I was in ICU way back in 2008 and never really concerned about why or for what reason these boxes were attached to my wrist with 2 stiches. From the scars they left I must of had 4 of them 2 on each wrist. They were smaller than a box of matches and had a sticker on it with ATRIAL nothing else? I know I had to have a few transfusions while in there (6 units one day) so assumed it was for that but do not know? You can see were a needle was inserted as that has left a scar also.