Amniotic fluid embolus: a review of the literature

Perimortem Cesarean Section in a Patient with Intrapartum Cardiorespiratory Arrest Due to a Massive Amniotic Fluid Embolism

We report and discuss the case of a 29-year-old tercigravida with intrapartum cardiorespiratory arrest due to a massive amniotic fluid embolism and disseminated intravascular coagulopathy. Perimortem caesarean section with B-Lynch compression uterine suture with simultaneous fetal and maternal resuscitation were performed with a favorable outcome for both the mother and the child.

Amniotic Fluid Embolism: Anaphylactic Reactions With Idiosyncratic Adverse Response

PROBLEM

Amniotic fluid embolism (AFE) is a rare but severe emergency in obstetrics. The aim of the present study was to investigate the pathophysiology of AFE.

METHODS

A search was conducted between 1966 and 2014 through the English-language literature (online MEDLINE PubMed database) using the keyword amniotic fluid embolism combined with anaphylaxis, anaphylactoid, complement activation, mast cells, fetal antigens, and idiosyncratic.

RESULTS

Amniotic fluid embolism is a rare clinical entity but a severe obstetric emergency that can be lethal even in previously healthy women in labor or in the early postpartum period. There appears to be at least 2 mechanisms. First, adverse reactions in AFE are usually unexpected and fetal antigen dose dependent. Given the disastrous entry of amniotic fluid into the maternal circulation, they experience a sudden cardiopulmonary collapse (mechanical obstruction subtype). Second, anaphylactic and anaphylactoid reactions of the remaining AFE are also relatively unexpected and fetal antigen dose independent and can occur at the first exposure to amniotic fluid components. They are associated with complement activation and subsequent postpartum hemorrhage. Cardiac mast cells constitute a central pathogenesis of anaphylactic (immunoglobulin E-dependent) and anaphylactoid (immunoglobulin E-independent) reactions.

CONCLUSIONS

Recent immunologic studies provide a new approach to the study of the pathophysiology of AFE.

Amniotic fluid embolism: an interdisciplinary challenge: epidemiology, diagnosis and treatment

BACKGROUND

Amniotic fluid embolism (AFE) is a life-threatening obstetric complication that arises in 2 to 8 of every 100 000 deliveries. With a mortality of 11% to 44%, it is among the leading direct causes of maternal death. This entity is an interdisciplinary challenge because of its presentation with sudden cardiac arrest without any immediately obvious cause, the lack of specific diagnostic tests, the difficulty of establishing the diagnosis and excluding competing diagnoses, and the complex treatment required, including cardio - pulmonary resuscitation.

METHOD

We selectively reviewed pertinent literature published from 2000 to May 2013 that was retrieved by a PubMed search.

RESULTS

The identified risk factors for AFE are maternal age 35 and above (odds ratio [OR] 1.86), Cesarean section (OR 12.4), placenta previa (OR 10.5), and multiple pregnancy (OR 8.5). AFE is diagnosed on clinical grounds after the exclusion of other causes of acute cardiovascular decompensation during delivery, such as pulmonary thromboembolism or myocardial infarction. Its main clinical features are severe hypotension, arrhythmia, cardiac arrest, pulmonary and neurological manifestations, and profuse bleeding because of disseminated intravascular coagulation and/or hyperfibrinolysis. Its treatment requires immediate, optimal interdisciplinary cooperation. Low-level evidence favors treating women suffering from AFE by securing the airway, adequate oxygenation, circulatory support, and correction of hemostatic disturbances. The sudden, unexplained death of a pregnant woman necessitates a forensic autopsy. The histological or immunohistochemical demonstration of formed amniotic fluid components in the pulmonary bloodflow establishes the diagnosis of AFE.

CONCLUSION

AFE has become more common in recent years, for unclear reasons. Rapid diagnosis and immediate interdisciplinary treatment are essential for a good outcome. Establishing evidence-based recommendations for intervention is an important goal for the near future.

