Novel device uses platelet function to assess transfusion need after trauma


NEW YORK (Reuters Health) - A microfluidic device that rapidly measures platelet function can help determine whether a trauma patient needs a blood transfusion, researchers say.

"Most platelet transfusions given during trauma resuscitations are given empirically due to time and logistical restraints involved with care of the acutely injured and bleeding patient," Dr. Nathan White of the University of Washington in Seattle told Reuters Health by email.

"Our device was designed to overcome these restraints," he said, "so that based upon a single measurement, decisions to transfuse platelets can be made faster and with more precision."

"Physicians rely on many different tests to ascertain the coagulation state of a patient, but (our) technology could be a strong indicator," coauthor Dr. Nathan Sniadecki, also of the University of Washington, said by email. "It is sensitive to platelet function, while many of the others can only make an indirect measurement."

"Platelets contract forcefully after their activation, contributing to the strength and stability of platelet aggregates and fibrin clots during blood coagulation," the authors explain. However, in some trauma patients - those taking aspirin, for example - platelets may be less able to apply the forces they need to form a clot.

To detect platelet dysfunction after trauma, the team designed a microfluidic device that measures platelet forces in real time, according to their March 13 report, online in Nature Communications.

They tested the device in blood samples and found that platelet forces were significantly reduced when the samples were treated with inhibitors of myosin, GPlb-IX-V, integrin alpha-IIb-beta-3, P2Y12 or thromboxane, all of which play a role in platelet aggregation.

They also tested the device in 110 trauma patients who had their blood sampled on admission to the ED and 10 healthy participants. They found a significant difference in platelet forces between patients who required a blood transfusion within the first 24 hours compared to patients who did not, and to non-injured controls.

Specifically, trauma patients' platelets had decreased forces compared to control participants' platelets, and the 17 trauma patients who required a blood transfusion had the lowest platelet forces.

Further, the authors state, "platelet forces significantly predicted the need for transfusion, with an area under the ROC curve of 0.72 (p = 0.006).

"Dr. White and I have formed a spin-out company, Stasys Medical, to commercialize the technology by getting FDA approval and scaling up the manufacturing," Dr. Sniadecki told Reuters Health. "We hope in a few years, the technology will be in the hands of clinicians around the world."

Dr. Lane Smith, Assistant Professor in the Department of Emergency Medicine at Wake Forest Baptist Health, called the study "interesting and novel."

"Ideally, the device will be small and portable," he told Reuters Health by email. "Large, immobile devices have limited uses outside of a central lab, which dramatically hampers getting sample results due to transport times."

"Users need a simple and quick method to insure the device is properly calibrated," he added. "Ideally, this will need to be done on a scheduled basis (i.e., every 24 hours or shift) rather than before every measurement," he said.

"The initial studies were small samples from a single institution," he noted. "The preliminary data looks good, but multicenter validation is needed. More robust numbers and classification of agents, including patients on anticoagulants or other confounding medications, will be needed in the future."

Nat Comm 2019.