Lengthening the golden hour: Improving the survivability of battlefield injuries

Thoracic and trauma surgeon Dr R Adams Cowley, who developed the first clinical shock trauma unit in the USA, coined the term ‘golden hour’ back in 1975. He wrote in an article that “the first hour after injury will largely determine a critically injured person’s chances for survival”. The universally recognized paradigm denotes the critical window of time from injury in which a patient requires definitive care. After these 60 minutes, morbidity and mortality significantly increase.

In 2009, US Secretary of Defense Robert M Gates mandated a standard of 60 minutes or less for pre-hospital helicopter transport of US military casualties with critical injuries, and a 2015 study confirmed an improvement in survival. However, there is controversy around the term’s validity, particularly in a military context, with army leaders believing that the golden hour needs to become the golden day.

“Given the potential for isolated battlefields with restricted resupply and evacuation, extending the ‘golden hour’ to a ‘golden day’ is crucial,” said Jan Sebastian Kühlsen, Senior Manager Technical Sales and Product Management for AeroMedical Solutions, Lufthansa Technik. “This necessitates the development of technologies and procedures that bridge the gap between the golden hour and arrival at a proper medical facility, ensuring a higher chance of survival for casualties until such facilities become available.”

What is clear is that early medical intervention and timely evacuation are crucial in trauma care. Improving combat casualty survival on the battlefield is key for the military and this relies on maximizing pre-hospital care by delivering the best possible battlefield trauma care. From lightweight, temperature-controlled military blood containers to wearable biosensors and portable imaging technologies, innovations are extending the golden hour and saving lives.

A joint effort

Technological advancements such as artificial intelligence are driving forward innovation in combat medical care

Vital to accelerating discovery and innovation is collaboration with key stakeholders across the medical and research landscape. “Army Medicine works with multiple partners across academia and industry to identify new and emerging technology,” said a spokesperson from Army Medicine, Office of the Surgeon General, US Army Medical Command. “We also work with partners in the research and development domain to refine current ways and explore new ways to improve survival. The ability to care for our soldiers is a joint effort and with the continued support from our sister services and other Army organizations, we will continue to improve survivability on the battlefield.”

Lufthansa Technik worked with medical experts to develop its Patient Transport Unit (PTU), as Kühlsen highlighted: “Our PTU ensures that during strategic evacuation (stratevac) of the patient, the environment is as good as possible. It’s designed for treatment of critically ill patients and was therefore developed in close collaboration with medical staff and following the strict requirements of the European Medical Device Regulations and European Norm DIN EN 13718-2 for air ambulances.”

AirMed&Rescue also spoke with Colonel James (Andy) Nuce, Commander of the US Army Medical Materiel Development Activity (USAMMDA), who underlined the importance of collaboration and research. “Research into various areas enabling prolonged casualty care is critical,” he stated. “We’ve recently worked with our combat development partners at Joint Base San Antonio (JBSA) on the requirement and development of the Prolonged Care Augmentation Detachment. This capability starts fielding at the end of this calendar year.

“Our materiel developers also partnered with the Fielded Force Integration Directorate at JBSA to add blood refrigeration far forward in our tactical combat medical care (TCMC) set, and placed ultrasound in the same set to enable far forward diagnostics.”

Indeed, the transportation of lifesaving blood to the battlefield is vital and requires adequate storage with requisite climatic conditions and time periods. Ben Williams, President of Phoenix Foundry, explained how these capabilities have improved: “Historically, military helicopter tactical evacuation missions (tacevac) did not have the capability to safely store whole blood. Around 10 years ago, the US military implemented a program called Vampire to utilize passive cold storage systems in conjunction with new blood transfusion processes onboard helicopter tacevac flights, allowing for the administration of whole blood products in-flight to frontline casualties while they are being transported to medical facilities. These passive cold storage systems utilized vacuum-insulated panels along with phase change materials (ice packs) to allow for the storage of blood for up to 48 hours in moderately hot temperatures.”

Innovations in combat medical care

Two different active thermal management systems for medical supplies developed by the US Department of Defense were acquired by Phoenix Foundry, where continued development of the systems is underway. “The first system is known as the Golden Hour Ambulatory Rescue Pack (Golden HARP),” stated Williams. “It is capable of storing whole blood products in a mobile/backpackable platform for up to seven days at 95°F (35°C) and up to 48 hours at 135°F (57°C) with a full solar load. The system is also capable of storing blood in extremely cold (0°F; -18°C) temperatures for up to eight days. It accomplishes this by incorporating an efficient and ruggedized refrigeration or heating system (depending on the environment), advanced insulation, thermal dispersion coating, and an actively cooled or heated blood storage container that is vacuum insulated with phase change materials. There is also an onboard flexible solar panel that is used to supplement power usage in hot environments, real-time temperature monitoring, and a user-feedback/diagnostics system to alert the user to any faults in the system.