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: 10-year retrospective study in a level III maternity hospital

OBJECTIVE

To provide updated data on amniotic fluid embolism (AFE) based on our population over a 10 year period, and to propose steps for improving current practice.

STUDY DESIGN

Retrospective study carried out in the Department of Gynaecology and Obstetrics at the Strasbourg University Teaching Hospital between 1 January 2000 and 31 December 2010. Dossiers of patients with AFE were identified using medical information system programme (MISP) coding and cross-checked with the pathology reports (hysterectomy, post-mortem examination).

RESULTS

Eleven dossiers were found (0.28/1000). Eight cases (73%) of AFE occurred during labour, two (18%) in the post-partum period and one (9%) outside of parturition. Induction was initiated in four patients (45%) and labour sustained with oxytocin in 9 patients (90%). Acute circulatory collapse with cardio-respiratory arrest (CRA) was the herald symptom of AFE in 2 patients, and secondary cardio-respiratory arrest occurred rapidly in 6 patients (55%) following a relatively non-indicative prodromal phase. Disseminated intravascular coagulopathy (DIC) was observed in 10 cases (91%) and massive transfusion was necessary in all patients. Seven haemostatic hysterectomies (63%) were performed, with secondary arterial embolisation in 2 cases (22%). Although all patients presented a clinical picture of AFE, confirmation through histology or laboratory test results was forthcoming in only 7 cases (63%). Three patients died (27%). When AFE occurred during labour, 8 fetuses (75%) received intensive care support. In all, 11 newborns survived (85%). Their pH was less than 7.00 in 3 cases (27%) and 4 fetuses (36%) had an Apgar score of less than 5 at 5 minutes of life.

CONCLUSION

AFE is a rare but extremely serious disease. Some risk factors for AFE have been identified but they do not allow its occurrence to be predicted. The diagnosis may be supported by specific laboratory test results but only a post-mortem examination provides a pathognomonic diagnosis: unfortunately it is always retrospective. Obstetrical and intensive care management is complex and must be adapted to the situation bearing in mind the significant risk of haemorrhage and DIC. Hysterectomy must be performed if there is the least doubt.

Medical responsibility in the operating room: the example of an amniotic fluid embolism

Amniotic fluid embolism (AFE) continues to be one of the most feared complications of pregnancy. A healthy 32-year-old woman died during delivery after a normal 39-week third pregnancy. The family filed a complaint with a criminal court as the causes of death appeared unclear. No risk factor associated with AFE was identified. Clinical presentation was typical, including sudden onset of cardiovascular and respiratory symptoms. Autopsy confirmed the histological diagnosis of amniotic embolism and excluded an iatrogenic cause of death or anesthetic malpractice. This article highlights the value of both antemortem records and histological features in establishing the diagnosis of AFE and demonstrates the fundamental importance of autopsy in an unexpected death related directly or indirectly to a medical procedure.

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.

Disseminated intravascular coagulation in obstetric disorders and its acute haematological management

As activation of the coagulation pathway is a physiological response to injury, the development of disseminated intravascular coagulation (DIC) is a warning signal to the clinician that the primary pathological disease state is decompensating. In pregnancy, DIC can occur in several settings, which include emergencies such as placental abruption and amniotic fluid embolism as well as complications such as pre-eclampsia. Whilst the acuteness of the event and the proportionality in the coagulant and fibrinolytic responses may vary between these different conditions, a common theme for pregnancy-associated DIC is the pivotal role played by the placenta. Removal of the placenta is the linchpin to treatment in most cases but appropriate blood product support is also key to management. This is necessary because DIC itself can have pathological consequences that translate clinically into a worse prognosis for affected patients. This article will describe how pregnancy-associated DIC can be diagnosed promptly and how treatment should be managed strategically. It also discusses the latest developments in our understanding of haemostatic mechanisms within the placenta and how these may have relevance to new diagnostic approaches as well as novel therapeutic modalities.

