Unique aspects of the conflict in the Middle East Area of Operations (MEAO) have brought about a refinement in battlefield surgical techniques including the widespread use of damage control surgery (DCS). In addition, the conflict has also seen a new range of battlefield innovations, each credited with decreasing injury and mortality1
Management principles in battlefield trauma care
The type of surgery
Damage control surgery is used extensively in the area of operations, with careful triage required to identify those battle casualties most likely to need DCS2.The main principles of DCS are to rapidly stop bleeding, to remove contamination and to minimise and correct hypothermia, coagulopathy and acidosis.An additional principle is to minimise further damage by limiting the extent of surgery, and not embark on impractical and prolonged procedures.Vascular shunts are utilised to restore blood flow to ischaemic limbs.Rapid external fixation of severe fractures is attempted.In addition to these techniques, patients are also moved expeditiously, with continual reassessment en-route, through the aeromedical echelons of care.Remarkably, patients are also moved with open abdomens to prevent abdominal compartment syndrome2.
In the initial phases of the campaign in the MEAO most wounds were from small arms fire.With the spread of the insurgency, injuries from small arms and rocket propelled grenades (RPG) were replaced with injuries from improvised explosive devices (IED) and vehicular-borne improvised exploding devices (VBIED).These devices resulted in multi-site injuries and fragmentation wounds3.
Historically, combat wounds have been described on the basis of muzzle velocity of the missile – with low velocity being defined as velocities less than 1000 to 2000 feet per second, and high velocity wounds being velocities greater than 2000 feet per second.Injuries from RPG and IED give mixed patterns of wounding, significant concussive effects and gross wound contamination – with effects not dissimilar to high velocity missile wounds.For this reason it is more appropriate to divide wounds into low energy and high energy wounds4.
The most commonly injured regions were upper (30%) and lower (30%) extremities, followed by head and neck injuries5.The pattern of injuries is unchanged when compared to previous combat wounding patterns, including the first Gulf War6. IED injuries involve multiple projectiles which cause multiple penetrating wounds.As the wounding patterns affect multiple body regions it has been highly beneficial to use teams from multiple disciplines.
Causes of death
With the use of prevention techniques, including more rigorous pre-deployment training and the use of body armour, as well as the implementation of the military trauma system, the overall fatality rate amongst wounded soldiers has decreased to 8.8%. Past conflicts have had significantly higher fatality rates with a figure of 16.5% in Vietnam7 and fatality rates between 20 to 30% for prior conflicts in the 20th century8.In addition to these factors, the implementation of the current Aeromedical Evacuation System (AES) has also played a significant role8.Combat casualties in the MEAO are more likely to survive their wounding than those injured in the first Gulf War8.Deaths occurring on the battlefield were due to total body disruption, haemorrhage and severe brain injury7.Haemorrhage from extremity wounds accounted for one tenth of this number and would appear an obvious focal point for further reduction7.
Some specific injuries in the MEAO
The treatment of casualties with spinal injuries is focussed on early immobilisation and prevention of secondary injury from hypoxia, haemorrhagic, septic and neurogenic shock and further mechanical disruption.Approximately 70% of all combat spinal injury patients will require surgery at some stage4.
Burns account for approximately 10% of battle casualties, and nearly 20% of these will be severe burns requiring significant resuscitation9.Consequences of under-resuscitation include decreased tissue perfusion associated with organ failure and increased mortality rates10.Over-resuscitation is also problematic, with the effects being ascribed the term “resuscitation morbidity”.Problems encountered from over-resuscitation include abdominal compartment syndrome (ACS), pulmonary oedema, extremity oedema and airway obstruction10. These phenomena will make the aeromedical evacuation of a burns patient technically challenging, and for this reason four-person burn flight teams are utilised during Aeromedical Evacutation (AME)11.The burns AME team carries up to 800 pounds (365 kilograms) of equipment, including patient warmers, pressure cycle ventilators and bronchoscopes11.ACS is reported to have a threshold for occurrence if there is more than 237mL/kg infused over 12 hours (16 litres in a 70 kg man)12.
Hypothermia remains problematic in the treatment of casualties, and when combined with acidosis and haemorrhagic shock, becomes a deadly triad2.Prevention of hypothermia is far preferable than attempting to treat it.Novel methods utilised in the MEAO include warming fluids, direct radiation from heaters, convection blower heaters under sheets, as well as commercial products such as Bair Huggers and the Thermal Angel (which is being used by the Australian Defence Force)2,13.Incorporation of the dangers of hypothermia into training has resulted in a decrease in the prevalence of hypothermia amongst casualties from 7% to less than 1%7.
