We all know the importance of blood; it transports essential substances around the body and removes cellular waste, it keeps the body in balance (temperature, pH) and it clots when needed to protect the body from losing blood. A number of HEMS operators carry prehospital blood onboard, which can increase survival rates. However, others don’t, due to the associated risks and costs and unanswered questions about patient outcomes. Much research has been done, and more is currently underway, on the benefits and risks associated with carrying blood products onboard HEMS.

For example, a 2017 study entitled Pre-hospital transfusion of packed red blood cells in 147 patients from a UK helicopter emergency medical service explored the characteristics of patients receiving a prehospital blood transfusion and their subsequent need for in-hospital transfusion and surgery. It determined that prehospital packed red blood cells (PRBC) transfusion significantly reduces the time to transfusion for major trauma patients with suspected major haemorrhage. Another, Prehospital blood transfusion: 5-year experience of an Australian helicopter emergency medical service, identified and reviewed all Greater Sydney Area HEMS (GSA-HEMS) prehospital missions involving a blood transfusion over a 66-month period and concluded that the carriage and use of blood is both feasible and safe in a physician-led HEMS.

We can bring blood products on patient transports in rural communities that often have limited or no blood supplies

AirMed&Rescue spoke to Chris Martin, Executive Director, Airlift Northwest (ALNW), who highlighted that one of many benefits of transporting blood products is that it doesn’t deplete local hospitals’ resources: “We can bring blood products on patient transports in rural communities that often have limited or no blood supplies,” he said. “Since our products come from Seattle, we don’t depend on or deplete the existing resources at local hospitals.” ALNW recently administered its 500th unit of blood products and said that, over the past two years, it has expanded its life-saving capabilities by carrying two units of PRBCs and two units of liquid plasma on all its emergency medical aircraft. 

A challenging capability

Still, carrying blood products can prove challenging, as ALNW acknowledges. “There is a push in the air medical transport industry to have the capability to carry blood products on all transports. However, having this capability is logistically challenging and not all agencies have the resources to accomplish this,” it said. 

The UK’s Midlands Air Ambulance Charity is one operator that doesn’t carry ‘blood’ onboard, as such, but is currently involved in a trial called REsuscitation with Pre-HospItaL bLood products (RePHILL) with a number of air ambulance organisations in the UK to identify the merits and potential risks of carrying blood to trauma patients. “The RePHILL study is the first of its kind and explores whether giving blood products in the prehospital phase of a patient’s care is both safe and confers benefit over the standard model of care. RePHILL is also important as it will help us to understand the logistical challenges of delivering blood at the scene of the accident – in effect bringing the hospital to the patient,” Jim Hancox, Critical Care Paramedic for Midlands Air Ambulance Charity, told AirMed&Rescue. “This will provide clinical evidence for the first time on the use of blood / blood products in the pre-hospital environment. The trial will be finished in a couple of years, as between the seven air ambulances taking part, we need to recruit 450 patients.” 

William Kelly Miller RN, CFRN, Air Methods’ Regional Clinical Manager, agrees that challenges abound: “There are still operators not carrying pre-hospital blood, including some Air Methods bases,” he said. “It is not because there is a lack of desire to carry pre-hospital blood products at these bases, but rather it may take years to manage the logistics within the state’s various blood centres. Air Methods currently carries blood products on each mission at more than half of our community bases. We are currently working with the American Red Cross to be able to complete our goal of all community-based aircraft having blood products on each transport through a national contract.” 

Strict procedures are followed to ensure that the blood is always kept at the right temperature and the seal on the blood boxes is only broken once GWAAC is absolutely certain the patient requires a blood transfusion

So, carrying blood products onboard all bases seems to be the end goal for HEMS operators, but is difficult to achieve due to logistical and financial barriers. The financial challenges associated with this can particularly affect charities, as Gary Wareham, Operational Manager for Air Ambulance Kent Surrey Sussex in the UK, highlighted: “An organisational project to put blood onboard is complex. It involves having partner organisations (local hospitals, blood bike groups) on side and is costly. Most UK HEMS organisations are charity based and the decision to carry blood onboard is not just an operational decision.”

Important preparations

For the HEMS operators that do carry blood products onboard, there are a number of preparations that a service must undertake to ensure that the blood is delivered in a timely manner to the base, and that it is stored and carried correctly. “The blood we carry at the UK’s Great Western Air Ambulance Charity (GWAAC) is specially prepared by the blood bank at Southmead Hospital (North Bristol National Health Service (NHS) Trust) and is stored in military grade cooling boxes to ensure it is maintained at exactly the right temperature,” noted Lead Critical Care Doctor at GWAAC Ed Valentine. “The blood supply is replenished every 24 hours by FreeWheelers, a motorbike charity that collects new blood from Southmead Hospital, delivers it to the air base and then picks up and returns any unused blood back to the hospital so it can be used in the hospital (to ensure that none of the blood products are ever wasted). If the team uses blood at a pre-hospital incident, then the blood bank at the hospital is informed and a replacement box of blood products is made available for us to collect within 30 to 40 minutes.” GWAAC has specific systems in place as the blood must be carefully maintained. For example, strict procedures are followed to ensure that the blood is always kept at the right temperature and the seal on the blood boxes is only broken once GWAAC is absolutely certain the patient requires a blood transfusion.

