A 34-year-old woman, gravida 3 para 2, presents to the labor and delivery unit at 39 weeks of gestation in active labor. Her pregnancy has been complicated by mild polyhydramnios diagnosed at 32 weeks, but she has otherwise been healthy. She undergoes an uneventful induction of labor. However, during the second stage of labor, she develops amniotic fluid embolism. Which of the following is the hallmark feature of amniotic fluid embolism (AFE)?
