Amniotic fluid embolism mortality rate

Histological differences among thrombi in thrombotic diseases

PURPOSE OF REVIEW

This review aims to summarize the histological differences among thrombi in acute myocardial infarction, ischemic stroke, venous thromboembolism, and amniotic fluid embolism, a newly identified thrombosis.

RECENT FINDINGS

Acute coronary thrombi have a small size, are enriched in platelets and fibrin, and show the presence of fibrin and von Willebrand factor, but not collagen, at plaque rupture sites. Symptomatic deep vein thrombi are large and exhibit various phases of time-dependent histological changes. Cancer-associated venous thromboemboli contain invasive cancer cells that penetrate the vascular walls, and small cancer cell aggregates are observed within the thrombi. The thrombus composition in atherosclerotic and cardioembolic ischemic strokes varies from case to case, while the thrombi in cancer-associated ischemic stroke are rich in platelets and fibrin. A pathological study on amniotic fluid embolism identified uterine vein thrombi and massive platelet-rich microthrombi in the lungs.

SUMMARY

Atherothrombus formation is induced by plaque disruption and may occlude a narrow lumen within a short time. Venous thrombi may grow to a large size in a multistage or chronic manner. Cancer cells can directly contribute to venous thrombus formation. The thrombus formation in amniotic fluid embolism may explain the occurrence of consumptive coagulopathy and cardiopulmonary collapse.

Amniotic fluid embolism: A case-series

Amniotic fluid embolism (AFE) is a rare but potentially catastrophic pregnancy complication. This is a 10-year retrospective study on women with AFE from 2014 to 2023. Cases that met Clark's criteria or in whom a clinical diagnosis was made after exclusion of other causes were included. Information on clinical characteristics, treatment, complications and outcomes were collected and analysed. Four cases of AFE were identified. Two met Clark's criteria and presented with cardiac arrest requiring extracorporeal membrane oxygenation, of which one had cognitive and functional impairment. Two women had atypical AFE, one with disseminated intravascular coagulation (DIC)-type AFE who did not survive, and another who had paradoxical intracranial emboli from a patent foramen ovale, who had full recovery. All had coagulopathy and postpartum haemorrhage. Early recognition and initiation of cardiovascular support is crucial in AFE. DIC and haemorrhage should be treated aggressively. Survival and good outcomes of AFE are possible.

[Cell salvage in obstetrics-Background and practical implementation]

Postpartum hemorrhage (PPH) remains a leading cause of maternal mortality worldwide, with an increasing incidence in western countries over the past decades. During this period the numbers of PPH-related allogeneic red blood cell (RBC) transfusions have also significantly increased. Given the increasing scarcity and risks of allogeneic RBC transfusions, which are also associated with adverse maternal outcomes, optimized blood management strategies are urgently needed in obstetrics. In recent years, patient blood management (PBM) has been increasingly integrated into medical care, resulting in a significant improvement in patient outcomes. Cell salvage (CS) is one of the PBM blood-sparing techniques that enables the collection, processing and retransfusion of the patient's own blood during major bleeding events. Although recent evidence indicates that CS can significantly reduce the demand for allogeneic RBC transfusions and improve patient outcomes, the utilization in obstetrics in German hospitals remains low, with a usage rate of only 0.07% of births with peripartum hemorrhage. It must be assumed that concerns about patient-related complications, such as amniotic fluid embolism and maternal alloimmunization contribute to this hesitancy, alongside a lack of familiarity with the technique. This article provides an overview of the current evidence on the use and safety of CS in obstetrics. To facilitate a practical implementation, fundamental considerations and organizational precautions were prepared based on the experiences of the University Hospitals in Würzburg and Frankfurt and presented in the form of graphics and checklists for the perioperative use of CS during cesarean sections.

Resuscitative endovascular balloon occlusion of the aorta: A novel approach for treating amniotic fluid embolism with disseminated intravascular coagulopathy-A report of two cases

We present two critical cases of life-threatening postpartum hemorrhage (PPH) due to amniotic fluid embolism (AFE) complicated by disseminated intravascular coagulopathy (DIC). These cases are the first to show the effectiveness of resuscitative endovascular balloon occlusion of the aorta (REBOA) for patient survival. In Case 1, the patient, experiencing critical conditions with severe PPH and DIC despite conventional treatments, including rapid blood transfusion and fibrinogen concentrate, was air-transferred to our hospital, where REBOA was promptly employed before hysterectomy was completed. Case 2 involved an ambulance-transferred patient with massive PPH and DIC despite conventional treatments. Prehospital REBOA was performed to prevent cardiac arrest during transfer, and hysterectomy was performed in the hospital. Given the rapid deterioration associated with AFE, REBOA can serve as a bridge until complete hemostasis to maintain vital signs and control bleeding in patients unresponsive to standard therapies before hemostatic interventions or during transfer.

