Characteristics and blood products requirements of thrombocytopenic patients in ICU

Objectives

To assess the epidemiology and prognosis of thrombocytopenia (TP) in ICU patients.

Design

A monocentric retrospective analysis of data prospectively collected in a databank.

Setting

A 10-bed adult medical ICU in a university hospital.

Patients

Three hundred and twenty-five consecutive ICU patients admitted for > 24 hours between January and December 2002 were included.

Measurements and main results

TP was defined by two consecutive platelet counts < 150 G/l. The main outcome measure was ICU mortality. The main reason for ICU admission of TP patients were acute respiratory failure (n = 37), shock (n = 21), sepsis (n = 18), coma (n = 13), acute renal failure (n = 12), metabolic disorders (n = 9), scheduled surgery (n = 5), acute poisoning (n = 4), trauma (n = 3), miscellaneous causes (n = 4). In the overall population, the mean platelet count upon admission was 314 ± 114 G/l. TP was observed in 126/325 (39%) and present on admission in 89 patients, with a mean count of 97 ± 340 G/l. ICU-acquired TP occurred with a median delay of 4.7 days (range 2–26 days) in 37/126. The ICU mortality was 29% (n = 37) in the TP population and 9% (n = 19) in the nonTP population. Bone marrow aspiration was performed in 35/126 TP patients. Before TP, a previous red blood cell (RBC) transfusion was recorded in seven cases, a previous plasma infusion in two cases, and prior exposure to heparin in 25 cases. The diagnosis of heparin-induced TP was excluded in 17/25 cases, unlikely in three cases, possible in three cases and very likely in two cases. TP was related to sepsis in 51 cases, to disseminated intravascular coagulation in 28 cases (among these, 14 were associated with sepsis), to central megacaryocyte depletion in five cases, and to hemophagocytic histiocytosis in four cases. A combination of two or more of these mechanisms was observed in 23 cases. In 57 patients, the etiology of TP was undetermined or related to another cause. In univariate analysis, TP was significantly associated (all P < 0.01) with higher SAPS II score (50 ± 22 vs 40 ± 20), higher SOA score (8.6 ± 4.3 vs 4.7 ± 4), need for renal replacement therapy (39% vs 20%), need for invasive mechanical ventilation (51% vs 36%), higher length of stay (11 ± 13 days vs 7 ± 6 days) and ICU mortality (29% vs 9%). No statistical difference was detected in patient characteristics between the two TP populations (TP present on admission or ICU acquired). Twenty-eight TP patients required platelet transfusions, and 81% of the 311 RBC concentrates and 85% of the 70 plasma concentrates administered during the study were infused to TP patients.

The presence of TP indicates a subgroup of patients with high mortality, which accounts for most of the blood product-related costs in the ICU.