DAMAGE CONTROL PROCEDURES

ARSC teams exist for unstable patients who cannot tolerate transport to a Role 2 (or next level of care); their function in the battlefield continuum of care is for the provision of early damage control resuscitation and surgery. ARSC teams should focus damage control principles as the primary approach for all surgical procedures which minimizes time, resources and personnel. This mindset and approach should be used for both traumatic and non-traumatic patients (such as appendicitis). There may be scenarios where the ARSC team will be the definitive level of care for host nation patients, however decision-making is still constrained by resource availability and by operational mission requirements.24

In most cases, emergency surgery for acute surgical diseases (e.g., acute cholecystitis and appendicitis) that do not clinically require a damage control strategy, should be temporized with antibiotics and expeditiously transferred to a higher level of care. If operational considerations require patients be held more than 24 hours, or if the patient presents with sepsis or hemodynamic instability due to an intra-abdominal source, surgery may be indicated.

For elective or semi urgent cases, the evacuation chain should be utilized in communication with the operational commander and the theater trauma director. Give the significant resource limitations, only true emergencies should be considered at this level of care.

ANESTHESIA AND INTRAOPERATIVE MONITORING

Delivering safe anesthesia in the austere environment must account for available medical capabilities and the tactical situation.

Patient Monitoring

Monitoring under anesthesia ideally includes understanding normal physiology of a patient and using your hands and eyes to monitor your patient. Adjuncts in this environment are additional cardiac monitoring, blood pressure, pulse oximetry, temperature, and for a ventilated patient, inspired oxygen analysis and end-tidal carbon dioxide (ETCO2) measurement.25 A range of devices are available to monitor vital signs with minimal space and maintenance. However, honing clinical skills to manually assess vital signs is important as monitoring devices may not always be available.

ETCO2: ETCO2 monitoring is an important capability as a physiologic indicator, even at the initial levels of care. The ETCO2 value is relevant during resuscitation and in TBI patients, in addition to its established role in verifying airway placement and monitoring ventilation.25 Under controlled ventilation, the ETCO2 level can also be used to estimate changes in cardiac index, or cardiac output over time.26 This knowledge can be applied within the clinical context, and can be used in cardiopulmonary resuscitation to predict patients who are more likely to achieve return of spontaneous circulation (PETCO2 >10mm Hg).26 As such, ETCO2 can be useful during triage.

Ultrasound: The presence of sonographically identified cardiac activity at any point during trauma bay or intraoperative resuscitation is associated with increased survival to hospital admission.27

Invasive pressure monitoring: Small in-line devices (i.e. Centurion Compass®) have been used successfully for monitoring aortic occlusion during Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA). These can also be used to measure and trend central venous pressures, bladder pressures, or myofascial compartment pressures. See JTS Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) for hemorrhagic shock CPG, 06 Jul 2017.28

Perioperative Anesthetic Considerations

Definitive airway control is challenging in the trauma patient. It becomes increasingly difficult in the austere environment and requires a significant commitment of resources such as the need for a ventilator, continuous monitoring and sedation. When intubation is indicated, the timing should be optimized in order to conserve resources. Even with depressed Glasgow Coma Scale, if a patient remains spontaneously breathing, it may be preferable to support their respirations non-invasively while resuscitation is initiated. Resuscitation prior to induction of anesthesia in an unstable patient may prevent hemodynamic collapse. Alternative anesthetic techniques such as moderate sedation or peripheral nerve block may conserve resources. With respect to airway management, consider the capabilities of the transport personnel, their available respiratory and monitoring equipment en route, and the capability of the next level of care. In patients with a potential for airway compromise, ensure a definitive airway is established prior to transport. Considerations must be made for supplemental oxygen delivery which can be challenging in this environment, an Austere Anesthesia CPG (under development) will address these issues specifically.

Maintenance of Anesthesia

The means to administer inhaled agents for the maintenance of anesthesia is not likely to be available in the austere setting. Electrical power and inspired gases used to drive vaporizers are problematic resources to obtain. Draw over methods could be considered, however can be challenging to titrate or administer when considering variables such as a non-spontaneously breathing patients or patient transportation. General anesthesia using a total intravenous anesthetic (TIVA) is a more effective means to provide adequate anesthesia and conserve equipment and resources. Practitioners should have an intimate knowledge of the benefits and limitations of intravenous anesthetic drugs available to allow for an effective, balanced anesthetic. Simple infusion pumps or quantitative drip sets can automate flow for prolonged infusions and providers should carefully select and train with their specific equipment. Since TIVA is commonly utilized in this environment, calculations and concentrations of the most commonly used drips have to be mastered by providers using this form of sedation and general anesthetic and the drip rates of Propofol, Fentanyl and Ketamine have to be well understood.

