Carrying blood products onboard aircraft
Increasingly, civilian air ambulance providers are carrying blood products onboard their aircraft – potentially life-saving for patients, but a challenging process for operators and staff. Stefan Mohamed looks at the background, and the ups and downs of carrying blood in the air
Air ambulance medics arriving at the scene of an emergency will in many cases find a patient who has lost a dangerous amount of blood, making every second count between arrival, diagnosis and treatment. Until relatively recently, it was typical for medics to either use a saline solution to replace the volume lost – although this does not replace the oxygen-carrying ability of the shed blood – or wait for blood supplies to be transported from local hospitals by police or ground ambulances, a time-consuming methodology, potentially complicated by a lack of blood supplies at hospitals, or any number of possible hindrances, from heavy traffic to impassable terrain. However, this is starting to change.
In 2011, Australia’s Ambulance Victoria announced it had become the first paramedic-operated helicopter emergency medical service (HEMS) provider in the world to begin transporting and transfusing blood on its own rotary and fixed-wing aircraft. The organisation’s chief executive officer Greg Sassella said at the time: “People who suffer serious external or internal bleeding as a result of car and other accidents can deteriorate quickly. Paramedics routinely provide fluid through a drip to help stabilise injured patients, but the most effective way of treating significant blood loss is with a blood transfusion. Seriously injured patients will now have the benefits of receiving blood in the field and whilst en route to hospital. Blood carries oxygen that is vital to major organs including the brain and as a result it gives a patient their best chance of survival.”
The process of transporting blood, particularly by air, with the attendant issues surrounding air pressure, temperature, etc., is both complex and costly
The process of transporting blood, particularly by air, with the attendant issues surrounding air pressure, temperature, etc., is both complex and costly, and aeromedical providers have only very recently started carrying blood onboard their aircraft – Shannon AirMed 1, a West Texas, US-based air ambulance, is a relative anomaly in that it adopted an early version of the process back in 2002. While Ambulance Victoria began transporting blood in 2011, London’s Air Ambulance (LAA), , the HEMS charity that covers the UK capital, became the first UK helicopter service to adopt the process in March 2012, and Air Med 1, another Texas-based air ambulance which covers Houston, started carrying blood on all its flights as of April this year. German fixed-wing air ambulance provider Med Call also implemented blood transportation facilities relatively recently.
These organisations’ medical aircraft – with more providers gradually adopting the process – now carry around four units of O-negative red blood cell concentrate, as O-negative is a universal donor group that can be given reasonably safely to any patient, regardless of their own blood type.
Clinically speaking, the benefits for patients are manifold. Red blood cells carry oxygen, thus when blood is lost, the patient’s ability to transport the necessary amount of oxygen to all areas of the body is dangerously diminished, and although saline-based options are effective enough to save lives, it doesn’t take a clinician to see that a transfusion of red blood cells is the better option.
“We have already seen patients surviving to delivery at hospital, where they receive the definitive care for their injuries, who may not have survived this part of their journey without the transfusion of the red cells,” says Gary Wareham, clinical manager for the UK’s Kent, Surrey and Sussex Air Ambulance, which began carrying blood in February of this year.
LAA’s lead clinician Dr Anne Weaver cites patients suffering from non-compressible haemorrhage as an example: “[Non-compressible haemorrhage] can only be controlled by invasive techniques such as surgery or interventional radiology. Many of these patients are compromised before they reach hospital. Even in an urban setting such as London, patients may not reach hospital in time to receive a blood transfusion. This is particularly well demonstrated for trapped patients e.g. in road traffic collisions, or unconscious patients who are found a while after the initial injury.”
In rural settings, Weaver adds, long journey times from the scene of the incident to hospital will also often mean potentially life-threatening delays between accident and full surgical control. “If a patient has lost a significant amount of blood and has gone into cardiac arrest,” Weaver goes on to say, “it is unlikely that the administration of crystalloid fluid will result in a return of spontaneous circulation. However, if you are able to give blood to these patients, it may be successful. If you have lost a large amount of blood, it needs to be replaced with blood in order to perfuse organs with oxygen. Crystalloid fluid does not carry oxygen and as such will not result in perfusion of the brain and other vital organs. Traumatic cardiac arrest due to hypovolaemia has a dismal outcome in the absence of blood transfusion and damage control techniques.” Weaver believes that carrying blood will dramatically increase the survival rate for such patients; indeed, LAA has already been able to resuscitate patients at the scene of an accident through this technique – patients that would likely otherwise have died before reaching hospital.
