FIELD MANAGEMENT AND PRIORITIES IN TRAUMA RESUSCITATION
The concept of early access to definitive care for the seriously injured patient is not new to the 20th century. During the early 18th century, Napoleon's chief surgeon, Baron Dominique Jean Larrey, realized the importance of providing expeditious care for those injured in battle and established the first organized triage and trauma system. The famous "Flying Ambulances of Larrey" were the first attempt to deliver wounded patients to a definitive care setting as early as possible. Larrey also situated hospitals as close as possible to battlefronts to minimize transport times. The success of the system was meticulously documented by Larrey, who also classified wounds and documented treatment-based outcomes.
The civilian community was slow to adopt Larrey's concepts of regionalized centers with quick and systematic access, as well as means to continuously monitor and improve care.
In North America, it was not until the early 1960s that trauma became obvious as a new disease that was primarily taking the lives of young people under age 40. The majority of trauma-related deaths would have potentially been preventable had an organized and systematic approach been available.
The first regional trauma center, which emerged in the early 1970s, quickly demonstrated significant improvement in patient survival and functional recovery post-injury. This article reviews the basic priorities in trauma patients that have significant impact upon their survival and functional recovery.
Trauma-related deaths occur in a trimodal distribution and are described in relation to the time interval from the injury. Immediate deaths (50% of trauma-related deaths) occur at the time of injury and are generally a result of severe head or cardiovascular injury. The only possible intervention for this group is an aggressive prevention program through public awareness and education. Early deaths (30%) occur during the first few hours following injury as a result of major torso or head injury. Many early deaths are preventable with appropriate care. Early care of injured patients has improved through quick stabilization in the field and rapid transport to appropriate definitive care facilities. The "Golden Hour" concept is derived from this group. Late deaths account for approximately 20% of trauma-related deaths and result from infectious complications or multiple organ system failure. are often related to inadequate initial resuscitation and can potentially be affected by improvements in early care. Through continued training, education and expedient care of the seriously injured patient, we can further reduce trauma-related mortality and morbidity.
Evaluation & Care
What are the priorities in evaluating and caring for the acutely injured patient? First and foremost is safety of the responding crew. No one benefits if the responders become victims in the course of performing their duty. Scene survey and size-up are important first steps upon arrival at the scene of an injury. Responding units must be aware of surrounding or potential hazards that may impede their ability to safely access, extricate, assess, care for and transport the victim.
In performing a scene survey, responding units can save a significant amount of time if the need for specialized equipment or personnel is identified and requested early. This allows the medic command facility time to determine the appropriate destination for all patients. Another consideration is whether the scene is safe: Is the assailant still in the area? Have appropriate law enforcement officials arrived to secure and protect the scene?
Once any environmental hazards are secured, the next priority is access to the victims and protecting them from further harm, which may require extrication from a vehicle, removal from a potential fire or chemical hazard, or diverting traffic flow. While securing the scene and extricating victims, information can be obtained regarding damage amount, use of safety belts, ejection and information gathered from passengers or other eyewitnesses.
Mechanism of Injury
Mechanism of injury can suggest certain injury patterns that often dictate evaluation protocols in patients arriving at a trauma facility. These protocols are based on previous studies of injury patterns for a given mechanism of injury and often lead to diagnosis of injuries that were not initially detected.
The most commonly missed injuries are orthopedic. While most orthopedic injuries are not immediately life-threatening, significant morbidity may occur in terms of functional recovery as a result of delayed or missed diagnoses. Evaluation of the trauma victim can be further complicated by the presence of altered sensorium from closed head injury, alcohol, drugs, spinal cord injury or other distracting injuries. Alcohol deserves special mention in that it is involved in 40%-50% of motor vehicle crashes, a large proportion of falls, assaults and pedestrian/auto impacts. Alcohol complicates victim assessment and predisposes them to the adverse effects of hypotension, hypothermia and the risk of airway compromise due to aspiration. Special attention must be given to adequate volume replacement, protection from hypothermia and protecting the airway.
In general, injuries are classified as blunt or penetrating, and are further divided as high or low injury.