Regional Anesthesia Adjuncts

The capability to perform regional anesthetic techniques enhances the ARSC team mission. Experience in Iraq and Afghanistan has highlighted the value of early aggressive pain management in the combat casualty,29 and reinforced the importance of multimodal pain management in the perioperative setting.30,31 The use of regional anesthesia, either in conjunction with or instead of general anesthesia, may reduce the resources and personnel required for operative, postoperative, and subsequent en-route care. The risk of masking a developing compartment syndrome must be considered. Ultrasound or stimulator-based techniques can be used to perform a variety of nerve blocks. Intercostal nerve blocks can be used to decrease respiratory pain associated with thoracostomy tube or thoracotomy or multiple rib fractures.32 A transversus abdominis plane block can be used as a part of multi-modal pain treatment to attempt early extubation after laparotomy, even in patients with a temporarily closed abdomen.33

Blood Transfusion Capability

In addition to surgical hemorrhage control, resuscitation with warmed blood is the most important intervention that the ARSC team can perform. Effective resuscitation of the trauma patient who has sustained massive blood loss consists of simultaneous hemorrhage control along with resuscitation to correct trauma-induced coagulopathy, acidosis, and hypothermia.33 Resuscitation with blood products rather than crystalloid or vasopressor administration is the standard in trauma care; calcium administration should be early during the resuscitation. Treatment of acute coagulopathy of trauma is addressed with transfusion of whole blood, plasma, cryoprecipitate, and platelets, however blood products in the austere environment may be limited and platelets and cryoprecipitate will unlikely be available. Whole blood administration, preferably stored low titer type O whole blood (LTOWB), provides the most balanced resuscitation and is easier to administer as a single product for minimally staffed ARSC teams. The capability to draw warm fresh whole blood from prescreened donors should be optimized. Also, the capability to warm blood products during massive resuscitation is required, although there is not always standardized equipment to support this requirement, every effort should be made to ensure these teams deploy with at least 1 rapid fluid infuser with warming capabilities. Effective rapid transfusion and warming devices are necessary and require adequate power to support.

In general, an ARSC team should plan to ideally maintain at least 20 units of whole blood or red blood cells (RBCs) + plasma (20 of each blood component). Mission requirements will also dictate inventory levels of blood (mission support vs. area support). The ARSC teams must be in regular communication with the theater Joint Blood Program Officer (JBPO) or Armed Service Blood Program Theater representative and keep their status updated (as much as possible) in TMDS to facilitate resupply. ARSC teams must have a well-rehearsed walking blood bank (WBB) capability. At times the WBB may rely on host national blood depending on the tactical and clinical environment. If using host nation blood supply, consideration must be given to endemic disease risk of donors and ability to perform rapid tests to mitigate risk. When supporting en route care missions, WBB is less feasible and stored blood is required depending on operational activity. Frequent communication with the supporting Blood Support Detachment and JBPO is essential.

SURGICAL AIRWAY MANAGEMENT

Airway obstruction represents 8% of potentially preventable prehospital deaths.34 Multiple attempts at orotracheal intubation should be avoided, and providers should maintain a low threshold to surgically manage the airway. Complex facial injuries require airway management and hemorrhage control for temporary stabilization.35 In this circumstance, obtaining an initial endotracheal tube or cricothyroidotomy is appropriate. As above, consider the level of the transport capability. Transferring a patient with significant maxillofacial injuries with a surgical airway as opposed to an orotracheal airway may be the safest option. It is important to have equipment for a surgical airway ready in the event that orotracheal intubation is unsuccessful. Always confirm airway placement with ETCO2.36 See JTS Airway Management of Traumatic injuries CPG, 17 Jul 2017.37

