How to code for TPA infusion in a pelvic drain???

History: 56F s/p lap cholecystectomy complicated with bile leak.
CT scan demonstrates a residual collection around her anterior
pelvis drain which was upsized. However, despite upsizing the
drain there is only scant output. Now referred for cavitary

Informed consent was obtained prior to the procedure. A total of
4 mg TPA mixed in 20 cc normal saline was injected via the
12-French anterior pelvis drain and the drain was clamped. The
drain was left in the clamped position for approximately 2 hours,
after which fluid was aspirated from the drain.

In addition to the volume of fluid which was injected into the
drain, an additional 60 cc cloudy fluid was aspirated. The drain
was then flushed once again and connected to the drainage bag. No
immediate complications.

Intracavitary fibrinolysis performed with 4 mg TPA, allowed to
dwell for two hours. Additional 60 cc cloudy fluid was then
successfully aspirated.