Effects of helicopter transport on red blood cell components

Noninferior Red Cell Concentrate Quality after Repeated Air Rescue Mission Transport for Prehospital Transfusion

BACKGROUND

Transfusion of red cell concentrates (RCCs) is an integral therapy after severe hemorrhage or trauma. Prehospital transfusion offers an immediate intervention in emergency cases. Air ambulance-based prehospital transfusion, already used in different countries, is currently established in Germany. Limited information is available for regulatory-compliant transport logistics of RCCs and their quality after repeated air rescue missions. Thus, the aim of this study was (i) to validate regulatory-compliant logistics and (ii) to assess product quality, analyzing biochemical parameters and RBC morphology.

STUDY DESIGN AND METHODS

Due to regulatory requirements, we adapted a rotation system of 1 day transport, 1 day quarantine storage and 1 day storage over the entire RCC shelf life. RCCs transported on air rescue missions (flight group) were compared against a control group, treated identically except for helicopter transport. RCCs were visually inspected, and their temperature was documented throughout the entire rotation cycles. RCCs at the end of shelf life (end point samples) were assessed for levels of hemoglobin, hematocrit, free hemoglobin, hemolysis, mean corpuscular volume, potassium and pH. In addition, morphological changes were assessed using flow morphometry.

RESULTS

In total 81 RCCs were assessed in the flight group and 50 in the control group. Within the flight group, 30 RCCs were transfused. RCCs were dispatched on average 11 times (7-13 times). The average flight time was 18.3 h (6.6-28.8 h). The rotation system ensured adherence to regulatory guidelines, especially compliance to storage conditions of +2 to +6°C of intermediate storage. Biochemical and morphological quality parameters did not exhibit any changes upon repeated air rescue missions. A correlation with respect to the flight time was not observed either.

DISCUSSION

The quality of RCCs after repeated air rescue missions is noninferior to control samples regarding biochemical and morphological parameters. The product quality is within German regulations for up to 42 days of storage. The logistics and maintenance of the thermal conditions are safe and feasible. Thus, a rotation system of RCCs offers a regulatory-compliant option to supply air rescue missions with RCCs to allow life-saving prehospital transfusions at the incident scene.

Blood Product Supply for a Helicopter Emergency Medical Service

Background

Long patient transport times to trauma centers are a well-known problem in sparsely populated regions with a low hospital density. Transfusion of red blood cell concentrates (RBC) and plasma improves outcome of trauma patients with severe bleeding. Helicopter emergency services (HEMS) are frequently employed to provide early advanced medical care and to reduce time to hospital admission. Supplying HEMS with blood products allows prehospital transfusion and may help to prevent exsanguination or prolonged hemorrhagic shock. We have investigated the maintenance of blood product quality under air transport conditions and the logistical steps to introduce a HEMS blood depot into routine practice.

Methods

A risk analysis was performed and a validation plan developed. A special, commercially available transport container for blood products was identified. Maintenance of temperature conditions between 2 and 6°C in the box were monitored at ambient temperatures up to 35°C over 48 h. Quality of blood products before and after helicopter air transport were evaluated including (1) for RBCs: hemoglobin, hematocrit, hemolysis rate; (2) for thawed plasma: aPTT, INR, single clotting factor activities. The logistics for blood supply of the regional HEMS were developed by the transfusion service of the Greifswald University Hospital in collaboration with the in-hospital transport team, the HEMS team, and the HEMS operator.

Results

The transport container maintained a temperature below 6°C up to 36 h at 35°C ambient temperature. Vibration during helicopter operation did not impair quality of RBC and thawed plasma. To provide blood products for HEMS at least two transport containers and an additional set of cooling tiles is needed as the cooling tiles need a special temperature priming over 20 h. The two boxes were used at alternate days. To reduce wastage, RBCs and thawed plasmas were exchanged every fourth day and reintegrated into the blood bank inventory for further in-hospital use.

Conclusions

Supplying HEMS with RBCs and plasma is feasible. Helicopter transport has no negative impact on blood product quality. The logistic challenges require close collaboration between the HEMS team and the blood transfusion service.

Quality Control of Red Blood Cell Solutions for Transfusion Transported via Drone Flight to a Remote Island

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 °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 ± 3.1 vs. 64.0 ± 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.

Bringing Packed Red Blood Cells to the Point of Combat Injury: Are We There Yet?

Objective

Hemorrhage is the leading cause of injury-related prehospital mortality. We investigated worst-case scenarios and possible requirements of the Turkish military. As we plan to use blood resources during casualty transport, the impact of transport-related mechanical stress on packed red blood cells (PRBCs) was analyzed.

Materials and Methods

The in vitro experiment was performed in the environmental test laboratories of ASELSAN®. Operational vibrations of potential casualty transport mediums such as Sikorsky helicopters, Kirpi® armored vehicles, and the NATO vibration standard MIL-STD-810G software program were recorded. The most powerful mechanical stress, which was created by the NATO standard, was applied to 15 units of fresh (≤7 days) and 10 units of old (>7 days) PRBCs in a blood cooler box. The vibrations were simulated with a TDS v895 Medium-Force Shaker Device. On-site blood samples were analyzed at 0, 6, and 24 h for biochemical and biomechanical analyses.

Results

The mean (±standard deviation) age of fresh and old PRBCs was 4.9±2.2 and 32.8±11.8 days, respectively. Six-hour mechanical damage of fresh PRBCs was demonstrated by increased erythrocyte fragmentation rates (p=0.015), hemolysis rates (p=0.003), and supernatant potassium levels (p=0.003) and decreased hematocrit levels (p=0.015). Old PRBC hemolysis rates (p=0.015), supernatant potassium levels (p=0.015), and supernatant hemoglobin (p=0.015) were increased and hematocrit levels were decreased (p=0.015) within 6 h. Two (13%) units of fresh PRBCs and none of the old PRBCs were eligible for transfusion after 6 h of mechanical stress.

Conclusion

When an austere combat environment was simulated for 24 h, fresh and old PRBC hemolysis rates were above the quality criteria. Currently, the technology to overcome this mechanical damage does not seem to exist. In light of the above data, a new national project is being performed.

Does prolonged storage of red blood cells cause harm?

Red blood cells (RBCs) degrade progressively during the weeks of refrigerated storage. No universally accepted definition of 'fresh' or 'old' RBCs exists. While practices vary from country to country, preservative solutions permitting shelf life as long as 7 weeks have been licenced. Transfusion of stored RBCs, particularly those at the end of the approved shelf life, has been implicated in adverse clinical outcomes. The results of observational analyses, animal models and studies in volunteers have proved provocative, controversial and contradictory. A recently completed randomized controlled trial (RCT) in premature infants exemplifies the difficulties with moderately sized clinical studies. Several other RCTs are in progress. The effect of RBC storage may well vary according to the clinical setting. Resolution of the importance of the storage lesion may require large pragmatic clinical trials. In the meantime, institutions involved in blood collection and transfusion should explore strategies that assure blood availability, while limiting the use of the oldest RBCs currently approved by regulation.