Diagnostic accuracy of insulin-like growth factor binding protein-1 for amniotic fluid embolism*:

Amniotic fluid embolism rescued by venoarterial extracorporeal membrane oxygenation

Background

Amniotic fluid embolism (AFE) is a rare but often catastrophic complication of pregnancy that leads to cardiopulmonary dysfunction and severe disseminated intravascular coagulopathy (DIC). Although few case reports have reported successful use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) with AFE, concerns can be raised about the increased bleeding risks with that device.

Methods

This study included patients with AFE rescued by VA-ECMO hospitalized in two high ECMO volume centers between August 2008 and February 2021. Clinical characteristics, critical care management, in-intensive care unit (ICU) complications, and hospital outcomes were collected. ICU survivors were assessed for health-related quality of life (HRQL) in May 2021.

Results

During that 13-year study period, VA-ECMO was initiated in 54 parturient women in two high ECMO volume centers. Among that population, 10 patients with AFE [median (range) age 33 (24–40), SAPS II at 69 (56–81)] who fulfilled our diagnosis criteria were treated with VA-ECMO. Pregnancy evolved for 36 (30–41) weeks. Seven patients had a cardiac arrest before ECMO and two were cannulated under cardiopulmonary resuscitation. Pre-ECMO hemodynamic was severely impaired with an inotrope score at 370 (55–1530) μg/kg/min, a severe left ventricular ejection fraction measured at 14 (0–40)%, and lactate at 12 (2–30) mmol/L. 70% of these patients were alive at hospital discharge despite an extreme pre-ECMO severity and massive blood product transfusion. However, HRQL was lower than age-matched controls and still profoundly impaired in the role-physical, bodily pain, and general health components after a median of 44 months follow-up.

Conclusion

In this rare per-delivery complication, our results support the use of VA-ECMO despite intense DIC and ongoing bleeding. Future studies should focus on customized, patient-centered, rehabilitation programs that could lead to improved HRQL in this population.

Fibrinogen may aid in the early differentiation between amniotic fluid embolism and postpartum haemorrhage: a retrospective chart review

This study aimed to determine whether blood loss and fibrinogen can differentiate amniotic fluid embolism (AFE) from postpartum haemorrhage (PPH). This retrospective case–control study included nine patients with clinical AFE (“AFE group”) and 78 patients with PPH managed at our tertiary care perinatal centre between January 2014 and March 2016. Patients meeting the Japanese diagnostic criteria for AFE were stratified into cardiopulmonary collapse-type AFE and disseminated intravascular coagulation (DIC)-type AFE groups. The relationship between blood loss and fibrinogen at onset was examined to compare DIC severity. Vital signs at onset were not significantly different. The AFE group had significantly less blood loss at onset (1506 mL vs 1843 mL, P = 0.0163), significantly more blood loss 2 h post-onset (3304 mL vs 1996 mL, P < 0.0001) and more severe coagulopathy and fibrinolysis. The blood loss/fibrinogen (B/F) ratio at onset was significantly higher in the DIC-type AFE group (23.15 ± 8.07 vs 6.28 ± 3.35 mL dL/mg, P < 0.0001). AFE was complicated by catastrophic DIC irrespective of blood loss at onset. Fibrinogen exhibited the strongest correlation among test findings at onset. The B/F ratio may help differentiate PPH from DIC-type AFE and diagnose clinical AFE, facilitating optimal replacement of coagulation factors during the early stages.

Biochemical effects of intraoperative cell salvage and autotransfusion during cesarean section: A prospective pilot study

AIM

Intraoperative cell salvage and autotransfusion (ICSA) is a useful technique for women undergoing cesarean sections who are predicted to experience significant bleeding. This method can reduce allogeneic transfusions as well as its associated risks and costs. Amniotic fluid embolism (AFE) is an abnormal maternal response to ICSA similar to the classic systemic inflammatory response syndrome, but its mechanism is not well understood. This study was conducted to investigate the biochemical aspects of AFE.

