POWERING THE PROSTHETIC LEG
TAKE A LOOK INSIDE A COMPUTERCONTROLLED KNEE
vessels or into bone marrow. When the body experiences heavy bleeding, its natural function is to cycle the formation of blood clots and then break them down again. When suffering traumatic injuries it’s important to preserve and stabilise any clot that has formed – this is the role of TXA. Along with TXA, battlefield medics are equipped with an array of trauma-tackling equipment, including adjuncts to keep airways open, chest seals for open chest wounds, splints for broken bones and pelvic binders to stem any internal bleeding within the pelvis.
By the hour mark, it’s hoped that highly trained paramedics, nurses and doctors will have intervened and begun work to resuscitate the patient. This typically centres around restoring respiratory function and replacing lost blood. The UK military has a medical system whereby the capability of the emergency room is taken to the patient to save precious time for the critically injured patient. This is a two to four person medical emergency response team (MERT). The aim of the MERT is to augment the life-saving treatment already given and provide critical care interventions, such as anaesthesia, to resuscitate and stabilise the patient during the transfer to the hospital. Blood products are carried cold by the MERT. They are transfused via a warming device so that the patient receives blood at body temperature. “We hope to be at the hospital doors within two hours of injury to enable further resuscitation,” says Pynn.
THE FUTURE OF MILITARY MEDICINE
Advances in military prehospital emergency care continue to evolve. Service personnel using wearable technology to monitor a soldier’s respiratory system and heart rate in combat will give medics vital information to plan treatment.
Drones are being trialled to transport blood products to areas of conflict too remote or dangerous for medics, as well as to transfer casualties short distances to safer areas where the MERT can continue life-saving interventions. Following advanced medical intervention, more advanced drones will be designed to ferry injured soldiers remotely out of the battlefield, transferring them without medical escort while controlling pumps, monitors and infusions in response to the patient’s currently physiology and delivering them to a hospital – the Israelis are trialling the Heron unmanned aerial vehicle for this purpose. It’s vital for military prehospital emergency care to evolve when not engaged in conflict so it’s ready when the time comes.
Pynn is defence consultant advisor in Pre-hospital Emergency Care (PHEC) to the UK Surgeon General. He has undertaken multiple operational tours across the world while serving in the Armed Forces over the last 22 years.
What is one of the biggest challenges medics face in the field?
The biggest challenges anyone providing medical care has to face on a battlefield is the situation itself. Very austere situations, climatically challenging situations – we don’t tend to go to war in nice places. That’s the overwhelming challenge to anyone trying to deliver care, that your own personal safety is not guaranteed.
In terms of logistics, getting blood products forward is challenging. But one thing the UK military has done very well is manage the logistic chain for blood products. We get great support from the NHS blood transfusion service. It’s got a shelf life of 28 days – you can maximally push it to 35 days, but for planning purposes it’s 28. That’s a huge logistic burden. We have a system that can deliver cold blood products as far forward as possible so that patients can be resuscitated at an early stage with blood products such as red cells. Plasma is more difficult and more logistically challenging, but what we tend to use far forward is freeze-dried plasma. In Germany and France they manufacture freeze-dried plasma – at points of injury you can reconstitute it with sterile water.
How do you maintain the temperature of blood stores?
Blood is kept cold in something called a golden hour box, which is a bit of a misnomer because it keeps blood cold for 48 to 72 hours. It’s an insulated box with big ice packs, which need to be reconstituted in a freezer every two to three days. These golden hour boxes can be anything from the size of a shoebox, carrying around two units of blood, to something a lot bigger that can carry 12 to 20 units of blood and keep blood cool for three to five days.
How has pre-hospital emergency care changed over your career?
There’s not much good that comes out of war, but one of the things that does come out of war is advances in medical capability and technology. Between periods of conflict, we tend to forget the lessons that we’ve learned in the last conflict, and we spend a little bit of time relearning those lessons. But we’ve had a sustained period of conflict across the globe over the last 20 to 30 years that the UK military has been involved in, to a greater or lesser degree. We have learned an awful lot of lessons from a medical standpoint that have crept, some slowly and some more quickly, into the NHS.
Things that have evolved are widespread use of tourniquets at points of injury and battlefield analgesia with fentanyl lozenges, which replaced the morphine auto-injectors. Also, something called haemostatic dressings.
These are dressings that have a clotting agent within them, so that when the dressings are stuffed down into the wound, they promote clotting. The UK military uses something called Celox
Rapid, which is basically a gauze that’s impregnated with something called chitosan. You stuff this dressing down into a wound and apply pressure, and that aids clotting, so it’s better than just stuffing a wound with gauze. Haemostatic dressings were developed by the US.
Now they are routinely carried by military team medics and by the NHS.