Current concepts in the use of cell salvage in obstetrics

PURPOSE OF REVIEW

The worldwide leading cause of maternal death is severe maternal hemorrhage. Maternal hemorrhage can be profound leading to an entire loss of blood volume. In the past two decades, Patient Blood Management has evolved to improve patient's care and safety. In surgeries with increased blood loss exceeding 500 ml, the use of cell salvage is strongly recommended in order to preserve the patient's own blood volume and to minimize the need for allogeneic red blood cell (RBC) transfusion. In this review, recent evidence and controversies of the use of cell salvage in obstetrics are discussed.

RECENT FINDINGS

Numerous medical societies as well as national and international guidelines recommend the use of cell salvage during maternal hemorrhage.

SUMMARY

Intraoperative cell salvage is a strategy to maintain the patient's own blood volume and decrease the need for allogeneic RBC transfusion. Historically, cell salvage has been avoided in the obstetric population due to concerns of iatrogenic amniotic fluid embolism (AFE) or induction of maternal alloimmunization. However, no definite case of AFE has been reported so far. Cell salvage is strongly recommended and cost-effective in patients with predictably high rates of blood loss and RBC transfusion, such as women with placenta accreta spectrum disorder. However, in order to ensure sufficient practical experience in a multiprofessional obstetric setting, liberal use of cell salvage appears advisable.

Routine use of cell salvage during cesarean section: A practice evaluation

INTRODUCTION

Intraoperative cell salvage is a well-documented alternative to donor blood transfusion given the scarcity of donor blood pools and the incumbent risk of allogenic blood transfusion. Its use in obstetrics has been limited by concern over fetal alloimmunization due to the risk of fetomaternal hemorrhage. However, there are a paucity of studies reporting on outcome. The aim of this study was to report on a four-year experience of routine use of intraoperative cell salvage and the impact on subsequent pregnancy outcomes.

MATERIAL AND METHODS

This was a tertiary center retrospective service evaluation cohort study and included all women undergoing cesarean section between December 2014 and November 2018 in a tertiary obstetric unit, identifying women who had reinfusion of intraoperative cell salvage. Data regarding index pregnancy as well as subsequent pregnancies at the hospital were extracted from hospital electronic records. Subsequent pregnancy outcome and maternal antibody status in that pregnancy were collected up until November 2022.

RESULTS

During the study period, 6656 cesarean sections were performed, with 436 (6.6%) receiving reinfusion of salvaged blood. The mean volume of reinfused blood was 396 mL. A total of 49 (0.7%) women received donor blood transfusion. Of those who received reinfusion of salvaged blood, 79 (18.1%) women had subsequent pregnancies over the eight-year follow-up period. There was one case (0.23%) of fetal cell alloimmunization demonstrated by the presence of anti-D antibodies on the subsequent pregnancy booking bloods.

CONCLUSIONS

Routine intraoperative cell salvage may be used to reduce the need for blood transfusion during cesarean section. The risk of fetal cell alloimmunization in a future pregnancy following reinfusion of intraoperative cell salvage is one in 436. Given an apparent small risk of fetal cell alloimmunization, further work is required to establish the safety profile of intraoperative cell salvage in pregnancy.

Massive platelet-rich thrombus formation in small pulmonary vessels in amniotic fluid embolism: An autopsy study

OBJECTIVE

To identify pulmonary/uterine thrombus formation in amniotic fluid embolism (AFE).

DESIGN

Retrospective, observational.

SETTING

Nationwide.

POPULATION

Eleven autopsy cases of AFE and control cases.

METHODS

We assessed pulmonary and uterine thrombus formation and thrombus area in AFE and pulmonary thromboembolism (PTE) as a control. The area of platelet glycoprotein IIb/IIIa, fibrin, neutrophil elastase, citrullinated histone H3 (a neutrophil extracellular trap marker) and mast cell chymase immunopositivity was measured in 90 pulmonary emboli, 15 uterine thrombi and 14 PTE.

MAIN OUTCOME MEASURES

Pathological evidence of thrombus formation and its components in AFE.

