Optimizing red blood cell transfusion therapy in the 21st century: the power of data analysis for past understanding and future guidance

Effect of Human or Mouse IL-7 on the Homeostasis of Porcine T Lymphocytes

Due to the inconsistent fluctuation of blood supply for transfusion, much attention has been paid to the development of artificial blood using other animals. Although mini-pigs are candidate animals, contamination of mini-pig T cells in artificial blood may cause a major safety concern. Therefore, it is important to analyze the cross-reactivity of IL-7, the major survival factor for T lymphocytes, between human, mouse, and mini-pig. Thus, we compared the protein sequences of IL-7 and found that porcine IL-7 was evolutionarily different from human IL-7. We also observed that when porcine T cells were cultured with either human or mouse IL-7, these cells did not increase the survival or proliferation compared to negative controls. These results suggest that porcine T cells do not recognize human or mouse IL-7 as their survival factor.

Preventing and managing catastrophic bleeding during extracorporeal circulation

The use of extracorporeal circulation for cardiac surgery and extracorporeal life support poses tremendous challenges to the hemostatic equilibrium given its diametric tendency to trigger hyper- and hypocoagulopathy. The necessity of anticoagulant therapy to counteract the hemostatic activation by the extracorporeal circuitry compounded by unfavorable patient and surgical factors significantly increase the risk of catastrophic bleeding in patients who require extracorporeal circulation. Preoperative measures, such as stratification of high-risk bleeding patients, and optimization of the modifiable variables, including anemia and thrombocytopenia, provide a crude estimation of the likelihood and may modify the risk of catastrophic bleeding. The anticipation for catastrophic bleeding subsequently prompts the appropriate preparation for potential resuscitation and massive transfusion. Equally important is intraoperative prevention with the prophylactic application of tranexamic acid, an antifibrinolytic agent that has promising benefits in reduction of blood loss and transfusion. In the event of uncontrolled catastrophic bleeding despite preemptive strategies, all effort must be centered on regaining hemostasis through surgical control and damage control resuscitation to protect against worsening coagulopathy and end organ failure. When control of bleeding is reinstated, management should shift focus from systemic therapy to targeted hemostatic therapy aimed at the potential culprits of coagulopathy as identified by point of care hemostatic testing. This review article outlines the strategies to appropriately intervene using prediction, prevention, preparation, protection, and promotion of hemostasis in managing catastrophic bleeding in extracorporeal circulation.

Development of a risk-adjusted blood utilization metric

BACKGROUND

Blood utilization has become an important outcome measure for surgical patients because of the recognized risks and costs associated with transfusion. However, comparisons of blood utilization between providers or institutions are difficult, because there is no standard method for risk adjustment when assessing surgical blood requirements. We examined whether accepted diagnosis-related group (DRG) case mix indexes can be used for this purpose.

STUDY DESIGN AND METHODS

We retrospectively analyzed electronic medical record data from 37,403 surgical inpatients to assess the relationship between intraoperative blood component transfusion requirements and the case mix indexes: weighted Medicare severity DRG and weighted all-patient refined DRG. Thirty-one surgeons from the general surgery service were compared to determine correlations between blood component utilization and case mix index in both a risk unadjusted and an adjusted fashion.

RESULTS

Case mix indexes and transfusion requirements were directly correlated for red blood cells (RBCs), plasma, and platelet (PLT) transfusions (p < 0.0001 for all three blood components, for both indexes). Surgeons with greater case mix index values had greater transfusion requirements, and adjustment for case mix index resulted in less variation among surgeons (p < 0.0001, p = 0.0003, and p < 0.0001 for unadjusted vs. adjusted utilization of RBCs, plasma, and PLTs, respectively).

CONCLUSIONS

The standard DRG-based case mix indexes used to determine hospital reimbursement were strongly correlated with intraoperative transfusion requirements. We propose that these methods can be used as a risk-adjusted blood utilization metric for surgical patients.