Exxcellence pearls: amniotic fluid embolism

Question 0

What is the proposed mechanism of pathophysiology for amniotic fluid embolism?

Answer 0

Amniotic fluid in the maternal circulation activates inflammatory mediators causing an anaphylactoid-like response.

Question 1

What is the incidence of amniotic fluid embolism?

What is the maternal mortality rate?

Answer 1

2-7 cases per 10,000 births.

20%.

Question 2

Amniotic fluid embolism accounts for what percentage of maternal deaths in developed countries?

Answer 2

10%

Question 4

What is the latest timing that amniotic fluid embolism has been reported?

Answer 4

48 hours postpartum

Question 5

What are risk factors for amniotic fluid embolism?

Answer 5

Advanced maternal age, multiparity, preeclampsia/eclampsia, diabetes mellitus, polyhydramnios or uterine over-distention. Also associated with precipitous labor, induction of labor, placental abruption, cervical laceration, and uterine rupture.

Question 5

What are the three phases of amniotic fluid embolism?

Answer 5

1. Respiratory distress and hypoxemia with altered mental status and hemodynamic collapse.
2. Coagulopathy and bleeding which may include DIC.
3. Tissue injury and end-organ system failure with pulmonary vascular constriction leading to pulmonary hypertension, right-sided heart failure and global myocardial depression.

Question 6

How does amniotic fluid embolism present?

Answer 6

Cardiovascular collapse with acute dyspnea, cyanosis and tachycardia. Tonic clonic seizures are the first sign in 10-50% of patients.

Question 7

How can coagulopathy during amniotic fluid embolism be corrected?

What surgical procedure maybe necessary to control hemorrhage?

Answer 7

Recombinant factor VII.

Hysterectomy.

Question 8

Describe the management of amniotic fluid embolism.

Answer 8

1. Get help. Anesthesiology, OR staff, interventional radiology, ICU.
2. Begin massive blood transfusion protocol.
3. Arterial catheter and central venous pressure catheter placement.
4. Serial ABG, blood counts and coags.
5. Oxygenation and circulatory support. Intubation, blood products, IV fluids, vasopressors, and even cardiopulmonary bypass.
6. Expeditious delivery. Cesarean if immediate vaginal delivery is not possible.

Question 9

Describe the ventilation settings necessary for a patient with amniotic fluid embolism?

Answer 9

High oxygen flow rate and increased positive end-expiratory pressures.