Amniotic Fluid Embolism

Question 1

What is an amniotic fluid embolism?

Answer 1

• an acute cardio-respiratory collapse within 6 hours after labour, birth or ruptured membranes with no other identifiable cause, followed by acute coagulopathy in those women who survive the initial event
• clinical diagnosis —> acute hypotension, cardiac arrest, acute hypoxia, coagulopathy
• pathological diagnosis —> presence of fetal squames or hair in the lungs

Question 2

What is the incidence of AFE?

Answer 2

• incidence estimated to be 1.7:100000
• high mortality rate of around 11-61%
• perinatal mortality and morbidity rates also high

Question 3

What is the pathophysiology of AFE?

Answer 3

• can cause an inflammatory response similar to anaphylaxis, haemodynamic, humeral and coagulation changes lead to the signs and symptoms of AFE
• tears in the fetal membranes and the uterine vessels which allow amniotic fluid to enter the uterine vein and into the maternal pulmonary arterial circulation
• initially leads to blockage to the pulmonary arterioles and alveolar capillaries causing pulmonary vasospasm, hypoxia, oedema, circulatory compromise

Question 4

What are some of the signs and symptoms?

Answer 4

• hypotension
• fetal distress
• pulmonary oedema
• cardiopulmonary arrest
• cyanosis
• coagulopathy
• respiratory distress
• convulsions
• uterine atony
• bronchospasm
• chest pain
• altered mental state
• fetal compromise

Question 5

What are some of the pre-disposing factors?

Answer 5

• situations where intra-amniotic pressure is increased and membranes rupture
• multiple pregnancy
• polyhydramnios
• abruption/placenta praevia
• multiparity
• induction/augmentation
• meconium
• maternal age >35 years
• eclampsia
• uterine hyperstimulation
• hypertonic contractions
• rapid or precipitate birth
• invasive interventions in labour

Question 6

How should AFE be managed?

Answer 6

• call for help
• IV access and IV fluids
• ventilation (oxygen administration, intubation)
• chest compressions if necessary (CPR)
• deliver the baby if necessary
• insert catheter
• consider blood transfusion
• maintain uterine tone
• maternal observations
• bloods FBC, group and X match, coagulation