Amniotic fluid embolism: a case study

A case study involving a young woman delivering twins illustrates the dangers of this rare occurrence, the precise cause of which is still unknown. A rare complication of pregnancy.

A step-by-step diagnosis of exclusion in a twin pregnancy with acute respiratory failure due to non-fatal amniotic fluid embolism: a case report

INTRODUCTION

Respiratory failure may develop during the later stages of pregnancy and is usually associated with tocolysis or other co-existing conditions such as pneumonia, sepsis, pre-eclampsia or amniotic fluid embolism syndrome.

CASE PRESENTATION

We present the case of a 34-year-old healthy woman with a twin pregnancy at 31 weeks and 6 days who experienced acute respiratory failure, a few hours after administration of tocolysis (ritodrine), due to preterm premature rupture of the membranes. Her chest discomfort was significantly ameliorated after the ritodrine infusion was stopped and a Cesarean section was performed 48 hours later under spinal anesthesia; however, 2 hours after surgery she developed severe hypoxemia, hypotension, fever and mild coagulopathy. The patient was intubated and transferred to the intensive care unit where she made a quick and uneventful recovery within 3 days. As there was no evidence for drug- or infection-related thromboembolic or myocardial causes of respiratory failure, we conclude that our patient experienced a rare type of non-fatal amniotic fluid embolism.

CONCLUSION

In spite of the lack of solid scientific support for our diagnosis, we conclude that our patient suffered an uncommon type of amniotic fluid embolism syndrome and we believe that this report highlights the need for extreme vigilance and a high index of suspicion for such a diagnosis in any pregnant individual.

Forensic Lung Pathology

Sudden and unexpected natural deaths and nonnatural deaths may result from various pulmonary conditions. Additionally, several nonpulmonary conditions of forensic significance may be complicated by the development of respiratory lesions. Certain situations with pulmonary pathology are particularly likely to be critically scrutinized and may form the basis of allegations of medical negligence, other personal injury liability, or wrongful death.1

Nonhemorrhagic primary obstetric shock

OBJECTIVE

Clinical evaluation of nonhemorrhagic primary obstetric shock (NHPOS).

METHODS

In a retrospective clinical study, data on 8 cases of NHPOS were analyzed. Data on patient age, parity, week of gestation, comorbidity, possible etiologic trigger, course of disease with clinical picture and laboratory findings of coagulopathy, and patient outcome including autopsy findings in two lethal outcomes were analyzed.

RESULTS

These 8 patients were treated in the intensive care unit. One patient died during delivery from cardiopulmonary arrest in the state of irreversible obstetric shock, verified by massive pulmonary thromboembolism at autopsy. Another patient died from stroke and cerebral coma caused by trophoblastic cerebrovascular embolism 5 days after artificial abortion, showing a clinical picture of shock and cardiopulmonary arrest. In 1 patient, severe septic shock developed several hours after premature stillbirth and abruptio placentae in the 26th week of pregnancy, associated with disseminated intravascular coagulopathy. Four patients developed intrapartum NHPOS, with a clinical picture of chest pain, dyspnea, tachycardia, hypotension, cyanosis, and disseminated intravascular coagulopathy, as demonstrated by laboratory findings. Based on clinical picture and laboratory findings, amniotic fluid embolism or trophoblastic embolism was suspected. All these patients survived. One patient developed NHPOS during the third labor stage after vacuum extraction because of a macrosomic child, followed by disseminated intravascular coagulopathy and secondary hemorrhage which necessitated B-Lynch procedures and total hysterectomy for massive bleeding. Hereditary thrombophilia was detected in subsequent patients.

CONCLUSIONS

NHPOS can be caused by amniotic fluid embolism, trophoblastic embolism or thromboembolism, and sepsis. These conditions may frequently prove fatal due to their abrupt and unexpected course, mostly during pregnancy, delivery, or immediately thereafter.

