TPA - ?off label/new use

[Halle Utter]

I had an interesting experience over the weekend I thought I'd share.  Was placing a PICC on a pt admitted with rapidly progressive pleural effusion, probable empyema over the weekend.  They had tried to tap him(thoracentesis) without success, so had inserted a chest tube, which wasn't draining. Before my arrival at bedside they had instilled TPA into the chest tube to break up the empyema, and clamped it for a 2 hour period.  While I was all set up with my sterile field the nurse came in and said it had been 2 hours and unclamped the tube.  The patient proceeded to dump a liter out of the pleural space in about 1-2 minutes.  He became extremely uncomfortable (played havoc with my sterile field!) for a few minutes with pain in the chest and feeling like he couldn't breathe, then kind of stabled out.  The nurse said she didn't expect there to be such a dramatic reaction - when she had seen it done before there wasn't such a fast exodus of fluid.  I had never heard (or seen the effectiveness!) of this use of TPA before, but I saw the chest xray taken a couple hours before I arrived, and the post PICC one, and let me tell you, practically his whole lung re-expanded BOOM!  It was fascinating.  Maybe you all out there have seen TPA used for this, but I hadn't.  Boy did it work.  But I did have questions about how much TPA was used and what the systemic implications would be, because it seemed logical to me that it would take a lot more than the 2mg vial of cathflo we are used to using for catheter declotting..   Wouldn't some of it be absorbed and effect clotting?  Has anyone seen this before?  What is the typical dose of TPA used, and the implications of reabsorption from the pleural space?  Or did it all drain out into the Pleurevac?  Comments?   Halle Utter, RN Intravenous Care, INC