Its fine to give heparin subQ to hemodialysis pts after dialysis. The half life of IV heparin is very short which is why IV heparin during dialysis is stopped for the last hour if the pt has a fistula or graft.
Here is a study done on hemodialysis pts, though older study, still good info and good source too: Heparin elimination and hemostasis in hemodialy... [Clin Nephrol. 1984] - PubMed - NCBI
Want to add too that if hemodialysis access, fistula or graft DOES begin to rebleed once the pt has left the dialysis unit, it is imperative that you quickly remove the dressing and apply POINT PRESSURE ONLY to the bleeding needle stick. It is not necessary to circumferentially wrap a dialysis access EVER. This is a pts lifeline, so point pressure only.