Levels refer to the level of care they can provide. Higher the number, higher the level of care.
And as I've been going on about ad nauseum today, is to be prepared emotionally for the fact that the NICU is not happy flower kitty land. In the past week we've had two major losses (and maybe 1 or two minor). First was a 9mo who had severe BPD and her little brain was just atrophied. Her incredibly brave parents saw that (it developed within the past month or two) realized that she was gone, but her body was just being tortured to hold on and they had the courage to turn off the vent and let her be at peace. The second was about 9 days old and had NEC totalis. Stomach to anus: dead.
And probably 3 more will be gone by next week. We have some really bad and sad cases up there right now.