RESULTS

Amniotic fluid embolism lung showed massive thrombus formation, with or without amniotic emboli in small pulmonary arteries and capillaries. The median pulmonary thrombus size in AFE (median, 0.012 mm2 ; P < 0.0001) was significantly smaller than that of uterine thrombus in AFE (0.61 mm2 ) or PTE (29 mm2 ). The median area of glycoprotein IIb/IIIa immunopositivity in pulmonary thrombi in AFE (39%; P < 0.01) was significantly larger than that of uterine thrombi in AFE (23%) and PTE (15%). The median area of fibrin (0%; P < 0.001) and citrullinated histone H3 (0%; P < 0.01) immunopositivity in pulmonary thrombi in AFE was significantly smaller than in uterine thrombi (fibrin: 26%; citrullinated histone H3: 1.1%) and PTE (fibrin: 42%; citrullinated histone H3: 0.4%). No mast cells were identified in pulmonary thrombi.

CONCLUSIONS

Amniotic fluid may induce distinct thrombus formation in the uterus and lung. Pulmonary and uterine thrombi formation may contribute to cardiorespiratory collapse and/or consumptive coagulopathy in AFE.

Post-abortion Complications: A Narrative Review for Emergency Clinicians

An abortion is a procedure defined by termination of pregnancy, most commonly performed in the first or second trimester. There are several means of classification, but the most important includes whether the abortion was maternally “safe” (performed in a safe, clean environment with experienced providers and no legal restrictions) or “unsafe” (performed with hazardous materials and techniques, by person without the needed skills, or in an environment where minimal medical standards are not met). Complication rates depend on the procedure type, gestational age, patient comorbidities, clinician experience, and most importantly, whether the abortion is safe or unsafe. Safe abortions have significantly lower complication rates compared to unsafe abortions. Complications include bleeding, retained products of conception, retained cervical dilator, uterine perforation, amniotic fluid embolism, misoprostol toxicity, and endometritis. Mortality rates for safe abortions are less than 0.2%, compared to unsafe abortion rates that range between 4.7-13.2%. History and physical examination are integral components in recognizing complications of safe and unsafe abortions, with management dependent upon the diagnosis. This narrative review provides a focused overview of post-abortion complications for emergency clinicians.

Sudden respiratory and circulatory collapse after cesarean section: Amniotic fluid embolism or other reasons? - a case report

Background

For a healthy parturient, a cardiopulmonary collapse that suddenly occurs shortly after an uneventful caesarean section is a relatively rare event and presents a significant challenge for the anesthesia provider.

Case presentation

Amniotic fluid embolism (AFE) is characterized by acute and rapid collapse and is well known to the obstetric team. Our patient experienced sudden cardiovascular collapse, severe respiratory difficulty and hypoxia, in the absence of other explanations for these findings at the time, and thus AFE was immediately become the focus of the consideration. However, there is no quick, standard laboratory test for AFE, therefore the diagnosis is one of exclusion based on presenting symptoms and clinical course. After given symptomatic treatment, the patient made an uneventful initial recovery in a short period and developed a rash. We recognized that the postpartum shock was associated with delayed anaphylaxis of antibiotics.

Conclusions

These observations have implications for understanding whenever administering drugs in surgery, which may affect the anesthesiologist’s judgment regarding the complications of anesthesia. Even though serious complications of common perioperative drugs may rarely occur, anesthesia providers should be aware of the consideration. Early recognition and effective treatment are more important than prompt diagnosis.

Cardiac Arrest during Cesarean Section - A Case Report and Review of the Differential Diagnosis

AIM

According to the World Health Organization, approximately 810 pregnant women die every day as a consequence of peripartum complications. A large proportion of deaths happen in developing countries. Peripartum cardiac arrest is a rare event that must be treated immediately. It is important to consider the differential diagnoses in order to save lives.

METHODS

In this review, we discuss a differential diagnosis of cardiac arrest according to the BEAU-CHOPS scheme of the American Heart Association in the relation to the case report of our 40-year-old G5/P3 patient who went into cardiac arrest during cesarean delivery.

RESULTS

Typical differentials for cardiac arrest during labor are bleeding, embolism, anesthetic complications, cardiovascular diseases, eclampsia, and sepsis. All of them were considered and ruled out in this patient. In the end, we suspect that physiological cardio-inhibitory reflexes triggered by sudden profound hypovolemia after placental separation along with the patient's risk factors, especially obesity and maternal age, and the administration of spinal anesthesia all potentially contributed to the cardiac arrest.