NECK INJURIES

Hard indications for surgical neck exploration in the ARSC environment are no different than at the Role 2 or Role 3 and include ‘hard signs’ of vascular injury with active hemorrhage or expanding or pulsatile hematoma. However, because of the lack of imaging, lack of resources and the inherent challenge of these injuries – casualties without hard signs, should be transferred to a higher level of care as long as they have an acceptable airway for transport (this could be their native airway or a definitive airway). In some cases, exploration is indicated when airway injury is suspected based on subcutaneous emphysema or air bubbling through the wound,38 however many cases of tracheal injury can be temporarily managed with endotracheal intubation with the cuff inflated below the level of injury. Be ready to immediately perform a surgical airway in these patients, as a relatively stable patient may have significant airway disruption. Proximal and distal vascular control is difficult for injuries approaching the base of the neck or skull base. In this environment, most penetrating wounds to the neck without immediate life-threatening hemorrhage should be transferred to a higher level of care for further diagnostic workup and subsequent formal surgical exploration. While penetration of the platysma alone is not an indication for neck exploration in the austere environment in the current trauma system, multiple factors must be taken into consideration (transport time, capabilities at sending and receiving facilities, the trauma system) as the level of injury may be difficult to ascertain without imaging. Maintain a low threshold to secure the patient’s airway prior to transfer. Additionally, communication to the higher level of care should be established to discuss the plan for these casualties.

TRAUMATIC BRAIN INJURY

Non-neurosurgeons should be cautious when performing craniotomy or craniectomy in the austere setting, this is no different from a surgeon at a Role 2. However, in this far forward environment, medical management and craniectomy have even more challenges. Lack of appropriate training and experience may make operative therapy more dangerous than medical management alone. In the austere setting, every attempt should be made to maximize medical management (i.e. ETCO2 monitoring, hypertonic saline, bed positioning, airway management, sedation, paralysis, keeping the head elevated and midline. Discuss the patient with and transfer to a neurosurgeon as soon as clinically possible.39 If transport is not possible, the provider should attempt to seek the guidance of a neurosurgeon in real time. In the absence of proper imaging, burr holes or needle drainage of suspected epidural hematomas are discouraged. See JTS Emergency Cranial Procedures by Non-neurosurgeons in Deployed Setting CPG, 23 Apr 2018.40

OPHTHALMOLOGY

Trained ophthalmologists are never available in this environment and every attempt should be made to contact an ophthalmologists at the Role 3; however, given the nature of the ARSC teams, communication is not always feasible. Injuries to the globe should be covered with an occlusive shield and parental antibiotics and anti-emetics should be administered. These patients frequently experience severe nausea; oral medications should be avoided. It is imperative to avoid pressure to the globe, ensure nothing is directly touching the injured globe, and no intraocular medications are administered. See the JTS Ocular Injuries and Vision-Threatening Conditions in Prolonged Field Care CPG, 01 Dec 2017.41 Lateral canthotomy and cantholysis should be performed if there is concern for retrobulbar hematoma or increased intraorbital pressure. In the rare circumstance that Telemedine support is available, it should be heavily utilized. Establish telemedicine consultation as soon as possible. AD.VI.S.OR, the Advanced VIrtual Support for OpeRational Forces system offers 24/7/365 on-demand real-time telemedicine consultations. https://prolongedfieldcare.org/telemed-resources-for-us-mil/

TORSO TRAUMA

Approximately 13% of combat casualty patients presented with injury patterns at risk of non-compressible torso hemorrhage (NCTH), and this was identified as a cause of death in 50-70% of patients assessed to have potentially survivable injuries in Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF).35,42-44 Truncal injury was characterized as 36% thoracic and 64% abdominopelvic.35 It is in this patient population that forward-positioned surgeons have the greatest potential to directly impact survival.45-48 The ability to perform Extended Focused Assessment with Sonography for Trauma (E-FAST) for identification of intra-thoracic injury and intra-abdominal hemorrhage is required because X-ray and CT scan may be unavailable. Ultrasound has its limitations and has been documented as having a higher false positive and negative rates in penetrating trauma. In one study looking at combat trauma, FAST only had a sensitivity of 12% for intraabdominal injury requiring laparotomy;49 this underscores the use of training to improve diagnostic sensitivity, as well as the challenges of these teams that do not have any additional diagnostic imaging. Diagnostic peritoneal lavage/diagnostic peritoneal aspiration (DPL/DPA) can be used to augment diagnostic capability when FAST results are equivocal, although DPL/DPA are only limited to evaluation of the peritoneal cavity. ARSC teams have to optimize requirement for ultrasound capability and providers must have the appropriate U.S. training. U.S. is limited for identification of pelvic or retroperitoneal hemorrhage, therefore a high index of suspicion should be maintained when the injury mechanism indicates potential retroperitoneal bleeding.

