Girls, we're on IV, we've already tried four different ones, and it's …

Girls, we're on IV, we've already tried four different ones, and it's all working. We're currently on Nutri-Lock, it's the least amount of blood. Yesterday the little one had bleeding with blood, yesterday everything was fine, but today again blood. I called the pediatrician, she said there's nothing to worry about. But it still scares me. Has anyone else experienced this? What did you do?