Motor vehicle crashes account for about 48% of unintentional deaths in the United States. The majority of victims are 25-50 years of age. Other mechanisms of blunt injury include falls, motorcycle and bicycle crashes, pedestrian/auto impacts and assaults. Factors that influence injury patterns include:
Victims of frontal crashes (with and without restraints) have an increased frequency of facial injuries, as well as fractures of the upper and lower extremities. Victims of lateral impact suffer pelvic, brain and thoracic injuries more commonly. Mortality from a lateral crash is twice that of a front impact: 8.2% vs. 4.2%. Proper use of a lapbelt decreases mortality by 50%, especially in frontal impacts. Conversely, the use of safety belts is associated with an increase in particular abdominal injuries, specifically of the small bowel and mesentery. The unrestrained front seat driver and passenger are prone to ejection from the vehicle, especially in rollovers, which results in a 300%-400% increase in mortality, as well as a significant increase in the risk of spinal injury. Addition of the shoulder belt and air bags further reduces injury for front seat passengers, especially facial fractures and closed-head injury.
Even properly worn safety belts can produce injury. Using a shoulder belt tends to result in right-sided rib fractures in the driver and left-sided rib fractures in the passenger. Lap belt use may result in intra-abdominal injuries, such as rupture of hollow organs like the duodenum. Lumbar spine fractures due to hyperflexion and Chance fractures (a transverse fracture through the bony and ligamentous portion of the lumbar spine) have been reported, as well as injury to the iliac vessels or abdominal aorta.
A visible lap belt mark across the abdominal wall should alert rescue personnel to the increased possibility of intra-abdominal or lumbar spine injury, especially in children. An abdominal lap belt sign in children is associated with lumbar spine or hollow visceral injury in 45% of patients. When used in conjunction with safety belts, air bags further reduce the risk of injury; however, air bag inflation may cause superficial abrasions (including corneal abrasions) and facial burns, and they have been known to cause death in small children. Hyperextension injuries of the cervical spine may occur with a restrained occupant, while hyperflexion injuries of the cervical and thoracic spine may result in the unrestrained occupant.
Expected injuries of unrestrained drivers in a high-speed frontal impact are shown in Table I;
Lateral impacts are shown in Table II. The driver and front seat passenger are prone to ejection if unrestrained and are often injured by direct intrusion, especially with lateral impacts.
The injury pattern for unrestrained front seat passengers differs from unrestrained drivers due to the lack of impact with the steering wheel or floor pedals (see Table III).
Injuries to rear seat passengers are similar to those of front seat occupants; however, the risk of injury to a front seat passenger doubles if there is an unrestrained rear seat passenger. An obese body habitus results in more frequent torso injuries and fewer facial injuries compared with non obese individuals.
TABLE II: LATERAL IMPACT INJURY PATTERNS (UNRESTRAINED DRIVER)
TABLE III: PASSENGER VS. DRIVER INJURY PATTERNS (UNRESTRAINED)
Motorcycles offer no protection to riders, regardless of impact type. In frontal crashes, the rider is usually ejected over the handlebars, resulting in injuries to the face, head, cervical and thoracic spine and abdomen. Lateral crashes tend to result in significant lower extremity and pelvic fractures. Wearing a helmet has been shown to reduce serious closed head injury and mortality by 30%-50%. Laying the bike down tends to slow the vehicle and separate the occupant, which may minimize injuries, but the patient may still suffer lower extremity fractures and significant soft tissue damage.
Impacts involving a pedestrian and automobile may result in injury at speeds of only 5-10 mph. Children, the elderly and intoxicated individuals are at highest risk for being struck; most adults tend to turn away from an oncoming vehicle. The bumper of a standard passenger car strikes a pedestrian in the lower legs, resulting in tibia or fibula fractures, knee dislocations and distal femur fractures. The next impact occurs when an individual's torso strikes the hood of a vehicle, resulting in rib fractures, pneumothorax, pulmonary contusion, thoracic vascular injury and abdominal visceral injury. Striking the head on the windshield at the same time may also result in cervical spine or closed head injury. The final impact results from striking the ground, which may produce upper extremity fractures in addition to closed head and cervical spine injuries.
A larger vehicle, such as a light truck or sport utility vehicle, may strike the adult victim in the lower torso, throwing him backward or running over him. These incidents tend to result in mid-shaft femur and pelvic fractures, as well as abdominal visceral injuries (lacerated liver or ruptured spleen). Children will be hit higher in the torso and thrown back or run over, resulting in thoracic, abdominal and pelvic injuries, as well as thoraco-lumbar spine fractures and closed head injury.
If a victim of an auto/pedestrian impact is found to have a closed head injury and lower extremity fractures, strongly suspect an abdominal visceral injury as well. Tire marks over the torso suggest the possibility of internal organ injury, and patients should be treated as such until proven otherwise. Children may develop significant internal injury but show little external evidence of trauma due to the extreme pliability of their immature skeletons.