Amniotic fluid embolism after blunt abdominal trauma

Amniotic fluid embolism (AFE) is a rare, but potentially fatal complication of pregnancy, with an incidence between 1 in 8000 and 1 in 80,000 pregnancies. The pathogenesis is not fully understood, but the generally accepted belief is that amniotic fluid enters the mother's circulation, most commonly via tears in the lower uterine segment. In the fluid there are substances with pro-inflammatory, vasospastic and pro-coagulative properties. AFE after blunt trauma is very rare, only described a few times in the literature. We report a case of fatal AFE after probable minor blunt trauma to the abdomen and give a review of the literature.

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.

Unusual Pulmonary Embolism Septic Pulmonary Embolism and Amniotic Fluid Embolism

BACKGROUND

Septic and amniotic fluid emboli are rare sources of pulmonary embolism (PE), so the present study sought to elucidate the background of these cases.

METHODS AND RESULTS

A total of 11,367 PE cases were identified from 396,982 postmortem examinations. The incidence of septic PE was 247 (2.2%) of the total. The origin of infection was found in 85.6% of the cases. Fungal embolus was detected more often than bacterial embolus. The most frequently detected fungus was aspergillus (20.8%). The primary disease associated with fungal embolus was leukemia (43.2%). The incidence of PE cases associated with pregnancy and/or delivery was 89 (0.8%) of the total PE cases. Among them, amniotic fluid embolism was found in 33 (73.3%) of 45 PE cases with vaginal delivery, and in 7 (21.2%) of 33 PE cases with cesarean delivery (p<0.0001).

CONCLUSION

Fungal embolus was more frequent than bacterial embolus, and leukemia was most frequent as the primary disease in cases of fungal embolus. The main cause of PE in cesarean section cases was thrombotic embolism, and the main cause in vaginal delivery cases was amniotic fluid embolism.

Aprotinin in the management of coagulopathy associated with amniotic fluid embolus

Amniotic fluid embolus, also known as anaphylactoid syndrome of pregnancy is a rare complication of pregnancy. When it occurs, the maternal mortality rate may be as high as 86%, and in survivors, the morbidity rate may be just as high. Hallmark clinical features include maternal cardiovascular collapse with disseminated intravascular coagulation, and fetal distress. Management centers on strategies to improve oxygenation, support circulation, and correct the coagulopathy. We report the case of a patient who developed amniotic fluid embolus and was effectively managed with aprotinin to control the coagulopathy associated with this devastating complication of pregnancy.

[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.

Cardiopulmonary distress during obstetrical anaesthesia: attempts to diagnose amniotic fluid embolism in a case series of suspected allergic anaphylaxis

BACKGROUND

Cardiopulmonary distress during obstetrical anaesthesia may result from a drug-induced allergic reaction, but, in the obstetrical setting, allergic anaphylaxis may be inseparable from amniotic fluid embolism in terms of the clinical presentation. Further investigations, using allergy tests and other laboratory analyses, are then needed to pursue a diagnostic clarification.

METHODS

Twelve women suspected of having developed anaphylaxis during obstetrical anaesthesia underwent allergy follow-up investigations and further serological tests with the amniotic fluid embolism marker sialyl Tn and complement factors (C3 and C4) in an attempt to differentiate amniotic fluid embolism from drug-induced allergic anaphylaxis.

RESULTS

The diagnostic programme revealed one case of probable amniotic fluid embolism and four cases of probable drug-induced allergic anaphylaxis. Of the remaining seven cases, there were two cases that, by diagnostic exclusion, could be classified as possible cases of amniotic fluid embolism. The cause of the reactions remained unresolved in five cases.

