My 6 yr old had a HIDA scan and has 3% ejection fraction...anyone know what that could mean?

My 6 yr old has had stomach issues for 2 yrs now. They have ped off as "nerves". She has been on "diets", zantac and counseling. Finally sent to a specialist who sent her for a HIDA scan and the nurse called today with appt for Pediatric surgeon to see if she needed surgery to have her gall bladder removed. Not sure what ejection fraction is and if she will be ok with that much function, can someone help me understand? Thanks