Clinical course of disseminated intravascular coagulopathy-type amniotic fluid embolism: A report of three cases

The Role of Thromboelastography during the Management of Postpartum Hemorrhage: Background, Evidence, and Practical Application

Postpartum hemorrhage (PPH) is a common cause of significant maternal morbidity and mortality that can be associated with coagulopathy, especially hypofibrinogenemia. There is interest in point-of-care viscoelastic hemostatic assays (POC-VHA) in PPH because prompt knowledge of coagulation status can aid diagnosis, identify cases of severe coagulopathy, and allow ongoing monitoring during rapid bleeding. The incidence of coagulopathy in most cases of PPH is low because of the procoagulant state of pregnancy, including raised fibrinogen levels of around 4 to 6 g/L. A Clauss fibrinogen of >2 g/L or POC-VHA equivalent has been found to be adequate for hemostasis during PPH. POC-VHA has been used successfully to diagnose hypofibrinogenemia (Clauss fibrinogen of ≤2 g/L) and guide fibrinogen treatment which has reduced bleed size and complications of massive transfusion. There are uncertainties about the use of POC-VHA to direct fresh frozen plasma and platelet administration during PPH. Several POC-VHA algorithms have been used successfully incorporated in the management of many thousands of PPHs and clinicians report that they are easy to use, interpret, and aid decision making. Due to the relative cost of POC-VHA and lack of definitive data on improving outcomes, these devices have not been universally adopted during PPH.

Obstetric Disorders and Critical Illness

In this article, we discuss some of the more common obstetric-related conditions that can lead to critical illness and require management in an ICU. These include the hypertensive disorders of pregnancy, postpartum hemorrhage, hemolysis, elevated liver enzymes, and low platelet syndrome, acute fatty liver of pregnancy, amniotic fluid embolism, and peripartum cardiomyopathy. We also discuss pulmonary embolism and Covid-19. Despite not being specific to obstetric patients, pulmonary embolism is a common, life-threatening diagnosis in pregnancy with particular risks and management aspects. Covid-19 does not seem to occur with higher frequency in pregnant women, but it leads to higher rates of ICU admissions and mechanical ventilation in pregnant women than in their nonpregnant peers. Its prevalence during our current global pandemic makes it important to discuss in this article. We provide a basis for critical care physicians to be engaged in informed conversations and management in a multidisciplinary manner with other relevant providers in the care of critically ill pregnant and postpartum women.

Summary of clinically diagnosed amniotic fluid embolism cases in Korea and disagreement with 4 criteria proposed for research purpose

OBJECTIVE

This study aimed 1) to investigate the clinical characteristics of amniotic fluid embolism (AFE) cases clinically diagnosed by maternal fetal medicine (MFM) specialists in Korea, 2) to check the disagreement with 4 recently proposed criteria by the Society for Maternal-Fetal Medicine (SMFM) for research purpose, and 3) to compare maternal outcomes between cases satisfying all 4 criteria and cases with at least 1 missing criterion.

METHODS

This study included 12 patients clinically diagnosed with AFE from 7 referral hospitals in Korea. We collected information, including maternal age, symptoms of AFE, the amount of transfusion, and maternal mortality.

RESULTS

The median maternal age was 33 years (range, 28-40 years). Regarding symptoms, cardiovascular arrest, hypotension, respiratory compromise, clinical coagulopathy, and neurologic signs were observed in 41.7%, 83.3%, 83.3%, 100%, and 66.7% of the cases, respectively. Among the 12 cases, 5 women died and 2 suffered severe neurologic disability, showing an intact survival rate of 41.7%. Disagreement with all 4 criteria proposed by the SMFM was found in 66.7% of the cases, due to the lack of criteria for disseminated intravascular coagulation or strict onset time (<30 minutes after delivery). There was no difference in maternal mortality and the amount of transfusion between cases satisfying all 4 criteria and cases with at least 1 missing criterion.

CONCLUSION

Two-thirds of clinically confirmed AFE cases did not satisfy all 4 criteria proposed by the SMFM, despite similar rates of maternal mortality with cases satisfying all 4 criteria. Our study suggests that there may be some discrepancy between the clinical diagnosis of AFE and the recent diagnostic criteria proposed by the SMFM for research purpose.

Rupture of hidden abnormal myometrial vessels during cesarean delivery of a patient with subserosal leiomyoma: A possible pathogenesis of sudden-onset disseminated intravascular coagulation

We report a case of sudden-onset disseminated intravascular coagulation during cesarean delivery for a patient with a subserosal leiomyoma. Rupture of hidden anastomotic vessels resulted in a significant decrease in fibrinogen levels and uncontrolled bleeding. Uterine venous flow disturbance caused by subserosal leiomyoma compression can possibly cause such a situation.

Amniotic fluid embolism mortality rate

AIM

The objective of this study was to determine the mortality rate of amniotic fluid embolism (AFE) using population-based studies and case series.

METHODS

A literature search was conducted using the two key words: 'amniotic fluid embolism (AFE)' AND 'mortality rate'. Thirteen population-based studies were evaluated, as well as 36 case series including at least two patients.

RESULTS

The mortality rate from population-based studies varied from 11% to 44%. When nine population-based studies with over 17 000 000 live births were aggregated, the maternal mortality rate was 20.4%. In contrast, the mortality rate of AFE in case series varies from 0% to 100% with numerous rates in between.

CONCLUSION

The AFE mortality rate in population-based studies varied from 11% to 44% with the best available evidence supporting an overall mortality rate of 20.4%. Data from case series should no longer be used as a basis for describing the lethality of AFE.

Comparison of the Different Definition Criteria for the Diagnosis of Amniotic Fluid Embolism

INTRODUCTION

There are several sets of criteria for the diagnosis of Amniotic Fluid Embolism (AFE), but little is known about their degree of agreement.

AIM

To evaluate the concordance of the Japan criteria for AFE in comparison with two definitions: the US AFE registration entry criteria (the US criteria) and UK Obstetric Surveillance System criteria for defining cases of amniotic fluid embolism (the UK criteria).

MATERIALS AND METHODS

A retrospective observational study was conducted in which the AFE cases registered in the Obstetrical Gynaecological Society of Kinki District in Japan for the period of April 2005 to December 2012 have been analysed by the expert steering obstetric committee, organized by the members of the Obstetric Research group. Cohen's kappa coefficient was used to calculate the agreement among three clinical diagnoses. For inter-group comparison, the Pearson Chi-square test was used (for categorical) and Mann-Whitney test was used (for continuous variables).

RESULTS

Among the 26 cases registered for this period, a total of 18 women were selected as having AFE according to the Japan criteria. Five women died (case fatality rate 27.8%). Agreement between the Japan criteria and the US and UK criteria was k = 0.453 and k = 0.538, respectively, reflecting moderate agreement. However, only 38.9% were given a diagnosis of AFE according to all three criteria. The factor that most often caused disagreement in diagnosis between the Japan criteria and the US criteria was "onset within 30 minutes postpartum". The UK criteria excluded "women with postpartum haemorrhage as the first presenting feature in whom there was no evidence of cardiorespiratory compromise". The case fatality rates in US and UK are higher than in Japan (50.0% and 38.5% vs 27.8%), but this did not result in a significant difference (p=0.497).

CONCLUSION

The groups of subjects identified as having AFE by the Japan criteria had a medium agreement with the US (k=0.453) or UK criteria (k=0.538). These three definition criteria identified different subgroups of patients. Such disagreement has serious implications for research and treatment.