Transfusions de concentrés plaquettaires aux soins intensifs pédiatriques : épidémiologie, indications, effets bénéfiques  et adverses potentiels

Abstract 1 Incidence of hypotension and acute isolated hypotensive transfusion reactions following platelet concentrate transfusions Background and objectives: Platelet concentrates (PCs) are associated with transfusion reactions involving hypotension, particularly bradykinin-mediated acute isolated hypotensive transfusion reactions. This study aims to determine the incidence of hypotensive events and more specifically acute isolated hypotensive transfusion reactions associated with PC transfusions. We also sought to ascertain whether these reactions are associated with high bradykinin levels. Materials and Methods: This is a prospective descriptive study of PCs administered at Sainte-Justine Hospital over 28 months. All PCs administered during this period were screened for hypotension through review of all transfusion-associated reaction reports (TARRs) sent to the blood bank. All residual PC bags were returned to the blood bank. TARRs associated with hypotension were reviewed by adjudicators who established the imputability of the PC transfusion to the reaction. Bradykinin levels were measured in the first 168 PC bags returned to the blood bank. Levels were compared between PCs associated with hypotension and control PCs not associated with hypotension. Results: A total of 3672 PC bags were returned to the blood bank; 25 PCs were associated with hypotension. Adjudicators ascertained that five hypotensive events were 8 imputable to PCs of which one was an acute isolated hypotensive transfusion reaction (incidence per transfusion: 0.03%). Bradykinin level in the latter PC was 10 pg/ml, whereas levels were 226.2 pg/ml (95%CI : 20.0-432.4 pg/ml) in the 143 control PCs. Conclusion: Our results show a low incidence of hypotension after PC transfusion. We identified only one acute isolated hypotensive transfusion reaction. No correlation between bradykinin level and the occurrence of acute isolated hypotensive reactions could be observed given that only one event was identified. Abstract 2 Platelet transfusions in pediatric intensive care Objectives: To characterize the epidemiology and the determinants of platelet transfusion (PT) in a pediatric intensive care unit (PICU) and determine whether there exists an association between PT and adverse outcomes. Design: Prospective observational single center study, combined with a self-administered survey. Setting: PICU of Sainte-Justine Hospital, a university-affiliated tertiary care institution. Patients: All children admitted to the PICU from April 2009 to April 2010. Intervention: None. Measurements and Main Results: Among 842 consecutive PICU admissions, 60 patients (7.1%) received at least one PT while in PICU. In the univariate analysis, significant determinants for PT transfusion were admission PRISM >10 (odds ratio (OR): 6.80; 95%CI: 2.5-18.3, p <0.01) and PELOD scores >20 (OR: 26.9; 95%CI: 8.88- 81.5, p<0.01), history of malignancy (OR: 5.08; 95%CI: 2.43-10.68, p <0.01), thrombocytopenia (platelet count <50 x 109/L or < 50,000/mm3) (OR: 141; 95%CI: 50.4- 394.5, p <0.01), use of heparin (OR:3.03; 95%CI 1.40-6.37, p <0.01), shock (OR: 5.73; 95%CI: 2.85-11.5, p<0.01) and multiple organ dysfunction syndrome (MODS) (OR: 10.41; 95%CI: 5.89-10.40, p <0.01). In the multivariate analysis, platelet count <50 x109/L (OR: 138; 95%CI: 42.6-449, p<0.01) and age less than 12 months (OR: 3.06; 95%CI: 1.03-9.10, p=0.02) remained statistically significant determinants. The attending physicians were asked why they gave a PT; the most frequent justification was prophylactic platelet transfusion in presence of thrombocytopenia with an average pre10 transfusion platelet count of 32 ±27 x109/L(median 21), followed by active bleeding with an average pre-transfusion platelet count of 76 ±39 x109/L(median 72). PTs were associated with the subsequent development of MODS (OR: 2.53; 95%CI: 1.18-5.43, p=0.03) and mortality (OR: 10.1; 95%CI: 4.48-22.7, p<0.01). Conclusions: 7.1% of children received at least one PT while in PICU. Thrombocytopenia and active bleeding are significant determinants of PT. Patients that received PTs had a higher risk of developing MODS and had a higher risk of mortality.

Keyphrases: platelet concentrates, platelet transfusion, transfusion reactions, cohort, pediatrics, intensive care, determinants, outcomes, thrombocytopenia