Novel Test Can Better Determine Which Trauma Patients Need Transfusions
May 25th, 2017
One of the most difficult aspects of treating trauma patients is accurately determining which ones are most in need of a massive blood transfusion.
An article published by the Journal of the American College of Surgeons introduces a novel method of improving that decision-making.
University of Colorado Department of Surgery researchers proposed combining the International Normalized Ratio (INR) with a new test of blood clot strength, based upon thromboelastography (TEG).
Background information in the article describes how more than 80% of deaths in the operating room and half of all deaths in the first 24 hours after injury are related to overwhelming blood loss and impaired coagulation.
"When someone is massively bleeding, you need to give certain blood products early, and the blood bank has to mobilize blood products that are resource scarce, such as platelets, which have only a five-day shelf life,” explains lead author Hunter B. Moore, MD. “You want to quickly identify patients who will require a large quantity of blood products to save lives and mobilize the blood bank only when you need it.”
A further dilemma, according to the study, is that clinical scoring systems for predicting the need for massive transfusion can be highly subjective and variable. Some clinics use vital signs, such as blood pressure and heart rate, while others require extensive imaging and laboratory tests.
The new test, however, modifies the TEG by adding tissue plasminogen activator (tPA) to a patient's blood sample.
To determine the effectiveness of the measure, the researchers gathered information on more than 300 patients treated for trauma between 2014 and 2016; 17% required a massive transfusion. One-third of the deaths in the study group were caused by uncontrolled hemorrhage.
Results indicate that the tPA-challenged TEG assay was highly sensitive and specific, and took only a few minutes to provide results, making it as much as 30 minutes faster than existing tests.
In addition, the predictive value of the tPA-challenged TEG assay was 40% better in identifying patients who needed transfusion. Overall, researchers report, the two-test combination correctly identified 97% of patients who did not require blood products and prevented unnecessary transfusions.
The researchers propose that the INR be used as a screening test to determine if a trauma patient is at risk of bleeding, and then the tPA-challenged TEG be employed as a follow-up to ensure accuracy.
While lab techs have been necessary to do the testing, Moore notes that fully automated TEG instruments are now available.