The principal goal of emergency medical services (EMS) providers caring for penetrating injury patients in an urban environment is rapid transport to definitive care while administering lifesaving interventions. The prehospital period involves expeditious evaluation of wounds and hemodynamics, stabilization and prevention of further injury, and rapid transportation of the patient to the closest appropriate facility where definitive care can be delivered. The care of the patient in the prehospital setting follows principles set out by the American College of Surgeons Committee on Trauma (ACS-COT) delineated in Advanced Trauma Life Support (ATLS) and the Prehospital Trauma Life Support (PHTLS), both of which are leading international programs of continuing education. The PHTLS course is taught to EMS providers in over 33 countries worldwide and complements the physician ATLS course that is currently taught in 40 countries. Although recent military experiences originate from an environment that differs from the civilian by the presence of a hostile setting, mass casualties, and less available resources and the foremost goal being completion of the current mission, various battlefield techniques are currently adapted for civilian use in prehospital setting. The Hartford Consensus was developed in 2013 after the recent active shooter events in the United States. Educational efforts have been directed to encourage nonprofessional, civilian first responders to provide rapid hemorrhage control, including with available, easy-to-use tourniquets. As professional first responders, EMS providers need to be trained to take appropriate actions including assessment, triage, and transport of the victims and further hemorrhage control measures as needed.

The benefits from extensive prehospital intervention for penetrating trauma, particularly in an urban environment, remain controversial. In critically injured patients, performance of other than lifesaving interventions can delay arrival to a facility that will provide definitive care and can have a negative impact on survival. In general, the “scoop and run” paradigm should be the rule and not the exception for penetrating trauma. While stabilizing procedures should be undertaken before and during transport, any monitoring or intervention (“stay and play”) that delays definitive treatment of penetrating injury – often an operation – is generally unhelpful.

In most circumstances, the appropriate mode of transportation for penetrating injured patients in an urban environment is via ground ambulance. The benefit of Advanced Life Support (ALS) units may be questioned as noted above; however, most protocols call for this additional level of expertise “just in case.” The use of whichever means gets the patient to the trauma center the soonest is optimal. Ambulance units should strive to keep the on-scene duration to 10 min or less to adhere to guidelines outlined by PHTLS. Depending on each particular region, the ground ambulance personnel who provide ALS may have similar interventional skills to that of the air transport crews, but knowledge and evaluation of local resources are necessary. Helicopter transport in urban settings is best utilized when the air transport time will be less than that of a ground ambulance. Within approximately 30 miles, ground transport is typically as fast as air when over favorable terrain in no traffic settings. Helicopter transport often flies in any inclement weather, including overcast skies with low ceilings.

Wound location and hemodynamic information should be communicated in a concise report before arrival to best prepare the trauma team to deliver rapid and appropriate lifesaving care. Initially, the injured patient should undergo assessment and management in an orderly, logical manner in a head-to-toe fashion. A patient with obvious penetrating trauma to the anterior torso can easily have a missed injury to the gluteal region if a careful inspection of all clothed areas is not performed. Such a missed injury can cause significant additional hemorrhage that may have been easily ameliorated by direct pressure. Few available devices offer diagnostic improvement over a thorough physical examination, including inspection, auscultation, percussion, and palpation by a well-trained medical provider. Additionally, data obtained from such additional devices must be verified as well, whether or not it is in a normal range.