As blood supplies are limited, they are extremely valuable and strict guidelines are in place to ensure proper handling and record-keeping to guarantee that none is wasted
In-air blood transportation is logistically challenging, as air ambulances must store and carry blood at no lower than 2°C (36°F) and no higher than 8°C (46°F), in line with industry standards, but also be able to warm it to near body temperature so it can be safely given to patients, when many of the protective safeguards of a hospital operating environment are not present. If these strict temperature levels are not maintained, blood can be damaged, lose its effectiveness or even become dangerous for a patient.
“As blood supplies are limited, they are extremely valuable and strict guidelines are in place to ensure proper handling and record-keeping to guarantee that none is wasted,” explains Ambulance Victoria team manager Murray Barkmeyer. “The blood is stored in specially designed, temperature-controlled and alarmed fridges at our air ambulance bases. They are carried in temperature-controlled blood shippers that are loaded into the aircraft at the start of the shift.”
Blood products have a shelf life of 42 days, but Ambulance Victoria rotates its stocks on a 14-day timetable. “Any blood not used in that time is taken back under temperature-controlled transport to the hospital … where it can be used, to ensure there is no wastage,” adds Barkmeyer.
German fixed-wing air ambulance provider Med Call, as detailed in a presentation by their medical director Marcus Tursch at the International Travel Insurance Conference in Lisbon in 2011, uses powered cool boxes (developed in partnership with the German Blood Donor and Transfusion Service) in order to keep blood at suitable temperatures through long-duration missions. These have been shown to perform well when plugged in – for example by hooking them up to a plane’s inverter – though less favourably when un-powered, or ‘passive’. Loss of power for around 30 minutes is viewed as acceptable, however, as the boxes’ active compressor and passive insulation can keep temperatures below 10°C (50°F), but, as Tursch told Waypoint: “Performance is behind our expectations under tropical conditions. We know this from our thermologger protocols [which monitor temperatures during transport to show that blood is maintained at regulation levels before transfusion]. For bridging times without an available power source, [such as at] security checks and border police or hotel check-in, we carry a transportable, external power source with us.”
LAA uses Cool Logistics’ Credo Thermal Isolation Chambers (TICs), which surround the payload using a phase change material (PCM) to control the temperature. The PCM changes from a liquid to a solid state at a temperature different from that at which water changes, and by adding various chemicals to the substance, the phase change temperature can be altered, making it an ideal material to use for such a temperature-sensitive process. As the temperature of the blood cannot fall lower than 2°C (36°F), using ice is out of the question.
“Phase change materials are specifically formulated for the unique needs of diverse medical materials from super frozen tissue to room-temperature and fridge-temperature vaccines and pharmaceuticals,” a spokesperson for LAA told Waypoint when the organisation first adopted the process. “The boxes are also returnable and resuable, making [them] an environmentally-friendly option.”
Weaver goes into more detail about the requirements: “[We] investigated different storage options. The container needed to be robust, lightweight and weatherproof. Ideally, the storage box would not require batteries or a power source. This avoided the requirement and expense of airworthiness testing. Affordability was an important consideration as many air ambulances are charitably funded.”
The Golden Hour boxes that the charity now uses ‘can hold four units of packed red blood cells (PRBC) at steady-state temperature (2°C to 6°C – 36°F to 43°F) for 48 to 72 hours’. They contain a data logger, through which temperature data can be downloaded in order to show compliance with regulations.
“Blood which has not been used can be returned to the transfusion stock for use in other areas,” adds Weaver. “The box had already survived rigorous testing by the armed forces in Afghanistan.”
So, why has in-air blood transportation been such a recent development for most organisations? One of the primary issues – in the UK, at least – has been regulatory, says Gary Wareham. “From my experience,” Wareham elaborates, “the reasons for this [delay in implementing the procedure] have been the difficulties of working within the UK legislation with regard to the Cold Chain Management [the 2°C to 6°C temperature stipulation] and the traceability requirements [whereby each unit of blood product needs to be fully traceable from donor to recipient]. These requirements are easy to control and monitor in hospitals. A large part of our project was to identify transfusions departments who were prepared to explore the possibilities of these requirements being achieved in the pre-hospital world.” He adds: “The challenge to our crews is the maintenance of the traceability of the units ... often at a busy and stressful scene. This generates the inevitable paperwork at both the scene and on the base. We aim to achieve 100-per-cent traceability as required by UK legislation.”
