A CT scаn demоnstrаtes оbliterаtiоn of the right lower lobe bronchus and subcarinal lymphadenopathy. Your bronchoscopy plan now involves biopsies. His medication list includes warfarin. Labs demonstrate platelet count 80,000/mm3, INR 2.1, creatinine 1.7 mg/dL, BUN 23 mg/dL. You explain to his team that in order to perform biopsies, it would be most appropriate to