Blunt rupture of the diaphragm occurs in only approximately 3% of abdominal trauma, but it often presents as severe shock. When intra-abdominal pressure is abruptly elevated, as with a crushing type of injury, the diaphragm (usually the left side) will rupture, allowing the abdominal viscera to move into the chest and ultimately compromising respiratory and cardiac function. This results in severe shock in 54% of patients and respiratory insufficiency in up to 81%. Although diaphragmatic rupture is difficult to diagnose clinically, it may be suspected with a high index of suspicion, diminished breath sounds in the left hemithorax, scaphoid abdomen, shock, hypoxia or, rarely, the presence of bowel sounds in the patient's chest.
Splenic laceration may be found in 24% of patients with a ruptured left hemidiaphragm, while liver laceration is present in 93% of cases with right-sided ruptures. Pelvic fractures are associated with blunt diaphragmatic injury 60% of the time. Application of the abdominal component of MAST trousers is contraindicated in these patients, as it will cause marked deterioration of cardiovascular and pulmonary status.
Falls are the leading cause of nonfatal injuries and the second leading cause of spine and brain injuries in North America. Children, intoxicated individuals and the elderly are at greatest risk of falling.
The elderly tend to fall while walking, resulting in hip fractures, facial or scalp lacerations and head injury. Children typically fall head first, whether from a standing position or a height, due to the top-heavy nature of their bodies, which results in more head injuries and upper extremity fractures. Fortunately, most children fall from heights of less than 10´, while adults tend to fall from heights greater than 20´. When falling from a height, adults fall to their feet or onto their backs. When an individual falls on his feet, stress is transmitted through the entire axial skeleton, resulting in factures of the feet, femur, hip dislocation or fracture, and thoraco-lumbar spine fractures. Other internal injuries that may result from this abrupt deceleration include splenic and liver lacerations and rupture of the thoracic aorta. Backward falls produce a more unpredictable pattern of injury and are associated with more lumbar and thoracic spine fractures, as well as retroperitoneal and thoracic vascular injuries.
Primary considerations when dealing with penetrating trauma are the type of injury (stabbing, gunshot, impalement), region of the body involved and hemodynamic status of the victim.
Assume that all patients with penetrating trauma to the head or torso have a potentially life-threatening injury that requires immediate evaluation at the nearest trauma facility. Also, be aware that internal injuries cannot be reliably predicted based on the size of the wound or initial stability of the patient, as the path of a gunshot wound may be unpredictable.
Initial hemodynamic stability may deteriorate quickly as compensatory mechanisms are overcome, particularly in younger patients.
Gunshot Wounds (GSW)
Gunshot wounds are classified based upon the energy of the projectile. Low-velocity wounds-produced by most handguns-result in injury primarily along the path of the bullet; however, two-thirds of the bullets do not exit the body, and the bullet may change course as it passes through or impacts soft tissues.
High-velocity wounds are produced by hunting or military weapons and cause damage well outside of the bullet's path. The temporary cavity produced can expand up to 40 times the diameter of the bullet and may result in massive internal tissue destruction despite small entrance and exit wounds. Shotgun injuries are classified separately, as their wounding ability is dependent upon distance. Close-range injuries are essentially high-velocity wounds with massive tissue destruction. At distances greater than 25 meters, injuries may be minimal. Knowledge of weapon type and distance can aid emergency providers in predicting the types and severity of injuries produced by a gunshot wound.
Penetrating injuries to the thorax require rapid assessment and stabilization in the field, with immediate transport to a trauma facility. Penetrating injury to the chest often results in shock due to bleeding into the chest cavity, pericardial tamponade or tension pneumothorax. Auscultation of the chest, palpation of a deviated trachea and presence of distended neck veins are helpful in delineating the etiology of shock.
Absent breath sounds with the trachea deviated away from the hemithorax is probably tension pneumothorax and should be treated with immediate needle decompression of that side. Muffled heart tones and distended neck veins are typical of pericardial tamponade and should be treated in the field with volume administration and rapid transport with a secure airway.
Open chest wounds must be covered and taped on three sides to restore breathing mechanics and allow proper ventilation of the patient.
Injuries due to penetrating wounds to the abdomen are more difficult to diagnose; bleeding into the abdominal cavity is an immediate threat to life. The abdominal cavity extends from the nipple line to the groin creases anteriorly and from the shoulder blades to iliac crests posteriorly. Any penetrating injury to this area may result in abdominal penetration.
Approximately 30% of patients with significant abdominal injury will have no physical findings on initial examination following injury. Stab wounds penetrate the abdominal cavity only 40% of the time and, of those that penetrate, only 30% cause any significant injury. Gunshot wounds, on the other hand, penetrate the cavity 80% of the time, with a greater than 90% chance of causing significant injury. Treatment of patients with abdominal injury requires a high index of suspicion and volume administration en route to a trauma center.