Other advances will include easily accessible and available freeze-dried plasma and US-sourced analgesic medication

“The second system is known as the Heat Ailment Recovery Pack (HARP). While using many of the same technologies as the Golden HARP, the HARP was designed specifically to treat heat-related injuries, which are the number one injury reported in the US military. The HARP is capable of rapidly cooling intravenous (IV) bags and drinking water from 125°F (52°C) to below body temperature in 15 minutes in extremely hot environments (up to 125°F) after any duration of time. Similar to the Golden HARP, it does this by incorporating the same ruggedized refrigeration system. The system can also be remotely monitored and controlled, has integrated tie-down straps and an onboard flexible solar panel to recharge the onboard battery in the field.” Phoenix Foundry is currently looking to partner with commercial entities to bring these technologies to the consumer market and international military markets.

Technological advancements such as artificial intelligence (AI) are driving forward innovation in combat medical care, including smaller and lighter devices. “For example, wearable devices can now provide vital patient information, which enables the medic to address medical conditions early without compromising soldier mobility,” said the spokesperson for Army Medicine. “Recent innovations in AI and new algorithms on hemorrhagic shock can alert medics earlier than traditional diagnostic symptoms. This can improve rates of survival and decrease the amount of treatment supplies needed.

“Lastly, innovation in technology and engineering together are enabling us to develop patient evacuation suites inside our ground and air platforms which improve the enroute care delivered.”

Nuce said that a key focus for USAMMDA is on logistics. “We’re working with our Combat Development partners, industry and academia on ways to become more predictive with our logistics. Science and technology partners, as well as industry and government entities, are working on algorithms for existing logistics IT systems to enable medics at the point of injury to treat an injury while a handheld device scans a QR code, or a camera digitally captures a treatment,” he said. “In both scenarios, we log the patient encounter via the IT platforms, with one feed logging the health IT encounter and supplying that information to the evacuation platform and/or the next higher level of care, while on the logistics side, we capture Class VIII medical supplies being expended during that casualty encounter. The information captures current operations while simulations occur in the background, and the constant feed of real-time data ensures we have an accurate prediction of need by our providers. When resupply trains are available, our medical resupply pushes forward to where it’s needed.”

Army Medicine is also focused on logistics: “Logistics plays a huge role in medical care in combat. Army Medicine is working with the logistics community to enable predictive logistics while also eliminating the need for some medical items to be carried forward,” the spokesperson said. “Oxygen is one of those supplies that we are attempting to eliminate through generation. Instead of providing oxygen bottles that weigh approximately 9lbs and contain 400L of oxygen, we are looking to use small oxygen generators that produce the required amount of oxygen at a fraction of the weight.”

Future solutions

As research and development continues apace, military medical solutions will continue to evolve and, looking ahead, emerging innovations will expand possibilities, improve efficiencies and expedite pre-hospital healthcare delivery in often challenging environments. “Some innovative things that I fully expect to see are items like rapid donor screening, where we can identify low titer and blood type at the point of injury to enable whole blood transfer,” said Nuce. “Battlefield wound infection mitigation is another good example, especially in a prolonged casualty care scenario. Other advances will include easily accessible and available freeze-dried plasma and US-sourced analgesic medication.”

Williams anticipates the continued development of portable medical supply storage systems. “At Phoenix Foundry we believe the future of these systems is dual active cooling and heating technologies integrated into a modular and ruggedized platform. While cooling and heating technologies may change, the active thermal management of medical supplies in mobile platforms is the only way to safely provide extended storage capabilities on the move,” he said.

Ruggedized equipment is important given the often harsh environments military equipment is used in. “Medical devices will become more rugged, more independent from power supply, and telemedicine will play a greater role to ensure that patient data is kept, archived and comprehensible along the complete rescue chain,” said Kühlsen. “The same applies for increased reliability of medical equipment supply – especially considering potential cyberattacks.”

Army Medicine believes that, in the future, 3D printing may be used to produce required equipment parts. “Maintaining medical devices in a combat environment is a must. While our medical device maintainers carry as many parts as possible when they deploy, it is impossible to have every part needed. The ability to 3D-print parts while deployed is being actively explored, to decrease the logistical burden of carrying multiple items and allow for the item to be created in the field.”

There are also expanding potential future applications for AI. “Army Medicine has been researching the use of AI and autonomous systems. Utilizing AI and autonomous systems to assist with treatment recommendations, management of patients and the movement of patients will address some of the challenges with the anticipated high number of casualties. While some of these solutions are on the near horizon, others will be far-term solutions that require extensive research, experimentation and policy guidance.”

Dr Cowley said in an interview: “There is a golden hour between life and death. If you are critically injured you have less than 60 minutes to survive. You might not die right then; it may be three days or two weeks later – but something has happened in your body that is irreparable.” But what if we can extend the golden hour with the help of technological innovation? The need to administer lifesaving care on the battlefield as quickly and effectively as possible is pressing and unwavering, but if the critical time period can extend from a golden hour to a golden day, this may bridge the gap between the golden hour and arrival at a medical facility, saving more lives.

Disclaimer: The views and/or opinions expressed by Phoenix Foundry do not necessarily represent the views of the US Department of Defense or its components.