METHODS

A prospective case-controlled pilot study was conducted in a general perinatal hospital in Japan. ICSA was performed using a two-step retransfusion process. Blood samples were collected presurgery, immediately postsurgery, and 24 h after surgery. Changes in sialyl Tn antigen (STN), complement C3 and C4, fibrinogen, and fibrin degradation product and D-dimer, C1 esterase inhibitor, and interleukin-8 (all considered AFE-related markers) activities were compared between patients who underwent cesarean sections with ICSA (ICSA group) versus without ICSA (control group).

RESULTS

Fibrinogen levels were significantly lower in the ICSA group than in the control group before surgery but not immediately after or 24 h after surgery. D-dimer was significantly higher immediately after surgery but not 24 h later. STN was significantly lower only before surgery. None of the AFE-related markers showed significant differences between the groups after 24 h. No adverse events were observed in the ICSA group.

CONCLUSIONS

There is no clinical evidence that ICSA alters the biochemical statuses of AFE-related markers in a manner that could lead to adverse maternal responses.

Contribution of blood detection of insulin-like growth factor binding protein-1 for the diagnosis of amniotic-fluid embolism: a retrospective multicentre cohort study

OBJECTIVE

To assess the contribution of maternal blood detection of IGFBP-1 for the diagnosis of amniotic-fluid embolism in clinical daily practice.

DESIGN

A retrospective multicentre cohort study.

SETTING

Three tertiary care obstetric units in France.

SAMPLE

Data of 86 women for whom amniotic-fluid embolism had been suspected and maternal serum detection of IGFBP-1 had been performed between 2011 and 2019 were analysed.

METHODS

The criteria defined by the United Kingdom Obstetric Surveillance System (UKOSS) were used for the retrospective diagnosis of amniotic-fluid embolism. The more structured definition proposed by the Society for Maternal-Fetal Medicine and the Amniotic Fluid Embolism Foundation (SMFM) was also used as secondary endpoint.

MAIN OUTCOME MEASURES

Agreements between biological and clinical assessments were tested. The performance of blood detection of IGFBP-1 for the diagnosis of amniotic-fluid embolism according to the UKOSS criteria, and to the SMFM definition, was also assessed.

RESULTS

There was only slight agreement between clinical and laboratory diagnosis of amniotic-fluid embolism (Cohen's Kappa coefficient: 0.04). Blood detection of IGFBP-1 had a sensitivity of 16%, a specificity of 88%, a positive and a negative likelihood ratio of 1.3 and 0.95, respectively, and a positive and a negative predictive value of 58 and 50%, respectively, for the diagnosis of amniotic-fluid embolism based on the UKOSS criteria. The use of the more structured SMFM definition of amniotic-fluid embolism did not substantially change the results.

CONCLUSION

These results question the usefulness of blood detection of IGFBP-1 for the early diagnosis of amniotic-fluid embolism in daily clinical practice.

TWEETABLE ABSTRACT

This retrospective multicentre study questions the contribution of IGFBP-1 detection for the diagnosis of AFE.

Anesthesia for Obstetric Disasters

Over the past 30 years, maternal mortality has increased in the United States to 18 deaths per 100,000 live births. Obstetric emergencies, including hemorrhage, hypertensive disorders in pregnancy, HELLP syndrome, and amniotic fluid embolism, and anesthesia complications, including high neuraxial blockade, local anesthetic systemic toxicity, and the difficult obstetric airway, contribute to maternal cardiac arrest and maternal and fetal morbidity and mortality. Expeditious intervention by the obstetric anesthesiologist is critical in these emergent scenarios, and knowledge of best practices is essential to improve maternal and fetal outcomes.

Anesthesia for Obstetric Disasters

Over the past 30 years, maternal mortality has increased in the United States to 18 deaths per 100,000 live births. Obstetric emergencies, including hemorrhage, hypertensive disorders in pregnancy, HELLP syndrome, and amniotic fluid embolism, and anesthesia complications, including high neuraxial blockade, local anesthetic systemic toxicity, and the difficult obstetric airway, contribute to maternal cardiac arrest and maternal and fetal morbidity and mortality. Expeditious intervention by the obstetric anesthesiologist is critical in these emergent scenarios, and knowledge of best practices is essential to improve maternal and fetal outcomes.

