Results of several surveys that compared the acceptance of an urgent Rhesus (Rh)-positive blood transfusion with the risk associated with the potential development of hemolytic disease of the fetus and newborn (HDFN) have shown that individuals appear to value the benefits over the potential risk associated with an urgent RhD-positive transfusion during a traumatic medical event.
A total of five surveys on the topic were conducted to evaluate patient attitudes toward transfusion and future pregnancy risks. Findings from a review of these surveys have been published recently in the journal Transfusion.
In situations in which the resuscitation of a patient who is experiencing life-threatening bleeding is of utmost urgency, it is highly unlikely that the individual’s ABO and RhD blood groups will be known. In these scenarios, group O red blood cells (RBCs) or low-titer group O whole blood (LTOWB) must be transfused in order to guarantee serologic compatibility with the recipient’s naturally occurring anti-A and/or anti-B.
Although the choice of RhD type of blood products that is administered early in the resuscitative process is not as definitive, “the convention has been to use RhD-negative blood products if the recipient’s RhD type is unknown or negative,” with a key focus on the use of RhD-negative blood products in females of childbearing potential.
Read more about HDFN testing and diagnosis
Practices involving the administration of RBCs and LTOWB at both adult and pediatric trauma centers have demonstrated a general preference for using RhD-negative blood products among girls and women. In fact, supply restrictions on RhD-negative LTOWB at some centers have led to the use of RhD-positive LTOWB in the setting of life-threatening bleeding in females of childbearing potential or as a first-line treatment.
Risks associated with transfusions
The risk associated with administering a transfusion of RhD-positive RBCs or LTOWB is that the patient may become D-alloimmunized. Among males and in females who are no longer deemed females of childbearing potential, the production of this antibody is of minimal concern and is associated primarily with possible delays in the provision of RhD-negative transfusions in the future.
In contrast, becoming D-alloimmunized might lead to future pregnancies being complicated by the development of HDFN if the individual becomes pregnant with an RhD-antigen–positive fetus. Even though the administration of RhD-negative blood products to individuals of unknown RhD status might be the safest route to take, only around 10% of total RBC distributions are group O RhD-negative, whereas 39% of them are group O RhD-positive.
The relative scarcity of RhD-negative blood products compared with RhD-positive blood products causes the former type to become difficult to supply to hospitals at which trauma and patients with massive bleeding events are rarely observed, as well as to emergency medical services that provide prehospital transfusions.
Even so, if an RhD-positive blood unit is transfused to an injured FCP who is identified as being RhD-negative, experiencing severe complications associated with anti-D–mediated HDFN in future pregnancies is an unlikely scenario if the patient has access to modern antenatal health care.
“In summary, these five surveys show that the respondents valued improving their chances of survival in trauma by accepting an urgent transfusion over the risk that [that] transfusion might pose to future pregnancies,” the authors stated. “This finding was consistent when respondents were asked to reply with what they would like for themselves in this situation, as well as when asked to reply on behalf of a female child.”
