients who develop cardiovascular collapse and DIC, frequently attributed to AFE. It may be possible to identify a subset of patients who have biochemical and immunological evidence of systemic inflammation at the time of admission, and before a catastrophic event occurs.

Amniotic fluid embolism: an evidence-based review

We conducted an evidence-based review of information about [corrected] amniotic fluid embolism (AFE). The estimated incidence of AFE is 1:15,200 and 1:53,800 deliveries in North America and Europe, respectively. The case fatality rate and perinatal mortality associated with AFE are 13-30% and 9-44%, respectively. Risk factors associated with an [corrected] increased risk of AFE include advanced maternal age, placental abnormalities, operative deliveries, eclampsia, polyhydramnios, cervical lacerations, [corrected] and uterine rupture. The hemodynamic response in [corrected] AFE is biphasic, with initial pulmonary hypertension and right ventricular failure, followed by left ventricular failure. Promising therapies include selective pulmonary vasodilators and recombinant activated factor VIIa. Important topics for future research are presented.

Responding to amniotic fluid embolism

Amniotic fluid embolism (AFE), an uncommon disorder with a high fatality rate, is an obstetric emergency that requires swift recognition and intervention to save both the mother's life and that of her child.The high mortality rate and varying theories as to its cause make it difficult to diagnose AFE, which can occur at any point during labor and delivery, including during cesarean birth. These factors make it important for perioperative nurses to understand and recognize AFE when it occurs in the OR. Rapid delivery of the fetus is imperative for the survival of both mother and child. Monitoring and aggressively providing respiratory and circulatory support interventions are required if the mother is to survive AFE.

Amniotic fluid embolism

The disastrous entry of amniotic fluid into the maternal circulation leads to dramatic sequelae of clinical events, characteristically referred to as Amniotic fluid embolism (AFE). The underlying mechanism for AFE is still poorly understood. Unfortunately, this situation has very grave maternal and fetal consequences. AFE can occur during labor, caesarean section, dilatation and evacuation or in the immediate postpartum period. The pathophysiology is believed to be immune mediated which affects the respiratory, cardiovascular, neurological and hematological systems. Undetected and untreated it culminates into fulminant pulmonary edema, intractable convulsions, disseminated intravascular coagulation (DIC), malignant arrhythmias and cardiac arrest. Definite diagnosis can be confirmed by identification of lanugo, fetal hair and fetal squamous cells (squames) in blood aspirated from the right ventricle. Usually the diagnosis is made clinically and by exclusion of other causes. The cornerstone of management is a multidisciplinary approach with supportive treatment of failing organs systems. Despite improved modalities for diagnosing AFE, and better intensive care support facilities, the mortality is still high.

Transesophageal echocardiography and noncardiac surgery

The use of transesophageal echocardiography (TEE) for monitoring during cardiac and noncardiac surgery has increased exponentially over the past few decades. TEE has evolved from a diagnostic tool to a monitoring device and a procedural adjunct. The close proximity of the TEE transducer to the heart generates high-quality images of the intracardiac structures and their spatial orientation. The use of TEE in noncardiac and critical care settings is not well studied, and the evidence of the benefits of its use in these settings is lacking. Despite the widespread availability of TEE equipment in US hospitals, less than 30% of anesthesiologists are formally trained in the use of perioperative TEE. In this review, the safety and indications of TEE are reviewed and detailed analysis of the best available evidence in this regard is presented. Landmark trials evaluating the use of TEE and its therapeutic impact in noncardiac surgical setting are critically reviewed. This article details recommendations to familiarize anesthesiologists with TEE technology to exploit it to its fullest potential to achieve better patient monitoring standards and eventually improve outcome. Training of greater numbers of anesthesiologists in TEE is needed to increase awareness of the indications and contraindications. Until relatively inexpensive TEE equipment is available, the initial cost of equipment acquisition remains a significant prohibitive factor limiting its widespread use.

Anaphylactoid syndrome of pregnancy immediately after intrauterine pressure catheter placement

A 35-year-old multipara woman underwent intrauterine pressure catheter placement during labor. Immediately afterwards, she had severe dyspnea develop, became unresponsive, and had a prolonged fetal bradycardia. During emergency cesarean section, she required cardiopulmonary resuscitation repetitively. She then had disseminated intravascular coagulopathy develop and underwent hysterectomy. Anaphylactic reaction may be associated with intrauterine pressure catheter placement.

Amniotic fluid embolism managed with success during labour: report of a severe clinical case and review of literature

BACKGROUND

AFE (amniotic fluid embolism) is widely known as a disastrous rapid-progressing clinical entity. The incident ranges from 1:800 to 1:8,000. The mortality rate reaches 61-86%. Neonatal survival is reported at 70%.

METHODS

We describe the case of a healthy 29-year old primigravida developing amniotic fluid embolism during labour. Acute respiratory failure and hypotension combined with seizures were the initial symptoms. The patient under went an urgent caesarean section with extreme blood loss, complicated by disseminated coagulopathy.

RESULTS

A total hysterectomy was performed due to profuse bleeding. Aggressive management was practiced with continuous transfusion of blood products and administration of vasocopressors.

CONCLUSION

Amniotic fluid embolism or anaphylactoid syndrome of pregnancy is a life-threatening condition. Diagnosis is one of the exclusion. Its management is very difficult and requires quick management and cooperation of physicians from different specialties.

