Incidence and risk factors of thrombocytopenia in critically ill trauma patients

OBJECTIVE: To determine the incidence of thrombocytopenia (<100 platelets x 10(3)/mm(3)) and potential risk factors, including medications, associated with the development of thrombocytopenia in critically iu trauma patients. DESIGN: Prospective, observational study. SETTING: A 20-bed trauma intensive care unit (ICU) at a university hospital. PATIENTS: Sixty-three critically ill trauma patients without baseline thrombocytopenia admitted to the trauma ICU for at least 48 hours. INTERVENTIONS: Patients were followed for up to 14 days. Platelet counts were determined daily. The following data were collected and analyzed as potential risk factors for the development of thrombocytopenia: medications, age, sex, race, trauma score, mode and type of injury, alcohol history, units of packed red blood cells (PRBC) and platelets transfused, surgical procedures, duration of ICU stay, and the development of systemic inflammatory response syndrome or disseminated intravascular coagulation. RESULTS: Thrombocytopenia occurred in 26 (41%) of the patients. Among risk factors studied, nonhead injury, age, trauma score, duration of ICU stay, and the number of PRBC transfusions were significantly associated with the development of thrombocytopenia (p < 0.05). However, nonhead injury, age, and trauma score were useful variables in predicting the development of thrombocytopenia by using multivariate analysis. Medications were not associated with the development of thrombocytopenia. CONCLUSIONS: The type of injury sustained, the quantity of platelet-deficient transfusions, and age are the greatest risk factors associated with the development of thrombocytopenia in critically ill trauma patients. Drug-induced thrombocytopenia appears to play a minor role in the development of thrombocytopenia; therefore, medications should not be automatically discontinued or substituted when thrombocytopenia occurs.