Baby Luzinski

Baby Luzinski was the lost newborn in the Season 6 episode Lockdown. It is the child of Sarah Luzinski and Donald Luzinski and the half-sibling of Walker Luzinski. 
While Donald and Walker were out of the room and Sarah was sleeping, Nurse Maldonado, who had suffered from a partial complex seizure. Without knowing it, she had taken the baby and put it in a laundry cart with the towels she removed. 
The hospital was locked down while they looked for the baby. Lisa Cuddy finally found it unharmed in the laundry cart.