2 day old baby lumbar puncture. please read.

Emily
My 2 day old nephew has an infection (antibiotics given through cannula and a tube in his nose to help feeding) and had jaundice (which has cleared up wonderfully). Upon leaving the hospital today he returned from a lumbar puncture to test for meningitis and other infections testing his spinal fluid and the fluid around the brain. 
I was wondering if anyone else had a similar experience and what happened? 
My sister had 4 miscarriages and finally has had a beautiful boy and we are so upset that he's been poorly. He started feeding again we're just very worried. Hoping all will be ok..