Penetrating Injury to the Head
Penetrating injuries to the head, especially gunshot wounds, carry a high mortality, primarily due to direct brain or brainstem injury, as well as mass effect and compression of vital centers due to blood or swelling.
Damage to the brain occurs not only from the bullet, but also from secondary projectiles such as bone particles or fragments of the bullet produced upon impact with the skull. The primary consideration in dealing with head injury, whether penetrating or blunt, is avoidance of hypotension and hypoxia to prevent secondary brain injury.
Recent studies have demonstrated that the brain is ischemic during the first 24 hours post-injury despite near normal pressures. A single episode of hypotension (systolic BP>90 mmHg) increases mortality by 50%. The injured brain also loses the ability to auto-regulate its flow. Elevation of the head may further diminish flow and exacerbate ischemic changes. Assuring a secure airway and adequate fluid administration to keep systolic BP above 100 mmHg are essential in caring for the head-injured patient. Routine hyperventilation is no longer recommended, as several studies have demonstrated increased cerebral ischemia as a result of the vasoconstriction that occurs with decreased blood CO2 levels. Prompt neurosurgical evaluation is essential to decrease the mortality and increase functional recovery of these patients.
As with all trauma patients, the primary goals in caring for victims of penetrating injury are to secure the airway if needed, restore circulating blood volume and stop ongoing bleeding as quickly as possible. However, there is controversy about how best to volume resuscitate these patients and to what endpoints. Recent data suggest that the optimal BP for a victim of penetrating truncal injury may not be normotensive level but rather a systolic pressure of 90 mmHg (assuming no other comorbid conditions that would be worsened by this degree of hypotension such as coronary artery disease or a concurrent significant head injury). Rationale is that the lower BP will allow temporary hemostasis. On the other hand, elevating the BP to normal levels may dislodge clots and accentuate bleeding. Studies also suggest that small volume resuscitation with hypertonic saline may be superior to standard crystalloid therapy.
Although rare, impalement injuries present complex problems, as they are typically a combination of both penetrating injury and blunt injury from a fall or motor vehicle accident. Both mechanisms must be considered in evaluating and treating these patients. The impaled object should be left in place and stabilized during transport to prevent further injury.
Regardless of mechanism of injury, interventions that must be done in the field or en route to a trauma facility include: maintain an airway, ventilate effectively and restore blood volume to some degree while halting any obvious hemorrhage.
Trauma is a time-sensitive process, with survival decreasing as the time to definitive treatment increases. Ideally, on-scene time for assessment and stabilization should be less than 10 minutes, excluding complicated extrications. Attempts at IV access should be made en route, unless a long transport time is anticipated. In these cases, IV access may be obtained prior to transport. Immediately life-threatening situations such as tension pneumothorax should be decompressed as soon as identified. Monitor the patient's vital signs frequently, including pulse, BP and O2 saturation to ensure adequate oxygenation and volume replacement.
The single most important field intervention in trauma patients is securing and protecting the airway. If this is not achieved, little else will matter. The airway is quickly assessed in the field by paying special attention to the patient's level of consciousness, physical findings and vital signs. Other considerations are the possibility of cervical spine injury, which may preclude certain airway maneuvers, as well as the assumption that all trauma patients have full stomachs and are at risk of aspiration -especially intoxicated or pregnant patients.
An altered level of consciousness may not only be a manifestation of head injury, but also a sign of hypoxia or hypovolemia with poor tissue perfusion. Physical findings associated with poor oxygen delivery include labored breathing, abdominal breathing, and cool, moist skin with poor capillary refill. Monitoring other vital signs including pulse, respirations and blood pressure is important; however, normal values do not preclude the presence of significant underlying injury or ensure a stable airway (i.e. the unconscious, intoxicated, head-injured patient with normal respirations may still require intubation to protect the airway during transport).
The primary maneuver in stabilizing the airway in a patient with altered sensorium begins with positioning the airway. Since all trauma patients are assumed to have a cervical spine injury, the initial maneuver is the jaw thrust or chin lift while maintaining in-line cervical immobilization, along with high-flow oxygen, preferably through a nonrebreathing mask to ensure maximal O2 delivery. Suctioning the airway to remove secretions, blood and vomit, and inserting a nasal cannula in the semi-alert patient or oropharyngeal airway in the obtunded patient, are excellent adjuncts in maintaining patency.
