CareFlight is a leading air medical retrieval organization in Australia, with operations across the country. Operating the Top End Medical Retrieval Service on behalf of the Northern Territory Government, CareFlight covers an area of around 600,000km². Our high-acuity service cares for almost all patients who are seriously unwell and require medical retrieval. This service is provided by a fleet of Beechcraft King Air B200 fixed-wing aircraft, with one-way flight times upwards of two hours for many locations, with a round trip for a patient retrieval commonly taking six hours or more. Our helicopter service provides us with access to more challenging locations, for example those without a suitable air strip or which may be remote national parks, and for this we use AgustaWestland AW139 helicopters with hoist capability. CareFlight is the preferred provider for interstate retrievals, frequently transferring patients from Darwin to a higher level of care in other locations in Australia using our Gulfstream G150 aircraft, with most of these transfers covering at least 3,000km and taking around eight hours. When required, we will retrieve patients from overseas, usually back to Australia.

In the Northern Territory (NT), CareFlight operates a flight doctor and flight nurse model, with all our doctors being either specialists or senior trainees in one of the critical care specialties (anesthesia, intensive care, or emergency medicine). Clinical responsibility rests with our duty medical retrieval consultants, who are all drawn from a critical care specialty and have extensive experience in pre-hospital and retrieval medicine. This model allows very effective delivery of critical care to those patients who are very unwell. We respond to patients with a wide range of medical, surgical, and obstetric issues, and across all age ranges from neonates up to end-of-life care. A
large portion of our work is attending trauma, with motor vehicle accident-related trauma and penetrating injury being particularly common. Additionally, we treat numerous patients with bleeding related to pregnancy, predominantly post-partum hemorrhage (PPH).

What is fibrinogen concentrate?

When an injury occurs causing bleeding, the process of coagulation is initiated. Along with other aspects, clotting factors are integral to successful coagulation. Clotting factors are predominantly proteins circulating in blood which are activated to help form a blood clot and hence stop bleeding. In both the traditional clotting cascade model and the newer cell-based coagulation model, fibrinogen is a critical clotting factor. Fibrinogen is generated in the liver, and the final step in forming a blood clot is the conversion of fibrinogen to fibrin – which is integral to clot stability in conjunction with platelets.

In patients with significant bleeding, clotting factors fall (often rapidly), and fibrinogen is usually the first factor to do so. Consequently, blood clotting may be impaired. Other parameters also have an influence, such as the patient’s temperature (clotting is impaired with low body temperature), and the pH of the blood (clotting is impaired when the blood is acidic – which is common in bleeding patients). Good management of the bleeding patient therefore addresses these additional factors to optimize coagulation.

Why do we carry fibrinogen concentrate?

In patients undergoing significant bleeding, replacement of fibrinogen levels may reduce bleeding, reduce blood transfusion requirements, and improve mortality. This is the subject of ongoing active research. Fibrinogen replacement can be achieved in several ways, but the most practical in an air medical environment is using fibrinogen concentrate. Indeed, evidence shows that this is probably the fastest way to replace fibrinogen, being more rapid than using cryoprecipitate (another blood product).

In patients undergoing significant bleeding, replacement of fibrinogen levels may reduce bleeding, reduce blood transfusion requirements, and improve mortality

In a hospital setting, correction of clotting abnormalities would often be guided and dictated by viscoelastic testing, e.g. rotational thromboelastometry or thromboelastography (ROTEM or TEG), but, given the size and weight of equipment required, this is usually impractical in an air medical setting. Fibrinogen concentrate may therefore be given empirically, when we believe there may be a benefit to the patient. Robust guidelines and clinical governance underpin its use.

NT Health partnership

CareFlight works closely with NT Health to support the delivery of critical care across the region. Through this collaboration, CareFlight can carry universal blood type units of packed red blood cells (PRBCs) for emergency use. Recent efforts by NT Health have also ensured that fibrinogen concentrate is available through the blood bank at Royal Darwin Hospital (RDH), providing an important resource for patient care when needed.

How do we package and store it?

Fibrinogen concentrate requires storage at between 2°C and 8°C. Temperatures in the NT can commonly reach 35°C in the shade and 40–50°C in a closed aircraft on the tarmac, while in the clinical room (where the fibrinogen concentrate is routinely stored), temperature is a constant 21°C. This wide variation in temperatures in which the fibrinogen concentrate is stored provides a challenging set of conditions.

This wide variation in temperatures in which the fibrinogen concentrate is stored provides a challenging set of conditions

Three vials of fibrinogen concentrate are packaged each morning by the RDH blood bank staff, and collected by a CareFlight ground support officer (GSO) for transport to the hangar. Peli BioThermal Crēdo products are used for this task, and are conditioned and packed by the RDH staff. Temperature tracking and logging devices are used to ensure that the products remain within the desired temperature range and are never wasted. CareFlight has been at the forefront of temperature monitoring and management in this environment for many years, and uses Bluetooth-connected data loggers and alerting systems to protect our equipment and drugs.

What is the impact on our patients?

We attend multiple patients who are experiencing significant bleeding from trauma or for obstetric reasons. These patients will benefit most from the administration of fibrinogen concentrate, in conjunction with other blood products and our routine high standards of medical, surgical, obstetric and trauma care.