CONCLUSIONS

This review highlights that the cardiac arrest during labor can be triggered by the multifactorial etiology, but firstly the typical differential diagnosis needs to be excluded.

The Role of Extra Corporeal Membrane Oxygenation in Amniotic Fluid Embolism: A Case Report and Literature Review

Amniotic fluid embolism (AFE) is a rare and life-threatening complication related to pregnancy. Early diagnosis and prompt intervention are important tools for the survival of the patient. Despite early intervention, mortality rate remains high. We present a case of a 19-year-old female who was admitted for labor induction and delivery. Her delivery course was complicated by meconium-stained amniotic fluid. The patient went into acute hypoxic respiratory failure (AHRF) and hemodynamic compromise within half an hour following delivery secondary to AFE. We hereby discuss the role of timely initiation of extra corporeal membrane oxygenation (ECMO) in a case of AFE which could have otherwise turned out to be fatal.

Extracorporeal Life Support in Pregnancy: A Systematic Review

Background The use of extracorporeal life support (ECLS) has expanded to include unique populations such as peripartum women. This systematic review aims to (1) quantify the number of cases and indications for ECLS in women during the peripartum period reported in the literature and (2) report maternal and fetal complications and outcomes associated with peripartum ECLS. Methods and Results This review was registered in PROSPERO (CRD42018108142). MEDLINE, Embase, and CINAHL were searched for case reports, case series, and studies reporting cases of ECLS during the peripartum period that reported one or more of the following outcomes: maternal survival, maternal complications, fetal survival, and/or fetal complications. Qualitative assessment of 221 publications evaluated the number of cases, clinical details, and maternal and fetal outcomes of ECLS during the peripartum period. There were 358 women included and 68 reported fetal outcomes in cases where the mother was pregnant at the time of cannulation. The aggregate maternal survival at 30 days was 270 (75.4%) and at 1 year was 266 (74.3%); fetal survival was 44 (64.7%). The most common indications for ECLS overall in pregnancy included acute respiratory distress syndrome 177 (49.4%), cardiac failure 67 (18.7%), and cardiac arrest 57 (15.9%). The most common maternal complications included mild to moderate bleeding 66 (18.4%), severe bleeding requiring surgical intervention 48 (13.4%), and intracranial neurologic morbidity 19 (5.3%). The most commonly reported fetal complications included preterm delivery 33 (48.5%) and neonatal intensive care unit admission 19 (27.9%). Conclusions Reported rates of survival in ECLS in pregnant and postpartum women are high and major complications relatively low.

Low Incidence of Maternal Near-Miss in Zhejiang, a Developed Chinese Province: A Cross-Sectional Study Using the WHO Approach

Background and Aim

Maternal near-miss (MNM) surveillance has been developed to identify severe complications in pregnancy since 2011 in China. However, very little is known about MNM in China. This study aims to explore the prevalence of MNM, the risk factors, and perinatal outcomes using the WHO near-miss approach in a developed Chinese province.

Materials and Methods

We used data from China’s National Maternity Near Miss Obstetrics Surveillance System for the period 2012 to 2017, which included 18 hospitals in Zhejiang Province. Chi-squared tests were used to compare the socio-demographic factors, obstetric complications and perinatal outcomes between women with and without MNM. Logistic regression was used to examine the independent risk factors for MNM.

Results

A total of 612,264 pregnant women were recruited. There were 3208 MNM cases and 34 maternal deaths. The MNM incidence ratio was low at 5.9 per 1,000 live births, with an MNM mortality ratio of 98:1 and mortality index of 1.1%. Among 3208 women with MNM, postpartum hemorrhage was the commonest cause at 76.3% followed by severe anemia at 23.7% and placenta previa at 23.0%. Embolism was identified as having the highest risk for MNM (AOR 46.0; 95% CI 19.1–110.7), followed by postpartum hemorrhage (AOR 41.0; 95% CI 35.7–47.0), and severe anemia (AOR 36.6; 95% CI 16.0–84.1). MNM cases were significantly associated with severe perinatal outcome, including premature birth, low birth weight, multiple fetuses, stillbirth rates and neonatal mortality.

Conclusion

Overall near-miss indicators suggested a relatively high quality of maternal health care in a developed province of China. The identified risk factors may be helpful in developing targeted interventions for improving maternal safety.