Massive transfusion protocols adopted from the military have conferred a significant survival advantage for some civilian trauma patients, but they remain controversial. Not everyone agrees that 10 or more units of packed red blood cells along with fresh frozen plasma and platelets in the first 24 hours for exsanguinating trauma patients should be the standard. The experience of three prominent researchers – Dr. Christopher Dente, Dr. Bryan Cotton, and Dr. Jeffry Kashuk – helps shed some light on developments in this emerging field.
Improved patient management is one advantage of the massive transfusion protocol (MTP), according to Dr. Dente, associate director of trauma at Grady Memorial Hospital in Atlanta. “I didn't think the effect it would have on how we can manage patients and how we can close their fascias earlier would be as profound as it is. The amount of bowel edema we see is much less as we reduced the amount of crystalloid. The ability to actually finish operations as opposed to doing damage-control laparotomy and leaving packs in – all of these things are more dramatic than I anticipated,” he said.
Empirical vs. tailored therapy, however, is still subject to debate. Currently, most protocols at civilian level I trauma centers dictate administration of a fixed 1:1:1 ratio of packed red blood cells, fresh frozen plasma (FFP), and platelets. This strategy was associated with increased survival at 6, 24, and 30 days and fewer ICU, ventilator, and hospital days, compared with patients who received lower proportions of FFP and platelets in a retrospective study of 466 trauma patients (Ann. Surg. 2008;248:447–58).
An empirical protocol increases efficiency, said Dr. Dente, by allowing the surgeon to start the process with a single phone call, after which the blood bank continues to make products for pick-up every half-hour.
Although survival improves with this empirical approach, there are concerns about “unbridled administration of fresh frozen plasma and platelets with objective evidence of their specific requirement,” Dr. Kashuk and his colleagues wrote in a review article (Ann. Surg. 2010;251:604–14).
Instead, Dr. Kashuk is a proponent of thromboelastography (TEG), a rapid, point-of-care test to determine the necessity and optimal ratio of blood products for a particular exsanguinating trauma patient.
The key with the ratio “is really trying to get back to the physiology and looking at function rather than numbers. No two patients are necessarily the same,” he said in an interview. “The difference between ratios can be enormous when approaching massive transfusion numbers. That's a lot of products being used if not absolutely necessary, especially considering the impact nationally on the blood banks, as well as the untoward effects, such as multiple organ failure.” Dr. Kashuk is a trauma surgeon at Pennsylvania State Milton S. Hershey Medical Center, Hershey.
“Unfortunately, thromboelastography is not readily available,” Dr. Dente said.
“We have seen a significant learning curve for adoption of this technology,” Dr. Kashuk said. Additional expense, time, and quality control to ensure accurate, reproducible results also are required, he added. “We have found, however, that once the team becomes comfortable with this approach, they begin to realize that old, standard lab values were essentially paramount to functioning in the dark.”
The identification of appropriate candidates for an MTP is another area of controversy. “We know about 25% of the most critically injured patients after trauma come in coagulopathic. Trying to identify these people is really the crux of the problem,” Dr. Dente said.
Several randomized, controlled trials of MTP are in the design phase, according to Dr. Dente. “The next step is to test this [empirical] protocol vs. a protocol that is more directed by point-of-care coagulation studies like thromboelastography,” he said.
Exactly how to identify which patients require an MTP also is unclear. Initiation of most protocols is based primarily on the surgeon's call, but some early predictive factors have been identified. For example, Dr. Dente and his colleagues demonstrated that gunshot patients were more likely to require an MTP if the bullet trajectory was multicavity or transpelvic or if the patient had significant, initial base deficit (J. Trauma 2010;68:298–304).
Scoring systems also can help to quickly identify candidates. For example, the ABC (Assessment of Blood Consumption) system, developed by Dr. Cotton and his colleagues, correctly identified 85% of 596 trauma patients who required a massive transfusion (J. Trauma 2009;66:346–52). ABC scoring is based on four factors: emergency department systolic blood pressure of 90 mm Hg or less; ED heart rate of 120 bpm or greater; a penetrating mechanism of injury; and positive fluid on abdominal ultrasound.