Military medicine often has a steep learning curve when conflicts start. People taken from civilian life needing to deal with medical problems and traumas and military medics used to peacetime may have not seen some natures of injuries in years. Likewise, some types of injuries that appear in terrorist incidents do not occur often in civilian populations. Many civilian medics have rarely, if ever, diagnosed or treated blast injuries. In many countries, doctors and hospitals rarely see or treat gunshot injuries. Simulation is therefore a necessity in this sector.
A wide variety of technologies and products have evolved, over decades, to assist medical personnel or even lay-persons who want or need first aid training. Some of the types of problems that doctors, nurses, and other medical staff need to deal with are not daily occurrences, so the requisite knowledge base needs to be built up with training rather than experience. There are also complex medical situations that will require a variety of mental skills, physical skills, and specialty equipment to diagnose or treat, and thus need extensive training that is made easier with technology and simulation. Finally, you do not want people who are just starting out to learn by working on living patients if there is an alternative by which trainees can learn from mistakes without endangering life or causing unnecessary suffering.
From a commercial perspective, medical simulation is a broad and heavily fragmented market; it makes little sense trying to profile literally hundreds of companies. The segment is full of small and medium enterprises (SMEs) and artisanal work. In addition, some developments are occurring within public institutions or academia. From a technical perspective, it is not always easy to divide the defence and security space from the sizeable non-military market either. Many products and services designed for the civil medical marketplace end up used in military training and vice versa.
The Need for Simulation
Since antiquity, those educating medical providers have understood the fundamental truth that the first time a new trainee does a medical procedure, it might be best not to set them loose on a human patient. Furthermore, injuries and illnesses are unpredictable in real life. This correspondent’s own medical training – an emergency medical technician course in 2002– involved working shifts both in an ambulance setting and in an emergency department at a busy hospital. The exposure one got to serious injuries and illnesses varied tremendously. A trainee may or may not get to see penetrating chest trauma or anaphylactic shock, merely due to chance.
Because of these obvious issues, both human cadavers and animals have been used in medical training. Supply of human cadavers is relatively sparse, and, obviously, they do not behave like living humans. Even within the timeline of this author’s own career, animal models were used for training and simulation of human casualties. Generations of military medics have treated gunshot wounds in animals like goats or nerve agent poisoning in monkeys. Ethical, economic, and political considerations have served to greatly reduce the instances of such training in recent decades. Substitutes and surrogates are needed to make training more available.
Using Live Humans as Mock Casualties
Casualty simulation has long been used in stage and film dramas, with human actors used to play injured victims. Both professional and amateur actors have long been used in medical training. This correspondent once worked with a CBRN training site which had a working relationship with an amateur theatre group. Even Scout troops have been used to simulate paediatric victims in mass casualty exercise. Mock victims can be given descriptions of signs and symptoms that they can mimic or describe to responders. There are even companies that will provide amputees for extra realism. Obviously, the quality of such simulation varies by individual.
Actors on their own can only do so much. Tools to help simulate injury have evolved, first for stage, then for film, and finally for medical training. The oldest is moulage, which is the use of make-up, cosmetics, prosthetics, and various devices to simulate visual injuries. Literally hundreds of companies make moulage kits ranging from the simple to the extremely sophisticated. Various physical traumas such as lacerations, firearms injuries, burns, and open fracture can be simulated. Blood packs can even simulate various types of bleeding. However, there is a practical limit to this. Human actors cannot be subjected to medical interventions that bear risk. You do not shock human actors with defibrillators, for example, or conduct invasive or painful interventions. Their primary value is in diagnosis, rather than advanced treatment.
Advanced Human Surrogates
Simulated bodies and body parts have had a long history in medical training. For instance, the use of pig skin for surgical training is a time-honoured practice, and most people are familiar with CPR dummies. A whole industrial segment provides a mock body or body part for practically every conceivable medical procedure. Some of these are simple, such as arms for practice of IV insertions or heads for practice of intubation. Such training aids have existed for a long time and are relatively inexpensive.
Modern materials and 3D printing techniques ease the construction of realistic bodies or parts by creating simulated bone, flesh, and other bodily tissues that have physical characteristics very close to an authentic human body. Modern technology can now 3D print simulated bones and organs that are, in terms of their response to physical stimuli and trauma, very close to the real thing. ‘Biofidelic,’ a term not known to this correspondent before researching this article, is now used to mean a product as close to the real body component as possible. Biofidelic body parts can be used for ultrasound training, as one example, to train medical personnel on using ultrasonic imaging for tasks like catheter emplacement. At the largest end of this market segment are entire synthetic cadavers, surgical models that accurately represent the entire human body. An industry leader in this is SynDaver (USA), but other companies do similar work. SynDaver also produces a diverse array of individual tissues and organs as well.
