###### Abstract  
Long-distance transoceanic transport of blood using drones has never been reported. This study aimed to prove that blood transportation via drones can meet the rapid demand for blood transfusions anywhere in Japan, including remote islands. We demonstrated the transport of red blood cells (RBCs) packs using a drone over the sea from Sasebo to Arikawa port. Drone operations were conducted visually only at take-off and landing. Cruise flights were conducted via satellite-based remote control from Tokyo. The RBC solutions were transported at 2-6 \({}^{\circ}\)C to avoid hemolysis. Hemolysis was assessed visually and by measuring lactate dehydrogenase (LDH) levels before departure and upon arrival at Tokyo Metropolitan Bokutoh Hospital to evaluate whether RBCs were transfusable. LDH levels of the RBC solutions before and after transport were 57.5 \(\pm\) 3.1 vs. 64.0 \(\pm\) 2.9. RBC solutions were transported via air and land from Tokyo to Sasebo and showed no remarkable signs of hemolysis. Remote RBC solution transport by uncrewed helicopters with temperature control is feasible and allows RBC transportation in emergencies involving disrupted land transportation, such as the COVID-19 pandemic. blood transfusion; drone; seas; transportation; COVID-19; temperature; unmanned helicopter +
Footnote †: journal: Journal of Physics B  
0021  
[PERSON]  
appropriate choice to prevent blood degradation. We and [PERSON] et al. have previously conducted basic experiments on blood transport using multi-copters but were limited to visual flights and did not involve unseen flights [7; 8]. Moreover, this is not feasible for transoceanic transport without terrestrial cable installation. Therefore, transoceanic flights are only feasible using non-visual flights via satellite communications. Consequently, there have been no reports of successful RBC solution transportation using multi-copters or autonomous helicopters. On the other hand, there have been many reports on emergency blood transport by manned conventional helicopters and a review of reports to consider actual helicopter emergency transport [9; 10]. In addition, helicopter blood transfusion transport is now allowed in New York City, where it had not been allowed before [11]. Recent reports indicate that vertical take-off and landing aircraft type drones have been used to transport blood products over long distances and to isolated islands in Lake Victoria [12]. In areas in Japan with a large population, a stable supply of blood for transfusion is needed to ensure that the blood stored in hospitals is maintained and the additional requirement for blood is met, especially when the demand for blood is high. This system provides an additional supply chain for the quick transport of blood to the hospital. Blood transportation in Japan is via automobiles and in the absence of a land traffic blockage caused by a particular disaster, the supply of blood is stable by car. We have also found no blood deterioration during transport by automobile [13]. Japan has many remote islands inhabited by people in the western Pacific Ocean. Most of these islands have medical facilities and encounter events requiring blood transfusions. There has been an effective supply of blood demonstrated by the day-long transport of RBC solution by ship as far as 1000 km away in the Ogasawara Islands [14; 15], where a stable system has been established for normal RBC solution supply while maintaining the quality of the RBC solution. However, the transportation of an RBC solution by aircraft during an emergency has not been adapted. A distance of 50 km is considerable, especially during an emergency, and blood transport by ship can be affected by high waves. The trial we conducted is a novel approach for supplying blood that cannot be accomplished by sea transport. We investigated the feasibility of using a remotely operated, uncrewed helicopter (UH) for the transport of RBC solution over a distance of 55,000 m to a remote island of Japan.