Hematologic Challenges in ICU Patients with Malignancy

Thrombotic and hemorrhagic complications are a common cause of morbidity and mortality in patients with cancer and associated with a high economic burden. Oncogenes activate blood coagulation as an integral feature of neoplastic transformation whereby cancer cells support clot formation and clotting proteins support cancer growth and dissemination. A complex coagulopathy develops characterized by activation of clotting mechanisms to different extents, and its manifestations may range from a subclinical asymptomatic hypercoagulable state to overt thrombosis of the large vessels and further to systemic disseminated intravascular coagulation with severe bleeding. ICU risk factors including mechanical ventilation, pharmacologic sedation, immobilization, vasopressor use, and central venous catheters place cancer patients at higher risk of venous thromboembolism. Other hematologic challenges associated with cancer and its treatment include thrombotic microangiopathies, thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, and heparin-induced thrombocytopenia. Hemorrhagic complications are often related to thrombocytopenia, thrombocytopathies, and coagulation factor deficiencies. Hematologic toxicity from chemotherapy and novel immunotherapeutic agents are also an important consideration in ICU patients with malignancy.