There are three main pieces of information that data regarding the wounding should convey. First, the trauma team needs to know where the wound(s) is (are) to plan diagnostic and therapeutic maneuvers. Because the final destination of the missile or knifepoint may not be known from the external wound, it is key that EMS personnel not refer to wounds as affecting the “chest” or “abdomen” or “back.” A wound at the sixth left intercostal space in the anterior axillary line may, in fact, involve abdominal structures and require a laparotomy for definitive treatment. Referring to it as a “chest” wound may set different expectations for the receiving trauma team. Similarly a “back” wound may involve chest or abdominal structures with different diagnostic and therapeutic maneuvers required. Although the receiving team recognizes that rapid assessment on the spot may be flawed (particularly if the scene is not secured), it is most helpful to have identified all wounds prehospital and whether they appear to be tangential or superficial. Of course, it is safest to assume that no wound is an “exit” wound or infer trajectories without imaging or direct inspection that may not be possible in the field. Next, by conveying hemodynamic information as described below, prehospital providers can allow the trauma team to infer whether or not operative intervention might be warranted. This may result in alternate triage (i.e., some trauma centers might transport directly to the operating theater), activation of massive transfusion protocols, or release of other resources. Finally, by conveying information on wound location and hemodynamics in concert, the receiving trauma team may get a sense of what kind of operation (laparotomy versus thoracotomy) is warranted.

Direct manual pressure should be immediately applied to any active bleeding from external wounds. Further, a recent study from civilian experience supports the use of prehospital tourniquet in patients with extremity trauma. Tourniquets should be properly placed proximal to the bleeding site. The second tourniquet can be applied if the first tourniquet did not control hemorrhage significantly. The initial tourniquet time needs to be documented to prevent serious complications including limb ischemia. There are different types of topical hemostatic agents commercially available for external bleeding in areas where tourniquets cannot be applied. These agents are usually in gauze or bandage format to be applied with pressure techniques.

Prehospital hemodynamic assessment utilizes the rapid “ABC” approach of airway, breathing, and circulation adequacy determination. The airway should be examined while maintaining cervical spine protection and monitored for blockage with gurgling from vomitus, blood, or foreign body. Obtunded or nearly moribund patients may benefit from endotracheal tube placement en route as described below.

Breathing and ventilation are monitored by signs of full, symmetric chest wall movement, without crepitus or paradoxical motion. The patient should have a midline trachea with a normal respiratory rate and depth. A tension pneumothorax is a life-threatening condition that can be a cause of preventable death. Hyperresonance with percussion of the thoracic cavity and diminished breath sounds, especially in the face of a suspicious wound, are indications of a pneumothorax. Increased air pressure between lung parenchyma and parietal pleural in the thoracic cavity reduces venous return and causes tachypnea, dyspnea, air hunger, and eventual cardiovascular collapse. Tracheal deviation, hypotension, and distended neck veins are all late hallmarks. Diagnosis is often established by therapeutic decompression as described below.

Patients are also monitored for the status of their circulation with appropriate concomitant hemorrhage control. Signs of hemorrhagic shock include diaphoresis, cool clammy skin with peripheral vasoconstriction, and diminished peripheral pulses. Capillary refill may be normal or delayed. Systemic hypotension may be seen late or only with profound shock. Hemodynamic status can be evaluated by the presence and character of the radial pulse when other reliable means are not available. Manual assessment of a weak but present radial pulse correlates with a systemic blood pressure (SBP) of approximately 80 mmHg, but studies have shown that estimates of SBP tend to overestimate the actual pressure. Unfortunately, a change in the pulse, blood pressure, or mental status is a late sign of central hypovolemia and does not provide adequate warning of impending circulatory collapse. Both radial and arm pulses should be initially compared, as the occasional patient will have an asymmetric arm blood pressure in the pre-injured state from a subclavian artery stenosis, old injury, or atheroscleromatous plaque. The arm with the higher pressure should then be used for monitoring systemic blood pressure and circulation.

The ACS-COT, in conjunction with the American College of Emergency Physicians and the National Association of EMS Physicians, has published a pamphlet recommending certain equipment deemed essential on an ambulance unit. In general, the degree and level of monitoring should be individualized based on the availability of resources and training of individual municipalities. For example, if ALS is to be provided, then pulse oximetry, end-tidal CO₂ (ETCO₂) detection, along with electrocardiography, a defibrillator, and external cardiac pacemaking should be present and available. However, care must be taken not to delay transport beyond the benefit received by the intervention. It is up to the individual emergency medical director and local governing bodies to determine the practice guidelines to which the trauma system will adhere.