Although not proven with prospective outcome data, REBOA has shown potential in the austere environment as a bridge to prompt surgical intervention, to obtain rapid proximal vascular hemorrhage control, reduce blood transfusion requirements, improve exposure by reducing hemorrhage, facilitate rapid normalization of hemodynamics,50 and as a force multiplier during MASCAL scenarios.51,52 Early femoral arterial access (18 gauge A-line, 4 or 5 Fr. micropuncture) and monitoring can help identify patients who will die from hemorrhage earlier. Placing arterial access is strongly encouraged and does not require placement of a REBOA, but improves monitor. This can be upsized to the 7 Fr femoral sheath for balloon occlusion should the patient deteriorate. The sheath may be left in-situ connected to a pressure monitor during evacuation to higher levels of care or if repeat catheterization is probable, but comes at a risk of limb ischemia and even limb loss. Sheath complications are not uncommon and the sheath should be removed at the earliest time after the patient has demonstrated stability. After sheath removal the vascular must be evaluated to ensure that there is good distal perfusion. While the sheath is in place, distal pulses must be followed closely. See the JTS Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) for Hemorrhagic Shock CPG, 06 Jul 2017.28 All ARSC providers require REBOA training. There are multiple training courses available.

Laparotomy

Concern for NCTH with hemodynamic instability requires surgical intervention at the earliest opportunity that resources and personnel permit, this is no different from other roles of care. Damage control laparotomy is the standard in the unstable trauma patient and may be performed in forward environments.13,53 In the deployed setting, damage control surgery and temporary abdominal closure are recommended when significant intra-abdominal injuries are found.

In OIF and OEF, the rate of non-therapeutic laparotomy was as high as 32%.54 A non-therapeutic laparotomy is likely safer than a potentially prolonged transfer in a casualty that might have a missed injury. These decisions are very challenging, but succumbing to injuries in flight is never acceptable. Selective non-operative management55 should only be considered where CT scan, as well as, extended observation are possible.

Thoracotomy

The incidence of thoracic trauma in modern conflict is approximately 5%, with mortality ranging from 12%-24%.44,56 Patients with severe thoracic trauma have a significant survival advantage if they reach surgical capability within one hour or less.57-58 Thoracotomy should be performed when indicated with the damage control mindset and the goals of rapid control of hemorrhage and contamination. The chest may be temporarily packed and closed over chest tubes.

Cardiac Injury

Imaging is usually limited to a handheld ultrasound. Maintain a low threshold to perform a subxyphoid or transdiaphragmatic pericardial window if the injury pattern is concerning for mediastinal or cardiac injury. If there is blood in the pericardium, explore as indicated. See the JTS Wartime Thoracic Injury CPG, 26 Dec 2018.59 Rarely, some patients with hemopericardium may present with normal hemodynamics which may represent a superficial injury to the myocardium and sternotomy may be avoided if the pericardial space is irrigated with warmed fluid, and the bleeding is noted to have stopped.60-62 Place a closed suction drain and record output. A period of observation is recommended prior to transfer.

VASCULAR

Like every deployed surgeon, the ARSC surgeon should have training and experience in expeditious exposure of all named vessels to identify and control hemorrhage. The initial damage control and stabilization of injured vessels includes control of exsanguinating hemorrhage, recognition of extremity ischemia, rapid restoration of flow to the ischemic limb with vascular shunts, and fasciotomies to treat or prevent compartment syndrome.13,62 All of the above, is exceptionally more difficult in the ARSC environment, emphasizing the importance of readiness and training for this skill set prior to deployment.

Shunt placement is a required skillset. When placing a shunt, thrombectomy of the distal vessel should be performed prior to shunt placement if vigorous back-bleeding is not present. Secure all shunts with suture as close to the vascular injury as possible to preserve native vessel length. Leaving all vessel loops used for proximal and distal control loosened and in place will allow the next surgeon to quickly identify relevant anatomy and provides rapid control of a vessel if the shunt dislodges in transport. Cover the operative field with dressings, and consider a temporary skin closure to protect the shunt. Primary patency rates are high for proximal shunts (86%) and low for distal shunts (12%).62 Primary repair of partially injured vessels, such as large veins, is preferable if greater than 50% stenosis can be avoided. Shunting of large veins is preferable to ligation when primary repair is not feasible and may increase patency rates of associated arterial shunts. Definitive reconstruction such as vein graft should be delayed to a higher level of care when possible.13 If the vascular repair is associated with a fracture, immobilization with an external fixator is recommended; external fixation prior to definitive vascular shunting is recommended if the warm ischemia time allows. In the case of popliteal and femoral artery injuries, the use of shunts as opposed to primary amputation, even in an unstable patient, does not increase risk of death and improves overall amputation free survival.63-64 Balloon catheters (REBOA or Fogarty) can be employed to provide temporary vascular control. Refer to the JTS Vascular Injury, 12 Aug 2016.65