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.

Anaphylactoid Syndrome of Pregnancy

Anaphylactoid syndrome of pregnancy (ASP) is a widespread, proinflammatory, anaphylactic-like reaction that can occur when amniotic fluid enters the maternal blood circulation. ASP is characterized by four cardinal findings: respiratory distress, altered mental status, hypotension, and disseminated intravascular coagulation. ASP is commonly associated with maternal and neonatal mortality. Early recognition followed by prompt and aggressive treatment can improve survival rates and are among the most critical activities for nurses and other clinicians caring for women with ASP.

Squamous cell carcinoma antigen as a novel candidate marker for amniotic fluid embolism

AIM

We aimed to evaluate the clinical usefulness of serum squamous cell carcinoma (SCC) antigen for the diagnosis of amniotic fluid embolism (AFE).

METHODS

Sera and information of 20 patients with AFE (autopsy-proven AFE, four cases; clinical AFE, 16 cases) were obtained from the Japan Amniotic Fluid Embolism Registration Center at Hamamatsu University School of Medicine. As controls, we included 74 gestational-age-matched healthy women who gave birth to healthy newborns during the period from December 2012 to January 2014. Receiver-operator curves (ROC) were used to evaluate the diagnostic performance of SCC levels for prediction of AFE.

RESULTS

Serum SCC antigen levels in women with autopsy-proven AFE (112.0 ± 169.4 ng/mL, P = 0.001) and clinical AFE (9.5 ± 10.3 ng/mL, P = 0.004) were significantly higher than those in healthy controls with normal delivery (4.4 ± 2.2 ng/mL). On ROC analysis, the optimal cut-off value for SCC antigen levels was 7.15 ng/mL, for which the sensitivity and specificity for AFE prediction was 60.0% and 89.2%, respectively (area under the ROC, 0.785; 95% confidence interval, 0.663-0.908; P < 0.001).

CONCLUSION

Serum SCC antigen may be a promising predictor of the entry of amniotic fluid into the maternal circulation, potentially serving as a candidate marker for noninvasive diagnosis of AFE.

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 complicating medical termination of pregnancy

BACKGROUND

Amniotic fluid embolism is always a severe complication and generally occurs during labour or immediately after childbirth.

CLINICAL FEATURES

We report the case of a patient falling victim to amniotic fluid embolism after the medical termination of her pregnancy at 24 weeks of amenorrhea following the discovery of a teratoma-carrying foetus. The amniotic fluid embolism diagnosis was strongly suspected in the face of the sudden onset of severe arterial hypotension, hypoxic respiratory distress, a coma state and disseminated intravascular coagulopathy immediately after the delivery. Additional tests were conducted to support the diagnosis: cytological testing of a peripheral venous sample and maternal broncho-alveolar lavage fluid, dosing of tryptase and alpha-fetoprotein levels as well as screening for insulin-like growth factor binding protein 1.

CONCLUSION

Amniotic fluid embolism is a rare and difficult diagnosis, especially in unconventional settings, yet it can be facilitated by screening for amniotic markers and tryptase.

Amniotic fluid embolism pathophysiology suggests the new diagnostic armamentarium: β-tryptase and complement fractions C3-C4 are the indispensable working tools

Amniotic fluid embolism (AFE) is an uncommon obstetric condition involving pregnant women during labor or in the initial stages after delivery. Its incidence is estimated to be around 5.5 cases per 100,000 deliveries. Therefore, this paper investigated the pathophysiological mechanism, which underlies AFE, in order to evaluate the role of immune response in the development of this still enigmatic clinical entity. The following databases (from 1956 to September 2014) Medline, Cochrane Central, Scopus, Web of Science and Science Direct were used, searching the following key words: AFE, pathophysiology, immune/inflammatory response, complement and anaphylaxis. The main key word "AFE" was searched singularly and associated individually to each of the other keywords. Of the 146 sources found, only 19 were considered appropriate for the purpose of this paper. The clinical course is characterized by a rapid onset of symptoms, which include: acute hypotension and/or cardiac arrest, acute hypoxia (with dyspnoea, cyanosis and/or respiratory arrest), coagulopathies (disseminated intravascular coagulation and/or severe hemorrhage), coma and seizures. The pathology still determines a significant morbidity and mortality and potential permanent neurological sequelae for surviving patients. At this moment, numerous aspects involving the pathophysiology and clinical development are still not understood and several hypotheses have been formulated, in particular the possible role of anaphylaxis and complement. Moreover, the detection of serum tryptase and complement components and the evaluation of fetal antigens can explain several aspects of immune response.