Patients who have sustained exposure to the supersonic pressure wave encountered in blast injuries have a variety of shearing injuries at tissue-air interfaces.This includes the tympanic membranes and the lung.AME transfer of blast-injured patients may be complicated with problems relating to expansion of trapped gasses in pneumothoraces, and the development of tension pneumothorax.Blast victims frequently require very large volumes of fluid resuscitation as well as prolonged positive pressure ventilation14,15.
Broad spectrum antibiotic coverage is started as soon as possible for the battle casualty, usually being commenced at an Echelon II or III facility (Forward Surgical Team or Combat Support Hospital).The antibiotics are continued for 48 to 72 hours and then ceased unless there has been an infection identified, or there is an abdominal viscus injury, whereupon the antibiotic is continued for 7 to 14 days4.There have been reports of late infectious complications with unusual organisms such as Acinetobacter14.
Combat casualties – the advances
The aeromedical evacuation system operating from the MEAO is part of a wider sophisticated system that is being developed over time.Areas that are currently the focus of military research include7:
- Personal protective equipment
- Body armour extensions
- Kevlar helmet revisions
- Battlefield torniquets
- Haemostatic dressings
- Recombinant factor VIIa
- Hypotensive resuscitation
- Haemostatic resuscitation
- Patient data – collection, tracking and transfer.
There is no doubt that body armour has decreased the incidence of injury from penetrating wounds to the abdomen and torso.There is evidence to support this when comparisons are made between coalition forces wearing body armour, and Iraqi forces who do not wear the same protection5.The combination of body armour and “up-armouring” of vehicles has limited the number of torso injuries5. Whilst this has led to greater numbers of survivors, there has also been a parallel increase in the number of survivors with multiple extremity injuries.
Increased vehicle armour or “up-armouring” of vehicles occurred in response to observed injury patterns implicating poor protection from vehicle panels.Unfortunately in response to the increase in vehicle armour, insurgents elevated the position of their IED’s and attacked the sides of vehicles with roadside bombs3.
Tourniquets and dressings
In response to the observations of medics in the battlefield, and after analyses of causes of death, there has been an introduction of new haemostatic dressings and tourniquets.Combined with this is the pre-deployment training of all combat personnel in the use of these items for self and “buddy” aid.Examples of these devices are the Combat Application TourniquetTM and the HemConTM Bandage16,17.Battlefield research confirms that these devices are proving effective in the control of haemorrhage18.
In 2001 the US Air Force commenced use of a new system called the Transportation Command Regulating and C2 (Command and Control) Evacuation System (TRAC2ES)19.This is a patient tracking system utilised by the DoD [Department of Defense], allowing planners to decide which patients should be transported on the available aircraft.It also determines which AME teams and equipment should be utilised and where the casualty should be moved19.TRAC2ES is run by the Global Patient Movement Requirements Center (GPMRC) which is an organisational element of US Transport Command (USTRANSCOM)20.
Joint Patient Tracking System (JPTS)
With large numbers of combat troops in theatre at any one time, there arose a need to develop a readily accessible, real time tracking system permitting multiple providers, including aeromedical staff, access to injury status.In effect the JPTS is a real-time, web-based patient medical record system that is accessible to health staff who log on using an access code7.Another novel proposal is to place memory bus devices (thumb drives) into a soldier’s dog tags – thus permitting transfer of a large amount of data with the casualty2,7.
Joint Theatre Trauma Registry (JTTR)
To assist in research and development, the US Army Institute of Surgical Research commenced a trauma registry called the Joint Theatre Trauma Registry2. This database now contains over 7,500 soldier injury records7.Analysis of this data will influence the course of combat trauma in the next few decades.
Unique medical and surgical innovations during the conflict in the MEAO have translated into significant advances in patient care.The innovations range from more sophisticated immediate first aid through to the refinement of advanced resuscitative techniques such as damage control surgery. The conflict has also heralded a new age in data communication, with instant transfer of patient information and en route patient tracking systems now accepted as standard practice.
The views, opinions, and/or findings in this report are those of the author and should not be construed as an official policy of the Royal Australian Air Force or the Australian Defence Force.