An organisational project to put blood onboard is complex. It involves having partner organisations (local hospitals, blood bike groups) on side and is costly

These types of precautions and practices are crucial and appear to be standard around the world. Having carried blood products in the form of red blood cells onboard helicopter missions in New South Wales (NSW) for more than three decades, NSW Ambulance Greater Sydney Area Helicopter Emergency Medical Service has extensive experience in this area: “Initially, this was accomplished by having a dedicated blood fridge on base with blood packed into temporary storage boxes when missions were tasked. This always ran the risk of losses of stores due to thermal irregularities or improper packing practices and so instead, for the last decade, we have made use of the Credo CubeTM blood boxes (Minnesota Thermal Science). These are phase change material storage containers developed for military use,” Dr Karel Habig, Medical Manager/Lead Clinician, told AirMed&Rescue. “We have worked closely with NSW Health pathology to develop standardised protocols to enable the transport of blood and to minimise wastage. The blood products are packed into the prepared containers by the local hospital blood banks and can remain in the boxes for up to 72 hours without overheating. In our service, we change these blood boxes out three times per week and unused blood goes back to the tertiary hospital blood bank.” This has enabled the service to keep wastage to a minimum and to achieve a current wastage rate of less than two per cent – even with summer temperatures often exceeding 40°C and some very long missions. “To reduce the risk of thermal losses, we keep the Credo cubes in air-conditioned environments, on base or in vehicles as all vehicles are air-conditioned,” Dr Habig added.

Midlands Air Ambulance Charity’s Hancox provided an insight into some of the procedures and measures the charity is taking as part of the RePHILL trial: “As part of our participation in RePHILL, we work in partnership with Midland Freewheelers who deliver new RePHILL boxes every 48 hours. This ensures that integrity of the contents isn’t compromised and, on the occasions when we don’t use blood products, they are able to be returned to the national stock and used in other areas of healthcare,” he said. “We do not know the contents of the boxes delivered to the airbase, and don’t know what the contents of the box are until an eligible patient is recruited to the study. Not only does this ensure that the trial is run in a robust and unbiased fashion, it means that we treat all of the boxes delivered as if they did contain blood products.”

Partnerships and training

There must be a strong partnership with a supplier that will not only supply the blood products but also ensure quality control

ALNW highlighted the importance of a solid partnership with a supplier for carrying blood products: “There must be a strong partnership with a supplier that will not only supply the blood products but also ensure quality control,” it said. “In our case, it was Harborview Medical Center’s Transfusion Services that was integral in helping to supply all our aircraft with two units of PRBCs and two units of liquid plasma. The capability to carry blood products is only made possible through the tireless work and commitment of our partners at Harborview Medical Center’s Transfusions Services, Bloodworks Northwest and UW Medicine, which enables us to have this life-saving resource available to our patients.” Further considerations for ALNW are the need to maintain blood products at a very narrow temperature range until they are used in order to meet the established standards of safety, which they achieve with the use of specially designed portable coolers. The coolers are able to maintain a constant temperature for an extended period of time outside of refrigeration. The team can track the temperature of the blood coolers to ensure that each one remains within the correct temperature range, and if any products are found to be outside of this range then they are discarded. 

In addition to these preparations and procedures, in order for blood products to be carried onboard HEMS, it is crucial that all staff and medics are adequately trained. Indeed, Air Methods reviews every aspect of its policies and procedures with clinicians and crew when a base begins carrying blood products to ensure everyone is fully prepared. “Air Methods then performs our quality assurance processes with the clinical teammates to review for competency,” Miller explained. “A recent, highly effective training step we added is requiring crew to carry and monitor ordinary saline for a week prior to going live with blood products. This simulation has been a great addition to our training process as it offers hands-on experience and allows clinical teammates to identify unexpected issues at their base and on missions.” 

GWAAC ensures training takes place regularly in order to safeguard practices. “All of our Critical Care Doctors and Specialist Paramedics who are authorised to administer blood have completed standard NHS blood transfusion training, and then undergo a training programme locally to ensure that they follow unit protocols and policies. The local training is repeated on a regular basis to make certain competence is maintained,” said Valentine. 