Rapid reversal of critical haemodynamic compromise with nitric oxide in a parturient with amniotic fluid embolism

We describe a case of amniotic fluid embolism presenting as cardiovascular collapse during labour. After initial resuscitation and emergency caesarean section, the patient was transferred to the intensive care unit with profound hypoxaemia, a high inotropic drug requirement and severe coagulopathy. A transoesophageal echocardiogram demonstrated acute right ventricular overload, severe pulmonary artery hypertension and marked diastolic dysfunction of the left ventricle secondary to a dilated right ventricle. The introduction of nitric oxide at 40 ppm produced a dramatic improvement in her cardiorespiratory status. Mother and baby both survived with no apparent long term sequelae.

A hypothesis regarding complement activation and amniotic fluid embolism

Amniotic fluid embolism, a rare, sudden and often fatal illness of pregnancy may not be a true embolic event resulting from the physical obstruction of the pulmonary vasculature. The high degree of variability in symptoms, the lack of characteristic findings on radiological exam, the absence of a dose-response effect on symptoms, and the occasional occurrence of coagulopathies are not entirely consistent with a physical block to the circulation as the main mechanism of disease. Alternatively, it might be the result of complement activation initiated by fetal antigen leaking into the maternal circulation. This rare immune response may be initiated by a rare pathological antigen, or by common antigens presented uncommonly--in amount, timing, or frequency of entry into the maternal circulation. Some very early evidence in AFE patients supports this hypothesis but is not conclusive. Complement levels remain well within the normal range during uncomplicated parturition. A prior theory that AFE might be a result of maternal anaphylaxis to fetal antigen has much less evidence to support it. The disseminated intravascular coagulation often seen in this and other serious obstetrical illnesses may be a secondary result of complement activation rather than the direct introduction of pro-coagulants into the maternal circulation although the link between the complement and coagulation pathways, if any, remains poorly defined. Through currently available laboratory testing, both the complement hypothesis and the anaphylaxis mechanism are able to be assessed. Direct measurement of serum complement as well as serum tryptase and urinary histamine are readily obtained tests in community hospitals as well as tertiary care hospitals. If the hypothesis proves true, this investigation may be of profound importance to understanding immune tolerance. Rather, than asking why one pregnant woman in 20,000 develops a violent immune reaction to the fetus, a better question is why do not all pregnant women reject the fetus which is a large collection of foreign antigens?

[Amniotic fluid embolism: a review]

Amniotic fluid embolism occurs rarely but is a leading cause of maternal mortality. It is a difficult and somewhat intangible diagnosis that warrants a high index of suspicion by physicians. AFE is an unpredictable, unpreventable, and, for the most part, an untreatable obstetric emergency. Management of this condition includes prompt recognition of the signs and symptoms, aggressive resuscitation efforts, and supportive therapy. Any delays in diagnosis and treatment can result in increased maternal and/or foetal impairment or death. Whereas once the invariable outcome of AFE was death of the mother, today the prognosis is somewhat brighter thanks to increased awareness of the syndrome and advances in intensive care medicine. No laboratory test is specific to attest the diagnosis and autopsy must to be realised in case of maternal death. Although non-specific, the diagnosis of AFE could be supported by the observation of amniotic fluid in the central venous blood as well as in the bronchoalveolar fluid. This easy and quick test will be helpful in decision-making. Prompt and aggressive supportive treatment is required to lessen an otherwise dismal outcome, which may include death and permanent disability. This article provides an account of the protean clinical features, pathogenesis, and principles involved in treatment.

Amniotic fluid embolism

INCIDENCE

Amniotic fluid embolism is a catastrophic syndrome that occurs during pregnancy or in the immediate postpartum period. Multiple case reports have described the clinical findings and have reported variable success with supportive care. There has been discrepancy with respect to the incidence and mortality of amniotic fluid embolism. One likely explanation for this inconsistency is the lack of sensitive and specific diagnostic studies to definitively identify cases of amniotic fluid embolism, leading to both over- and underreporting. Despite the variation in reported incidence and mortality, amniotic fluid embolism remains a life-threatening condition with significant morbidity and mortality for the pregnant woman. It is the fifth most common cause of maternal mortality in the world.

DIAGNOSIS

The diagnosis of amniotic fluid embolism continues to be a clinical diagnosis and a diagnosis of exclusion based on the rapid development of a complex constellation of findings with sudden cardiovascular collapse, acute left ventricular failure with pulmonary edema, disseminated intravascular coagulation, and neurologic impairment. Given the significant morbidity and mortality associated with this condition, a high index of suspicion is warranted. Suspected risk factors have included tumultuous labor, trauma, multiparity, increased gestational age, and increased maternal age. However, many patients who develop amniotic fluid embolism have no obvious risk factors.

MANAGEMENT

Patients with amniotic fluid embolus are best managed using a multidisciplinary approach. There are no pharmacologic or other therapies that prevent or treat the amniotic fluid embolism syndrome, and supportive care typically involves aggressive treatment of multiple types of shock simultaneously. In this article we discuss the clinical presentation of amniotic fluid embolism syndrome as well as current opinions regarding pathophysiology, diagnosis, and management.