Nailah Winkfield said she convinced her daughter, Jahi McMath, 13, to undergo the surgery despite reservations because doctors said it would help address her chronic sleep apnea.
McMath entered Oakland Children's Hospital Monday for the routine procedure. After it was over she began suffering severe side-effects including blood clots. When McMath's grandmother, Sandra Chatman, said it became clear things were not right she summoned nurses and asked what was happening, KGO-TV, San Francisco reported Sunday.
"I went in and I said 'is this normal, do you guys find this to be normal?' And they said 'I don't really know,' and I said 'well then get a doctor,'" Chatman said.
Shortly after that, McMath slipped into cardiac arrest. Hospital personnel were able to revive her but she remains comatose with no brain activity and the family must face the decision on whether to keep the young girl on life support.
Winkfield and Chatman said they're calling on the hospital to investigate how such a routine surgery could lead to a child's death.
Oakland Children's Hospital spokeswoman Melinda Kriegel released a statement on the case: "We're very sad about this outcome, about what's happened to her, but at this point I have no information on the details of the surgery. We will certainly investigate what happened. In any surgery there are risks and there can be unexpected, unanticipated complications."
Notable deaths of 2014 [PHOTOS]