Thrombocytopenia in a surgical ICU.

STUDY
OBJECTIVES: To assess the incidence of thrombocytopenia in surgical ICU patients, the factors associated with thrombocytopenia, the outcome of thrombocytopenic patients, and the possible mechanisms involved.
DESIGN: Prospective study.
SETTING: An 8-bed surgical ICU in an 885-bed teaching hospital. PATIENTS: 147 consecutive patients admitted to the surgical ICU during a 6-month period. MAIN OUTCOME MEASURES: Incidence of thrombocytopenia (defined by a platelet count < 100,000/mm3), risk factors for thrombocytopenia, or death in thrombocytopenic patients identified by a stepwise logistic regression analysis, as well as the mechanisms involved.
RESULTS: Thrombocytopenia occurred in 52 patients (35%) with a mortality rate of 38%, compared with a 20% mortality rate in nonthrombocytopenic patients (p = 0.02). Sepsis, episodes of bleeding or transfusions, and an acute physiology and chronic health evaluation (APACHE) II score of > 15 were the independent risk factors identified for thrombocytopenia. The correction of thrombocytopenia was a protective factor reducing the risk of mortality in thrombocytopenic patients. Disseminated intravascular coagulation was found in 40% of thrombocytopenic patients, elevated platelet-associated IgG in 33%, and hemophagocytic histiocytes in 67%. Combinations of two of these mechanisms were demonstrated in one quarter of thrombocytopenic patients.
CONCLUSIONS: Sepsis was the major independent risk factor identified. Thrombocytopenic patients had a higher ICU mortality due to the severity of overall clinical status. Bone marrow examination could be diagnostic when no obvious causes are demonstrated. Thrombocytopenia probably reflects the severity and course of an underlying pathologic condition, as its correction appears to be a good prognostic factor.