Causes and consequences of critical bleeding and mechanisms of blood coagulation.

Pharmacists who practice in the critical care setting require a solid background on the causes and consequences of bleeding, as well as the mechanisms of hemostasis. This article provides an overview of these topics. Bleeding and outcomes as a result of surgery and trauma, from medical and pharmacologic causes, and in obstetrics and gynecology are discussed. Patients with brain trauma, those with inherited and acquired bleeding disorders, and patients undergoing therapeutic anticoagulation are addressed, as these are populations at special risk for severe bleeding. Bleeding events as a result of hypothermia, acidosis, and disseminated intravascular coagulation are also discussed, as is the pathophysiology of massive blood loss. Traditional and newer cell-based models of coagulation mechanisms are described and compared. Application of this information in pharmacy practice will help ensure that therapies to manage and arrest blood loss are used appropriately in a wide variety of clinical scenarios.