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: the known and not known

Amniotic fluid embolism was first recognized in 1926, in a Brazilian journal case report, on the basis of large amounts of fetal material in the maternal pulmonary vasculature at autopsy. The first English language description appeared in 1941 and consisted of eight parturients dying suddenly in which, once again, fetal material was seen in the pulmonary vasculature. A control group of 34 pregnant women dying of other recognized causes did not have fetal material in their lungs. The incidence of recognized, serious illness is on the order of two to eight per 100,000, with a mortality rate ranging from 13% to 35%. The diagnosis rests largely on one or more of four clinical signs: circulatory collapse, respiratory distress, coagulopathy, and seizures/ coma. The only confirmatory laboratory test remains autopsy findings although serum tests for fetal antigen, insulin-like growth factor binding protein-1, and complement are currently being investigated. One of the paradoxes of diagnosis is that fetal material in the pulmonary circulation at autopsy is specific for amniotic fluid embolism, while the same finding in the living is not. The mechanism of disease remains uncertain although the best available evidence suggests that complement activation might have a role. In contrast, mast cell degranulation probably is not a mechanism, so amniotic fluid embolism is not an anaphylaxis or anaphylactoid reaction as has been occasionally suggested. Perhaps the greatest unknown is not why 1 in 50,000 pregnant women develop what appears to be an immune response to their fetus, but rather why the other 49,999 do not?

Pathogenesis and management of peripartum coagulopathic calamities (disseminated intravascular coagulation and amniotic fluid embolism)

Acute coagulopathic peripartum calamities are relatively rare but contribute importantly to maternal morbidity and mortality in the Western world. Abruptio placenta, amniotic fluid embolism, and retained fetal or placental material may lead to fulminant intravascular activation of coagulation which results in thromboembolic complications and consumption coagulopathy causing severe hemorrhage. The central underlying pathophysiological pathway in the coagulopathy associated with these syndromes is the occurrence of tissue factor, released from the placenta and amniotic fluid, in the circulation, in combination with low levels of physiological anticoagulant factors during pregnancy. The diagnosis of DIC may be made trough conventional composite scoring systems employing routine coagulation tests, whereas for the diagnosis of amniotic fluid embolism measurement of insulin like growth factor binding protein-1 seems promising. Therapy is aimed at removing the precipitating factor combined with supportive adjunctive treatment options.

[Amniotic fluid embolism: an update]

Amniotic fluid embolism (AFE) results from the passage of fœtal and amniotic fragments into the maternal circulation, occurring mostly within minutes before or after delivery. Although maternal and fœtal mortality of AFE remains high (about 40%), AFE should no longer be considered as having an ineluctable fatal course. Diagnosis is often made upon clinical presentation but histological confirmation is difficult owing favorable outcome and because an autopsy has not been performed. Identification of squamous cells in the maternal circulation could not confirm the diagnosis because of their possible maternal origin. High plasma level of insulin-like growth factor-binding protein-1 (IGFBP-1) has recently been identified as a biomarker of amniotic fluid passage into the maternal circulation and might therefore be used to confirm the diagnosis when lung tissue histology is not available. Treatment of AFE remains supportive with a special focus on correction of the coagulopathy and search for acute core pulmonale. In this later case, physicians should consider initiating an extracorporeal life support when facing a patient with refractory shock. Finally, caution is needed with the use of recombinant factor VIIa in this context.