Health care providers monitoring anticoagulated patients are often asked to make recommendations regarding anticoagulant management during periods when illness or treatment may complicate anticoagulant therapy. Two particularly difficult clinical problems concern the indications for and management of anticoagulant therapy in patients with cancer and the management of anticoagulated patients who must undergo some type of surgical procedure. Cancer is a significant risk factor for a variety of thromboembolic disorders, particularly venous thromboembolism. Venostasis from immobility, vessel wall damage from tumor invasion, and especially tumor-mediated activation of the coagulation system are important contributors to the prethrombotic state in cancer patients. The risk of venous thromboembolism is greatest during surgery, chemotherapy, and long-term use of central venous catheters. For selected patients, prophylaxis with subcutaneous heparin, low-intensity warfarin, or very low-intensity warfarin may substantially reduce this risk. A related concern for primary care clinicians is the increasing evidence that idiopathic venous thromboembolism may be the first manifestation of occult cancer. Whether and how these patients should be screened for malignancy is currently uncertain. Prior to surgical procedures in anticoagulated patients, clinicians must compare the risk of bleeding if anticoagulation is continued with the risk of recurrent thrombosis if anticoagulation is stopped. Bleeding risk is influenced by how a specific procedure affects the ability to assess and control bleeding and the intensity of anticoagulation at the time of the procedure. Thromboembolism risk is determined by the specific indication for the anticoagulation and the length of time during which anticoagulant therapy must be discontinued. Guidelines are suggested for perioperative anticoagulant management of patients with different thromboembolic disorders undergoing a variety of surgical procedures.

The in vitro activity of aztreonam and 10 other antibiotics was determined for clinical isolates of Pseudomonasaeruginosa from 18 cystic fibrosis patients obtained before, at the end of, and 7–14 days after the completion of therapy with aztreonam. The percent of isolates susceptible to aztreonam at each sampling period were 79%, 78%, and 81% respectively.