The UK’s Medicines and Healthcare Products Regulatory Agency (MHRA), which regulates medicines and medical devices, mandates that full traceability is ensured ‘from donation to the point of delivery for not less than 30 years’, and final responsibility for traceability rests with the destination hospital (even if, for example, a transfusion is carried out en route from a different hospital), two of many stipulations that add to the challenging – and costly – nature of the process. “The rules and regulations make the practice of blood transfusion necessarily onerous,” says Weaver, “which on the face of it can appear to be impossible to negotiate for non-hospital based organisations, e.g. air ambulances. Blood transfusion is governed by strict legislation and extensive guidance. Hospital transfusion departments are quite rightly protective of the use of blood products. Legislation exists to ensure that patients are protected from transfusion errors and that products are not wasted or used inappropriately.”
Likely to continue?
Wasted blood products must be avoided at all costs and unnecessary waste would be a drawback as O-negative blood is a precious resource
So, is uptake of the process among air ambulance organisations likely to increase? The professionals Waypoint spoke to seem to think so.
“In the two years since we began carrying blood onboard the first helicopter, it has been used more than 70 times,” says Ambulance Victoria’s Murray Barkmeyer, “with the majority of cases involving multi-trauma car accidents, while one patient who was hurt in an explosion was also given an in-flight transfusion. It has also been used in inter-hospital transfers involving life threatening haemorrhage, including an Irish backpacker who had an ectopic pregnancy while in a remote town in Victoria’s far east.”
On the financial side of things, costs vary depending on the organisation, be it a HEMS charity that is tied to a particular hospital, or a private air ambulance organisation.
“We have an agreement in place with the National Blood Service (NBS) at the John Radcliffe Hospital, part of the Oxford University Hospitals Trust for the provision for O-neg blood,” AirMed UK’s Jane Topliss told Waypoint. “There is a cost attached to the provision of these blood products, which we have to pass on to the client. If there is a potential requirement identified, we will always carry a minimum of four units of blood with the cost associated being approximately £600 in total (£150 per unit).”
There are even variations between different UK HEMS charities, as Clive Dickin, national director of the Association of Air Ambulances, comments. “The equipment onboard the aircraft tends to be relatively cheap,” he explains. “The costs are more logistical than anything. London’s Air Ambulance, for example, is based on top of a major trauma centre, so has instant access to blood, making delivery and storage pretty straightforward. For others, the blood must be transported to the air ambulance, which can be costly, and as most air ambulances aren’t based at major trauma centres, hospitals need to be reassured that stocks won’t be wasted in transfer. However, there is definitely a desire to start taking [the process] up all around the UK.”
Both Dr Anne Weaver and Gary Wareham say that their respective organisations have encountered no major drawbacks or unforeseen issues. “LAA has delivered over 100 pre-hospital transfusions during the first 12 months of this innovation,” says Weaver. “The teams have a traceability record of 100 per cent, which is superior to that of many hospital departments. Wasted blood products must be avoided at all costs and unnecessary waste would be a drawback as O-negative blood is a precious resource. Only one unit of blood has been wasted due to a communication error with the transfusion laboratory.”
Marcus Tursch is also confident that Med Call will continue to utilise the process: “We will continue working with the powered cool box, as we did not find a passive system to guarantee the cooling chain on an overnight mission. However, I think the most important thing is to use a thermologger [and] a recording thermometer inside the cool box to prove that the cooling chain is not interrupted.”
In the UK, helicopter charity the Thames Valley and Chiltern Air Ambulance Service has also started carrying blood, as has fixed-wing provider CEGA Air Ambulance.
“Other air ambulances have shown interest in the results of this work,” adds Weaver, “and may well decide to offer this additional service.”
So long as organisations can adhere to the strict regulatory requirements – and overcome any potential financial barriers – the future seems bright for in-air blood transport and, by extension, for patients.
“I’m sure that we are one of the first [organisations] of many,” concludes Wareham. “The benefits of pre-hospital blood transfusions far outweigh any procedural ‘hassles’, and if we are honest it is something that we have wanted for some time. The next step will be to look at other blood products that may be beneficial to the patient, such as those that will assist in the clotting process. Onwards and upwards!”