June 23, 2023
In traumatic injury, numerous studies have found that having an immediate supply of red blood cells is critical and lifesaving, according to Manish J. Gandhi, M.D., a pathologist and medical director of Mayo Clinic's transfusion lab at its Minnesota campus.
Traumatic hemorrhage can lead to numerous sequelae. It is a leading cause of both death and disability, according to a 2017 report by the Centers for Disease Control and Prevention. For patients who experience traumatic injury, hemorrhage is a common reason for shock, which is life-threatening. In a study published in 2020 in Annals of Surgery, hemorrhage accounted for 55.1% of preventable and potentially preventable deaths.
The complexities of post-injury transfusion
While potentially lifesaving or disability sparing, transfusion for patients who experience traumatic hemorrhage is not straightforward and simple, according to Dr. Gandhi. One of the biggest concerns with these patients is providing ABO and Rh factor (D) antigen-compatible blood. These antigens are the most immunogenic. Blood group O Rh negative is the most compatible red blood cell type medical professionals can use for transfusion when the recipient's blood group is unknown. However, only 7% of the population is O negative, while 37% of the population is O positive.
Thus, emergency services at medical centers carry both O negative and O positive blood. O negative blood is preferentially transfused to women of childbearing age to mitigate the risk of hemolytic disease of the fetus and newborn.
Due to the shortage of O negative blood compared with O positive blood, there are situations when medical professionals need to transfuse a patient with O positive blood to save the patient's life. So it is common for emergency rooms to have protocols for use of O positive blood for all traumas or after O negative blood is no longer available. This is based on studies that have shown that two-thirds of patients who experience traumatic injury are males, says Dr. Gandhi. Additionally, 85% of patients who have a traumatic injury are Rh positive. Of the remaining percentage of patients who experience trauma and are female, only a portion of those patients are of childbearing age. Studies have demonstrated that only a portion of the Rh negative patients who receive Rh positive red cells develop anti-D antibodies, according to Dr. Gandhi.
Currently, companies are trying to create the mechanisms to convert all blood to Rh negative, yet no great successes have occurred to date, says Dr. Gandhi.
The priorities in post-injury transfusion
Priorities for post-traumatic injury are distinct from those of other situations in which a patient requires blood transfusion.
"In a normal situation, you'd screen the patient for antibodies," says Dr. Gandhi. "But in a trauma situation, you can't always do that due to the need to give blood to the patient as soon as possible. In a trauma situation, my first criterion is 'How do I save the patient?' "
With the immediate need to transfuse blood at the scene and during transport to a hospital to keep a patient alive, it is possible to administer B positive blood to a patient who has B negative blood. The risk of losing the patient can be higher than the risk of administering the wrong blood type.
"Nothing is risk-free," says Dr. Gandhi. "But the risk is low."
At Mayo Clinic, professionals keep an O negative and O positive blood supply in transport vehicles and at the hospital. This allows them to start with O negative blood for a woman who has experienced trauma and is of childbearing age.
However, if a mass casualty incident occurs far away from a hospital and all affected patients are women of childbearing age, trauma professionals need to determine how to proceed.
Still, the priority remains addressing acute sequalae and saving the patients' lives, says Dr. Gandhi.
"Weighing the pros and cons, saving patients' lives is most important," he says.
Blood supply shortages
Dr. Gandhi says that an O negative blood type donor is always a prize donor. He indicates this is especially the case because patients who have had a traumatic injury can require O negative blood and a shortage nearly always exists for this blood type.
Dr. Gandhi also says that blood shortages are growing for all blood types. This is especially so because the younger U.S. population does not feel as strongly as older generations that giving blood is a civic duty, he says. Dr. Gandhi also says younger generations have not grown up in an era with low blood supply.
He urges trauma professionals to encourage those in their communities to give blood. He cites that social media such as Twitter, Facebook and Instagram are particularly helpful in getting the word out to young people about the need to donate blood. He also says that emails and phone calls still work to promote blood donation. For many people, donating at a mobile unit can be a convenient way to give, he says. Dr. Gandhi also notes that for those who donate blood twice, blood donation is much more likely to become a habit.
If you or others in your community want to donate blood, you may contact your local hospital's blood donation center, call Mayo Clinic Blood Donor Program in Minnesota at 507-284-4475 or email donateblood@mayo.edu. Or input your zip code on the Red Cross blood drive locator.
For more information
Murphy SL, et al. Mortality in the United States, 2017. Centers for Disease Control and Prevention.
Drake SA, et al. Establishing a regional trauma preventable/potentially preventable death rate. Annals of Surgery. 2020;271:375.
Refer a patient to Mayo Clinic.