With blood loss as the leading cause of death in trauma victims, blood transfusions are a vital part of emergency medicine.
For more than 20 years, MedEvac helicopter teams at UPMC have given trauma patients transfusions before reaching the hospital, but the life–saving effects of this procedure have not been confirmed until now.
To study the effectiveness of in-flight transfusion, UPMC researchers analyzed data collected between 2007 and 2012 on patients flown to the hospital in MedEvac helicopters, according to study author Joshua Brown, MD. Brown and his team found that patients who were given blood in-flight were more likely to survive their first 24 hours at the hospital, less likely to need additional blood, and less likely to arrive at the emergency room in shock than patients with the same injuries who did not receive blood.
While the military has been interested for years in the use of in-flight transfusions in Iraq and Afghanistan, this is the largest civilian study of the technique to date. According to Brown, 720 patients were carefully matched based on injury severity then compared. UPMC had studied the issue before, Brown said, but never on such a large scale.
“We were interested in seeing, based on what we’d seen in our prior study, whether we could see a larger and more defined population of people being transferred by helicopter whether the blood appeared to confer the same survival benefits,” Brown explained.
Brown said the careful matching of patients based on injury severity was important, because comparing survival rates of all patients who received blood transfusion to all patients who did not would not reveal meaningful results.
“Obviously, people who receive transfusion are going to be generally sicker and more injured than those who don’t,” Brown said. “So we’re really doing an apples to apples comparison.”
UPMC has guidelines for when MedEvac patients receive transfusions. If there is major blood loss and the patient shows signs of shock, such as elevated heart rate, paramedics give the patient a liter of saline then follow with universal donor blood. However, Brown said the positive results of the study might lead to paramedics giving blood without giving saline first.
Blood transfusions are not without risks, Brown pointed out, since some patients can have serious allergic reactions. He also said blood transfusions have been linked to increased risk of lung disease.
“So it is important to identify the patients who are going to benefit from this because you really don’t want to be giving this to people who might not benefit, because of the risk.”
There are also logistical issues surrounding air-lift transfusions. Blood must be carefully stored in freezers at the helicopter base and in refrigerators on-board aircraft. UPMC registered all 18 of its helicopter bases as satellite blood banks to comply with Pennsylvania regulations.
Last year, Jason Sperry, co-author of Brown’s study, started a similar analysis of the effectiveness of combining in-flight blood transfusions with plasma injections. Plasma is a translucent yellow liquid that makes up a little more than half of blood’s volume. Sperry’s study is still in progress.