CONCLUSIONS

It can be difficult to differentiate between anaphylaxis and amniotic fluid embolism, especially amongst survivors. Diagnostic markers that can be applied on peripheral blood samples are promising, but larger studies are needed to validate their use in the diagnosis of causes of cardiopulmonary distress during obstetrical anaesthesia.

Pregnancy-associated deaths: a 15-year retrospective study and overall review of maternal pathophysiology

Pregnancy-related death is defined by the International Classification of Diseases, Tenth Revision (ICD-10) as the death of a woman while pregnant or within 42 days of termination of pregnancy, irrespective of the cause of death. In the year 2000, a collaborative effort involving World Health Organization (WHO), UNICEF, and UNFPA estimated 660 maternal deaths in the United States. This averages 11 maternal deaths per 100,000 live births reported. Many pregnancy-associated deaths are not easily identified as such since the presence of a recent or current pregnancy may not be listed on the death certificate. Thus, the WHO estimates that in the United States, the maternal mortality is approximately 17/100,000 pregnancies. This is significantly higher than the goal set by the US Department of Health and Human Services in Healthy People 2010, which sets the target for maternal mortality at less than 3.3/100,000 live births. The most common causes of maternal death vary somewhat from region to region in the United States. They include pulmonary thromboembolism, amniotic fluid embolism, primary postpartum uterine hemorrhage, infection, and complications of hypertension including preeclampsia and eclampsia. Pulmonary disease, complications of anesthesia, and cardiomyopathy also are significant contributors to maternal mortality in some populations. The death of a pregnant or recently pregnant individual poses a wide scope of challenges to the forensic pathologist and investigator. The pathologist must have a broad knowledge of the physiologic and biochemical changes that occur during pregnancy, as well as the clinical and pathological manifestation of these changes. Conditions that may be "benign" in the nonpregnant individual may be lethal in the puerperal period. In addition, it should be kept in mind that deaths during pregnancy may be due to unnatural causes. Accident, homicide, and suicide must be ruled out in each case. The authors reviewed all forensic cases referred for autopsy to the Forensic Section of the Medical University of South Carolina from January 1989 through December 2003. All decedents listed as pregnant or postpartum were analyzed as to maternal age, race, past medical history, previous pregnancies and outcome, prenatal care, gestational age, fetal or neonatal outcome, location of delivery, placental findings, maternal autopsy findings, toxicology, cause of death, manner of death, and fetal or neonatal autopsy findings. The authors present this retrospective study to better determine the factors leading to maternal demise and discuss the autopsy/ancillary techniques useful in determining the cause of death in this challenging area.

Acute respiratory distress syndrome in pregnancy

OBJECTIVE

To summarize the pathophysiology and treatment of acute lung injury and acute respiratory distress syndrome (ARDS) during pregnancy.

DATA SOURCE

Review of select articles from MEDLINE, including published abstracts, case reports, observational studies, controlled trials, review articles, and institutional experience.

DATA SUMMARY

ARDS occurs in pregnancy and may have unique causes. Despite extensive clinical research to improve the management of ARDS, mortality remains high, and few strategies have shown a mortality benefit. Furthermore, in most published studies, pregnancy is an exclusionary criterion, and thus, few treatments have been adequately evaluated in obstetric populations. The treatment of ARDS in pregnancy is extrapolated from studies performed in the general ARDS patient population, with consideration given to the normal physiologic changes of pregnancy. In general, the best support of the fetus is support of the mother. From the age of viability (24-26 wks at most institutions) until full term, decisions regarding delivery should be made based primarily on the standard obstetric indications.

CONCLUSIONS

Little evidence exists regarding the management of ARDS specifically in pregnancy, and thus, treatment approaches must be drawn from studies performed in a general patient population. A multidisciplinary approach involving maternal-fetal medicine, neonatology, anesthesiology, and intensivist clinicians is essential to optimizing maternal and fetal outcomes.

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.

