Risk markers for thrombocytopenia in critically ill patients: a prospective analysis.

Study Objective: To identify independent risk markers for thrombocytopenia in critically ill patients.
Design: Prospective, observational study.
Setting: Eleven-bed intensive care unit-coronary care unit (ICU-CCU) in a community hospital.
Patients: Three hundred sixty-two consecutive patients meeting inclusion criteria during 1 year.
Intervention: Potential risk marker data were collected on admission to the ICU-CCU and for the period before development of thrombocytopenia (defined as two or more consecutive platelet counts < 150 x 10(3)/mm3 obtained at least 12 hours apart), or for the duration of ICU-CCU stay if thrombocytopenia did not develop.
Measurements and Main Results: Thrombocytopenia developed in 68 patients (18.8%). Multivariate logistic regression analyses identified patients at risk on admission, but the predictive, potential of the regression model improved when all risk marker exposures during the ICU-CCU stay were considered. Independent risk markers included fresh frozen plasma administration, sepsis, musculoskeletal diagnosis, pulmonary artery catheter insertion, gastrointestinal diagnosis, packed red blood cell administration, and nonsurgical respiratory diagnosis. Higher admission platelet count and aspirin administration were associated with a lower risk of thrombocytopenia. Heparin administration was not identified as a risk marker, and no patient developed heparin-induced thrombocytopenia with thrombosis. Patients with thrombocytopenia had longer ICU-CCU and hospital stays, and higher ICU-CCU and hospital mortality than those without thrombocytopenia.
Conclusions: Development of thrombocytopenia in critically ill patients is associated with specific diagnoses, packed red cell and fresh frozen plasma transfusions, pulmonary artery catheter insertion, and admission platelet count.