When these methods fail or prove impractical, insert a more definitive airway, such as an endotracheal tube, Combitube, laryngeal mask airway (LMA) or surgical airway. All advanced airways require special training, but once learned can be effectively utilized.
Orotracheal intubation is the method of choice. (Nasotracheal intubation can be attempted in a breathing patient with clenched teeth.) Orotracheal intubation is performed through direct visualization via a laryngoscope or through digital intubation. Ideally, a 7.5-8.0 F cuffed tube should be used in adult patients, if possible. Apply cricoid pressure (Sellick maneuver) during all attempts to minimize the risk of aspiration. Confirmation of placement should immediately follow with visualization of symmetric chest wall motion and auscultation for bilateral equal breath sounds. End tidal CO2 confirmation and pulse oximetry also help confirm a successful intubation. When endotracheal intubation is not possible, the Combitube or LMA may suffice. In 15% of attempts, the Combitube is inserted into the trachea, requiring ventilation through the tracheal port. Failure to recognize this will result in hypoventilation. The major disadvantage of the Combitube is a lack of tracheal isolation predisposing to aspiration, and the need to correctly identify tracheal insertion. The LMA is easily and rapidly placed; however, it requires correct sizing and there is controversy regarding its ability to prevent aspiration.
When all else fails, a surgical airway may be necessary. Cricothyroidotomy is the preferred method in adults; however, translaryngeal needle jet insufflation can serve as a temporary measure prior to a definitive airway. Appropriately trained nurses and paramedics can safely and quickly perform a cricothyroidotomy in the field. If possible, insert the tube and advance it just beyond the cuff, then confirm placement as with endotracheal tubes. Possible complications include bleeding, esophageal perforation, malposition or dislodgement of the tube and mainstem bronchus intubation.
Needle insufflation requires a high-pressure oxygen device (40-50 psi) and high-pressure oxygen tubing. The technique requires placing a 14-16 G catheter through the cricothyroid membrane and ventilating for one second while allowing three seconds for exhalation. This technique can be used safely for 45-50 minutes, after which CO2 will rise enough to produce respiratory acidosis. Complications include barotrauma to the lungs, malposition of the needle resulting in subcutaneous emphysema, and hypotension from overinflation.
Once an airway is secured, connect a bag-valve-mask device with 15 liter flow to provide 90%-95% oxygen concentration and monitor for adequate ventilation.
Conditions leading to inadequate ventilation that can be addressed in the field include malposition of the endotracheal tube, tension pneumothorax or open pneumothorax. An absence of breath sounds and deviation of the trachea to the opposite side are diagnostic of a tension pneumothorax. In any instance of a patient in shock with absent breath sounds, needle decompression of the affected side is justified and potentially life-saving. An open pneumothorax is usually obvious and should be covered with a three-sided occlusive dressing.
The next priority in the trauma patient is to restore circulating volume. Both hypovolemia and hypoxia can seriously affect long- and short-term survival of trauma victims. External blood loss or cavitary bleeding (chest, abdomen, pelvis and thighs) are principal causes of hypovolemia in trauma patients.
The endpoints of volume resuscitation differ according to the mechanism of injury and associated injuries. Blunt injury with hypotension is due to cavitary bleeding until proven otherwise, and is treated with aggressive crystalloid administration to systolic blood pressures of 100 mmHg or better. Hypotension (<90 mmHg) and hypoxia must be avoided to prevent secondary brain injury.
In penetrating injury, the resuscitative endpoints are lower (systolic BP 80-90 mmHg) to minimize ongoing bleeding. Transport should not be delayed to obtain IV access; this should be done en route or while awaiting appropriate transportation.
The evolution of trauma systems has significantly impacted survival of the multiply injured patient through a systematic approach that begins in the field. Appropriate initial care with attention to airway management, ventilation, volume resuscitation and spinal precautions (if warranted) results in significant improvement in both short- and long-term functional recovery of trauma patients.
Mechanism of injury may suggest a set of potential injuries that may be confirmed during initial assessment; however, the ability to exclude certain injuries is limited, if not impossible, in the prehospital situation. Therefore, patients must be aggressively treated and triaged based on the potential for serious underlying injury. This approach has led to survival from injuries that, as little as 10 years ago, were considered fatal.
Continued research and allocation of resources to the care of trauma patients will likely reduce mortality and morbidity further, but little of this matters if patients with potential life-threatening injuries do not receive rapid, appropriate care.
Continuous monitoring of our results and training of those involved in the initial care of trauma patients is a vital component in improving outcomes in the trauma population. Survival following injury is time-sensitive, and the actions taken early in the course of events must be aggressive and definitive to positively impact the survival of these patients.