Cardiac arrest during pregnancy

This case involves cardiac arrest of a 29-week old pregnant African American woman, occurring 2 days after surgical correction of an incarcerated ventral hernia with small bowel obstruction. The patient could not be resuscitated from this arrest. Details of the case are presented, and diagnostic and unique management considerations for this uncommon occurrence are set forth.

Ancillary Studies in Amniotic Fluid Embolism

The incidence of amniotic fluid embolism during pregnancy is approximately 1/50,000 and has a mortality rate in excess of 80%. The postmortem diagnosis of amniotic fluid embolism can be challenging for forensic investigators and pathologists. At autopsy, usually signs of disseminated intravascular coagulation suggest an amniotic fluid embolism. A definitive diagnosis of amniotic fluid embolism cannot be made until ancillary studies are performed on the decedent's tissues. We report a case of a 37-year-old G3P2 white female who was 36 weeks gestation when her membranes spontaneously ruptured. She suddenly became breathless, went into cardiogenic shock, and died. The autopsy revealed gross and microscopic findings of amniotic fluid embolism, which was confirmed with ancillary studies consisting of special stains, immunohistochemistry, and a serum tryptase level. The authors hope this case report, including gross and microscopic autopsy findings with procedural and ancillary studies, and review of the literature will help investigators and pathologists in the diagnosis of amniotic fluid embolism.

[Fatal amniotic fluid embolism. Extraction by Caesarean section of a living child without neurological after-effects]

The authors report on the case of an amniotic fluid embolism, proven by post mortem, which was the result of an inaugural and irreversible cardiac arrest in a 37-year-old woman at 39 weeks of normal pregnancy. The Caesarean section was carried out as an extreme emergency in the labour room, while efforts were being made to resuscitate the mother, so as to deliver a living newborn without any neurological after-effects. The haemostatic consequences were showed up only on blood tests.

Fetal bradycardia and disseminated coagulopathy: atypical presentation of amniotic fluid emboli

We present a parturient who developed an atypical case of amniotic fluid emboli presented by sudden fetal bradycardia, followed by maternal disseminated coagulopathy. The typical feature of cardiopulmonary collapse was absent in this patient implying that in some cases of amniotic fluid emboli (AFE), fetal hypoxia or acidemia is unrelated to maternal cardiopulmonary status.

Amniotic fluid embolism during caesarean section

Amniotic fluid embolism occurs rarely but is a leading cause of maternal mortality. A high index of clinical suspicion is necessary to make an early diagnosis to reduce morbidity and mortality. We report a non-fatal case of amniotic fluid embolism occurring during a caesarean section, with special emphasis on the mode of development and diagnosis. The initial presentation of this syndrome was a coagulopathy, followed by the usual complications of massive bleeding. Although non-specific, the diagnosis of amniotic fluid embolism was supported by the observation of amniotic fluid in the central venous blood as well as in the broncho-alveolar fluid.

Mast cell tryptase: a review of its physiology and clinical significance

Mast cells, which are granulocytes found in peripheral tissue, play a central role in inflammatory and immediate allergic reactions. beta-Tryptase is a neutral serine protease and is the most abundant mediator stored in mast cell granules. The release of beta-tryptase from the secretory granules is a characteristic feature of mast cell degranulation. While its biological function has not been fully clarified, mast cell beta-tryptase has an important role in inflammation and serves as a marker of mast cell activation. beta-Tryptase activates the protease activated receptor type 2. It is involved in airway homeostasis, vascular relaxation and contraction, gastrointestinal smooth muscle activity and intestinal transport, and coagulation. Serum mast cell beta-tryptase concentration is increased in anaphylaxis and in other allergic conditions. It is increased in systemic mastocytosis and other haematological conditions. Serum beta-tryptase measurements can be used to distinguish mast cell-dependent reactions from other systemic disturbances such as cardiogenic shock, which can present with similar clinical manifestations. Increased beta-tryptase levels are highly suggestive of an immunologically mediated reaction but may also occur following direct mast cell activation. Patients with increased mast cell beta-tryptase levels must be investigated for an allergic cause. However, patients without increased mast cell tryptase levels should be investigated if the clinical picture suggests severe anaphylaxis.

