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Amniotic Fluid Embolism

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Amniotic Fluid Embolism, Pulmonary Embolism of Amniotic Fluid, Anaphylactoid Syndrome of Pregnancy

  • See Also
  1. Pulmonary Embolism in Pregnancy
  2. Pulmonary Embolism
  • Epidemiology
  1. Incidence: 1 in 8000 to 80,000 live births
  • Pathophysiology
  1. Amniotic fluid released into maternal circulation
  2. Amniotic fluid induces anaphylactoid-type immunologic response
  3. Results in transient pulmonary artery spasm
  4. Causes Hypoxia, pulmonary capillary injury and left ventricular injury
  5. Results in Left Ventricular Failure, ARDS, DIC and multi-system failure
  • Symptoms
  1. Severe, sudden onset Dyspnea
  • Signs
  1. Tachypnea
  2. Hypoxia
  3. Severe shock of rapid onset
  4. Altered Mental Status or encephalopathy
  5. Cyanosis
  6. Hypotension
  7. Cardiopulmonary arrest
  • Risk Factors
  1. Trauma in Pregnancy
  2. Amniotomy
  3. Strong uterine contractions
  • Differential Diagnosis
  1. Pregnancy Induced Hypertension
  2. Abruptio Placentae
  3. Uterine Rupture
  4. Aspiration Pneumonia
  • Lab
  1. Arterial Blood Gas
  2. Complete Blood Count with Platelets
    1. Thrombocytopenia
  3. Urinalysis
  4. Type and Cross 4-6 units Packed Red Blood Cells
  5. Coagulation studies
    1. D-Dimer
    2. ProTime (PT, INR)
    3. Partial Thromboplastin Time (PTT)
    4. Fibrin split products (Fibrin Degradation Products)
    5. Fibrinogen (low)
    6. Clot Test
  • Imaging
  1. Chest XRay
    1. Bilateral infiltrates may be seen with progression
  • Diagnostics
  1. Electrocardiogram (EKG)
    1. Sinus Tachycardia
    2. Dysrhythmias
  • Management
  1. Emergent supportive care
    1. Oxygen Supplementation
    2. Intravenous Access
    3. Endotracheal Intubation
    4. Vasopressors
    5. Fluid Resuscitation
    6. Correct coagulation deficits
  2. Advanced Measures to consider
    1. Venoarterial ECMO
    2. Uterine Artery Embolization
    3. Exchange Transfusion
  3. A-OK Amniotic Fluid Embolism Protocol
    1. Atropine 1 mg IV (vagolytic) AND
    2. Ondansetron 8 mg IV (Serotonin blockade) AND
    3. Ketorolac 30 mg IV (Thromboxane production blockade)
    4. Rezai (2017) Case Rep Obstet Gynecol +PMID: 29430313 [PubMed]
      1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5753013/
  4. Admit to Intensive Care unit
  5. Consultations
    1. Maternal-fetal medicine
    2. Medicine
    3. Neonatology
  • Monitoring
  1. Check Hemoglobin every 1 hour (keep above 10 mg/dl)
  2. Check Hematocrit every 1 hour (keep above 30)
  3. Check coagulation studies every 2 hours
  4. Fetal scalp electrode
  5. Tocometry or intrauterine pressure catheter
  6. Monitor strict intake and output
    1. Keep Urine Output > 30 cc per hour
  • Prognosis
  1. Mortality approaches 61% for mothers
    1. Low survival rate for fetus if still in utero
    2. Surviving mothers have intact neurologic function in only 15% of cases
  • References
  1. Krywko and Jennings (2018) Crit Dec Emerg Med 32(4): 3-11
  2. Lively and Clare (2022) Crit Dec Emerg Med 36(5): 4-10
  3. Clark (1995) Am J Obstet Gynecol 172(4): 1158-69 [PubMed]