Webinar by Dr Yunis Shah Consultant Anaesthesiologist USA

1. Amniotic Fluid Embolism
Yunus M. Shah
MBBS, DABA, DABIPP, DABPM

2. Disclaimer
● Financial disclosures: none
● Off-label medication use

3. Patient Vignette
● Healthy 33 year old G2P1 at 38 weeks
● History of one cesarean delivery (due to breech presentation)
● Undergoing a trial of labor after cesarean (TOLAC)
● Intrapartum cesarean delivery called due to failure to progress &
preeclampsia with severe features
● Well-functioning labor epidural & cardiovascularly stable.

4. Patient Vignette (cont.)
●In OR, cesarean delivery in progress, healthy fetus is delivered
●Patient complains of shortness of breath & odd sensation (of
something not being right)
●Patient manifests grand mal seizure & hemodynamic deterioration
requiring induction of general anesthesia
●OB states diffuse oozing and poor hemostasis

5. Introduction
●Amniotic fluid embolism (AFE): Anaphylactoid Syndrome
of Pregnancy
○Amniotic material enters bloodstream
○Possible cause: breakdown in placental barrier
●Incidence of AFE: 1.9 to 6.1 cases per 100,000 deliveries
○ Difficult to know true numbers due to reporting differences

6. AFE Related Morbidity & Mortality
● AFE related mortality estimated to be between 5 and 15% of all
maternal deaths.
● Case fatality rate between 11-80%
● Perinatal mortality rates between 7–44%
● Among survivors, persistent neurological impairment in 6 to 61% of
women.
● Significant morbidity including cerebral palsy and ischemic
encephalopathy occurring in infant survivors.
Curr Opin Anesthesiol 2016, 29:288–296

7. Risk Factors
●Obesity
●Advanced Maternal Age
●Polyhydramnios
●Placental abnormalities
○Previa
○Abruption
○Accreta
●Preeclampsia/eclampsia
●Male fetus
● Cesarean delivery
● Instrumental vaginal delivery
● Dilatation & Evacuation
● Induced/Augmented labor
● Cervical Laceration

8. Etiology & Pathogenesis
●Breakdown of placental
barrier
●Exposure of maternal
circulation to fetal antigens
●Resultant Anaphylactoid
maternal reaction
Sadera G, Vasudevan B. Amniotic fluid embolism. J Obstet Anaesth Crit Care [serial online] 2015 [cited 2020 May 1];5:3-8.

9. Presentation
●Sudden/unexplained cardiovascular collapse
●Chest pain (inconsistent)
●Feeling of impending doom
●Altered neurological status
●Coagulopathy
●Respiratory Compromise
○Dyspnea
○Cyanosis

10. Diagnostic Criteria
●Sudden onset of cardiorespiratory arrest, OR
hypotension (systolic blood pressure <90 mm Hg) with
evidence of respiratory compromise (O2 saturation <
90%)
●Clinical onset during labor or within 30 minutes of
placental delivery
●Absence of fever (≥38°C) during labor

11. Diagnostic Criteria (cont.)
● Documentation of overt DIC using the scoring system of the Scientific
and Standardization Committee on DIC of the International Society on
Thrombosis and Hemostasis (ISTH), modified for pregnancy:
○ Platelet count >100,000/mL = 0 points, <100,000 = 1 point, <50,000 = 2 points
○ Prolonged prothrombin time or international normalized ratio <25% increase =
0 points, 25 to 50% increase = 1 point, >50% increase = 2 points
○ Fibrinogen level >200 mg/dL = 0 points, <200 mg/dL = 1 point
○ A score ≥3 is compatible with overt DIC. Coagulopathy must be detected
before dilutional or shock-related consumptive coagulopathy are attributed to
causing hemorrhage.

12. ATOTW 383 – Maternal Early Warning Scores (10th July 2018)

13. ATOTW 383 – Maternal Early Warning Scores (10th July 2018)

14. Mutschler M, Nienaber U, Münzberg M, et al. Assessment of hypovolaemic shock at scene: Is the PHTLS classification of hypovolaemic shock really valid?
Emerg Med J. 2014;31(1):35–40.

15. ROSE (Rapid Obstetric Screening
Echocardiography) = A B C D E F
● Acceptable and Applicable
● Bedside test at left hand side of patient
● Comfortable and Concise examination
○ parasternal and apical view scans
● Diagnosis and response to therapy
● Embolism
○ Right heart function/size
● Fetal heart rate assessment

16. Approach to Management
● Differentiate between medical & obstetric disorders with similar
presentations
○ Hypertension
○ Proteinuria
○ Rising Creatinine
○ Thrombocytopenia
○ Seizures
● Optimize organ function

17. Expand Differential

18. Management: Respiratory/Pharmacological Support
●Pharmacological Support
○AOK Protocol (Atropine 0.2 mg, Ondansetron 4 mg,
Ketorolac 30 mg) **all given IV
●Respiratory Support
○Usually requires intubation & ventilation
○ Initial severe pulmonary vasoconstriction and V/Q
mismatch successfully treated with inhaled nitric oxide and
aerosolized prostacyclin

19. Hemorrhage Management
● Almost universal Uterine atony
● Manage with Uterotonics (Oxytocin / Carboprost /
Methylergonovine/ Misoprostol)
● Surgical Interventions: Bakri balloon, B-Lynch suture,
Uterine artery ligation/embolization, Hysterectomy
● REBOA ( Resuscitative Endovascular Balloon Occlusion
of Aorta)

21. Management: Hemodynamic Support
● Invasive Line Placement
○ A-line/central line, assist with transfusion & labs
● Labs
○ CBC, CMP, Coags (DIC profile), ABG
● Temperature Support
○ Ensure Normothermia

22. Management: Hemodynamic Support (cont.)
●Circulatory support
○Large bore IV access (above diaphragm)
○Active resuscitation with IV fluids via rapid infuser
○Massive transfusion protocol initiated
○Use of vasopressors
○Mechanical support (chest compressions, IABP, ECMO)

23. Massive Transfusion Protocol

24. Critical Importance of Serum Fibrinogen

25. Massive Hemorrhage Management (cont.)
● Goal directed management
● PRBC : FFP : Platelet ratio 1:1:1
● Use Cryoprecipitate / Fibrinogen concentrate
● Use Visco-Elastic testing to guide ( ROTEM, TEG)
● Early use of Tranexamic acid
● Factor VIIa and Heparin : likely worse outcomes

26. Emerging and Future directions
● Biomarkers of interest : C1 esterase inhibitor, BNP, STN,
ZnCP-1, POMC
● Non-standard treatments : Anti-Thrombin concentrate, High
dose steroids, Synthetic C-1 esterase inhibitors, Plasma
exchange transfusion, Hemofiltration
Curr Opin Anesthesiology 2016, 29:288–296

27. References
● Knight M, Berg C, Brocklehurst P, et al. Amniotic fluid embolism incidence, risk
factors and outcomes: a review and recommendations. BMC Pregnancy
Childbirth. 2012 Feb 10;12:7
● Clark SL, Romero R, Dildy GA, et al. Proposed diagnostic criteria for the case
definition of amniotic fluid embolism in research studies. Am J Obstet Gynecol.
2016;215:408-12
● Stafford IA, Moaddab A, Dildy GA, et al. Evaluation of proposed criteria for
research reporting of amniotic fluid embolism. Am J Obstet Gynecol.
2019;220:285-87
● Rezai S, Hughes AC, Larsen TB, Fuller PN, Henderson CE. Atypical amniotic fluid
embolism managed with a novel therapeutic regimen. Case Rep Obstet Gynecol.
2017;2017:8458375