Amniotic fluid embolism

Amniotic fluid embolism (AFE) (also known as anaphylactoid syndrome of pregnancy)is a catastrophic condition that occurs during pregnancy or shortly after delivery. It is found throughout the world in developed and undeveloped countries and occurs at an incidence of between 1 in 80000 live births. In the United States, AFE occurs in 1 in 20000 to 80000 deliveries.

Successful Use of Levosimendan in a Patient with Peripartum Cardiomyopathy

This case represents the first reported use of levosimendan, a calcium-sensitizing drug with additional vasodilation properties, for treatment of a woman with peripartum cardiomyopathy. Levosimendan induced a steady decline of increased pulmonary capillary wedge pressure, followed by a definitive increase in cardiac stroke volume. The patient recovered from this serious episode of heart failure, and she ultimately regained left ventricular function.

IMPLICATIONS

Acute heart failure is a life-threatening event that only rarely occurs during childbirth. We report a case of a woman who experienced cardiovascular collapse during vaginal delivery. We determined that she met current diagnostic criteria for peripartum cardiomyopathy, and we successfully treated her with levosimendan, a calcium-sensitizing drug with additional vasodilation properties.

Two cases of hemorrhage secondary to amniotic fluid embolus managed with uterine artery embolization

PURPOSE

To describe the anesthetic management of two cases of amniotic fluid embolus (AFE) and disseminated intravascular coagulation (DIC) who underwent bilateral uterine artery embolization to control their postpartum hemorrhage.

CLINICAL FEATURES

We report the clinical course and management of two women who suffered sudden cardiorespiratory events during labour. The first patient had a cardiac arrest whereas the second developed respiratory failure and altered neurological status. They were diagnosed as having had an AFE. Both of these events were accompanied by severe postpartum hemorrhage and DIC. They suffered prolonged bleeding and received massive transfusions. Successful management of hemorrhage was optimized by uterine artery embolization, thus avoiding ongoing problems with bleeding and possible hysterectomy. The role of uterine artery embolization is described, along with its advantages and anesthetic considerations.

CONCLUSION

Women with severe postpartum hemorrhage, with or without DIC, should be considered for uterine artery embolization.

Amniotic fluid embolism with involvement of the brain, lungs, adrenal glands, and heart

The case of a healthy 31-year-old woman in the 40th week of second pregnancy is presented. During preparation for an emergency caesarean section, she developed an amniotic fluid embolism (AFE) with unusual and unique features. The acute onset of disease with cardiorespiratory failure with hypotension, tachycardia, cyanosis, respiratory disturbances and loss of consciousness, suggested at first a pulmonary thromboembolism, but the appearance of convulsions led to the diagnosis of AFE. The patient died after 5 days due to an untreatable brain edema. At autopsy, AFE with the usually associated disseminated intravascular coagulation was found in the lungs, brain, left adrenal gland, kidneys, liver and heart. Eosinophilic inflammatory infiltrates were found in the lungs, hepatic portal fields and especially in the heart, suggesting a specific hypersensitivity reaction to fetal antigens. Moreover, intravascular accumulation of macrophages in the lungs also favored a non-specific immune reaction to amniotic fluid constituents.

