Clinical pathology abstracts editor: Deborah Sesok-Pizzini, MD, MBA, associate professor, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, and medical director, Blood Bank and Transfusion Medicine, Children’s Hospital of Philadelphia.
Anti-D alloimmunization after D-incompatible platelet transfusions
Because a small but immunogenic dose of red blood cells may be contained in apheresis platelets, transfusion services establish protocols to provide D– recipients with D– platelets to prevent anti-D alloimmunization. This is of particular concern for young females as there is potential for hemolytic disease of the newborn. In cases where D+ platelets are given to D– recipients, Rh immune globulin (RhIG) may be used to help prevent sensitization. The authors retrospectively analyzed during a 14-year period the anti-D formation in D– recipients who received D+ platelets without the use of RhIG. They examined 130 D– patients, of whom 48 percent were women and 57 percent immunocompetent, who received a total of 565 apheresis platelets. The patients were transfused with 100 percent apheresis-derived prestorage leukoreduced platelets, consistent with current standard practice. The authors determined that none of the eligible study patients formed anti-D. This is consistent with other studies, which showed the lack of formation of anti-D following D-incompatible apheresis platelet transfusions. The authors concluded that due to the potential for adverse events and the cost of RhIG administration, RhIG may not be needed following the use of D+ apheresis platelets in D+ or D– patient populations.
O’Brien KL, Haspel R, Uhl L. Anti-D alloimmunization after D-incompatible platelet transfusions: a 14-year single-institution retrospective review. Transfusion. 2014;54:650–653.
Correspondence: Kerry L. O’Brien at email@example.com
Randomized trial of protocol-based care for early septic shock
Severe sepsis and septic shock occur in more than 750,000 U.S. patients annually. The mortality rate is 20 percent or more. A 2001 study showed significantly lower mortality among patients with severe sepsis or septic shock treated in a single urban emergency department using a protocol-driven approach than among those given standard therapy. The early goal-directed therapy (EGDT) involved central venous catheterization to monitor central venous pressure and central venous oxygen saturation, both of which were used to guide targeted therapy, including intravenous fluids, vasopressors, packed red-cell transfusion, and dobutamine. Investigators in this study sought to determine if protocol-based resuscitation was superior to usual care and whether a protocol with central hemodynamic monitoring was better than a simpler protocol. They conducted a randomized trial at 31 emergency departments in which they randomly assigned patients with septic shock to one of three groups for treatment: protocol-based EGDT; protocol-based standard therapy that did not require placement of a central venous catheter, administration of inotropes, or blood transfusions; or usual care. A total of 1,341 patients were enrolled in the trial for a primary end point of 60-day in-hospital mortality. Secondary outcomes included longer-term mortality and need for organ support. By 60 days, there were 92 deaths in the protocol-based EGDT group, 81 in the protocol-based standard therapy group, and 86 in the usual care group. The results showed a relative risk of 1.04 with protocol-based therapy versus usual care and relative risk of 1.15 with protocol-based EGDT versus protocol-based standard therapy. No significant differences were noted in 90-day mortality, one-year mortality, or need for organ support. The investigators concluded that their study showed no improvement in outcomes in the protocol-based resuscitation of patients in whom septic shock was diagnosed in the emergency department. They noted that the results differ from the aforementioned 2001 EGDT study but that their study was not a direct replication.
The ProCESS investigators. A randomized trial of protocol-based care for early septic shock. N Engl J Med. 2014;370(18):1683–1693.
Correspondence: Dr. Derek C. Angus at angus firstname.lastname@example.org
Red blood cell transfusion in critically ill children
Red blood cell transfusions have been associated with adverse outcomes in intensive care patients. These outcomes involve mortality, length of hospital stay, mechanical ventilation, infection, and transfusion reactions. A study that appeared in the literature in 2008 showed that 49 percent of children admitted to a pediatric intensive care unit (PICU) for more than two days received at least one RBC transfusion. The authors conducted a study to determine transfusion practice in the PICU; compare this practice with that observed 10 years earlier; and estimate compliance to the main recommendation of the Transfusion Requirements in Pediatric Intensive Care Unit (TRIPICU) study, which is to consider giving RBC transfusions to stable or stabilized critically ill children without cyanotic heart disease only if their hemoglobin level drops below 70 g/L. The authors conducted a single-center prospective observational study over a one-year period. They obtained information through medical charts. Determinants of transfusion were sought daily until the first transfusion in transfused patients or until PICU discharge for nontransfused patients. The authors used a questionnaire to assess the justifications for transfusion. Of the 842 patients included in the study, at least one RBC transfusion was given in 144 patients (17.1 percent). The authors noted that the three most frequent justifications for RBC transfusion were a low hemoglobin level, intent to improve oxygen delivery, and hemodynamic instability. A multivariate analysis showed that young age, congenital heart disease, low hemoglobin level, severity of illness, and some organ dysfunctions are significant determinants of RBC transfusions. The main recommendation of the TRIPICU study was applied in 96.4 percent of the first transfusion events. The authors concluded that RBC transfusions are frequent in the PICU and are associated with specific comorbid conditions. The majority of the first transfusions were prescribed according to recent recommendations.
Demaret P, Tucci M, Ducruet T, et al. Red blood cell transfusion in critically ill children. Transfusion. 2014;54:365–375.
Correspondence: Jacques Lacroix at email@example.com