It means something achieved (or escaped) by a narrow margin.Debbie said it was devastating to watch her daughter spend 10 months in isolation, where everyone had to wear gloves and a mask. At that time, she said, doctors would not do a bone marrow transplant without an identical match.
That all changed when Dr. Erwin Gelfand, immunologist-in-chief at the Hospital for Sick Children in Toronto, made a radical and risky move by harvesting the marrow from Kiela's father, Randy.
"The first transplant, Kiela kicked him out of her system," her mother said. "She ended up getting sick with a bunch of diseases and pneumonia. We had some really close calls with her."
What's the meaning of "call" in this text, please?
Student or Learner