This looks like one of the plastic sleeves you find around a needle when you are being given an IV, they insert he needle with this sleeve and then extract the needle and leave the sleeve in its place. In the video you can see a clear plastic tube.
Not in the medical field but the most benign thing I can think of that this might be is one of those vitamin IV's they give to people who are massively wasted or attempting to stay awake for days. I can't thank of anything else they would need to give him through an IV that is less serious. The flip side of this on the more extreme end, maybe its something like BAN2401, I've heard that they give this to Alzheimer's patients twice a month. Totally shot in the dark, but that stuff is given only twice a month and I couldn't imagine they would need to be giving it to him during the damn debate. For that reason alone I'm inclined to believe it was some kind of upper.
I think it's time to hang some of these DAs. If a DA is releasing dangerous people back into the public and that person is killing when they easily should have been behind bars for years the first time they were arrested, then that DA needs to pay with their life.
I love how direct this answer is, haha.