Instead of being inert dummies, it is possible to provide devices that provide interaction and feedback. Models can provide outputs such as pulse and breathing similar to a live human. Sensors can be included to measure various inputs. One example is advanced anaesthesiology simulation, which is at the higher end of the market. Mannequins are instrumented with sensors that monitor levels of medication and react appropriately. Various problems can be programmed in order to realistically teach trainee doctors. Such systems are quickly becoming widespread in medical school anaesthesiology training programmes.
Simulation as a scientific tool
Once you start populating a simulated body or body part with sensors and data collection capability, such models – ‘biofidelic phantoms’ in the language of the trade – become useful for tasks beyond just training students. It became clear when researching this article that the state of the art in biomedical simulation is being advanced along many fronts and that there are use-cases that are not just as training aids. Biofidelic phantoms can be used as aids for research into injury and illness.
Many types of injuries are still not well understood by modern science and medicine. To put it rather indelicately, when soldiers get injured in explosions, they are not wearing a network of sensors to help scientists understand the physics and biology of injuries like blast damage to lungs or traumatic brain injury. As with other types of simulation, cadavers and animals have been some use in the past, as have post-mortem examinations of victims. Use of consistent biofidelic phantoms helps scientific efforts by making it far easier to increase both the volume of tests and the reproducibility of tests. It might take a decade to gather data on a certain type of combat trauma, and the individual circumstances will vary greatly. The statistical reliability of research, important to establish the validity of conclusions, is greatly increased if consistent reliable simulated bodies and organs are used.
Most are familiar with crash test dummies, which have long been used to simulate the mechanics of car crashes. Simulation technology can do the equivalent for modes of injury, such as head injuries. Imagine a faithful reproduction of a human head, with bone and tissues that behave, in terms of mechanics, just like the real thing. This head could be instrumented with accelerometers to precisely measure movement in every dimension. Hydrophones could measure the travel of shockwaves through soft tissue. Microphones could measure sound, relevant to hearing damage. Such an anatomically correct head could be used to study traumatic brain injuries, trauma from gunshot wounds, the effect of blast waves from explosions, and similar mechanisms of injury. Work in this sphere is presently underway.
Other work along similar lines includes the use of biofidelic legs to study landmine injuries. Blast-induced lung injury can be studied with biofidelic chest and lung models. In doing so, science and medicine gain a better understanding of how these injuries occur, leading to improvements in things like diagnosis, personal protective equipment (PPE) such as body armour and helmets, and treatment. Design of armoured vehicles can also be improved to reduce injury in various scenarios.
Simulation of Mass Casualty Incidents
Going beyond dealing with individual cases, training and exercises are needed to improve handling of mass casualty incidents. Civilian hospitals and emergency medical services may need to react to disasters or terrorism and could be confronted with many more victims than they normally deal with. Although one approach to training for such incidents is to try to use the techniques and technologies above at scale, such an effort can be prohibitively expensive or difficult. Furthermore, management of a mass casualty incident is as much, if not, more a test of management processes and procedures than a test of individuals assessing and treating patients.
Numerous companies now make a variety of tools and aids to assist command post exercises, operations centres, and table-top exercises in mass casualty management. Such exercises emphasise decision-making. Various simulation tools provide fictional scenarios and dozens or even hundreds of fictional patients. These scenarios can be adapted to local conditions, allocation of resources, triage of patients, and logistical decisions.
Where is this interesting segment heading? One prospect that comes to mind in this sector is fusion with telemedicine. If you can’t get the patient to the specialist or the specialist to the patient, there are now ways to bridge that gap. There are many efforts to provide medical expertise and interventions remotely, with a skilled surgeon or other specialist acting remotely through sensors and telecommunications. This raises many prospects for simulation and training, because the medic is responding to inputs and providing outputs through information technology. A lot of telemedicine scenarios could be simulated virtually.
The trajectory is fairly clear in this segment, at least to this correspondent. Both quality and quantity will increase over time. The quality of simulation tools, in terms of their ability to provide high fidelity replication of human injury and illness, will continue to improve. In terms of quantity, the cost of such items will generally come down as manufacturing becomes easier. This could allow more tools to be made available in more places, more environments, and at more levels. Tools presently reserved for training doctors at university level may soon be available for paramedic and combat medic training. Greater realism at more levels will be the key trend to watch.