Subclavian Vessels

This injury pattern carries a high mortality rate. Most venous bleeding and some arterial bleeding can be controlled with wound packing. A temporary skin closure over the packing may improve tamponade. Maneuvers to obtain proximal vascular control include intrathoracic exposures such as sternotomy, supraclavicular, clavicular resection, trap door approaches as well as retrograde placement of Fogarty catheter through the brachial artery or through the zone of injury. Additionally, inflating a Foley balloon within the wound track may provide tamponade, particularly if able to maintain compression against the clavicle or chest wall. A chest tube should be placed on the same side as the subclavian vascular injury if there is a concern for intrathoracic hemorrhage.

Inguinal Vessels

Contralateral placement of a REBOA catheter with aortic occlusion in zone 3 is a rapid and effective way to obtain temporary proximal control of a junctional groin injury. Extraperitoneal control of the iliac vessels above the level of the inguinal ligament also achieves proximal control of the injured vessel outside of the zone of injury, but a low threshold for intra-abdominal proximal control should be applied, given the often unpredictable trajectories of combat injuries.

Fasciotomy

Maintain a low threshold to perform fasciotomies for the combat injured extremity.13 Delay in diagnosis of compartment syndrome can occur due to multiple patient handovers during the transport process.13 Be proficient with techniques for both the upper and lower extremity – especially the common pitfalls: missing the deep posterior compartment in the lower extremity and not coming all the way across the carpal tunnel in the upper extremity. Even without evidence of compartment syndrome, early prophylactic fasciotomy may be considered in the setting of vascular injury with a temporary repair and may improve limb salvage rate, especially in patients who are going to be transported and do not have immediate access surgical care.66

EXTREMITY TRAUMA

Extremity trauma is the most common injury on the battlefield. Having proficiency with bony, soft tissue and vascular techniques in the extremities is extremely important for the ARSC surgeon – not always thoroughly trained in general surgery residencies. The austere surgeon must be familiar with all open surgical and non-surgical techniques to control hemorrhage and re-perfuse injured limbs. Transport of a patient with a tourniquet should be avoided. When tourniquets are left in place for more than 4-6 hours, the risk of severe rhabdomyolysis, kidney failure, limb loss, and death are high.67 Closed reduction, splinting, and/or traction are often adequate temporary stabilization techniques of long bone fractures if these procedures adequately align the bony injury.

External Fixation

For combined orthopedic and vascular injuries, consider external fixation of long bone fractures after shunting and prior to definitive repair. Pelvic binder placement is effective for temporary control of most pelvic hemorrhage.68 In delayed evacuation scenarios, pelvic binders should optimally remain in place no longer than 48-72 hours.

Mangled Extremity

Every effort should be made to temporize the mangled extremity and transfer the patient to a higher level of care. However, when blood product and resource availability are limited, limb salvage may not be feasible. Initial management of the mangled extremity includes hemorrhage control, irrigation, and debridement of clearly non-viable tissue. Traumatic amputations should not be formalized in the austere setting, though familiarity with formal amputations is required in order to anticipate future soft tissue coverage needs. Wounds should be left open in anticipation of repeated exploration and debridement. See JTS Amputation: Evaluation and Treatment CPG, 01 Jul 2016.69

Soft Tissue Wounds

Early debridement of soft tissue wounds and burns improves outcomes and morbidity. However, the ability to fully debride soft tissue wounds may be limited in the ARSC setting because of limited access to surgical energy devices, blood products, sterility, and irrigation fluid. Aggressive management of soft tissue injuries should be weighed against the available resources and operational considerations such as resupply and overall sustainment of the mission. In general, the ARSC team is not resourced to manage large soft tissue wounds that require serial debridement. Potable water is as effective as sterile fluid for surgical irrigation.70 Sharp debridement is the standard of practice for soft tissue wounds. Commercial negative pressure dressings are unlikely to be available in the ARSC environment. Standard gauze (or hemostatic gauze) or occlusive dressings over closed suction drains are suitable for transport. See JTS Initial Management of War Wounds CPG, 25 Apr 201270 and JTS Acute Traumatic Wound Management in the Prolonged Field Care Setting CPG, 24 Jul 2017.71