products attached to a
S900-model drone.
Photo courtesy of
Johns Hopkins Medicine
A proof-of-concept study suggests that large bags of blood products can maintain temperature and cellular integrity when transported by drones.
Researchers say these findings, published in Transfusion, add to evidence that remotely piloted drones are an effective, safe, and timely way to quickly get blood products to remote accident or natural catastrophe sites, or other time-sensitive destinations.
“For rural areas that lack access to nearby clinics, or that may lack the infrastructure for collecting blood products or transporting them on their own, drones can provide that access,” said study author Timothy Amukele, MD, PhD, of the Johns Hopkins University School of Medicine in Baltimore, Maryland.
Drones also can help in urban centers to improve distribution of blood products and the quality of care, he added.
Dr Amukele and his colleagues previously studied the impact of drone transportation on the chemical, hematological, and microbial makeup of drone-flown blood samples and found that none were negatively affected.
Study design, methods
In the new study, the team examined the effects of drone transportation on larger amounts of blood products used for transfusion, which have significantly more complex handling, transport, and storage requirements compared to blood samples for laboratory testing.
The researchers purchased 6 units of red blood cells (RBCs), 6 units of platelets, and 6 units of unthawed plasma from the American Red Cross. They then packed the units into a 5-quart cooler, 2 to 3 units at a time, in keeping with weight restrictions for the transport drone.
The cooler was then attached to a commercial S900-model drone. This particular drone model comes equipped with a camera mount, which the team removed and replaced with the cooler.
For each test, the drone was flown by remote control a distance of approximately 13 to 20 kilometers (8 to 12 miles) while 100 meters (328 feet) above ground. This flight took up to 26.5 minutes.
The researchers designed the test to maintain temperature for the RBCs, platelets, and plasma units. They used wet ice, pre-calibrated thermal packs, and dry ice for each type of blood product, respectively.
Temperature monitoring was constant, keeping with transport and storage requirements for blood components.
The team conducted the tests in an unpopulated area, and a certified, ground-based pilot flew the drone.
Following flight, all units were transported to The Johns Hopkins Hospital and compared to blood products that had not taken a drone trip.
Results
Dr Amukele and his colleagues checked the RBCs for signs of hemolysis. They checked the platelets for changes in pH, the number of platelets, and mean platelet volume. And they checked the plasma units for evidence of air bubbles, which would indicate thawing.
The researchers found no evidence of hemolysis in the control RBCs or the RBCs that had taken the drone flight.
There was no significant difference in pH, platelet counts, or mean platelet volume between control and drone-flown platelets.
And there was no apparent change in the size or shape of air bubbles in the plasma units before and after drone flight.
However, the researchers did find that, for all flown units, there was a decrease in temperature of between 1.5°C and 4°C during the course of the flight. They said the cause of this decrease was probably the ambient temperature in the case of the platelet units, the wet ice in the case of the RBCs, and the dry ice in the case of the plasma.
The team also found an up to 2°C difference between individual flights for both the RBCs and the plasma units. They said this difference is likely due to the differences in the amounts of wet and dry ice placed in the cooler.
The researchers are planning further and larger studies in the US and overseas, and they hope to test methods of active cooling, such as programming a cooler to maintain a specific temperature.
“My vision is that, in the future, when a first responder arrives to the scene of an accident, he or she can test the victim’s blood type right on the spot and send for a drone to bring the correct blood product,” Dr Amukele said.
Funding for this study was provided by Peter Kovler of the Blum-Kovler Foundation.