Furthermore, there are also regulations to be considered, which may vary depending on the country in question. For example, in Australia, where NSW Ambulance Greater Sydney Area is based, blood products are heavily regulated, and some are not available, which has prompted exciting research, as Dr Habig explains: “Blood products are highly regulated in Australia as befits a liquid ‘transplant’ donated by fellow citizens. A comprehensive tracking of all blood products administered must be maintained in case of blood-borne disease issues. Some products have not yet been approved by the Australian Red Cross but are available elsewhere in the world. For example, freeze-dried plasma and whole blood are currently not available in Australia. We have been investigating the possibility of Fibrinogen Concentrate as a treatment for those at risk for or in the early stages of acute traumatic coagulopathy. We have also been conducting pilot research into thrombo-elastography (TEG) testing in-flight in a helicopter, with initial testing conducted in our full-motion flight simulator and soon to progress to volunteers during training flights. This might open the door to TEG-guided blood component therapy even in pre-hospital care.”

Respecting regulations

Air Methods ensures its policies and procedures meet or exceed all Food and Drug Administration and American Association of Blood Banks standards, as well as considering local EMS and state regulations. Miller explained: “Some state EMS regulations do not allow the paramedic to transfuse blood, which means one of our nurses needs to be available. Other states may require annual inspections of our processes. Regardless, local blood centres are always great resources to learn about any additional regulations that may need to be considered.” Valentine pointed out that, in the UK, strict legislation, as laid down by the UK NHS’ Blood Transfusion services, needs to be followed, which is particularly important as this ensures that every blood product administered to a patient can be traced and that the blood transfusion process is always carried out safely.

Ultimately, the goal behind HEMS carrying blood products is to save lives. ALNW is currently in the process of examining outcomes for patients who received blood product transfusions during transport initiated by ALNW and said that early findings are promising. Midlands Air Ambulance Charity’s Hancox pointed out that the impact of carrying blood products for patients is unknown and that RePHILL is hoping to shed better light on this: “At present, we simply don’t know, and that is what the trial is examining. The use of blood products to resuscitate trauma patients in hospital is routine practice but replicating the same care outside of an Emergency Department is extremely difficult. By participating in RePHILL, we will contribute to discovering if the way blood products can be used outside of hospital confers any benefit to patients.” Dr Habig agrees that there are many unanswered questions, but that ultimately, carrying blood onboard has helped save lives: “Evidence of benefit in prehospital transfusion has been thin on the ground but those of us working in New South Wales are convinced that many of our sickest patients would not survive the distances that are required in such a big state, and there are certainly patients in outer urban areas of Sydney with severe injuries whose survival would be very unlikely without blood products to buy time. We are definitely against large volume crystalloid infusions for trauma patients if alternatives are available,” he said. 

We can easily capture data when patients are transferred, but to then obtain outcome data from hundreds of receiving centres across the US is not feasible at this point

A lifeline

GWAAC’s Valentine also believes carrying blood has helped save lives, despite the lack of concrete evidence: “Demonstrating improved patient outcomes is very difficult, as a prehospital blood transfusion is only one part of a whole range of interventions that the GWAAC team carries out for each patient. Anecdotally, we have several cases of patients who we feel would previously have died on scene and by virtue of having blood, have now survived to reach hospital. The vast majority of patients to whom we administer prehospital blood products go on to receive many more units of blood when they arrive at hospital (which confirms that blood was indicated and appropriate).”

For Air Methods’ Miller, tracking changes in patient outcomes is the most challenging aspect of carrying blood products at Air Methods’ bases. “We can easily capture data when patients are transferred, but to then obtain outcome data from hundreds of receiving centres across the US is not feasible at this point,” he said. “We have looked at isolated areas to recognise that initial lab results, specifically those associated with metabolic acidosis, are better in hypotensive trauma patients who received pre-hospital blood products compared to those who did not. Air Methods is currently conducting a large-scale outcomes study, which should be helpful as more of our bases begin managing blood products.”

Research remains to be done in this area and, indeed, is in progress. However, despite challenges, there are many benefits to carrying blood products onboard HEMS, not least that it can potentially save lives, as Dr Richard B. Utarnachitt, ANLW Medical Director, explained: “Prehospital transfusion of red blood cells and human plasma allows ANLW to begin reversing the deadly spiral of bleeding and clot disorders that occur in the setting of traumatic haemorrhage. By doing this, we bring lifesaving resources from the major trauma centre to our patients well before they actually arrive at the hospital.” While replicating the level of care received in hospital onboard HEMS may not be possible, if carrying blood onboard can help provide a bridge between the HEMS and the hospital, it is surely worthwhile. It will be exciting to hear the outcomes of the research currently underway in this area and to garner more concrete evidence of the life-saving potential of carrying blood onboard.