Modulation and roles of the endothelins in the pathophysiology of pulmonary embolism

Recent research on the endothelins (ETs) and their pathways in acute pulmonary embolism (APE) has led to significant advances in the understanding of this disease. ETs are potent vasoconstrictors and bronchoconstrictors found abundantly in the lung and can be released by stimuli such as endothelial injury, hypoxia, or thrombin, a key product in the coagulation cascade. Many studies using different approaches and methods of inducing pulmonary embolization, both in vitro and in vivo in various species, have mostly shown that ETs play an important role in the pathophysiology of APE. These results were obtained by comparing the hemodynamic data in the presence or absence of various ETs inhibitors, but also by assessing the modulation of the ET-related elements of this system by molecular, cell biology, and pharmacological methods. Based on the current understanding, a mechanism involving the ET pathway in the pathophysiology of APE is proposed for the reader's considerations. We postulate that ETs are primary mediators in APE based on the following: (i) their source from pulmonary endothelial cells where the primary injury takes place; (ii) their direct vasconstrictive, bronchoconstrictive, and promitogenic effects via distinct ET receptors; and (iii) their indirect effects associated with the secondary release of thromboxane and other mediators, which are released from inflammatory cells and platelets, which together can potentiate the overall hemodynamic response, most specifically the pulmonary vascular bed. Such combined effects of ETs on bronchomotor and vasomotor tone in the lung can adversely affect ventilation perfusion matching and lead to severe hypoxemia without causing significant changes in the chest X-ray of these patients. Thus, we may consider ET inhibitors as future current therapeutic agents in patients with PE.

Amniotic fluid embolus: can we affect the outcome?

PURPOSE OF REVIEW

Amniotic fluid embolism is a rare catastrophe unique to pregnancy. Its mortality rate remains high despite efforts at prompt and aggressive management protocols, highlighting the need to maintain a high index of suspicion.

RECENT FINDINGS

The intrusion of amniotic fluid into the maternal bloodstream may lead in certain women to a complex series of physiological reactions mimicking those seen in human anaphylaxis or sepsis, negating the purely embolic phenomenon theory as previously understood. The clinical picture is the sudden onset of cardiovascular collapse, cyanosis, haemorrhage or disseminated intravascular coagulopathy, during or soon after delivery.

SUMMARY

The mainstay of a successful outcome remains the identification of high-risk patients, as well as early clinical diagnosis and management.

Embolism during pregnancy: thrombus, air, and amniotic fluid

Pulmonary embolism is the primary cause of acute respiratory decompensation during pregnancy. Regardless of the nature of the embolism, a high index of suspicion, early diagnosis, and aggressive resuscitation need to be instituted to achieve a successful maternal and fetal outcome. Several clinical characteristics will assist practitioners to distinguish among the different forms of embolism and to institute specific measures of treatment.

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.

[Amniotic fluid embolism during labor]

Amniotic fluid embolism is an unpredictable but dramatical complication of pregnancy that occurs when amniotic fluid enter into the maternal circulation. The classical clinical feature is acute respiratory distress, circulatory distress, seizures and coagulopathy. However there is no routine laboratory diagnosis, so that is a diagnosis of exclusion. We report here the case of a patient, on labor with an epidural analgesia who suddenly suffered from seizures, circulatory arrest, and haemorrhage. A symptomatic management was instituted and a caesarean section was performed. An haemostatic hysterectomy was required. The patient survived without any sequelae. Neurological outcome of the child is still reserved.

[Amniotic fluid embolism: successful evolution course after uterine arteries embolization]

A 28-year-old woman, G3P3, who was otherwise healthy and had taken no medication and had no known allergy, was admitted to our hospital for delivery after a normal pregnancy. An epidural catheter was inserted for analgesia and labour was induced with oxytocin. Two hours later, she suffered a sudden cardiac arrest. She was immediately treated and, since a normal cardiac rhythm and a blood pressure of 90 mmHg has been obtained 30 minutes later, a 3750 g child was delivered by caesarean section. Soon after delivery, a life-threatening uterine haemorrhage appeared, due to DIC. Evolution was favourable, after bilateral uterine arteries embolization had been performed. The diagnosis of amniotic fluid embolism was established by the clinical course, the absence of local cause and the presence of a large number of amniotic cells in the mother's peripheral blood. Tryptase blood concentration was normal in the mother's blood.